We are all familiar with saying such as “Slow down or you’ll have a heart attack,” or “He died of a broken heart.” Well, it turns out there is some truth in these metaphors. Scientists are now finding out that chronic stress can literally break your heart, while compassion and mindful breathing may help to heal it. Stephen Porges, a psychophysiologist and Professor at the University of Illonois at Chicago has proposed a Polyvagal Theory that ties our unconscious perceptions of threat and safety to heart rate rhythm and the ability to regulate physiological arousal. This theory proposes that the vagus nerve communicates between the brain and the heart and affects human response to threat as well as social engagement and bonding. This theory can explain why negative emotions such as depression, frustration, or hostility may stress the heart, while positive emotions, slow, deep breathing, exercise and social support may calm it.
According to Porges, our response systems to threat exist in a layered hierarchy that is functional for survival. At the bottom layer is a primitive response system, similar to that found in reptiles, that causes us to freeze and go numb when we sense danger but are immobilized and unable to escape it. Similar to the mouse that plays dead in the cat’s mouth, the numbing response, accompanied by rapid decreases in heart rate and interruptions in breathing may desensitize us to the pain of being eaten by a predator or other inescapable danger.
The middle layer is a more sophisticated vagal system, unique to mammals. If our brains perceive a potentially escapable threat, the vagus nerve will shut down this primitive system and, instead, activate the autonomic nervous system’s “fight or flight” response. The sympathetic nervous system causes our breathing to become shallower, and our heart rates to increase so that more blood can be pumped to the arms and legs to allow us to deal actively with the danger. This is associated with an irregular heart rhythm.
At the highest level of the nervous system, when our brains detect that the environment is safe, the vagus will shut down the fight or flight response and instead, activate a more recently developed system, unique to humans. In this system, the prefrontal cortex can communicate with lower brain centers to send a message that we are safe and no longer have to be vigilant about threat. This, then, triggers the social engagement system that allows us to be physiologically receptive to contact and communication with other human beings. This system involves the muscles of the face and inner ear. It is through the social engagement that infants learn to attend to and be soothed by their mothers’ voices and facial expressions.
This system is functional for human survival in that it conserves energy, allows us to escape predators, and allows for supportive social bonds to develop that can calm us down physiologically. It also operates very quickly and below the level of consciousness. For example, we may experience an increase in heart rate if we hear footsteps behind us, before we even know what is there. If we turn around and see a familiar face, our brains will signal safety and the parasympathetic nervous system will put the brakes on sympathetic arousal so that our heart rates return to normal. We will be more able to listen to the ongoing conversation, rather than listening for footsteps.
Faulty Neuroception & Mental Disorders
This theory can also explain the characteristics of many mental disorders as due to a functional threat perception system acting dysfunctionally in certain situations. For example, a child who has been restrained or held down while sexually abused may respond to threat signals as an adult by temporarily going into a “freeze” response mode. This may include feeling numb and spacing out, while being unable to focus on, listen to, or be comforted by human voices. This can explain the dissociation and emotional numbing that are characteristics of posttraumatic stress disorder.
Many people with depression and anxiety disorders may chronically perceive threat and danger that isn’t really there or may overreact physiologically to minor threats, such as being stuck in slow traffic. These are not chosen or even, necessarily, conscious responses. Chronically engaging the “fight or flight” system may result in the heart being chronically activated and unable to calm down. The physiological system becomes inflexible, responding to everything as if it is dangerous, which produces wear and tear on the heart. Physiologically, this manifests as an invariable pattern in the waves or rhythm of the heart and we say that the person has lower “heart rate variability.” In other words, heart rate in different moments is uniformly high and constant, rather than responding flexibly to the environment. Research has shown that depression is a strong, independent risk factor for dying in the first two years following a heart attack. Depressed people have lower heart rate variability, which could explain this relationship. Interestingly, depressed people also use less variation in their voices and are less facially expressive, which suggests they may have deficits in activating the social engagement system.
How Do We Heal the Heart?
How can we increase heart rate variability so as to protect the heart and lower the risk of cardiac mortality? Research is ongoing, but preliminary findings suggest that the following may work:
Aerobic exercise, such as walking or jogging, increases the amount of oxygen in the blood and improves circulation and cardiac flexibility, leading to decreased risk of heart attack or stroke.
Biofeedback is practiced by health psychologists and other health professionals. Heart rate variability biofeedback involves hooking the individual up to a device that measures three waves or rhythms of the heart that have different frequencies. The individual is able to see heart wave responses whenhe/she thinks about different events and learns to engage deep, smooth, rhythmic breathing to smooth out the heart waves and make them more variable. Yoga and Mindfulness Meditation may also alter breathing patterns and teach calmness in the face of physical or emotional discomfort.
If we can activate the social engagement system, the autonomic nervous system will be turned off and heart rate should become smoother and more variable. Research has shown that providing supportive feedback and encouragement, or having familiar others or even pets present during a stressful laboratory task reduces autonomic arousal.
Some research suggests that negative emotions, such as anger or hostility, are associated with more irregular, less variable heart rates, while positive emotional states create smoother heart waves and more integration or “coherence” between the brain, autonomic nervous system, hormonal and immune systems. A company called HeartMath has conducted research showing that humans can learn to be more compassionate and loving, and that inducing these states through having people fthink about people they love or feelings of empathy actually increases heart rate variability.
It is still early days, but this area of research and intervention has exciting implications. Spiritual and psychological practices that allow us to be more open to our own experiences, less judgmental, and more accepting of others, as well as healthy lifestyles, exercise and loving relationships may literally heal our hearts, allowing us to engage more fully with others and live longer, happier lives.
Melanie Greenberg is a Clinical Psychologist in private practice in Mill Valley, Marin County, CA. She is also a life coach and national speaker with expertise in mind-body health, stress-management, trauma recovery, weight & eating disorders, psychological aspects of physical illness, mood and anxiety disorders.
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