The Coherent Heart
Heart–Brain Interactions, Psychophysiological
Coherence, and the Emergence of System-Wide Order
Rollin McCraty, Ph.D., Mike Atkinson, Dana Tomasino, B.A.,
and Raymond Trevor Bradley, Ph.D.1
Abstract: This article presents theory and research on the scientific study of emotion that
emphasizes the importance of coherence as an optimal psychophysiological state. A
dynamic systems view of the interrelations between psychological, cognitive and
emotional systems and neural communication networks in the human organism provides
a foundation for the view presented. These communication networks are examined from
an information processing perspective and reveal a fundamental order in heart-brain
interactions and a harmonious synchronization of physiological systems associated with
positive emotions. The concept of coherence is drawn on to understand optimal
functioning which is naturally reflected in the heart’s rhythmic patterns. Research is
presented identifying various psychophysiological states linked to these patterns, with
neurocardiological coherence emerging as having significant impacts on well being.
These include psychophysiological as well as improved cognitive performance. From
this, the central role of the heart is explored in terms of biochemical, biophysical and
energetic interactions. Appendices provide further details and research on;
psychophysiological functioning, reference previous research in this area, details on
research linking coherence with optimal cognitive performance, heart brain
synchronization and the energetic signature of the various psychophysiological modes.
Keywords: Cognitive performance, coherence, emotion, heart rate variability, heart-brain
interactions, neurocardiology, psychophysiological coherence, quantum holographic
principles.
This volume draws on the basic research conducted over the last decade at the Institute of HeartMath by
Dr. Rollin McCraty and Mike Atkinson. The original manuscript for this article was drafted between 1998
and 2003 by Rollin McCraty and Dana Tomasino. Mike Atkinson conducted the analysis of the research
reported here and also constructed the figures and graphs displaying the statistical information. Dr.
Raymond Bradley joined the project in 2004 to work on a major revision and expansion of the manuscript
to help bring the article to its present form.
Correspondence should be directed to Dr. Rollin McCraty, Director of Research, HeartMath Research
Center.
14700 West Park Avenue
Boulder Creek, California 95006
Office: 831-338-8727
rollin@heartmath.org
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Prologue ................................................................................................................................... 13
Introduction .............................................................................................................................. 14
Theoretical Considerations ...................................................................................................... 16
Conceptual Framework ........................................................................................................ 16
Information and Communication ..................................................................................... 16
The Concept of Coherence ............................................................................................... 17
Theory .................................................................................................................................. 18
The Psychophysiological Network: A Systems Perspective.................................................... 19
Heart Rate Variability and Measurement of Psychophysiological Modes .......................... 20
Emotions and Heart Rhythm Patterns .................................................................................. 20
Psychophysiological Coherence .......................................................................................... 22
Heart Rhythm Coherence ................................................................................................. 23
Physiological Correlates................................................................................................... 23
Psychological and Behavioral Correlates......................................................................... 26
Drivers of Coherence ....................................................................................................... 26
Benefits of Psychophysiological Coherence .................................................................... 27
A Typology of Psychophysiological Interaction.................................................................. 28
Psychophysiological Hyper-States ................................................................................... 32
Heart Coherence and Psychophysiological Function............................................................... 34
Vagal Afferent Traffic.......................................................................................................... 35
Pain Perception .................................................................................................................... 36
Respiration ........................................................................................................................... 36
Emotional Processing ........................................................................................................... 38
Coherence and Cognitive Performance.................................................................................... 41
The Heart Rhythm Coherence Hypothesis: A Macro-Scale Perspective ............................. 42
A More Complex Picture ..................................................................................................... 43
Complexity of Cardiac Afferent Signals .......................................................................... 43
Afferent Input to Brain Centers other than the Thalamus ................................................ 44
Heart–Brain Synchronization ........................................................................................... 45
System Dynamics: Centrality of the Heart in the Psychophysiological Network ................... 45
A Systems Approach ............................................................................................................ 46
Neurological Interactions ..................................................................................................... 47
Coherence Within the Brain ............................................................................................. 47
More Than a Pump ........................................................................................................... 50
Biochemical Interactions...................................................................................................... 51
Biophysical Interactions ....................................................................................................... 54
Energetic Interactions........................................................................................................... 55
Energetic Signatures of Psychophysiological Modes .......................................................... 56
The Holographic Heart ......................................................................................................... 56
Conclusion ............................................................................................................................... 58
References ................................................................................................................................ 61
wholesocialscience@sbcglobal.net Appendixes ...................................................................... 73
Appendixes............................................................................................................................... 73
Appendix A: Modes of Psychophysiological Function ........................................................... 73
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Modes of Everyday Psychophysiological Function ............................................................. 76
Mental Focus .................................................................................................................... 76
Psychophysiological Incoherence .................................................................................... 77
Relaxation ........................................................................................................................ 77
Psychophysiological Coherence ...................................................................................... 78
Modes Distinguished by Low Variability ............................................................................ 79
Emotional Quiescence...................................................................................................... 80
Extreme Negative Emotion .............................................................................................. 81
Appendix B: Previous Research............................................................................................... 84
The Baroreceptor Hypothesis: A Micro-Scale Perspective ................................................. 84
Appendix C: Research on Coherence and Cognitive Performance ......................................... 88
HeartMath Institute Research............................................................................................... 88
UK Research ........................................................................................................................ 90
HeartMath’s TestEdge Program on Test Anxiety and Performance .................................... 94
Appendix D: Heart Brain Synchronization ............................................................................ 101
Appendix E: Energetic Signatures of Psychophysiological Modes ....................................... 109
Mental Focus .................................................................................................................. 109
Psychophysiological Incoherence .................................................................................. 110
Extreme Negative Emotion ............................................................................................ 111
Relaxation ...................................................................................................................... 112
Psychophysiological Coherence .................................................................................... 113
Emotional Quiescence.................................................................................................... 114
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…there are organism states in which the regulation of life processes becomes efficient, or
even optimal, free-flowing and easy. This is a well established physiological fact. It is not a
hypothesis. The feelings that usually accompany such physiologically conducive states are
deemed “positive,” characterized not just by absence of pain but by varieties of pleasure.
There also are organism states in which life processes struggle for balance and can even
be chaotically out of control. The feelings that usually accompany such states are deemed
“negative,” characterized not just by absence of pleasure but by varieties of pain. … The
fact that we, sentient and sophisticated creatures, call certain feelings positive and other
feelings negative is directly related to the fluidity or strain of the life process.
(Damasio, 2003, p. 131)
Chris, a 45-year-old business executive, had a family history of heart disease, and was
feeling extremely stressed, fatigued, and generally in poor emotional health. A 24-hour
heart rate variability analysis3 revealed abnormally depressed activity in both branches of
his autonomic nervous system, suggesting autonomic exhaustion ensuing from
maladaptation to high stress levels. His heart rate variability was far lower then would be
expected for his age, and was below the clinical cut-off level for significantly increased
risk of sudden cardiac death. In addition, Chris’s average heart rate was abnormally high
at 102 beats per minute, and his heart rate did not drop at night as it should.
Upon reviewing these results, his physician concluded that it was imperative that Chris
take measures to reduce his stress. He recommended that Chris begin practicing a system
of emotional restructuring techniques that had been developed by the Institute of
HeartMath. These positive emotion-focused techniques help individuals learn to self-
generate and sustain a beneficial functional mode known as psychophysiological
coherence, characterized by increased emotional stability and by increased
synchronization and harmony in the functioning of physiological systems.
Concerned about his deteriorating health, Chris complied with his physician’s
recommendation. Each morning during his daily train commute to work, he practiced the
Heart Lock-In technique, and he would use the Freeze-Frame technique in situations when
he felt his stress levels rise.4
Excerpted from McCraty & Tomasino (2006), pp. 360-361.
The analysis of heart rate variability (HRV), a measure of the naturally occurring beat-to-beat changes in
heart rate, provides an indicator of neurocardiac fitness and autonomic nervous system function.
Abnormally low 24-hour HRV is predictive of increased risk of heart disease and premature mortality.
HRV is also highly reflective of stress and emotions.
4
The Heart Lock-In tool is an emotional restructuring technique, generally practiced for 5 to 15 minutes,
that helps build the capacity to sustain the psychophysiological coherence mode for extended periods of
time. The Freeze-Frame technique is a one-minute positive emotion refocusing exercise used in the
moment that stress is experienced to change perception and modify the psychophysiological stress
response. For in-depth descriptions of these techniques, see Childre & Martin (1999) and Childre &
Rozman (2005).
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At first Chris was not aware of the transformation that was occurring. His wife was the
first to notice the change and to remark about how differently he was behaving and how
much better he looked. Then his co-workers, staff, and other friends began to comment on
how much less stressed he appeared in responding to situations at work and how much
more poise and emotional balance he had. A second autonomic nervous system
assessment, performed six weeks after the initial one, showed that Chris’s average heart
rate had decreased to 85 beats per minute and it now lowered at night, as it should.
Significant increases were also apparent in his heart rate variability, which had more than
doubled! These results surprised Chris’ physician, as 24-hour heart rate variability is
typically very stable from week to week, and it is generally quite difficult to recover from
autonomic nervous system depletion, usually requiring much longer than six weeks.
In reflecting on his experience, Chris started to see how profoundly his health and his life
had been transformed. He was getting along with his family, colleagues, and staff better
than he could remember ever having enjoyed before, and he felt much more clearheaded
and in command of his life. His life seemed more harmonious, and the difficulties that
came up at work and in his personal relationships no longer created the same level of
distress; he now found himself able approach them more smoothly and proactively, and
often with a broadened perspective.
The true story of Chris’s transformation is not an isolated example, but rather is only one of
many similar case histories that people like Chris have shared with HeartMath, illustrating the
amazing transformations that can occur when one learns how to increase psychophysiological
coherence.
Many contemporary scientists believe that the quality of feeling and emotion we experience in
each moment is rooted in the underlying state of our physiological processes. This view is well
expressed by neuroscientist Antonio Damasio in the epigram that opened this article. The
essence of his idea is that we call certain emotional feelings “positive” and others “negative”
because these experiences directly reflect the impact of the “fluidity or strain of the life process”
on the body, as is clearly evident in Chris’ case, above. The feelings we experience as “negative”
are indicative of body states in which “life processes struggle for balance and can even be
chaotically out of control” (Damasio, 2003, p. 131). By contrast, the feelings we experience as
“positive” actually reflect body states in which “the regulation of life processes becomes
efficient, or even optimal, free-flowing and easy” (Damasio, p. 131).
While there is a growing appreciation of this general understanding in the scientific study of
emotion, here we seek to deepen this understanding in three primary ways. First, our approach is
based on the premise that the physiological, cognitive, and emotional systems are intimately
interrelated through ongoing reciprocal communication. To obtain a deeper understanding of the
operation of any of these systems, we believe it is necessary to view their activity as emergent
from the dynamic, communicative network of interacting functions that comprise the human
organism. Second, we adopt an information processing perspective, which views communication
within and among the body’s systems as occurring through the generation and transmission of
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rhythms and patterns of psychophysiological activity. This points to a fundamental order of
information communication—one that both signifies different emotional states, operates to
integrate and coordinate the body’s functioning as a whole, and also connects the body to the
external world. And third, we draw on the concept of coherence from the physics of signal
processing to understand how different patterns of psychophysiological activity influence bodily
function. Efficient or optimal function is known to result from a harmonious organization of the
interaction among the elements of a system. Thus, a harmonious order in the rhythm or pattern of
psychophysiological activity signifies a coherent system, whose efficient or optimal function is
directly related, in Damasio’s terms, to the ease and “fluidity” of life processes. By contrast, an
erratic, discordant pattern of activity denotes an incoherent system, whose function reflects the
difficulty and “strain” of life processes.
In this article we explore the concept and meaning of coherence in various
psychophysiological contexts and describe how coherence within and among the physiological,
cognitive, and emotional systems is critical in the creation and maintenance of health, emotional
stability, and optimal performance. It is our thesis that what we call emotional coherence—a
harmonious state of sustained, self-modulated positive emotion—is a primary driver of the
beneficial changes in physiological function that produce improved performance and overall
well-being. We also propose that the heart, as the most powerful generator of rhythmic
information patterns in the body, acts effectively as the global conductor in the body’s symphony
to bind and synchronize the entire system. The consistent and pervasive influence of the heart’s
rhythmic patterns on the brain and body not only affects our physical health, but also
significantly influences perceptual processing, emotional experience, and intentional behavior.
There is abundant evidence that emotions alter the activity of the body’s physiological
systems. Yet the vast majority of this scientific evidence concerns the effects of negative
emotions. More recently, researchers have begun to investigate the functions and effects of
positive emotions. This research has shown that, beyond their pleasant subjective feeling,
positive emotions and attitudes have a number of objective, interrelated benefits for
physiological, psychological, and social functioning (Fredrickson, 2002; Isen, 1999).
In contributing to this work, we discuss how sustained positive emotions facilitate an
emergent global shift in psychophysiological functioning, which is marked by a distinct change
in the rhythm of heart activity. This global shift generates a state of optimal function,
characterized by increased synchronization, harmony, and efficiency in the interactions within
and among the physiological, cognitive, and emotional systems. We call this state
psychophysiological coherence. We describe how the coherence state can be objectively
measured and explore the nature and implications of its physiological and psychological
correlates. It is proposed that the global synchronization and harmony generated in the coherence
state may explain many of the reported psychological and physiological health benefits
associated with positive emotions.
Our discussion of the major pathways by which the heart communicates with the brain and
body shows how signals generated by the heart continually inform emotional experience and
influence cognitive function. This account includes a review of previous research on heart–brain
interactions and theories regarding how the activity of the heart affects brain function and
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cognitive performance. We then present research conducted in our laboratory, which brings a
new perspective, focusing on the pattern of the rhythm of heart activity and its relationship to
emotional experience. From this vantage point, we derive a new hypothesis—that sustained, self-
induced positive emotions generate a shift to a state of system-wide coherence in bodily
processes, in which the coherent pattern of the heart’s rhythm plays a key role in facilitating
higher cognitive functions.
In short, the science reviewed in this article shows that through regular heart-based practice, it
is possible to use positive emotions to shift one’s whole psychophysiological system into a state
of global coherence. When sustained, the harmonious order of coherence generates vital benefits
on all levels and can even transform an individual’s life, as we saw in the prologue describing
Chris’s story.
Theoretical Considerations
We begin by introducing the basic concepts and theoretical ideas that inform the material
presented in this article.
Integral to the understanding of psychophysiological interaction developed in this work are
the concepts of information and communication. As we will see next, coherence is a particular
quality that emerges from the relations among the parts of a system or from the relations among
multiple systems. And since relations are constitutive of systems, the communication of
information plays a fundamental constructive role in the generation and emergence of coherence.
Although the communication of information is largely implicit in the interactional basis of the
three basic concepts of coherence we begin with in this conceptual framework, we go onto
develop a detailed account of the nature, substance, and dynamics of the psychophysiological
interactions between the heart, the brain, and the body as a whole.
Information and Communication
The most basic definition of information is data which in-form, or give shape to, action or
behavior, such as a message that conveys “meaning” to the recipient of a signal (Bradley &
Pribram, 1998). In human language, abstract symbols like words, numbers, graphical figures, and
even gestures and vocal intonations are used to encode the meaning conveyed in a message. In
physiological systems, changes in chemical concentrations, the amount of biological activity, or
the pattern of rhythmic activity are common means by which information is encoded in the
movement of energy to inform system behavior.
But in order to be used to shape or regulate system behavior, the information must be
distributed to and “understood” by the system elements involved. Thus, by communication we
mean a process by which meaning is encoded as a message and transmitted in a signal to be
received, processed, and comprehended by the various elements of a system.
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In this article we describe the relationship between different patterns of psychophysiological
activity and physiological, emotional and cognitive functions by drawing on three distinct but
related concepts of coherence used in physics; global coherence, cross coherence and auto-
coherence. The most common definition of coherence is "the quality of being logically
integrated, consistent and intelligible," as in a coherent argument. A related meaning is "a
logical, orderly and aesthetically consistent relationship of parts" (McCraty & Tomasino, 2006,
p. 4). In the following discussion we delve deeper into the meaning of coherence.
Coherence in ordinary language means correlation, a sticking together, or connectedness;
also, a consistency in the system. So we refer to people's speech or thought as coherent, if the
parts fit together well, and incoherent if they are uttering meaningless nonsense, or presenting
ideas that don't make sense as a whole (Ho, 1998). Thus, coherence in this context refers to
wholeness and a global order: This is coherence as a distinctive organization of parts, the
relations among which generate an emergent whole that is greater than the sum of the individual
parts. In the example of organizing words in a coherent sentence, the meaning and purpose
conveyed by the arrangement of the words is greater than the individual meaning of each word.
It is important to note that all systems, to produce any function or action, must have the
property of global coherence. The efficiency and effectiveness of the function or action can vary
widely, however, and therefore does not necessarily result in a coherent flow of behavior. Global
coherence does not mean that everybody or all the parts are doing the same thing at the same
time. Think of a jazz band for example, where the individual players are each doing his or her
own thing, yet keeping in tune and step with the whole band. Coherence in this sense maximizes
local freedom and global cohesion and resonance with the musical theme (Ho, 1998).
In a living system global order or coherence must be sustained and maintained over time. For
example, biochemist and geneticist Mae-Wan Ho (1998) has suggested that a whole living
system is a domain of coherent, autonomous activity that is coordinated across a continuum from
the molecular to macroscopic to social levels.
In physics, the concept of coherence is also used to describe the interaction or coupling
among different oscillating systems in which synchronization is the key idea in this concept.
Synchronization describes the degree to which two or more waves are either phase or frequency-
locked together, or when communication occurs between systems or modes without obstruction.
Returning to the music example, a chord is composed of notes of different frequencies yet
resonate as a harmonious order of sound waves. In physiology, coherence is similarly used to
describe the degree of coupling and harmonious interaction between two or more of the body's
oscillatory systems such as respiration and heart rhythms. There are modes where they are
operating at different frequencies, and modes when they become entrained and oscillate at the
same frequency. This is also true for brain states in which the brainwaves can be momentarily in
phase at different locations across the brain. The term cross-coherence is used to specify this
type aspect of coherence.
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Another example, from a physiological systems perspective, is that people's thoughts,
emotions and attitudes can either be aligned and coherent or incoherent. When individuals think
one way, feel another, and behave inconsistently, they are in an inefficient and ineffective state-
that's non-coherence. A situation adults commonly face illustrates another kind of incoherence.
For example, if a child has hit another child and must be taught to be kind to others and that
hitting is not acceptable, consider the internal state of an adult in the following two scenarios:
1. The adult who punishes the child with a spanking for hitting another child.
2. The adult who takes time to teach and encourage the child to apologize and render an act
of service or kindness to the other child. In this instance, the thoughts, feelings and actions
of the adult are in coherent alignment with the message being taught. Then the child is
more likely to have a coherent understanding of the lesson being taught.
Another aspect of coherence relates to the dynamics of the flow of action produced by a
single system (McCraty & Tomasino, 2006). This is coherence as a uniform pattern of cyclical
behavior. Because this pattern of action is generated by a single system, the term auto-coherence
is used to denote this type of coherence. This concept is commonly used in physics to describe
the generation of an ordered distribution of energy in a waveform. An example is a sine wave,
which is a perfectly coherent wave. The more stable the frequency, amplitude, and shape of the
waveform, the higher the degree of coherence. In physiological systems, this type of coherence
describes the degree of order and stability in the rhythmic activity generated by a single
oscillatory such as the hearts rhythmic activity. When coherence is increased in a single system
that is coupled to other systems, it can pull the other systems into coherence or entrainment,
resulting in increased cross-coherence in the activity of the other systems, even across different
time scales of activity. An example of this is in the increased heart-brain synchronization that
occurs in a heart coherent mode.
The material presented in this article is informed by the following theoretical considerations.
Our psychophysiological systems process an enormous amount of information, which must be
continuously communicated from one part of the brain or body to another and often stored as a
memory of one type or another. The traditional approach to understanding how the body’s
systems interact adopts an activation perspective, in which variation in the amount of a substance
or the amount of a given physiological activity is viewed as the basis of communication.
Although the amount of activity is clearly an important aspect of communication, the generation
and transmission of rhythms and patterns of physiological activity appear reflective of a more
fundamental order of information communication—one that signifies different emotional states
and operates to integrate and coordinate the body’s functioning as a whole.
Throughout the body, information is encoded in waveforms of energy as patterns of
physiological activity. Neural, chemical, electromagnetic, and oscillatory pressure wave patterns
are among those used to encode and communicate biologically relevant information. By these
means, the body’s organs continually transmit information to the brain as patterns of afferent
(ascending) input. In turn, as we will see below, changes in the patterns of afferent input to the
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brain cause significant changes in physiological function, perception, cognition, emotion, and
intentional behavior.
A primary proposition explored in this article is that different emotions are associated with
distinct patterns of physiological activity. This is the result of a two-way process by which, in
one direction, emotions trigger changes in the autonomic nervous system and hormonal system,
and in the other direction, specific changes in the physiological substratum are involved in the
generation of emotional experience. Research at the Institute of HeartMath has identified six
distinct patterns of physiological activity generated during different emotional states. We call
these psychophysiological modes. Each of these is described in detail in Appendix A. Of
particular significance is the psychophysiological coherence mode, which is characterized by
ordered, harmonious patterns of physiological activity. This mode has been found to be
generated during the experience of sustained positive emotions. The psychophysiological
coherence mode has numerous physiological and psychological benefits, which can profoundly
impact health, performance, and quality of life.
A second proposition is that the heart plays a central role in the generation and transmission
of system-wide information essential to the body’s function as a coherent whole. There are
multiple lines of evidence to support this proposition: The heart is the most consistent and
dynamic generator of rhythmic information patterns in the body; its intrinsic nervous system is a
sophisticated information encoding and processing center that operates independently of the
brain; the heart functions in multiple body systems and is thus uniquely positioned to integrate
and communicate information across systems and throughout the body; and, of all the bodily
organs, the heart possesses by far the most extensive communication network with the brain. As
described subsequently, afferent input from the heart not only affects the homeostatic regulatory
centers in the brain, but also influences the activity of higher brain centers involved in
perceptual, cognitive, and emotional processing, thus in turn affecting many and diverse aspects
of our experience and behavior. These are the central ideas that guide what follows.
The Psychophysiological Network: A Systems Perspective
As science has increasingly adopted a systems perspective in investigation and analysis, the
understanding has emerged that our mental and emotional functions stem from the activity of
systems—organized pathways interconnecting different organs and areas of the brain and body—
just as do any of our physiological functions. Moreover, our mental and emotional systems
cannot be considered in isolation from our physiology. Instead, they must be viewed as an
integral part of the dynamic, communicative network of interacting functions that comprise the
human organism.
These understandings have led to the emergence and growth of new scientific fields of study,
such as psychophysiology. Psychophysiology is concerned with the interrelations among the
physiological, cognitive, and emotional systems and human behavior. It is now evident that
every thought, attitude, and emotion has a physiological consequence, and that patterns of
physiological activity continually influence our emotional experience, thought processes, and
behavior. As we will see shortly, the efficacy of this perspective has been substantiated by our
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own research, as well as that of many others, examining how patterns of psychophysiological
activity change during stress and different emotional states.
Heart Rate Variability and Measurement of Psychophysiological Modes
In the early stages of our work at the Institute of HeartMath, we sought to determine which
physiological variables were most sensitive to and correlated with changes in emotional states. In
analyzing many different physiological measures (such as heart rate, electroencephalographic
and electromyographic activity, respiration, skin conductance, etc.), we discovered that the
rhythmic pattern of heart activity was directly associated with the subjective activation of
distinct emotional states, and that the heart rhythm pattern also reflected changes in emotional
states, in that it covaried with emotions in real time. We found strong differences between quite
distinct rhythmic beating patterns that were readily apparent in the heart rhythm trace and that
directly matched the subjective experience of different emotions. In short, we found that the
pattern of the heart’s activity was a valid physiological indicator of emotional experience and
that this indicator was reliable when repeated at different times and in different populations.
In more specific terms, we examined the natural fluctuations in heart rate, known as heart rate
variability (HRV). HRV is a product of the dynamic interplay of many of the body’s systems.
Short-term (beat-to-beat) changes in heart rate are largely generated and amplified by the
interaction between the heart and brain. This interaction is mediated by the flow of neural signals
through the efferent and afferent pathways of the sympathetic and parasympathetic branches of
the autonomic nervous system (ANS). HRV is thus considered a measure of neurocardiac
function that reflects heart–brain interactions and ANS dynamics.
From an activation theory perspective, the focus is on changes in heart rate or in the amount
of variability that are expected to be associated with different emotional states. However, while
these factors can and often do covary with emotions, we have found that it is the pattern of the
heart’s rhythm that is primarily reflective of the emotional state. Furthermore, we have found
that changes in the heart rhythm pattern are independent of heart rate: one can have a coherent or
incoherent pattern at high or low heart rates. Thus, it is the rhythm, rather than the rate, that is
most directly related to emotional dynamics and physiological synchronization.
Emotions and Heart Rhythm Patterns
As mentioned at the outset, researchers have spent much time and effort investigating how
emotions change the state and functioning of the body’s systems. While the vast majority of this
body of work has focused on understanding the pathological effects of negative emotions, recent
research has begun to balance this picture by investigating the functions and effects of positive
emotions.
A synthesis of the voluminous work in developmental neurobiology has shown that the
modulation of positive emotions plays a critical role in infant growth and neurological
development, which has enormous consequences for later life (Schore, 1994). Other research on
adults has documented a wide array of effects of positive emotions on cognitive processing,
behavior, and health and well-being. Positive emotions have been found to broaden the scope of
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perception, cognition, and behavior (Fredrickson, 2001, 2005; Isen, 1999), thus enhancing
faculties such as creativity (Isen, 1998) and intuition (Bolte, Goschke, & Kuhl, 2003). Moreover,
the experience of frequent positive emotions has been shown to predict resilience and
psychological growth, (Fredrickson, Tugade, Waugh, & Larkin, 2003) while an impressive body
of research has documented clear links between positive emotions, health status, and longevity
(Blakeslee & Grossarth-Maticek, 1996; Danner, Snowdon, & Friesen, 2001; Medalie &
Goldbourt, 1976; Moskowitz, 2003; Ostir, Markides, Black, & Goodwin, 2000; Ostir, Markides,
Peek, & Goodwin, 2001; Russek & Schwartz, 1997; Seeman & Syme, 1987). In addition, there is
abundant evidence that positive emotions affect the activity of the body’s physiological systems
in profound ways. For instance, studies have shown that positive emotional states speed the
recovery of the cardiovascular system from the after-effects of negative emotions (Fredrickson et
al., 2000), alter frontal brain asymmetry (Davidson et al., 2003), and increase immunity
(Davidson et al.; McCraty, Atkinson, Rein, & Watkins, 1996; Rein, Atkinson, & McCraty,
1995). Finally, the use of practical techniques that teach people how to self-induce and sustain
positive emotions and attitudes for longer periods has been shown to produce positive health
outcomes. These include reduced blood pressure in both hypertensive and normal populations,
(McCraty, Atkinson, Lipsenthal, et al., 2003; McCraty, Atkinson, & Tomasino, 2003) improved
functional capacity in patients with heart failure (Luskin, Reitz, Newell, Quinn, & Haskell,
2002), improved hormonal balance, (McCraty, Barrios-Choplin, Rozman, Atkinson, & Watkins,
1998) and lower lipid levels (McCraty, Atkinson, Lipsenthal, et al., 2003).
In investigating the physiological foundation of this important work, we have utilized HRV
analysis to show how distinct heart rhythm patterns characterize different emotional states. In
more specific terms, we found that underlying the experience of different emotional states there
is a distinct physiology directly involved. Thus we have found that sustained positive emotions
such as appreciation, care, compassion, and love generate a smooth, sine-wave-like pattern in the
heart’s rhythms. This reflects increased order in higher-level control systems in the brain,
increased synchronization between the two branches of the ANS, and a general shift in
autonomic balance towards increased parasympathetic activity. As is visually evident (Figure 1)
and also demonstrable by quantitative methods, heart rhythms associated with positive emotions,
such as appreciation, are clearly more coherent—organized as a stable pattern of repeating sine
waves—than those generated during a negative emotional experience such as frustration. We
observed that this association between positive emotional experience and this distinctive
physiological pattern was evident in studies conducted in both laboratory and natural settings,
and for both spontaneous emotions and intentionally generated feelings (McCraty, Atkinson,
Tiller, Rein, & Watkins, 1995; Tiller, McCraty, & Atkinson, 1996).
By contrast, our research has shown that negative emotions such as frustration, anger, anxiety,
and worry lead to heart rhythm patterns that appear incoherent—highly variable and erratic.
Overall, this means that there is less synchronization in the reciprocal action of the
parasympathetic and sympathetic branches of the ANS (McCraty et al., 1995; Tiller et al., 1996).
This desynchronization in the ANS, if sustained, taxes the nervous system and bodily organs,
impeding the efficient synchronization and flow of information throughout the
psychophysiological systems. Furthermore, as studies have also shown that prefrontal cortex
activity is reflected in HRV via modulation of the parasympathetic branch of the ANS (Lane,
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Reiman, Ahern, & Thayer, 2001), this increased disorder in heart rhythm patterns is also likely
indicative of disorder in higher brain systems.
Figure 1. Emotions are reflected in heart rhythm patterns. The heart rhythm pattern shown in
the top graph, characterized by its erratic irregular pattern (incoherence), is typical of negative
emotions such as anger or frustration. The bottom graph shows an example of the coherent heart
rhythm pattern that is typically observed when an individual is experiencing sustained,
modulated positive emotions, in this case appreciation.
Psychophysiological Coherence
In our research on the physiological correlates of positive emotions we have found that when
certain positive emotional states, such as appreciation, compassion, or love, are intentionally
maintained, coherent heart rhythm patterns can be sustained for longer periods, which also leads
to increased synchronization and entrainment between multiple bodily systems. Because it is
characterized by distinctive psychological and behavioral correlates as well as by specific
patterns of physiological activity throughout the body, we introduced the term
psychophysiological coherence5 to describe this mode of functioning.
In earlier publications (Tiller et al., 1996), the psychophysiological coherence mode was referred to as
the “entrainment mode” because a number of physiological systems entrain with the heart rhythm in this
mode.
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The development of heart rhythm coherence—a stable, sine-wave-like pattern in the heart rate
variability waveform—is the key marker of the psychophysiological coherence mode. Heart
rhythm coherence is reflected in the HRV power spectrum as a large increase in power in the low
frequency (LF) band (typically around 0.1 Hz) and a decrease in the power in the very low
frequency (VLF) and high frequency (HF) bands. A coherent heart rhythm can therefore be
defined as a relatively harmonic (sine-wave-like) signal with a very narrow, high-amplitude peak
in the LF region of the HRV power spectrum and no major peaks in the VLF or HF regions.
Coherence thus approximates the LF/(VLF + HF) ratio. (See Appendix A for an explanation of
the HRV power spectrum and a description of the physiological significance of the different
frequency bands.)
A method of quantifying heart rhythm coherence is shown in Figure 2. First, the maximum
peak is identified in the 0.04–0.26 Hz range (the frequency range within which coherence and
entrainment can occur). The peak power is then determined by calculating the integral in a
window 0.030 Hz wide, centered on the highest peak in that region. The total power of the entire
spectrum is then calculated. The coherence ratio is formulated as:
(Peak Power / (Total Power − Peak Power)) (Childre & Martin, 1999)
This method provides an accurate measure of coherence that allows for the nonlinear nature of
the HRV waveform over time.
Figure 2. Heart rhythm coherence ratio calculation.
At the physiological level, psychophysiological coherence embraces several related
phenomena—autocoherence, entrainment, synchronization, and resonance—which are
associated with increased order, efficiency, and harmony in the functioning of the body’s
systems. As described above, this mode is associated with increased coherence in the heart’s
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rhythmic activity (autocoherence), which reflects increased ANS synchronization and manifests
as a sine-wave-like heart rhythm pattern oscillating at a frequency of approximately 0.1 Hz.
Thus, in this mode the HRV power spectrum6 is dominated by a narrow-band, high-amplitude
peak near the center of the low frequency band (see Figures 3 below and 8 in Appendix A)
(McCraty et al., 1995; Tiller et al., 1996).
Another physiological correlate of the coherence mode is the phenomenon of resonance. In
physics, resonance refers to a phenomenon whereby an unusually large oscillation is produced in
response to a stimulus whose frequency is the same as, or nearly the same as, the natural
vibratory frequency of the system. The frequency of the vibration produced in such a state is
defined as the resonant frequency of the system. When the cardiovascular system is operating in
the coherence mode, it is essentially oscillating at its resonant frequency; this is reflected in the
distinctive high-amplitude peak in the HRV power spectrum around 0.1 Hz. Most mathematical
models show that the resonant frequency of the human cardiovascular system is determined by
the feedback loops between the heart and brain (Baselli et al., 1994; DeBoer, Karemaker, &
Strackee, 1987). In humans and in many animals, the resonant frequency of the system is
approximately 0.1 Hz, which is equivalent to a 10-second rhythm. The system naturally
oscillates at its resonant frequency when an individual is actively feeling a sustained positive
emotion such as appreciation, compassion, or love, (McCraty et al., 1995) although resonance
can also emerge during states of deep sleep.
Furthermore, increased heart–brain synchronization is observed during coherence;
specifically, the brain’s alpha rhythms exhibit increased synchronization with the heartbeat in
this mode. This finding is discussed in greater depth in Appendix D.
Finally, there tends to be increased cross-coherence or entrainment among the rhythmic
patterns of activity generated by different physiological oscillatory systems. Entrainment occurs
when the frequency difference between the oscillations of two or more nonlinear systems drops
to zero by being “frequency pulled” to the frequency of the dominant system. As the body’s most
powerful rhythmic oscillator, the heart can pull other resonant physiological systems into
entrainment with it. During the psychophysiological coherence mode, entrainment is typically
observed between heart rhythms, respiratory rhythms, and blood pressure oscillations; however,
other biological oscillators, including very low frequency brain rhythms, craniosacral rhythms,
and electrical potentials measured across the skin, can also become entrained (Bradley &
Pribram, 1998; Tiller et al., 1996).
Figure 3 shows an example of entrainment occurring during psychophysiological coherence.
The graphs plot an individual’s heart rhythm, arterial pulse transit time (a measure of beat-to-
beat blood pressure) (Bradley & Pribram, 1998), and respiration rate over a 10-minute period. In
this example, after a 300-second normal resting baseline period the subject used a heart-based
positive emotion refocusing technique known as Freeze-Frame, (Childre & Martin, 1999) which
Spectral analysis decomposes the HRV waveform into its individual frequency components and
quantifies them in terms of their relative intensity using power spectral density (PSD) analysis. Spectral
analysis thus provides a means to quantify the relative activity of the different physiological influences on
HRV, which are represented by the individual oscillatory components that make up the heart rhythm.
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involves focusing attention in the area of the heart while self-generating a sincere positive
emotion, such as appreciation. After the subject used the Freeze-Frame technique, the three
rhythms shifted from an erratic to a sine-wave-like pattern (indicative of the coherence mode)
and all entrained at a frequency of 0.12 Hz. (Tiller et al., 1996). The entrainment phenomenon is
thus an example of a psychophysiological state in which there is increased coherence within each
system (autocoherence) and among multiple oscillating systems (cross-coherence) as well. This
example also illustrates how the intentional generation of a self-regulated positive emotional
state can bring about a phase-shift in physiological activity, driving the physiological systems
into a globally coherent mode of function.
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Figure 3. Entrainment. The top graphs show an individual’s heart rate variability, pulse transit
time, and respiration rhythms over a 10-minute period. At the 300-second mark, the individual
used the Freeze-Frame positive emotion refocusing technique, causing these three systems to
come into entrainment. The bottom graphs show the frequency spectra of the same data on each
side of the dotted line in the center of the top graph. Notice the graphs on the right show that all
three systems have entrained to the same frequency.
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Psychological and Behavioral Correlates
The experience of the coherence mode is also qualitatively distinct at the psychological level.
This mode is associated with reduced perceptions of stress, sustained positive affect, and a high
degree of mental clarity and emotional stability. In Appendix C we also present data indicating
that coherence is associated with improved sensory-motor integration, cognition, and task
performance. In addition, individuals frequently report experiencing a notable reduction in
internal mental dialogue, increased feelings of inner peace and security, more effective decision
making, enhanced creativity, and increased intuitive discernment when engaging this mode.
In summary, psychophysiological coherence is a distinctive mode of function driven by
sustained, modulated positive emotions. At the psychological level, the term “coherence” is used
to denote the high degree of order, harmony, and stability in mental and emotional processes that
is experienced during this mode. Physiologically speaking, “coherence” is used here as a general
term that encompasses entrainment, resonance, and synchronization—distinct but related
phenomena, all of which emerge from the harmonious activity and interactions of the body’s
subsystems. Physiological correlates of the coherence mode include: increased synchronization
between the two branches of the ANS, a shift in autonomic balance toward increased
parasympathetic activity, increased heart−brain synchronization, increased vascular resonance,
and entrainment between diverse physiological oscillatory systems.
Although the physiological phenomena associated with coherence can occur spontaneously,
sustained episodes are generally rare. While specific rhythmic breathing methods may induce
heart rhythm coherence and physiological entrainment for brief periods, cognitively directed
paced breathing is difficult for many people to maintain for more than about one minute
(discussed in detail later). On the other hand, we have found that individuals can intentionally
maintain coherence for extended periods by self-generating, modulating, and sustaining a “heart-
focused” positive emotional state. Using a positive emotion to drive the coherence mode appears
to excite the system at its resonant frequency, and coherence emerges naturally, making it easy to
sustain for long periods.
Self-regulation of emotional experience is a key requisite to the intentional generation of
sustained positive emotions—the driver of a shift to coherent patterns of physiological activity.
Emotional self-regulation involves moment-to-moment management of distinct aspects of
emotional experience. One aspect involves the neutralization of inappropriate or dysfunctional
negative emotions. The other requires that self-activated positive emotions are modulated to
remain within the resonant frequency range of such emotions as appreciation, compassion, and
love, rather than escalating into feelings such as excitement, euphoria, and rapture, which are
associated with more unstable psychophysiological patterns.
A series of tools and techniques, collectively known as the HeartMath System, provide a
systematic process that enables people to self-regulate emotional experience and reliably
generate the psychophysiological coherence mode (Childre & Martin, 1999; Childre & Rozman,
2002, 2005). The primary focus of these techniques is on facilitating the intentional generation of
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a sustained, heart-focused positive emotional state. This is accomplished by a process that
combines a shift in attentional focus to the area of the heart (where many people subjectively
experience positive emotions) which the self-induction of a positive feeling, such as
appreciation. Our work has shown that this shift in focus and feeling experience allows the
coherence mode to emerge naturally and helps to reinforce the inherent associations between
coherence and positive feelings. Our research also suggests that the intentional application of
these coherence-building techniques, on a consistent basis, effectively facilitates a repatterning
process whereby coherence becomes increasingly familiar to the brain and nervous system, and
thus progressively becomes established in the neural architecture as new, stable
psychophysiological baseline or set point (McCraty, 2003; McCraty & Childre, 2004; McCraty
& Tomasio, 2006). Once the coherence mode is established as the familiar pattern, the system
then strives to maintain this mode automatically, thus rendering coherence a more readily
accessible state during day-to-day activities, and even in the midst of stressful or challenging
situations.
At the physiological level, the occurrence of such a repatterning process is supported by
electrophysiological evidence demonstrating a greater frequency of spontaneous (without
conscious practice of the interventions) periods of heart rhythm coherence in individuals
practiced in the HeartMath coherence-building techniques. Furthermore, a number of studies
suggest that this “repatterning” process can produce enduring system-wide benefits that
significantly impact overall quality of life (discussed below).
While evidence clearly shows that the HeartMath positive emotion refocusing and emotional
restructuring techniques lead to increased psychophysiological coherence, other approaches have
also been shown to be associated with increased coherence. For example, in a recent UCLA
study, Buddhist monks meditating on generating compassionate love tended to exhibit increased
coherence, and another study of Zen monks found that the more advanced monks tended to have
coherent heart rhythms, while the novices did not (Lehrer et al., 2003). This does not imply,
however, that all meditation approaches lead to coherence; as we and others have observed,
approaches that focus attention to the mind (concentrative mediation), and not on a positive
emotion, in general do not induce coherence.
Benefits of Psychophysiological Coherence
In terms of physiological functioning, coherence is a highly efficient mode that confers a
number of benefits to the system. These include: (1) resetting of baroreceptor sensitivity, which
is related to improved short-term blood pressure control and increased respiratory efficiency; (2)
increased vagal afferent traffic, which is involved in the inhibition of pain signals and
sympathetic outflow; (3) increased cardiac output in conjunction with increased efficiency in
fluid exchange, filtration, and absorption between the capillaries and tissues; (4) increased ability
of the cardiovascular system to adapt to circulatory requirements; and (5) increased temporal
synchronization of cells throughout the body. This results in increased system-wide energy
efficiency and metabolic energy savings (Lehrer et al., 2003; Langhorst, Schulz, & Lambertz,
1984; Siegel et al., 1984).
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Psychologically, the coherence mode promotes a calm, emotionally balanced, yet alert and
responsive state that is conducive to cognitive and task performance, including problem-solving,
decision-making, and activities requiring perceptual acuity, attentional focus, coordination, and
discrimination. Individuals generally experience a sense of enhanced subjective well-being
during coherence due to the reduction in extraneous inner “noise” generated by the mental and
emotional processing of daily stress and the positive emotion-driven shift to increased harmony
in bodily processes. Many also report increased intuitive clarity and efficacy in addressing
troublesome issues in life.
The use of coherence-building interventions has been documented in numerous studies to give
rise to significant improvements in key markers of both physical and psychological health.
Significant improvements in several objective health-related measures have been observed,
including immune system function (McCraty et al., 1996; Rein et al., 1995), ANS function and
balance (McCraty et al., 1995; Tiller et al., 1996), and the DHEA/cortisol ratio (McCraty et al.,
1998). At the emotional level, significant reductions in depression, anxiety, anger, hostility,
burnout, and fatigue and increases in caring, contentment, gratitude, peacefulness, and vitality
have been measured across diverse populations (Arguelles, McCraty, & Rees, 2003; Barrios-
Choplin, McCraty, & Cryer, 1997; Luskin et al., 2002; McCraty et al., 1998; McCraty, Atkinson,
Lipsenthal, et al. 2003; McCraty, Atkinson, & Tomasino, 2001, 2003). Other research has
demonstrated significant reductions in key health risk factors (e.g., blood pressure, glucose,
cholesterol) (McCraty, Atkinson, Lipsenthal, et al., 2003) and improvements in health status and
quality of life in various populations using coherence-building approaches. More specifically,
significant blood pressure reductions have been demonstrated in individuals with hypertension
(McCraty, Atkinson, & Tomasino); improved functional capacity and reduced depression in
patients with congestive heart failure (Luskin et al.); improved glycemic regulation and quality
of life in patients with diabetes (McCraty, Atkinson, & Lipsenthal, 2000); and improvements in
asthma (Lehrer, Smetankin, & Potapova, 2000). Coherence-building interventions have also been
found to yield favorable outcomes in organizational, educational, and mental health settings
(Arguelles et al., 2003; Barrios-Choplin et al.; Barrios-Choplin, McCraty, Sundram, & Atkinson,
1999; McCraty et al., 2001; McCraty, Atkinson, Lipsenthal, et al.; McCraty, Atkinson,
Tomasino, Goelitz, & Mayrovitz, 1999; McCraty & Childre, 2004; McCraty & Tomasio, 2004).
In short, our findings on psychophysiological coherence essentially substantiate what human
beings have known intuitively for thousands of years: namely, that positive emotions not only
feel better subjectively, but they also increase the synchronous and harmonious function of the
body’s systems. This optimizes our health, well-being, and vitality, and enables us to function
with greater overall efficiency and effectiveness.
A Typology of Psychophysiological Interaction
In the Appendix A we identify six distinct patterns of HRV, which appear to denote six
different modes of psychophysiological interaction. Four of these modes are readily generated in
the context of everyday life. We have termed these Mental Focus, Psychophysiological
Incoherence, Relaxation and Psychophysiological Coherence. Two further modes, Emotional
Quiescence and Extreme Negative Emotion, are generated under more extraordinary life
circumstances. This appendix provides empirical data and detailed descriptions for each of these.
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Looking more closely at our data, we found a number of empirical clues that point to a more
fundamental conceptualization of the relationship between HRV patterns (which include both
heart rate and rhythm) and different emotional states. The first clue is that there is a general
relationship between coherence and emotional valence, in that positive emotions are associated
with physiological coherence and negative emotions with incoherence. The second clue is that,
for certain emotions, we found a relationship between the morphology of the HRV waveforms
and specific emotional states. The third finding of significance here is that we also found
evidence of HRV waveform patterns (namely, those characteristic of the Emotional Quiescence
and Extreme Negative Emotion modes) that appear to involve a rapid phase transition into a
qualitatively different category of physiological function. In short, the empirical generalization
suggested by these findings is that the morphology of HRV waveforms covaries with different
emotional experiences.
Following the logic of this general relationship, we can thus use the six psychophysiological
modes to construct a typology—a conceptual “map”—showing the expected relationship
between different categories of subjective emotional experience and the different patterns of
physiological activity associated with them (see Figure 4). This general theoretical scheme
applies to normal, healthy individuals experiencing emotions and feelings of relatively short
duration (minutes to hours).
Figure 4. Graphic depiction of everyday states and hyper-states of psychophysiological
interaction distinguished by the typology. Two qualitatively different categories of
psychophysiological interaction are depicted—the area within the inner circle represents the
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range of emotional experience of “normal,” everyday life; the area beyond the outer circle
represents psychophysiological hyper-states of extreme emotional experience. The
psychophysiological transition from one region to another involves an abrupt phase transition,
which is depicted graphically by the white space between the two circles. Two dimensions
differentiate the varieties of emotional experience shown; for simplification, the relevant
psychological and physiological variables are superimposed on the axis for each dimension. One
dimension is the degree of emotional arousal (vertical axis, high to low)—known to be covariant
with ANS balance. The second dimension is the valence of the emotion (horizontal axis, positive
or negative)—assumed covariant with the degree of activation of the hypothalamic-pituitary-
adrenal (HPA) axis. Different patterns of HRV are predicted from the particular combination of
arousal and valence values on the two dimensions. Within the inner circle are six segments, each
of which demarcates a range of emotion experienced in everyday life. Typical HRV patterns
associated with each emotion are shown. The area beyond the outer circle depicts six hyper-
states, in which intense emotional experience drives the activity of physiological systems past
normal function into extreme modes. The known and predicted HRV waveform patterns
associated with these hyper-states are also shown. The labels “Depletion” and “Renewal,” on the
left and right-hand side of the diagram, respectively, highlight the relationship between the
valence of feelings and emotions experienced and the psychophysiological consequences for the
individual. Negative emotional states can lead to emotional exhaustion and depletion of
physiological reserves. By contrast, positive emotional states are associated with increased
psychophysiological efficiency and regeneration.
Although the mapping is not isomorphic between data and concept, the typology provides a
compelling and fruitful way of conceptualizing and organizing these phenomena. In addition to
offering some understanding of the relationships between different types of emotional experience
and their associated physiological processes, this scheme also aims to predict the distinguishing
physiological correlates of emotional states that, to our knowledge, have yet to be empirically
described.
The typology distinguishes between two general classes of psychophysiological interaction.
One class reflects “normal” psychophysiological states associated with the variety of subjective
experiences of everyday life. This area is represented by the space within the inner circle shown
in Figure 4. This area has been divided into six segments, each representing a different basic
range of emotion. The second class is a qualitatively different category of psychophysiological
interaction associated with extreme emotional experience, represented by the space beyond the
outer perimeter of the circle in the figure. Because the patterns of psychophysiological
interaction in this space are predicted to show an abrupt movement—a phase shift—from
patterns associated with feelings typically experienced in everyday life to qualitatively distinct
psychophysiological patterns associated with the experience of extreme positive or extreme
negative emotions, well beyond the range of normal feelings, we have labeled them as hyper-
states. Evidence of such a phase shift can clearly be seen as an abrupt reduction in amplitude and
a corresponding increase in frequency in the waveform patterns showing the movement from
Psychophysiological Coherence to the Emotional Quiescence, a positive hyper-state (Figure 9,
Appendix A) and also in the movement from Psychophysiological Incoherence to Extreme
Negative Emotion, a negative hyper-state (Figure 10, Appendix A).
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Two dimensions common to the phenomenon of psychophysiological interaction provide the
basis for differentiating varieties of emotional experience in the typology. As evident in the term
“psychophysiological,” there is a psychological element and a physiological element. 7 For
purposes of simplification, we have superimposed the relevant psychological and physiological
variables on the axis representing each dimension in the figure.8 One dimension is the degree of
emotional arousal (high to low), which is known to be covariant with ANS balance. Thus, during
short-term emotional experiences, the relative balance between the activity of the sympathetic
and parasympathetic branches of the ANS is driven by the degree of emotional arousal.
Accordingly, we have mapped emotional arousal and ANS balance together on the vertical axis
in Figure 4.
The second dimension is the valence (positive or negative) of the emotion, which is
represented by the horizontal axis in Figure 4. Again for purposes of simplification, the valence
is assumed to be covariant with the degree of activation of the hypothalamic-pituitary-adrenal
(HPA) axis, which controls the release of cortisol. For short-term emotional experiences, there is
an increase in cortisol during negative emotional states and a decrease in cortisol release during
positive emotional states.
HRV patterns can be distinguished on the basis of amplitude, frequency, and degree of
coherence. Empirical findings show that the two elements of the psychological dimension in our
scheme play a predominant role in determining the characteristics of the HRV pattern. The
amplitude of the HRV waveform is modulated by both the degree of emotional arousal (which
corresponds to ANS activation) and emotional valence. In general, greater degrees of arousal
within normal heart rate ranges produce waveforms of greater amplitude.9 However, as heart rate
increases, the amplitude of the HRV waveform decreases in linear relationship to heart rate until
it reaches a point beyond which the amplitude of the HRV waveform is compressed. This is due
to a biological constraint known as the cycle-length dependence effect. In terms of emotional
valence, the amplitude of the HRV waveform increases during positive emotions, while it
decreases during negative emotions. The frequency of the HRV waveform is influenced by the
pattern of ANS activation; increased parasympathetic activity leads to higher-frequency (faster)
changes in the heart rhythm, while increased sympathetic activity is associated with lower-
frequency, higher-amplitude (slower) changes. Finally, the degree of coherence of the HRV
waveform is largely determined by the emotional valence, with positive emotion increasing
coherence and negative emotion decreasing coherence. Different patterns of HRV can therefore
Although the psychological component involves at least three factors for a given emotional
experience—emotional arousal, emotional valence, and the degree of cognitive engagement—we have
excluded cognitive engagement to avoid the enormous complexity introduced when all three factors are
considered simultaneously.
8
In reality the relationship is much more complicated. While there is a close intra-relationship between
each pair of variables on the axis, there are many life circumstances that give rise to a more complex
interaction between the emotional and physiological levels.
9
A secondary modulator of the HRV amplitude is the degree of cognitive engagement. High cognitive
engagement tends to reduce HRV, while low cognitive engagement increases HRV. As noted, for
purposes of simplification this factor is not considered in this model.
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be predicted from the conjunction of the particular combination of arousal and valence values on
the two dimensions in our typology.
Following this logic, therefore, each of the six segments within the inner circle in Figure 4
demarcates a range of emotion and its corresponding representative HRV waveform patterns for
the variety of emotional experiences that typify everyday life. Organized in terms of degree of
arousal and valence, and rotating clockwise around the figure, these are the familiar emotions we
experience from day to day. They are labeled: Happiness–Excitement, Love–Appreciation,
Contentment–Serenity, Sadness–Apathy, Frustration–Resentment, and Anger–Anxiety. At the
center of the circle, in a small area surrounding the intersection of the two axes, is the space of
Emotional Impassivity (not labeled in Figure 4). Involving little or no emotional feeling, either
positive or negative, emotional impassivity is typically experienced when the individual is
mentally engaged in performing a familiar action or routine task. These seven areas within the
circle of day-to-day emotional life denote substantively different emotions and feelings
subjectively experienced by the individual.
Psychophysiological Hyper-States
Qualitatively distinct from the feelings of daily life are six distinct psychophysiological hyper-
states reflecting the body’s response to extreme emotions. Because these hyper-states involve a
phase shift in physiological organization and psychological experience that is discontinuous from
the states of normal, everyday emotional life, they are set apart beyond the perimeter of the outer
circle in Figure 4.
Generally speaking, the psychophysiological hyper-states are indicative of two quite different
directions of movement in bodily processes. As described below, hyper-states involving extreme
positive emotions are transcendent states in which the individual’s emotional experience
involves the feeling of spiritual connectedness to something larger and more enduring beyond
themselves. Typically these states are associated with selfless actions and are also generative of
bodily renewal. By contrast, hyper-states of extreme negative emotions are all-consuming states
of self-absorption and self-focus. These states are usually associated with highly destructive
behavior—either directed at the self and/or projected out onto others—and have detrimental,
even devastating, consequences. Negative hyper-states lead to a depletion of the body’s energy
and resources which, in the long term, results in the degeneration of bodily function.
Shown beyond the high end of the arousal axis are two states of hyper-arousal characterized
by extreme emotional activation. The extreme emotional activation can result in a loss of self-
control, which may lead to unpredictable behavior. It is important to understand that these
extreme emotions are associated with the highest level of physiological activation. This drives
the heart rate past physiological norms to such a degree that the amplitude of the HRV waveform
becomes extremely low.
On the negative side, violent, uncontrollable anger and rage, or overwhelming fear and
anxiety are the hyper-aroused emotions experienced here. As already mentioned, we have
empirical data documenting the HRV pattern associated with this state (see the waveform pattern
showing the movement to “intense anger” in Figure 10, Appendix A). On the positive side,
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uninhibited rejoicing and jubilation, or overpowering exaltation and ecstasy are predicted, in the
absence of any empirical data documenting this hyper-state. We believe it is this
psychophysiological state that is accessed during collective rituals that lead to trance states and
spiritual rapture. It also may be possible to enter this state from hyper-aroused, uncontrolled
positive emotions that induce a positive hysteria, such as can result from an unexpected,
overwhelmingly positive event—for example, reuniting with a loved one who was in a life-
threatening situation.
At the low end of the arousal axis are two states of hypo-arousal, the complement to the two
states of hyper-arousal we have just described. On the positive side, the individual experiences
an ego-less feeling of profound inner peace and deep spiritual connectedness. Typically, this
state is accessed by self-disciplined meditative and spiritual practice. Physiologically, the
emotional experience of this state of extremely low arousal is characterized by HRV waveform
patterns of very low amplitude with some degree of coherence, reflecting the body’s state of
complete calm and rest.
On the negative side, individuals can enter a state of hypo-arousal when they have been in an
enduring negative emotional state (weeks to months). This is a state of self-engrossing desolation
and despair and is accompanied by obsessive negative mental and emotional activity, such as
that experienced in prolonged grief or long-term depression. However, an episode of severe
trauma or negative emotion can rapidly propel an individual into this state. Either way, this can
result in a depletion of physiological reserves, which is in turn reflected in a very low-amplitude
HRV waveform. Often, individuals in this hypo-state are emotionally numb and socially
alienated or withdrawn.
If this state is sustained on a long-term basis, there is further depletion of both the sympathetic
and parasympathetic systems. In the first stages of this process, sympathetic activity becomes
substantially reduced, resulting in an autonomic imbalance. As the process continues,
parasympathetic activity (vagal tone) is correspondingly reduced. The process culminates with a
phase-transition into exhaustion and breakdown.
Between the four states of extreme hyper-arousal and extreme hypo-arousal in the mid-range
of emotional arousal, are two other states of extraordinary emotional experience. On the positive
side, there is the state of wholly self-less spiritual love in which the individual experiences a
deep feeling of all-embracing “big love”—Agape, as defined by the dictionary: a love that is
open to and non-judgmental about all perceptions, cognitions, and intuitions. To enter this hyper-
state requires a deep, heart-focused, self-less love, which can be associated with contemplative
introspection. This hyper-state is accessed via a phase transition when this deep heart-focused
introspection is sustained for a few minutes or more. This state is experienced as a substantial
reduction in mental and emotional “chatter” to a point of internal quietness, often associated with
a profound feeling of peace and serenity. This is the phase space within which the Emotional
Quiescence mode falls. We also expect this hyper-state to be associated with other types of
emotional experience that may have a spiritual dimension, such as those accessed by a number of
introspective disciplines and practices.
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Physiologically, there are two likely mechanisms to explain how this hyper-state occurs. One
is that, in this state, the sympathetic and parasympathetic outflow from the brain to the heart is
substantially reduced—reduced to such a degree that the amplitude of HRV waveform becomes
very low. The other logical possibility is that the heart acts as an antenna to a field of information
beyond space and time surrounding the body that directly informs the heart and modulates its
rhythmic patterns. As astounding as this may sound, there is compelling evidence from our study
of the electrophysiology of intuition that points in this direction (McCraty, Atkinson, & Bradley,
2004a, 2004b).
On the negative side, there is a hyper-state in which the individual is consumed by powerful
malevolent feelings of extreme ill-will and hatred. These ego-centric feelings occupy virtually all
of the individual’s time and energy and engage one’s whole attention. Typically, these feelings
of evil and harm are not directed inwards against the self, but, instead, are projected outwards to
be expressed as an intense pathological desire to cause great pain and suffering to others.
Sustained, fanatical feelings of ill-will toward others can propel an individual into this hyper-
state. Subjectively, there is a substantial reduction in mental and emotional “chatter” and a
correspondingly heightened state of calm, malevolent feelings. The emotional calm reflects the
individual’s disassociation from the humanity of others and the total acceptance of the all-
consuming negative thoughts and emotions experienced in this state. We expect this hyper-state
to be one that can be entered by individuals who hold fanatical beliefs based on extreme negative
stereotypes or caricatures of others. This is often the case with radical groups on the margins of
society who see themselves suffering a great injustice or harm from the hands of those they hate.
Physiologically, this hyper-state likely involves a zombie-like state in which there is such
emotional disassociation that the amplitude of HRV waveform becomes very low but with some
variability spikes which may reflect the individual’s momentary transitions between different
emotions.
To conclude, the typology provides a more general conceptual framework from which to view
the six modes of psychophysiological interaction we identified in our empirical studies. We have
found the typology a useful way of conceptually organizing the broad range and highly variable
phenomena in this domain. It will be up to future research to test the degree to which the
typology offers a fruitful map of the nature and organization of the different types of emotional–
physiological interaction.
Heart Coherence and Psychophysiological Function
So far, we have discussed how changes in the patterns of neural activity can encode and
transmit information in the psychophysiological networks independent of changes in the amount
of activity and how this level of information processing may well play a more fundamental role
in information exchange than changes in the amount and/or intensity of neural activity. In this
section we will see that increased coherence is associated with favorable changes in various
aspects of physiological function, which in turn are associated with psychological benefits. We
introduce this discussion by describing how the amount of information traveling through the
afferent nerves increases during coherence, and we then examine the role that cardiac afferent
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input plays in the neural pathways involved in pain perception, respiratory function, emotional
processing, and cognitive performance.
The vagus nerve is a major conduit though which afferent neurological signals from the heart
and other visceral organs are relayed to the brain. Psychophysiologist Paul Lehrer has shown that
by using heart rhythm feedback to facilitate a state of physiological coherence (which he calls
“resonance”), a lasting increase in baroreflex gain10 is accomplished independent of respiratory
and cardiovascular changes, thus demonstrating neuroplasticity of the baroreflex system (Lehrer
et al., 2003). This shift in baroreflex gain indicates that with repeated episodes of coherence, the
activation threshold of some of the mechanosensory neurons in the baroreflex system is reset
and, as a result, these neurons increase their output accordingly.
In addition, a basic property of mechanosensory neurons is that they generally increase their
output in response to an increase in the rate of change in the function they are tuned to (heart
rate, blood pressure, etc.). During heart rhythm coherence, there is an increase in beat-to-beat
variability in both heart rate and blood pressure, which is equivalent to an increase in the rate of
change. This results in an increase in the vagal afferent traffic sent from the heart and
cardiovascular system to the brain. With regular practice in maintaining the coherence mode, it is
likely that increased vagal afferent traffic would also be observed even when one is not in this
mode. This is due to the fact that the mechanosensory neurons’ threshold is reset as a result of
the coherence-building practice, thus establishing a new baseline level of afferent traffic.
Generating an increase in vagal afferent traffic through noninvasive approaches such as heart-
based emotion refocusing techniques and heart rhythm coherence feedback has a number of
potential benefits. In recent years, a number of clinical applications for increasing vagal afferent
traffic have been found; however, the increase in afferent activity is usually generated by
implanted or external devices that stimulate the vagal afferent pathways, typically in the left
vagus nerve. Vagal stimulation is an FDA-approved treatment for epilepsy and is currently under
investigation as a therapy for obesity, depression, anxiety, and Alzheimer’s disease (Groves &
Brown, 2005; Kosel & Schlaepfer, 2003). It has been established that an increase in the normal
intrinsic levels of vagal afferent traffic inhibits the pain pathways traveling from the body to the
thalamus at the level of the spinal cord (discussed below) and a recent study has found that
stimulation of the afferent vagal pathways significantly reduces cluster and migraine headaches
(Mauskop, 2005). Vagal nerve stimulation has also been shown to improve cognitive processing
and memory (Hassert, Miyashita, & Williams, 2004)—findings that are consistent with those of
several recent studies of individuals using heart rhythm coherence-building techniques
(discussed later in this article).
Baroreflexes are homeostatic reflexes that regulate blood pressure. Through them, increases in blood
pressure produce decreases in heart rate and vasodilation, while decreases in blood pressure produce the
opposite. Baroreflex gain is commonly calculated as the beat-to-beat change in heart rate per unit of
change in blood pressure. Decreased baroreflex gain is related to impaired regulatory capacity and aging.
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Afferent signals from the heart modulate the neural pathways involved in the perception of
pain. Numerous reports from individuals using the HeartMath coherence-building techniques
indicate that they are able to greatly reduce their experience of bodily pain, often to a point
where they can reduce or eliminate pain medications. This is true of both visceral and cutaneous
pain. The HeartMath system is currently employed by numerous clinicians as a pain management
aid, and has proven effective in patients with a wide range of conditions, including chronic joint
pain, serious burns, and traumatic brain injury. The generation of increased vagal afferent
activity during the coherence mode provides a likely mechanism to account for the reduction of
pain associated with increased heart rhythm coherence.
Several mechanisms have been identified that explain how increased vagal afferent activity
decreases pain sensitivity and increases pain threshold. Nociceptive information (pain signals)
from the skin and internal organs is carried to cell bodies located in the dorsal root ganglia of the
spinal cord. Axons from neurons in the dorsal root ganglia penetrate the spinal cord and convey
afferent pain information to localized regions of the gray matter in the cord. From there, afferent
information ascends in pathways to both the lateral and medial thalamus. Cells of the lateral
thalamus in turn project to the primary somatosensory cortex, where the location, intensity, and
duration of the painful stimulus are analyzed. Information is sent from the medial thalamus to the
insular cortex, amygdala, and cingulate gyrus, where motivational-affective components of pain,
including autonomic adjustments, occur. This pathway is called the spinothalamic tract (STT)
and, although not the only pain pathway, it is the main and most studied system that transmits
visceral sympathetic afferent pain information to the brain (Foreman, 1989).
Afferent fibers in the vagus nerve participate in the modulation of pain partly by modulating
the flow of pain signals in the STT. An increase in afferent vagal activity causes a general
inhibitory effect at most levels of the spinal cord on neurons that transmit nociceptive
information to the thalamus and then to areas of the brain involved in pain perception. Vagal
afferent fibers terminate primarily in the caudal medulla of the brain stem and nucleus tractus
solitarius (NTS), and evidence shows that suppression of spinal neuronal activity is dependent
upon the NTS connections. It has been demonstrated that the cardiac branch of the vagus nerve
makes up the major contribution for the inhibitory responses on the spinal pain signals and that
left vagal stimulation suppresses approximately 60% of the STT cells. Thus, the predominant
effect of increased vagal afferent activity, which is associated with increased coherence, is the
suppression of somatic and visceral input to STT cells, which provides a mechanism for
decreasing pain (Foreman, 1994, 1997).
It is well known that the respiratory rhythm modulates the pattern of the heart rhythm. This
breath-related modulation of the heart rhythm is called respiratory sinus arrhythmia (RSA)
(Hirsh & Bishop, 1981). RSA reflects the complex interaction of central respiratory drive,
autonomic afferent signals, efferent outflow from the brain stem, and respiratory mechanics
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within the thorax. The phenomenon is dependent on the frequency and amplitude of respiration
as well as on the underlying autonomic state of the organism.11
Since we have conscious control over our breathing, cognitively-directed breathing exercises
can be used to impose a breathing rhythm on the heart rhythms. Thus, when we breathe at a slow,
rhythmic rate (five seconds in and then five seconds out), we can facilitate coherence and
entrainment. However, we do not normally think about our breathing. It is automatic; our
breathing depth and rate varies without our conscious awareness due to changes in the inputs to
the respiratory centers in the brain stem that control respiration.
Among these inputs is the afferent neurological information from the heart and cardiovascular
system. Our breathing rate is affected by and often synchronized to the cardiac cycle, which
means that changes in our heart rate and rhythm can affect our breathing rate and patterns.12
During sleep or rest, coupling between the cardiac cycle and respiration is the strongest, and at
times of stress, coupling between the heart and respiration becomes disrupted (Langhorst,
Schulz, & Lambertz, 1986; Raschke, 1986a, 1986b; Turpin, 1986).
It is well established that changes in emotional states also alter breathing rates. Agitated states
such as anger and frustration increase the breathing rate and reduce tidal volume (the depth of the
breath), while positive emotional states slow the breathing rate and increase tidal volume. These
emotion-related changes in breathing are likely to result, at least in part, from changes in input
from the cardiovascular centers.
Because respiration modulates the heart rhythm, it can be intentionally used as a powerful
intervention that can have quick and profound body-wide effects. As we have conscious control
over our breathing rate and depth, we can consciously modulate the heart rhythm and thus
change the afferent neural patterns sent to the brain centers that regulate autonomic outflow,
emotion, and cognitive processes. Our experience with breathing exercises is that they are
effective primarily due to the fact that they modulate the heart’s rhythmic patterns.
However, it is important to emphasize that coherence is associated with positive emotions
independent of conscious alterations in one’s breathing rhythm. In our earlier studies, which
were focused on the physiological correlates of different emotional states, instructions to subjects
purposely made no mention of altering breathing rates or depths. We found that when sustained
positive emotional states were maintained, increased heart rhythm coherence and entrainment
The effects of lung inflation are mediated by sensory neurons in the lungs that respond to stretch. These
neurons increase their firing rate as the lungs expand upon inspiration. The output from these neurons
travels to the brain stem and inhibits the parasympathetic outflow from the brain to the heart, resulting in
an increase in heart rate. During expiration, the stretch is reduced and the inhibition is removed. The heart
rate is quickly reduced. This interaction between the lungs and brain stem is only one source of RSA;
however, it provides an easy way to conceptualize RSA.
12
The influence of afferent information from the heart on respiration was studied in great detail in the
1940s and 1950s. The cardiovascular afferent systems excite the respiratory centers, and if this input is
inhibited, so is respiration. For a review of this earlier research, see Chernigovskiy (1967).
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between the heart rhythm, blood pressure rhythms, and respiratory rhythms emerged independent
of any conscious alterations in breathing pattern (McCraty et al., 1995; Tiller et al., 1996).
Although breathing techniques may sometimes facilitate a feeling shift, coherence that is
driven through the use of such techniques alone does not necessarily shift one’s emotional state.
For example, it is possible to breathe at a rate of six breaths per minute (a 10-second rhythm) and
still be feeling anxiety or other feelings of unease. In addition, many people find it difficult to
consciously maintain breathing rates at a 10-second rhythm for more than about a minute. On the
other hand, by focusing attention on self-generating a positive emotion while pretending to
“breathe” this feeling through the area of the heart in a relaxed manner, smooth, coherent heart
rhythm patterns occur naturally and are easier to sustain for longer periods of time. This has the
added benefit of not only establishing coherence as the familiar pattern, but also strengthening
the connection between the constituent physiological patterns of coherence—of which heart
rhythm is key—and the positive feeling state.
Afferent input from the heart, and, in particular, the pattern of the heart’s rhythm, also plays a
key role in emotional experience. As described previously, our research suggested a fundamental
link between emotions and changes in the patterns of both efferent and afferent autonomic
activity, as well as changes in ANS activation, which are clearly reflected in changes in the heart
rhythm patterns. The experience of negative emotions is reflected in more erratic or disordered
heart rhythms, indicating less synchronization in both the activity of brain structures that regulate
parasympathetic outflow and in the reciprocal action between the parasympathetic and
sympathetic branches of the ANS. In contrast, sustained positive emotions are associated with a
highly ordered or coherent pattern in the heart rhythms, reflecting greater overall
synchronization in these same systems.
It is important to emphasize, however, that the heart’s rhythmic beating patterns not only
reflect the individual’s emotional state, but they also play a direct role in determining emotional
experience. At the physiological level, as shown in Figure 5, afferent input from the heart is
conveyed to a number of subcortical regions of the brain that are involved in emotional
processing, including the thalamus, hypothalamus, and amygdala. Moreover, cardiac afferent
input has a significant influence on the activity of these brain centers (Adair & Manning, 1975;
Cameron, 2002; Foreman, 1997; Frysinger & Harper, 1990; Oppenheimer & Hopkins, 1994;
Zhang, Harper, & Frysinger, 1986). For example, activity in the amygdala has been found to be
synchronized to the cardiac cycle (Frysinger & Harper, 1990; Zhang et al.). These
understandings support the proposition that afferent information from the heart is directly
involved in emotional processing and emotional experience.
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Afferent Pathways
Cerebral Cortex
• Body perception
• Pain perception
• Arousal (sleep/waking)
• Hunger perception
Hypothalamus
Thalamus
Periaqueductal
Gray
(PAG)
Parabrachial
Complex
Visual and
Auditory Input
• Fear/Anxiety
• Analgesia
• Autonomic modulation
• Fight-or-flight
• Affective defense
Dorsal Vagal Complex
Nucleus of Tractus
Solitarius (NTS)
• Receives afferent input from heart,
lungs, baroreceptor nerves,
chemoreceptors, upper respiratory and
alimentary tracts, and face
Vagus
Nerve
Facial
Input
Taste
Input
Area
Postrema
• Monitors blood
• Food poisoning
• Motion sickness
• Emesis (vomiting)
Figure 5. Diagram of the currently known afferent pathways by which information from
the heart and cardiovascular system modulates brain activity. Note the direct connections
from the NTS to the amygdala, hypothalamus, and thalamus. Although not shown, there is also
evidence emerging of a pathway from the dorsal vagal complex that travels directly to the frontal
cortex.
These findings and those from our own research led us to ponder the fundamental
physiological significance of the covariance between the heart’s rhythms and changes in
emotion. This question was especially intriguing in light of current views in neuroscience that
the contents of feelings are essentially the configurations of body states represented in
somatosensory maps (Cameron, 2002; Damasio, 2003). This was of course the essence of the
theory of emotion first proposed by William James (1884), which has been refined by many
researchers over the years.
A useful way of understanding how the heart is involved in the processing of emotional
experience is to draw on Pribram’s theory of emotion (Pribram & Melges, 1969). In this theory,
the brain is viewed as a complex pattern identification and matching system. Pribram’s basic
concept is that of a “mismatch” between familiar input patterns and current input patterns that
are different or novel. It is this mismatch that provides the mechanism by which feelings and
emotions are generated.
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According to Pribram’s model, past experience builds within us a set of familiar patterns,
which are instantiated in the neural architecture. Inputs to the brain from both the external and
internal environments contribute to the maintenance of these patterns. Within the body, many
processes provide constant rhythmic inputs with which the brain becomes familiar. These
include the heart’s rhythmic activity; digestive, respiratory and hormonal rhythms; and patterns
of muscular tension, particularly facial expressions. These inputs are continuously monitored by
the brain and help organize perception, feelings and behavior.
Familiar input patterns form a stable backdrop, or reference pattern, against which new
information or experiences are compared. When an input pattern is sufficiently different from the
familiar reference pattern, a “mismatch” occurs. This mismatch, or departure from the familiar
pattern, is what underlies the generation of feelings and emotions. In physiological terms,
Pribram suggests that the low-frequency oscillations generated by the heart and bodily systems
are the carriers of emotional information, and that the higher frequency oscillations found in the
EEG reflect the integration, perception, and labeling of these body states along with perception
of sensory input from the external environment. The mismatch between a familiar pattern and a
pattern that is new or novel in either of these informational inputs is what activates emotional
changes (McCraty, 2003; McCraty & Tomasio, 2006).
Although inputs originating from many different bodily organs and systems are involved in
the processes that ultimately determine emotional experience, it is now abundantly clear that the
heart plays a particularly important role. The heart is the primary and most consistent source of
dynamic rhythmic patterns in the body. Furthermore, the afferent networks connecting the heart
and cardiovascular system with the brain are far more extensive than the afferent systems
associated with other major organs (Cameron, 2002). Additionally, the heart is particularly
sensitive and responsive to changes in a number of other psychophysiological systems. For
example, heart rhythm patterns are continually and rapidly modulated by changes in the activity
of either branch of the ANS, and the heart’s extensive intrinsic network of sensory neurons also
enables it to detect and respond to variations in hormonal rhythms and patterns (Armour, 1994).
In addition to functioning as a sophisticated information processing and encoding center,
(Armour & Kember, 2004) the heart is also an endocrine gland that produces and secretes
hormones and neurotransmitters (Cantin & Genest, 1985, 1986; Gutkowska, Jankowski,
Mukaddam-Daher, & McCann, 2000; Huang et al., 1996; Mukoyama et al., 1991). As we will
see later, with each beat, the heart not only pumps blood, but also continually transmits dynamic
patterns of neurological, hormonal, pressure, and electromagnetic information to the brain and
throughout the body. Therefore, the multiple inputs from the heart and cardiovascular system to
the brain are a major contributor in establishing the dynamics of the familiar baseline pattern or
set point against which the current input of “now” is compared.
A striking example illustrates the extensiveness of the influence of cardiac afferent input on
emotional experience as well as the operation of the mismatch mechanism. Research shows that
psychological aspects of panic disorder are actually frequently created by an unrecognized
cardiac arrhythmia. One study found that DSM-IV criteria for panic disorder were fulfilled in
more than two-thirds of patients with sudden-onset arrhythmias. In the majority of cases, once
the arrhythmia was discovered and treated, the symptoms of panic disorder disappeared
(Lessmeier et al., 1997). When the heart rate variability patterns of such an arrhythmia are
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plotted, the erratic, incoherent waveform appears quite similar to the heart rhythm pattern
produced during strong feelings of anxiety in a healthy person. Because the sudden, large change
in the pattern of afferent information is detected by the brain as a mismatch relative to the stable
baseline pattern to which the individual has adapted, it consequently results in feelings of anxiety
and panic.
The above example illustrates the immediate and profound impact that changes in the heart’s
rhythmic activity can have on one’s emotional experience. In this example—as is usually the
case—such changes occur unconsciously. One of the most important findings of our research,
however, is that changes in the heart’s rhythmic patterns can also be intentionally generated.
This shift in the heart’s rhythmic patterns is one of the physiological correlates of using the
HeartMath positive emotion-based coherence-building techniques, which couple an intentional
shift in attention to the physical area of the heart with the self-induction of a positive emotional
state. We have found that this process rapidly initiates a distinct shift to increased coherence in
the heart’s rhythms. This, in turn, results in a change in the pattern of afferent cardiac signals
sent to the brain, which serves to reinforce the self-generated positive emotional shift, making it
easier to sustain. Through the consistent use of the coherence-building techniques, the coupling
between the psychophysiological coherence mode and positive emotion is further reinforced.
This subsequently strengthens the ability of a positive feeling shift to initiate a beneficial
physiological shift towards increased coherence, or a physiological shift to facilitate the
experience of a positive emotion.
While the process of activating the psychophysiological coherence mode clearly leads to
immediate benefits by helping to transform stress in the moment it is experienced, it can also
contribute to long-term improvements in emotion regulation abilities and emotional well-being
that ultimately affect many aspects of one’s life. This is because each time individuals
intentionally self-generate a state of psychophysiological coherence, the “new” coherent
patterns—and “new” repertoires for responding to challenge—are reinforced in the neural
architecture. With consistency of practice, these patterns become increasingly familiar to the
brain. Thus, through a feed-forward process, these new, healthy patterns become established as a
new baseline or reference, which the system then strives to maintain. It is in this way that
HeartMath tools facilitate a repatterning process, whereby the maladaptive patterns that underlie
the experience of stress are progressively replaced by healthier physiological, emotional,
cognitive, and behavioral patterns as the “automatic” or familiar way of being (McCraty &
Tomasio, 2006).
Coherence and Cognitive Performance
It is now generally accepted that the afferent neurological signals the heart sends to the brain
have a regulatory influence on many of the ANS signals that flow from the brain to the heart, to
the blood vessels, and to other glands and organs. However, it is less commonly appreciated that
these same cardiovascular afferent signals involved in physiological regulation also cascade up
into the higher centers of the brain and influence their activity and function. Of particular
significance is the influence of the heart’s input on the activity of the cortex—that part of the
brain that governs thinking and reasoning capacities. As we will see, depending on the nature of
the heart’s input, it can either inhibit or facilitate working memory and attention, cortical
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processes, cognitive functions, and performance (Hansen, Johnsen, & Thayer, 2003; Lacey &
Lacey, 1974; Rau, Pauli, Brody, Elbert, & Birbaumer, 1993; Sandman, Walker, & Berka, 1982;
van der Molen, Somsen, & Orlebeke, 1985).
Our research on psychophysiological coherence has provided new insight into the relationship
between heart activity and cognitive performance. The context for this is described in detail in
Appendix B. It describes how psychophysiologists John and Beatrice Lacey’s baroreceptor
hypothesis identified a relationship between the heart’s activity and cognitive performance. This
work was furthered by Christoph Wölk and Manfred Velden in Germany, who identified the
importance of heart rate’s pattern and stability in influencing neurological functioning. Although
we agree with Wölk and Velden’s conclusions, the primary focus of previous work in this area
has been on micro-scale temporal patterns of cardiac activity, occurring within a single cardiac
cycle, or, at most, across 3–4 heartbeats. However, the interactions between the heart and brain
are much more complex and also occur over longer time periods (sequences of heartbeats
occurring over seconds to minutes). Based on the evidence we report below, we believe that
patterns of the heart’s rhythmic activity over a longer time scale are also involved in influencing
cognitive performance. Moreover, it appears that these macro-scale temporal patterns of
cardiovascular afferent activity can have a much greater effect on performance than micro-scale
patterns. Therefore, a broader hypothesis is called for.
The Heart Rhythm Coherence Hypothesis: A Macro-Scale Perspective
In the course of conducting our studies, we had received numerous reports from individuals
able to maintain the psychophysiological coherence mode that their performance in various
activities had noticeably improved. These involved faculties and abilities requiring the
processing of external sensory information (e.g., speed and accuracy, coordination, and
synchronization, such as in sports and the performing arts) as well as processes requiring
primarily internal focus (e.g., problem solving, decision making, creativity, and intuition, such as
in business and intellectual activities). This led us to postulate that psychophysiological
coherence and the associated macro-scale patterns of the temporal organization of the heart’s
rhythmic activity—heart rhythm patterns occurring over seconds to minutes—also have an
important effect on cognitive processes and intentional behavior. Focusing on the nature of the
organization of the heart’s rhythmic activity, which reflects emotional state, we hypothesize that
emotion-driven changes in global psychophysiological function, and the resulting change in the
pattern of heart rhythm activity, are also directly related to the facilitation or inhibition of the
brain processes involved in cognitive function. In specific terms, sustained positive emotions
induce psychophysiological coherence, which, in turn, is reflected in increased heart rhythm
coherence. Thus, the greater the degree of emotional stability and system-wide coherence, the
greater the facilitation of cognitive and task performance. We call this hypothesis the heart
rhythm coherence hypothesis.
A number of research projects have been carried out to test this hypothesis. Appendix C
describes three studies that show evidence supporting the hypothesis. The first showed that
macro-scale patterns of cardiac activity can produce a larger effect on the inhibition/facilitation
of cognitive performance than the much smaller inhibition/facilitation fluctuations in
performance observed by Wölk and Velden. It found an approximately six times greater
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improvement in performance than previous studies involving similar methods. The second was
an independent study conducted in the UK by Dr. Keith Wesnes, who concluded that learning
and practicing the HeartMath positive emotion-focused coherence-building techniques appears to
enhance an individual’s memory capacity and also improves self-reported calmness. The third
study was funded by the U.S. Department of Education and carried out with the cooperation of
the Claremont Graduate University’s School of Educational Studies involving tenth grade
students in two large California high schools. It found significant reduction in test anxiety as well
as higher test scores for students who learned the positive emotion-focused coherence-building
techniques in the TestEdge program.
Overall, the evidence provided by the three studies described in Appendix C indicates that a
specific macro-scale pattern of cardiac activity—heart rhythm coherence—is associated with
significant improvement in cognitive performance. Not only is this outcome observed in a simple
reaction time experiment, but the data suggest that this facilitative effect also extends across
more complex domains of cognitive function, including memory and even academic test
performance. It also appears that the influence of the coherence mode on cognitive performance
is substantially larger in magnitude than that previously documented for changes in cardiac
activity patterns on a micro scale.
Assuming these results are validated by other researchers, it is worth considering the likely
pathways and mechanisms that could explain these findings. This entails developing an
explanation that complements the micro-pattern hypotheses of the Laceys and Wölk and Velden,
by identifying other physiological mechanisms that may account for these results. The micro-
pattern hypothesis presents a somewhat simplified view of heart–brain interactions, which is not
adequate to describe the full range of information communication that takes place between the
heart and brain: it only addresses the smaller fluctuations in performance that are associated with
physiological changes occurring within a single cardiac cycle or across several heartbeats. As we
have seen, however, there are macro-scale temporal patterns that have a significant carry-over
effect on cognitive performance. To build an adequate understanding of the physiological
mechanisms involved requires developing a deeper understanding of the complexity of heart–
brain interactions. This is reflected in the discussion below in three primary ways: first, that the
influence of cardiovascular afferent input on the brain is more elaborate than that considered in
the micro-pattern hypothesis; second, that afferent input from the heart has effects on brain
centers other than the thalamus; and third, that the alpha rhythm is not the only brain rhythm
synchronized to the heart.
A More Complex Picture
Complexity of Cardiac Afferent Signals
One of the underlying assumptions of the micro-pattern hypothesis is that there is a one-to-
one correspondence between each heartbeat and the burst of neural activity sent to the brain from
the cardiac mechanosensory neurites. However, at the level of the macro-scale heart−brain
interactions investigated here, the dynamics of the generation and transmission of cardiovascular
afferent input involve many types of neurons and a multiplicity of pathways operating over
different time scales.
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There are approximately 40,000 sensory neurites in the human heart involved in relaying
afferent information to the brain. Of these, just 20% are mechanosensory neurons. Of this 20%,
only a small proportion actually fire in unison with each heartbeat. Moreover, there are at least
five different types of mechanosensory neurons. Almost all mechanosensory neurons are
sensitive to rate of change, in that their activity levels increase in a nonlinear manner in response
to change in the system. Some increase their firing rate only when blood pressure decreases,
while others increase only during pressure increases. Still others are only sensitive to large
movements in the rate of change of heart rate or blood pressure (Armour & Kember, 2004).
Thus, there is only a minority of sensory neurites whose output activity exhibits a one-to-one
relationship to the heartbeat and regional changes in ventricular blood pressure.
To add to the complexity, the heart’s intrinsic nervous system has both short-term and long-
term memory that affects cardiac function (and thus afferent signals) over two different time
scales: (1) variations in activity patterns that occur in response to rapidly occurring alterations in
local mechanical status over milliseconds; and (2) variations in activity patterns of a global
nature that operate over time scales of seconds to minutes (Armour, 2003; Armour & Kember,
2004). Thus, in addition to the information related to a single cardiac cycle, there is also
rhythmic information occurring over longer time scales that may modulate brain activity. The
fact that many of the neurons respond primarily to rate of change, and that changes in activity
patterns can last for minutes, are important factors in understanding how heart–brain interactions
are affected during coherence and can have an extended carry-over effect. This is because in the
coherence mode there is an increased rate of change in beat-to-beat variability of both heart rate
and blood pressure, in addition to the increased order in the temporal patterns of activity of the
cardiovascular system. While it is likely, under normal pressure variations and heart rates, that
the overall amount of afferent neural activity reaching the brain is the same or nearly the same
from one heartbeat to the next, it is our contention that the macro-scale patterns of neural
activity can be quite different.
In this regard, Wölk and Velden made an important observation in noting that the frequency
and stability of the afferent input were important factors affecting sensory-motor performance
(Wölk and Velden, 1989). In this context, however, we suggest that the concept of activity
pattern is more appropriate than the concept of frequency. This is because it is in the interspike
interval (the temporal space between consecutive spikes of the neural activity) that information is
encoded. Thus, it is the overall pattern of activity and not merely its frequency that contains the
meaning of the information enfolded in the signals. Furthermore, we consider the stability of the
pattern over longer time scales, those of seconds to minutes. Therefore, to understand the effects
of cardiovascular afferent signals on the brain, the heart’s rhythmic pattern over longer time
scales must also be considered as an important factor in itself, in addition to those of stimulus
intensity, heart rate, and pressure. As we have seen, it is likely that the macro-scale pattern of the
heart’s activity may have a much greater effect on performance than the within-cardiac cycle
effects.
Afferent Input to Brain Centers other than the Thalamus
Another important consideration, in relation to heart–brain interactions, is that while the
micro-pattern model focuses solely on cardiovascular input to the thalamus, there are other
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neural pathways by which the heart’s input can modulate cortical activity and thus performance.
As shown in Figure 5, cardiovascular inputs from the vagal afferent nerves first reach the nucleus
of tractus solitarius (NTS) and from there travel directly to the parabrachial complex,
periacqueductal grey, thalamus, hypothalamus, and amygdala. There are then connections by
which the afferent inputs move from the amygdala, hypothalamus, and thalamus to the cerebral
cortex. There is also evidence to suggest the existence of afferent pathways from the medulla
directly to the prefrontal cortex (McCraty et al., 2004b).
Although this diagram primarily shows the afferent pathways—one-way flow of input to the
brain—in most cases the regions are reciprocally interconnected such that information flows in
both directions. This reciprocally interconnected network allows for continuous positive and
negative feedback interactions and the integration of autonomic responses with the processing of
perceptual and sensory information. In addition, the numerous distributed parallel pathways
permit multiple avenues to process a given response.
Heart–Brain Synchronization
The third way in which the picture is more complicated is that whereas Wölk and Velden’s
hypothesis considers only the alpha rhythm, there are other brain rhythms that are also
synchronized to the heart. These include the beta rhythm as well as lower frequency brain
activity. Thus, it is likely that the effects of macro-scale cardiovascular dynamics on other
aspects of brain activity are also important in contributing to larger fluctuations in performance,
such as those observed in the studies reported here.
Appendix D presents evidence from a number of studies confirming that a significant amount
of alpha rhythm activity is indeed synchronized to the activity of the heart. We have also
presented additional evidence showing that Wölk and Velden’s contention appears to have an
empirical basis, in that we found that the alpha rhythm is synchronized to the cardiac cycle.
Moreover, our evidence suggests that alpha synchronization increases during
psychophysiological coherence and that other brain rhythms—namely, the beta rhythm and
lower frequency brain activity—also appear to be synchronized to the cardiac cycle.
System Dynamics: Centrality of the Heart in the
Psychophysiological Network
To this point our concern has been describing the nature, organization, and measurement of
six different psychophysiological modes. In particular we have focused on the
psychophysiological coherence mode and its impact on various aspects of psychophysiological
function, including pain perception, respiration, emotional processing, and cognitive
performance. Now we turn to the basic question of system dynamics: how the heart, as the most
powerful generator of rhythmic information patterns in the body, acts effectively to bind and
synchronize the entire system. This helps explain the mechanisms that underlie the heart’s role in
the generation of system-wide coherence in the body as a whole. In addition to an overview of
research in these areas, we also present our own findings, which, so far as we know, represent an
original contribution.
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Complex living systems, such as human beings, are composed of numerous interconnected,
dynamic networks of biological structures and processes. The recent application of systems
thinking in the life sciences has given rise to the understanding that the function of the human
organism as an integrated whole is determined by the multi-level interactions of all the elements
of the psychophysiological system. The elements influence one another in a network fashion
rather than through strict hierarchical or cause-effect relationships. Thus, any node within the
psychophysiological network—any organ, system, substance, or process—necessarily exerts an
impact, whether pronounced or subtle, on the functioning of the system as a whole. And while
certain nodes have a greater influence than others in a given network at a particular level of
system organization, those nodes that constitute multi-level linkages across different subsystems
and scales of organization will have a greater influence on the system as a whole. Abundant
evidence indicates that proper coordination and synchronization—i.e., coherent organization—
among the lateral and vertical networks of biological activity generated by these structures and
subsystems is critical for the emergence of higher-order functions.
As we have seen thus far, one of the primary ways that information is encoded and
communicated throughout our psychophysiological systems is in the language of dynamic
patterns. In the nervous system, for example, it is well established that information is encoded in
the time interval between action potentials—and, on a macro-scale, in the intervals between
bursts of neural activity. Likewise, in the endocrine system, patterns of “pulses” of hormone
release are used to convey biologically relevant information. This is an important principle of
operation, as it appears that the body uses this same encoding and transmission strategy—
encoding information in the time intervals between pulses of activity—in many systems and
across very different time scales. This is biologically efficient in that the body is organized to use
a common information communication mechanism across multiple systems.
There is substantial evidence that the heart plays a unique role in synchronizing the activity in
multiple systems of the body and across different levels of organization, and thus in orchestrating
the flow of information throughout the psychophysiological network. As the most powerful and
consistent generator of rhythmic information patterns in the body, and possessing a far more
extensive communication system with the brain than other organs, the heart is in continuous
connection with the brain and other bodily organs and systems through multiple pathways:
neurologically (through the transmission of neural impulses), biochemically (through hormones
and neurotransmitters), biophysically (through pressure and sound waves), and energetically
(through electromagnetic field interactions).
As we discuss each of these main communication pathways in more detail, it will become
clear that the heart is a central node in the psychophysiological network that influences multiple
systems, and is thus uniquely positioned to integrate and communicate information both across
systems and throughout the whole organism. Because of the extensiveness of the heart’s
influence on the physiological, cognitive, and emotional systems, the heart provides a point of
access from which the dynamics of bodily processes can be quickly and profoundly affected.
From this perspective, we will also see how intentional interventions that increase coherence in
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the heart’s rhythms can facilitate a rapid shift to the psychophysiological coherence mode, with
profound system-wide consequences.
In the light of these ideas, we can now postulate that information relative to global-scale
integration (the organization and function of the body as whole) is encoded in the interbeat
intervals of the heartbeat. Thus, the heart effectively acts as the central “conductor” of rhythmic
activity in the body: the neural, hormonal, biophysical, and energetic patterns generated by the
heart’s rhythmic activity provide a global synchronizing signal for the system as a whole.
Neurological Interactions
Of all the organs in the body, the heart has the most extensive neural connection with the
brain. Until relatively recently, much attention in biology has been focused on understanding
how the brain regulates all organs in the body, including the heart. However, as discussed above,
more recent understandings have begun to portray quite a different picture, in which the heart
actually exerts a significant influence on the brain. In this section we describe the various ways
in which the heart affects the brain and body via neurological pathways, and we examine in
particular its influence on the activity and function of higher brain centers and processes. In order
to understand this heart–brain relationship, it is necessary, first, to review some recent findings
of how the brain processes information and how the organization of neurological activity is
critical to brain function. This organization can be described in terms of the three concepts of
coherence introduced at the beginning of this article: coherence as global order, as
autocoherence, and as cross-coherence.
The brain is often analogized to the functions of a computer. But in terms of information
processing and computation the brain is nothing like a digital computer. It does not assemble
thoughts and feelings from digitized bits of serial data. Rather, the brain is more like an analog
processor that relates whole patterns and concepts to one another; it looks for similarities,
differences, or relationships between them. The brain is a highly efficient processor and analyzer
of information that is exquisitely sensitive to novelty—to rate of change and to the difference
between patterns.
At the macro-level of organization, global coherence must be present in order for the brain
and nervous system to function efficiently and effectively. This means that the neural activity,
which encodes information, must be stable and coordinated. It also means that the various
centers within the brain must be able to dynamically synchronize their activity in order for
information to be smoothly processed and perceived.
For example, autocoherence and cross-coherence in the electrical activity of diverse regions
of the brain are necessary for sensory perception to occur. Our “coherent” perception of an object
in the external world actually comes from millions of units of fragmented sensory information
that are made globally coherent by being brought together and organized into a single conscious
experience.
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A depiction of such macro-scale organization of neural activity is offered by studies using the
electroencephalogram (EEG), which measures macro-scale activity occurring in the dendritic
fields of the neurons. These fields reflect excitatory or inhibitory synaptic action over a large
number of neurons. (A single scalp electrode provides estimates of synaptic action averaged over
tissue masses containing between 10 million and 1 billion neurons.) There is a voluminous
literature concerning the relations between the different brain rhythms found in the EEG and the
many different aspects of cognition.13 For example, the alpha rhythm amplitude is lower during
mental calculations while the beta rhythms increase (Nunez, 2000).
Recent research has focused on the global organization of cooperative workings of local and
regional cell groups in order to better understand the brain’s dynamic complexity. At an
operational level, coherence in this context is a specific quantitative measure of functional
relations between paired locations. In general, this research has shown that separate regions in
the brain can exhibit high coherence in specific frequency bands and, at the same time, low
coherence in other bands. The resulting correlated activity between these brain regions is cross-
coherence, which is thought to emerge either from direct neural connections between the regions,
common input from the thalamus and other neocortical regions, or both (Nunez, 2000).
However, cross-coherence also occurs between distant cortical structures that are not necessarily
interconnected anatomically (Bressler, Coppola, & Nakamura, 1993). This raises the question of
what other mechanisms might account for this communication among distant brain regions.
A notable example of such cross-coherence has been described by Rodolfo Llinas, Chief of
Physiology and Neuroscience at the New York University School of Medicine. He observed that
specific areas of the cortex emit a steady oscillation, at a frequency of around 40 cycles per
second (40 Hz). He also found that remote areas of the cortex were phase-locked at this 40-Hz
frequency, meaning that the waves they produced all oscillated in synchrony. This led Llinas and
others to suggest that the neurons perform in synchrony because they follow a kind of conductor
(Ratey, 2001).
The prime candidate for the brain’s internal conductor is the many intralaminar nuclei, located
within the thalamus. These nuclei receive and project long axons to many areas of the brain.
They take in information, reply to it, and monitor the responses to their replies, thus creating
elaborate feedback loops in which resonant activity (~40 Hz) is modified by incoming sensory
input. If the intralaminar nuclei are damaged, the person enters a deep and irreversible coma.
Indeed, it appears that it is only when the “conductor” synchronizes the brain’s activity that we
become conscious. When this happens with a sufficient number of neural networks, the
oscillations become ordered and globally coherent. As they spread their influence, recruiting
more networks to join them, consciousness arises (Ratey, 2001).
The thalamus appears to play an active role in the generation of all the global EEG rhythms,
and it should be emphasized that phase synchrony has been shown to occur in all the frequency
The main rhythms that have been identified are: the delta rhythm (0–4 Hz), the theta rhythm (4-8 Hz),
the alpha rhythm (8-12 Hz), the beta rhythm (12-16 Hz), and most recently the gamma rhythm (~ 40 Hz).
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bands found in the EEG, not just in the 40 Hz band. 14 For example, different types of
synchronization occur in the alpha band during the different phases of memory processes
(encoding and retrieval) (Fingelkurts, Krause, Kaplan, Borisov, & Sams, 2003), and cross-
coherence increases in the theta band during mental calculations (Nunez, 2000). Coherence in
the alpha band is also correlated to perceptual and decision-making processes, and it increases in
the frontal cortex during task processing (Kolev, Yordanova, Schurmann, & Basar, 2001).
The organization of the many interconnected neural networks within the brain allows for
maximal flexibility in adapting to changing demands, such as focus on an external sensory input
or an internal process. However, the degree of coupling, which regulates synchronized activity in
the network, varies depending on the needs of the moment. When the network is either
excessively coupled or is too loosely coupled, the system is less able to dynamically recruit the
appropriate neural support systems it needs to respond to a particular demand. For example, the
alpha rhythm increases in amplitude and distribution when the neural populations in the brain are
more tightly coupled, which occurs when the brain regions involved are not processing
information. Under these circumstances cognitive performance is reduced, especially that
involving the processing of external sensory information. In terms of optimizing performance,
this means in general that one should not be too relaxed (increased coupling) or overly
stimulated (decreased coupling). Thus, in the light of the results of our studies of cognitive
performance and heart-brain synchronization discussed above, the psychophysiological
coherence mode appears to be a condition under which optimal coupling, and thus improved
performance, occurs across diverse systems in the body.
Relevant to this discussion are the findings from a recent study of long-term Buddhist
practitioners. This study found that while the practitioners generated a state of “unconditional
loving-kindness and compassion,” increases in gamma band oscillation and long-distance phase
synchrony were observed (Lutz, Greischar, Rawlings, Ricard, & Davidson, 2004). The study’s
authors suggest that the large increase in gamma band synchrony reflects a change in the quality
of moment-to-moment awareness. Moreover, because the characteristic patterns of baseline
activity in these long-term meditators were found to be different from those of a control group,
the results suggest that an individual’s baseline state can also be altered with long-term practice.
The authors of this study describe the Buddhist meditation as an “objectless meditation” in
which the practitioners do not directly attend to a specific object or the breath, but focus instead
on cultivating a feeling of “unconditional loving-kindness and compassion.” In many ways, the
focus of this practice is comparable to the focus of the Heart Lock-In technique of the HeartMath
system. It would therefore be interesting to investigate whether HeartMath practitioners, when in
a state of psychophysiological coherence, also produce the increases in gamma-band oscillation
The electroencephalogram (EEG) provides a very large-scale measure of the activity occurring in the
dendritic fields of the neurons. These fields reflect the excess of excitatory or inhibitory synaptic action
over a large number of neurons. A single scalp electrode provides estimates of synaptic action averaged
over tissue masses containing between 10 million and 1 billion neurons. Synchronizations of oscillatory
neural discharges are thought to play a crucial role in the constitution of transient networks that integrate
distributed neural processes into highly ordered cognitive and affective functions that can induce synaptic
changes.
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and long-distance phase-synchrony observed in this study. Although this study did not measure
heart rhythm coherence, another study of Buddhist monks using the same meditative focus of
“loving-kindness and compassion” found an increase in heart rhythm coherence during this
practice (Rapgay, n.d.). Because these studies were both conducted with samples of Buddhist
monks who were practicing the same meditative focus, this raises the possibility that heart
rhythm coherence and increased gamma-band phase synchrony are linked in a deeper way. This
is consistent with the hypothesis that heart rhythm coherence reflects a state of increased global
coherence in the body’s function as a whole.
In summary, the mechanisms that underlie the source of oscillatory rhythms in the thalamus
are complex, and there are a number of different hypotheses concerning these. The mechanisms
responsible for the synchronization of remote cells in the brain are even more complex, as there
are both local and global levels of synchronization and also interactions between the local and
global levels. Whatever the mechanisms turn out to be that facilitate synchronous activity in
remote cell assemblies, it is clear that the input from the heart to the brain affects the activity of
the thalamus and its ability to synchronize cortical activity. This is important in understanding
the relationship between global coherence, emotional stability, and optimal performance.
Over the past several decades, several lines of scientific evidence have established that, far
more than a mechanical pump, the heart functions as a sensory organ and as a complex
information encoding and processing center. Groundbreaking research in the relatively new field
of neurocardiology has demonstrated that the heart has an extensive intrinsic nervous system that
is sufficiently sophisticated to qualify as a “little brain” in its own right. Pioneer neurocardiology
researcher Dr. J. Andrew Armour first described the anatomical organization and function of the
heart brain in 1991 (Armour, 1991). Containing over 40,000 neurons, its complex circuitry
enables it to sense, regulate, and remember. Moreover, the heart brain can process information
and make decisions about cardiac control independent of the central nervous system (Armour,
2003; Armour & Kember, 2004).
The heart brain senses hormonal, heart rate, and blood pressure signals, translates them into
neurological impulses, and processes this information internally. It then sends the information to
the central brain via afferent pathways in the vagus nerves and spinal column. When different
hormones or neurotransmitters in the bloodstream are detected by the sensory neurites in the
heart, the pattern in the afferent neural output sent to the brain is modified (Armour, 1994). In
other words, in addition to its better-known functions, the heart is also a sensory center that
detects and transmits information about the biochemical content of the regional blood flow.
Neurological signals originating in the heart have an important and widespread influence in
regulating the function of organs and systems throughout the body. For example, it is now
known that in addition to modulating the activity of the nervous and endocrine systems, input
from the heart influences the activity of the digestive tract, urinary bladder, spleen, respiratory
and lymph systems, and skeletal muscles (Chernigovskiy, 1967). In more specific terms,
cardiovascular afferent signals regulate efferent ANS outflow, (Grossman, Janssen, & Vaitl,
1986) modulate pain perception (Randich & Gebhart, 1992) and hormone production (Drinkhill
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& Mary, 1989), and influence the activity of the locus coeruleus and that of the pyramidal tract
cells in the motor cortex (Coleridge et al., 1976; Svensson & Thoren, 1979). Also, spinal cord
excitability varies directly with the cardiac pulse, as does physiological tremor of normal skeletal
muscles (Forster & Stone, 1976).
Beyond the key role of cardiac afferent signals in physiological regulation, our earlier
discussion also illuminates the heart’s significant influence on perceptual and cognitive function
via its input to higher brain centers. Our discussion has thus far covered behavioral data showing
a relationship between the heart’s input and cognitive performance, as well as
electrophysiological studies demonstrating the synchronization of brain activity to the heart.
Beyond these findings, there is also a considerable body of other electrophysiological evidence
demonstrating the modulation of higher brain activity by cardiovascular afferent input (see Lacey
& Lacey, 1970; McCraty, 2003; and Sandman et al., 1982, for reviews).
Experiments carried out in Germany by psychophysiologist Rainer Schandry have
demonstrated that afferent input from the heart evokes cortical responses analogous to “classical”
sensory event-related potentials. These experiments have shown that afferent input from the
cardiovascular system is accompanied by specific changes in the brain’s electrical activity.
Schandry and colleagues found, as have we, that this activity is most pronounced at the
frontocortical areas, a region particularly involved in the processing of visceral afferent
information. In addition, psychological factors such as attention to cardiac sensations, perceptual
sensitivity, and motivation have been found to modulate cortical heartbeat evoked potentials in a
fashion analogous to the cortical processing of external stimuli (Lader & Mathews, 1970;
Montoya, Schandry, & Muller, 1993; Schandry & Montoya, 1996; Schandry, Sparrer, &
Weitkunat, 1986). In our own study, in which we investigated the electrophysiology of
information processing in relation to intuition, we also found that the heart’s afferent input
significantly modulates frontocortical activity, especially during the psychophysiological
coherence mode (McCraty et al., 2004a, 2004b).
The observation that the heart’s afferent input modulates frontal activity is concordant with
other findings that activity in the prefrontal cortex covaries with changes in the heart rhythm
(Lane et al., 2001). This is consistent with the biological principle of reciprocal connections in
neural systems. Therefore, in addition to the well-established routes (e.g., the thalamic pathway)
by which cardiovascular afferent signals modulate higher cortical function, there may well be
additional routes from the heart to the prefrontal cortex.
Biochemical Interactions
In addition to its extensive neurological interactions with the brain and body, the heart also
communicates with the brain and body biochemically, by way of the hormones it produces.
Although not typically thought of as an endocrine gland, the heart in fact manufactures and
secretes a number of hormones and neurotransmitters that have a wide-ranging impact on body
as a whole.
The heart was reclassified as part of the hormonal system in 1983, when a new hormone
produced and secreted by the atria of the heart was discovered. This hormone has been variously
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termed atrial natriuretic factor (ANF), atrial natriuretic peptide (ANP), or atrial peptide.
Nicknamed the “balance hormone,” and playing an important role in fluid and electrolyte
homeostasis, it exerts its effects on the blood vessels, kidneys, adrenal glands, and many of the
regulatory regions of the brain (Cantin & Genest, 1985, 1986). In addition, studies indicate that
atrial peptide inhibits the release of stress hormones (Strohle, Kellner, Holsboer, & Wiedemann,
1998), reduces sympathetic outflow (Butler, Senn, & Floras, 1994), plays a part in hormonal
pathways that stimulate the function and growth of reproductive organs (Kentsch, Lawrenz, Ball,
Gerzer, & Muller-Esch, 1992), and may even interact with the immune system (Vollmar, Lang,
Hanze, & Schulz, 1990). Even more intriguing, experiments suggest that atrial peptide can
influence motivation and behavior (Telegdy, 1994).
Several years following the discovery of atrial peptide, a related peptide hormone with similar
biological functions was identified. This was called brain natriuretic peptide (BNP) because it
was first identified in porcine brain. It soon became clear, however, that the main source of this
peptide was the cardiac ventricle rather than the brain, and brain natriuretic peptide is now
sometimes called B-type natriuretic peptide (Mukoyama et al., 1991).
Armour and colleagues also found that the heart contains a cell type known as intrinsic
cardiac adrenergic cells. These cells are so classified because they synthesize and release
catecholamines (norepinephrine, epinephrine, and dopamine), neurotransmitters once thought to
be produced only by neurons in the brain and ganglia outside the heart (Huang et al., 1996).
More recently still, it was discovered that the heart also manufactures and secretes oxytocin,
commonly referred to as the “love” or social “bonding hormone.” Beyond its well-known
functions in childbirth and lactation, recent evidence indicates that this hormone is also involved
in cognition, tolerance, trust, complex sexual and maternal behaviors, as well as in the learning
of social cues and the establishment of enduring pair bonds. Remarkably, concentrations of
oxytocin produced in the heart are in the same range as those produced in the brain (Gutkowska
et al., 2000).
In a preliminary study (10 participants), we examined changes in the blood concentrations of
oxytocin and atrial peptide before and after 10 minutes of maintaining the psychophysiological
coherence mode, which was generated by a loving emotional focus. While an increase in
oxytocin was observed for the whole sample, it was not statistically significant, although it likely
would have been with a larger sample. On the other hand, despite the small number of cases, the
decrease in atrial peptide was significant. As atrial peptide release is an index of the stretch and
contractile force of the atrial wall of the heart, these data suggest that cardiovascular efficiency
increases during the psychophysiological coherence mode. The results for the male and female
subgroups in this study are shown in Figure 6.
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Heart Hormones Before and After Coherence
Figure 6. Oxytocin and atrial peptide changes during heart rhythm coherence. Graphs show
changes in blood levels of oxytocin and atrial peptide for male and female subgroups from a
resting baseline mode to after maintaining the coherence mode for 10 minutes.
In addition to changes in the amount of a heart hormone released into the blood affecting
cellular and psychological systems, there is also evidence that the temporal pattern of the
hormonal release has substantial effects independent of the amount of the hormone released. It
has been known for some time that neurotransmitters, hormones, and intracellular “second
messengers” are released in a pulsatile fashion. Pulsatile patterns of secretion are observed for
nearly all of the major hormones, including ACTH, GH, LH, FSH, TSH, prolactin, beta-
endorphin, melatonin, vasopressin, progesterone, testosterone, insulin, glucagon, renin,
aldosterone, and cortisol, among many others.
Recent studies by German endocrinology researchers Georg Brabant, Klaus Prank, and
Christoph Schofl have shown that, in much the same way that the nervous system encodes
information in the time interval between action potentials, biologically relevant information is
also encoded in the temporal pattern of hormonal release, across time scales ranging from
seconds to hours (Schofl, Prank, & Brabant, 1995). As most heart hormones are released in
synchronicity with the contractions of the heart, there is a rhythmic pattern of hormonal release
that tracks the heart rhythm.
This is particularly relevant to our discussion of coherence, as it suggests that changes in heart
rhythm patterns—such as those generated during psychophysiological coherence—impact the
brain and body in yet another way: that is, they change the pattern of hormonal pulses released
by the heart. Although the influence of these changes in hormonal pulse patterns on biological,
emotional, and behavioral processes is still unknown, it is likely that the transmission of such
hormonal information constitutes another pathway by which the effects of psychophysiological
coherence on health, well-being, and performance are mediated.
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With every beat, the heart generates a powerful pressure wave that travels rapidly throughout
the arteries, much faster than the actual flow of blood. These waves of pressure create what we
feel as our pulse. The heart sounds, generated by the closing of the heart valves and cardiac
murmurs, can be heard all over the chest and can extend as far as the groin. Similarly, the
pressure waves traveling through the arteries and tissues can affect every organ in the body,
especially when the mechanisms that control blood pressure are compromised. In fact, the
physical shock wave generated by the heartbeat expands the chest wall to such an extent that the
heartbeat can be detected by measuring the chest expansion (this is called the
ballistocardiogram).
Important rhythms also exist in the oscillations of blood pressure waves. In healthy
individuals, a complex resonance occurs between blood pressure waves, respiration, and rhythms
in the ANS. Because pressure wave patterns vary with the rhythmic activity of the heart, they
represent yet another language through which the heart can communicate with the rest of the
body. In essence, all of our cells sense the pressure waves generated by the heart and are
dependent upon them in more than one way. At the most basic level, pressure waves force the
blood cells through the capillaries to provide oxygen and nutrients to the cells. In addition, these
waves expand the arteries, causing them to generate a relatively large electrical voltage. The
waves also apply pressure to the cells in a rhythmic fashion, causing some of the proteins
contained therein to generate an electrical current in response to the “squeeze.”
Experiments conducted in our laboratory have shown that a change in the brain’s electrical
activity can be seen when the blood pressure wave reaches the brain, around 240 milliseconds
after the contraction of the heart. An example is shown in Figure 7.
Figure 7. Evoked potentials in the EEG due to effects of the blood pressure wave. The top
trace is the EEG recorded at the Cz location, and the middle trace is the blood pressure wave,
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detected at the earlobe. Note that the blood pressure wave arrives at the brain around 240
milliseconds after the heartbeat, and a positive shift in the evoked potential in the EEG can be
clearly seen upon its arrival.
We hypothesize that, in a similar manner to the encoding of information in the space between
nerve impulses and in the intervals between bursts of hormonal activity, information is also
contained in the interbeat intervals of the pressure waves produced by the heart. Given that these
pressure waves can modulate brain activity and affect vital processes even down to the activity
of biomolecules at the cellular level, this represents yet another, potentially important pathway
by which information contained in changing heart rhythm patterns orchestrates system-wide
effects.
Thus far we have discussed the role of the heart in information processing and communication
in terms of neurological, hormonal, and biophysical interactions. In this section we explore how
the heart also communicates information to the brain and throughout the body via
electromagnetic field interactions.
To understand how communication occurs via these biological fields requires an energetic
concept of information—one in which data about patterns of organization are actually enfolded
into the waves of energy generated by the body’s activity and distributed throughout the body’s
electromagnetic field. This concept is quite different from the “lock and key” concept of
biochemical interactions, in which communication occurs through the action of biochemicals,
such as neurotransmitters, fitting into specialized receptor sites, much like keys open certain
locks (McCraty et al., 1998). To explain how energetic communication occurs in biological
systems, we take Pribram’s holographic approach. He believes, as we do, that the
communication of energetic information in biological systems is best understood in the terms of
the information processing principles of holographic theory (McCraty et al., 1998; Pribram,
1991; Pribram & Bradley, 1998).
Of all the organs, the heart generates by far the most powerful and most extensive rhythmic
electromagnetic field produced in the body. When electrodes placed on the surface of the body
are used to measure the ECG, it is the electrical component of the heart’s field that is detected
and measured. This electrical voltage, about 60 times greater in amplitude than the electrical
activity produced by the brain, permeates every cell in the body. Thus, the ECG can be detected
by placing electrodes anywhere on the body, from the little toe to the top of the head. The
magnetic component of the heart’s field, which is approximately 5,000 times stronger than the
magnetic field produced by the brain (Russek & Schwartz, 1996), is not impeded by the body’s
tissues and easily radiates outside of the body. This field can be measured several feet away from
the body with sensitive magnetometers (McCraty et al., 1998). These energetic emanations and
interactions provide a plausible mechanism for how we can “feel” or sense another person’s
presence and even their emotional state, independent of body language and other signals
(McCraty, 2004).
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The heart’s ever-present rhythmic field has a powerful influence on communicative processes
throughout the body. As already noted above, brain rhythms naturally synchronize to the heart’s
rhythmic activity, and the rhythms of diverse physiological oscillatory systems can entrain to the
heart’s rhythm. There is evidence that the heart’s field may even play a regulatory role at the
cellular level, in that we have found that changes in the cardiac field can affect the growth rate of
cells in culture (McCraty et al., 1998).
As can be seen in Figure 20, (Appendix D) the electromagnetic waves generated by the heart
are immediately registered in one’s brain waves and can have quite a large effect on the heartbeat
evoked potential. This same effect has been observed by Gary Schwartz and colleagues at the
University of Arizona, who also suggest that energetic interactions between the heart and brain
play an important role in psychophysiological processes (Russek & Schwartz, 1994, 1996; Song,
Schwartz, & Russek, 1998).
Energetic Signatures of Psychophysiological Modes
Our research has shown that information about a person’s emotional state is also
communicated throughout the body and into the external environment via the heart’s
electromagnetic field (McCraty et al., 1998). As described earlier, the rhythmic beating patterns
of the heart change significantly as we experience different emotions. Thus, negative emotions,
such as anger or frustration, are associated with an erratic, incoherent pattern in the heart’s
rhythms, whereas positive emotions, such as love or appreciation, are associated with a sine-
wave-like pattern, denoting coherence in the heart’s rhythmic activity. In turn, these changes in
the heart’s beating patterns create corresponding changes in the frequency spectra of the
electromagnetic field radiated by the heart.
This is observed when spectral analysis techniques are applied to the energy waveforms
generated by the heart (ECG or MCG) in the same way that is typically done when analyzing
waves generated by electrical activity in the brain. Different spectral patterns are correlated both
with the patterns of beat-to-beat variability and with the current psychophysiological state. These
spectral patterns can be interpreted as “information patterns” containing data about the
psychophysiological state of the individual in that moment in time. Appendix E shows waterfall
plots from the ECG data used to produce the examples of the six different psychophysiological
modes described at the outset of this article. These reveal distinctive spectral patterns associated
with each specific mode.
The spectra of ECG recordings in Appendix E illustrate the enormous richness and
complexity of the heart’s activity and the voluminous density of information encoding and
transmission that occurs, via the movement of energy, in the body’s internal electromagnetic
environment. As already noted, similar patterns of information are encoded in the space (time)
between nerve impulses and in the intervals between bursts of hormonal activity and pressure
waves. We propose, further, that information is encoded and communicated in same manner in
the intervals between heartbeats. Such an information encoding strategy would allow
communication via the neural and hormonal pulses that are produced with each heartbeat and
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also via the electromagnetic waves produced by the heart. As a means by which the heart can
transmit information both throughout the body’s psychophysiological networks and into the
external environment, the validity of this energetic communication mechanism can be
empirically verified. This concept of energetic communication provides the basis for explaining
how information about the organization and state of the system as a whole is distributed
throughout the body in an almost instantaneous way.
The heart’s rhythmic energetic activity lies at the center of our account. The heart generates a
continuous series of electromagnetic pulses in which the time interval between pulses varies in a
dynamic and complex manner. These pulsing waves of electromagnetic energy give rise to fields
within fields, which form interference patterns when they interact with magnetically polarizable
tissues and structures. In more specific terms, we postulate that as pulsing waves of energy
radiate out from the heart, the energy waves interact with organs and other structures to create
interference patterns. At the same time, the endogenous processes in each of the other organs,
structures, and systems, including those at the micro-scale of cells and membranes, also generate
patterns of dynamic activity. These patterns of dynamic activity radiate out into the body’s
internal environment as energy oscillations, and they interact with the energy waves from the
heart and to some degree with the energy waves of other organs and structures. In each of these
interactions the energy waves encode the features of the objects and their dynamic activity as
interference patterns. Because the heart generates by far the strongest energy field, which
interacts with both the macro and micro scales of the body’s organization, the waves it produces
operate effectively as global carrier waves that encode the information contained in the
interference patterns. These global carrier waves thus contain encoded information from all of
the body’s energetic interactions, and they distribute this information throughout all systems in
the body. In this holographic-like process, the encoded information acts to in-form the activity of
all bodily functions (McCraty et al., 1998). This energetic communication system thereby
operates as a global organizing mechanism to coordinate and synchronize psychophysiological
processes in the body as a whole.
This theory—that the heart encodes and distributes energetic information holographically—is
based on the same model that neuropsychologist Karl Pribram has used to describe the neural
processes in the brain that gives rise to perception and memory (Pribram, 1971, 1991). In this
model, as Pribram makes clear, the neural impulses are only relaying information from one part
of the brain to another. However, the actual processing of information occurs in the spectral
domain of energy frequency—a domain outside space and time in which the waves of energy
produced by the operation of the neural microstructure interact. Moreover, he has shown that that
the same mathematics that Gabor (1948) used to describe the quantum-holographic principles
involved in the physics of signal processing can also be used to describe the information
processing that occurs in the electromagnetic interactions between the dendritic and axon fields
of neurons (McCraty et al., 1998). While a discussion of this is beyond the scope of this article,
Pribram and other brain scientists have presented a large body of compelling experimental
evidence that supports the veracity of Pribram’s bioenergetic model of information processing
(King, Xie, Zheng, & Pribram, 1994; McCraty et al., 1998; Pribram, 1971, 1991; Santa Maria et
al., 1995). Thus, in addition to the energetic information processing that occurs in the brain, as
described by Pribram, we propose that there is also a heart-based global energetic system that
encodes and distributes information to coordinate and organize the function of the body as a
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whole.15 Thus, in addition to the energetic information processing that occurs in the brain, as
described by Pribram, we propose that there is also a heart-based global energetic system that
encodes and distributes information to coordinate and organize the function of the body as a
whole.
There is compelling evidence to suggest that the heart’s energy field is coupled to a field of
information that is not bound by the limits of time and space. This evidence comes from a
rigorous experimental study we conducted to investigate the proposition that the body receives
and processes information about a future event before the event actually happens (McCraty et al.,
2004a, 2004b). The study’s results provide surprising, even astounding data showing that both
the heart and brain appear to receive and respond to information about a future event. Even more
tantalizing is the evidence that the heart appears to receive intuitive information before the brain.
This suggests that the heart is directly coupled to a subtle energetic field of ambient information
that surrounds the body, which, in turn, is entangled and interacts with the multiplicity of energy
fields in which the body is embedded—including that of the quantum vacuum.
In short, it would appear that we are only just beginning to understand the fundamental role of
a bioenergetic communication system in processing information from sources both within and
outside the body to in-form physiological function, cognitive processes, emotions, and behavior.
In this system, it thus seems clear that the energy field of the heart plays a crucial role.
The origin of feelings is the body in a certain number of its parts. But now we can go
deeper and discover a finer origin underneath that level of description. . .
(Damasio, 2003, p. 132)
Damasio sums up the current understanding held by many of today’s scientists of the genesis
of feelings and emotions. This is the notion that the origin of the particular emotional feelings we
experience in each moment lies in the substrata of our body’s physiological processes. Positive
feelings emerge from body states in which the physiological regulation of the processes of life is
easy and free-flowing, while negative feelings reflect the strain of life processes that are difficult
for the body to balance and that may even be out of control. This general understanding has roots
in an earlier era in psychology and has recently reemerged in the scientific study of emotion.
However, the geography of this realm is largely uncharted and has only just begun to be mapped.
Needless to say, a more complete understanding awaits development. In this article we have thus
endeavored to “go deeper” by offering an account of the “finer origin” of the
psychophysiological processes involved in emotional experience.
In “going deeper,” we based our approach on the premise that the body’s physiological,
cognitive, and emotional systems are intimately intertwined through ongoing processes involving
reciprocal communication. We hold that an understanding of the workings of these systems must
view their activity as emergent from the dynamic, communicative network of interacting
See also the Appalachian Conferences volumes.
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functions that comprise the human organism. To describe these communicative processes we
adopted an information processing perspective. From this viewpoint, communication within and
among the body’s systems is seen to occur through the generation and transmission of rhythms
and patterns of psychophysiological activity. This focus stands in contrast to the traditional
approach, in which the amount of physiological activity is viewed as the primary basis of
communication. We believe a focus on rhythms and patterns of psychophysiological activity
illuminates a more fundamental order of information communication—one that signifies
different emotional states, operates to integrate and coordinate the body’s functioning as a whole,
and also links the body to the processes of the external world.
In order to understand the functional significance of the morphology of patterns of
physiological activity, we drew on the concept of coherence from the physics of signal
processing. This is the notion that the degree of efficiency and effectiveness of a system’s
functioning is directly related to the degree to which there is a harmonious organization of the
interaction among the elements of the system. Thus, a harmonious order in the rhythm or pattern
of activity signifies a coherent system, whose efficient or optimal function is directly related, in
Damasio’s terms, to the “fluidity” of life processes. By contrast, an erratic, nonharmonious
pattern of activity marks an incoherent system, whose function reflects the “strain” of life
processes.
In operationalizing this approach, we used the pattern of the heart’s rhythmic activity as our
primary physiological marker, as it was the most sensitive measure of changes in emotional
states. In reviewing the results of our empirical research, we identified six psychophysiological
modes distinguished by their physiological, mental, and emotional correlates. These are: Mental
Focus, Psychophysiological Incoherence, Psychophysiological Coherence, Relaxation, Extreme
Negative Emotion, and Emotional Quiescence. We showed that different emotions are associated
with different degrees of coherence in the activity of the body’s systems. While positive
emotions such as appreciation, care, and love drive the system toward increased physiological
coherence, negative emotions drive the system towards incoherence.
In particular, we highlighted the importance of the psychophysiological coherence mode.
Associated with the experience of sustained positive emotions, the coherence mode has
numerous psychological and health-related benefits, which have been demonstrated by a growing
body of research. Of note are the findings showing a direct relationship between this mode and
cognitive performance, as well as data linking this mode to intuition.
Using our empirical findings as a point of departure, we constructed a typology—a conceptual
“map”—of the reality of psychophysiological interaction. We differentiated twelve primary
types of psychophysiological interaction, distinguished by their values on two theoretical
dimensions. Each type describes a distinctive physiological substratum that underlies a different
primary emotion or psychophysiological state. Six of the types signify emotional states typically
experienced in the course of everyday life. Qualitatively distinct from the feelings of everyday
life are six additional types of psychophysiological interaction. Discontinuous from the
psychophysiological states of day-to-day life, these are hyper-states of extreme emotions
reflecting the body’s response to extraordinary circumstances. One interesting implication of the
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typology is the prediction of four additional hyper-states of psychophysiological interaction,
beyond the two hyper-states that we have been able to document empirically.
While our findings on the psychophysiological modes showed that the patterns of the heart’s
rhythmic activity are clearly reflective of different emotional states, in the second part of this
article we also presented an account of the heart’s constructive role in the physiological
processes by which emotional experience is generated. According to a model based on Pribram’s
theory, emotions result from the “mismatch” between familiar input patterns and current input
patterns that are different or novel. The heart is the primary source of dynamic rhythmic patterns
in the body and possesses extensive communication networks with the brain and other systems.
With each beat, it not only pumps blood, but also transmits patterns of neurological, hormonal,
pressure, and electromagnetic information through these networks. These multiple inputs to the
brain from the heart contribute significantly to the familiar reference pattern and also to those
deviations from the familiar that are experienced as changes in emotions.
We also presented evidence showing that the heart has a significant influence on the brain’s
neurological activity and even plays a role in modulating cognitive functions. While extensive
evidence had previously established that sensory-motor integration and cognitive processing is
modified by changes in heart rate (beat-to-beat cardiac accelerations and decelerations), our
research has expanded this understanding. We found that macro-scale patterns of the heart’s
rhythmic activity also significantly affect cognitive performance and intentional behavior well
beyond the micro-scale effects previously reported. We also demonstrated a significant
relationship between heart rhythm patterns and cognitive performance, in that increased heart
rhythm coherence leads to improved cognitive performance.
This along with other findings led us to propose that a global level of organization serves to
bind and synchronize the body as a whole. In this function we believe that the heart is a key
organ in orchestrating activity across multiple systems, encompassing both micro and macro
levels of organization. We proposed that information is encoded in the interbeat intervals of the
waveforms of neurological, hormonal, pressure, and electromagnetic activity generated by the
heart. Because of the heart’s wide-ranging linkage to the body’s major systems, information
encoded in the heart’s rhythmic patterns both reflects and influences the ongoing dynamics of the
body as a whole. Furthermore, when the heart’s rhythmic activity shifts into coherence,
synchronization and harmonious interaction within and among systems is the result. This, in turn,
produces optimal states of health, physical activity, and cognitive performance. Thus, the heart is
a critical nodal point in the psychophysiological network: it acts as the conductor in the human
symphony, setting the beat that binds and synchronizes the entire system.
An important, though little investigated, way in which the heart acts as a global conductor is
through its electromagnetic interactions. We proposed that the electromagnetic fields produced
by the heart form a complex energetic network that connects the electromagnetic fields of the
rest of the body. In doing so, the heart’s energetic field acts as a modulated carrier wave that
encodes and communicates information throughout the entire body, from the systemic to the
cellular levels, and even conveys information outside the body between individuals. In these
ways it provides a global signal that integrates the order of the system as a whole.
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The concept of an energetic information field is not a new one. Indeed, many prominent
scientists have proposed models in which information from all physical, biological and
psychosocial interactions is enfolded as a spectral order outside the space/time world in the
energy waveforms of the quantum vacuum. Holographic principles (Gabor, 1948) form the basis
of most of these theories and have been used to describe how information about the organization
of a whole is nonlocalized—enfolded and distributed to all parts and locations via the energy
waveforms produced by interactions in the brain, (Pribram, 1971, 1991) social structures,
(Bradley, 1987; Bradley & Pribram, 1998) and the universe (Bekenstein, 2003; Nadeau &
Kafatos, 1999). We adopted a holographic perspective to describe how energy waveforms
generated by the heart’s electromagnetic field encode and distribute information about all
structures and processes throughout the body from the cellular level to the body as a whole.
Moreover, the energy fields produced by the heart and other bodily structures are transmitted
externally. And because these energy fields are in continuous interaction with the multiplicity of
energy fields in the environment, it appears that information about nonlocal events and processes
is conveyed back to the body and processed as intuition.
We believe that the concept of energetic information holds promise as a way of understanding
how the body’s bioenergetic communication system operates to process information from
sources both within and outside the body. Based on the evidence we have presented, it seems
clear that the energy field of the heart plays a crucial role in in-forming physiological function,
cognitive processes, emotions, and behavior.
We have endeavored to present a deeper understanding of the central significance of the heart
in virtually all aspects of the body’s function. As a principal and consistent source of rhythmic
information patterns that impact the physiological, cognitive, and emotional systems, the heart
thus provides an access point from which a change in system-wide function can be immediately
effected. When positive emotions are used to shift the heart’s pattern of activity into coherence, a
global transformation in psychophysiological function occurs. As the evidence we have
presented clearly shows, this transformation results in increased physiological efficiency, greater
emotional stability, and enhanced cognitive function and performance. As a simple and direct
means by which one can shift into a state of psychophysiological coherence, the HeartMath tools
are a highly effective method to facilitate this transformation. In the case of Chris, with which we
opened this article, the use of these tools proved to be a life-saving and life-changing
intervention, leading to changes not only in his physical health, but also in his emotional life,
work performance, and relationships. We believe that the growing use of these and similar heart-
based tools around the globe by educators and students, health care workers and patients, and
managers and employees, among others, can play a significant part in improving the “life
processes” of humankind.
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