The Heart-Brain Connection
Two Way Communication
Most of us have been taught in school that the heart is constantly responding to “orders” sent by the brain in the form of neural signals. However, it is not as commonly known that the heart actually sends more signals to the brain than the brain sends to the heart! Moreover, these heart signals have a significant effect on brain function—influencing emotional processing as well as higher cognitive faculties such as attention, perception, memory, and problem-solving. In other words, not only does the heart respond to the brain, but the brain continuously responds to the heart.
Different patterns of heart activity (which accompany different emotional states) have distinct effects on cognitive and emotional function. During stress and negative emotions, when the heart rhythm pattern is erratic and disordered, the corresponding pattern of neural signals traveling from the heart to the brain inhibits higher cognitive functions. This limits our ability to think clearly, remember, learn, reason, and make effective decisions. (This helps explain why we may often act impulsively and unwisely when we’re under stress.) The heart’s input to the brain during stressful or negative emotions also has a profound effect on the brain’s emotional processes—actually serving to reinforce the emotional experience of stress.
In contrast, the more ordered and stable pattern of the heart’s input to the brain during positive emotional states has the opposite effect—it facilitates cognitive function and reinforces positive feelings and emotional stability. This means that learning to generate increased heart rhythm coherence, by sustaining positive emotions, not only benefits the entire body, but also profoundly affects how we perceive, think, feel, and perform.
Your Heart’s Changing Rhythm
The heart at rest was once thought to operate much like a metronome, faithfully beating out a regular, steady rhythm. Scientists and physicians now know, however, that this is far from the case. Rather than being monotonously regular, the rhythm of a healthy heart—even under resting conditions—is actually surprisingly irregular, with the time interval between consecutive heartbeats constantly changing. This naturally occurring beat-to-beat variation in heart rate is called heart rate variability (HRV).
Heart Rhythm Patterns and Emotions
Many factors affect the activity of the ANS, and therefore influence HRV. These include our breathing patterns, physical exercise, and even our thoughts. Affect our heart’s changing rhythm is our feelings and emotions. When our varying heart rate is plotted over time, the overall shape of the waveform produced is called the heart rhythm pattern. The emotions we experience directly affect our heart rhythm pattern—and this, in turn, tells us much about how our body is functioning.
In general, emotional stress—including emotions such as anger, frustration, and anxiety—gives rise to heart rhythm patterns that appear irregular and erratic: the HRV waveform looks like a series of uneven, jagged peaks. Scientists call this an incoherent heart rhythm pattern. Physiologically, this pattern indicates that the signals produced by the two branches of the ANS are out of sync with each other. This can be likened to driving a car with one foot on the gas pedal (the sympathetic nervous system) and the other on the brake (the parasympathetic nervous system) at the same time—this creates a jerky ride, burns more gas, and isn’t great for your car, either! Likewise, the incoherent patterns of physiological activity associated with stressful emotions can cause our body to operate inefficiently, deplete our energy, and produce extra wear and tear on our whole system. This is especially true if stress and negative emotions are prolonged or experienced often.
In contrast, positive emotions send a very different signal throughout our body. When we experience uplifting emotions such as appreciation, joy, care, and love; our heart rhythm pattern becomes highly ordered, looking like a smooth, harmonious wave (an example is shown in the figure below). This is called a coherent heart rhythm pattern. When we are generating a coherent heart rhythm, the activity in the two branches of the ANS is synchronized and the body’s systems operate with increased efficiency and harmony. It’s no wonder that positive emotions feel so good—they actually help our body’s systems synchronize and work better.
The Intelligent Heart
Many of the changes in bodily function that occur during the coherence state revolve around changes in the heart’s pattern of activity. While the heart is certainly a remarkable pump, interestingly, it is only relatively recently in the course of human history—around the past three centuries or so—that the heart’s function has been defined (by Western scientific thought) as only that of pumping blood. Historically, in almost every culture of the world, the heart was ascribed a far more multifaceted role in the human system, being regarded as a source of wisdom, spiritual insight, thought, and emotion. Intriguingly, scientific research over the past several decades has begun to provide evidence that many of these long-surviving associations may well be more than simply metaphorical. These developments have led science to once again to revise and expand its understanding of the heart and the role of this amazing organ.
In the new field of neurocardiology, for example, scientists have discovered that the heart possesses its own intrinsic nervous system—a network of nerves so functionally sophisticated as to earn the description of a “heart brain.” Containing over 40,000 neurons, this “little brain” gives the heart the ability to independently sense, process information, make decisions, and even to demonstrate a type of learning and memory. In essence, it appears that the heart is truly an intelligent system. Research has also revealed that the heart is a hormonal gland, manufacturing and secreting numerous hormones and neurotransmitters that profoundly affect brain and body function. Among the hormones the heart produces is oxytocin—well known as the “love” or “bonding hormone.” Science has only begun to understand the effects of the electromagnetic fields produced by the heart, but there is evidence that the information contained in the heart’s powerful field may play a vital synchronizing role in the human body—and that it may affect others around us as well.
Research has also shown that the heart is a key component of the emotional system. Scientists now understand that the heart not only responds to emotion, but that the signals generated by its rhythmic activity actually play a major part in determining the quality of our emotional experience from moment to moment. As described next, these heart signals also profoundly impact perception and cognitive function by virtue of the heart’s extensive communication network with the brain. The heart appears to play a key role in intuition. Although there is much yet to be understood, it appears that the age-old associations of the heart with thought, feeling, and insight may indeed have a basis in science.
Оn materials HeartMath Institute