Emotional Rescue - The Heart-Brain Connection
Emotional Rescue - The Heart-Brain Connection
Emotional Rescue - The Heart-Brain Connection
Editor’s Note: The silent, often subconscious conversation that is taking place inside us is
one of the most vital communications we will ever find ourselves engaged in. It’s the dialogue
of emotion-based signals between our hearts and our brains, also known as the heart-brain
connection. Our author tells us what research has uncovered and some of the keys to a
longer, healthier life.
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We’ve known for decades that smoking, hypertension, high cholesterol, and diabetes
account for most cardiovascular problems. But it wasn’t until publication of the Interheart
study (25,000 volunteers spanning 52 countries) that emotional stress was identified as
another key risk factor, accounting for about one-third of heart attacks and strokes.
Previously, in the 1970s, when volunteers were asked to begin to count to 100 and then to
serially subtract seven’s in quick succession (in a test of “mental stress”), blood vessels
constricted as if they had taken and failed a cardiac stress test. Except in these cases, testing
occurred at rest.
In other words, external stressors that are not effectively managed have direct internal
implications by placing undue stress on the heart. Fast forward from the 1970s to the
present era, and a recent study of more than 135,000 men and women in Sweden that
found a history of stress-related disorders, such as post-traumatic stress syndrome,
increased the risk of cardiovascular disease by more than 60 percent within just the first
year of diagnosis.
Another cardiac condition that can result from acute emotional stress is Takotsubo
cardiomyopathy, named for the Japanese octopus-trapping pot that the heart comes to
resemble. Most commonly occurring after a sudden catastrophic event such as losing a
spouse, an outpouring of adrenaline creates a transiently “shocked” state characterized by
markedly abnormal contractions in a section of left ventricle and by heart failure. Resolution
of the emotional crisis coupled with supportive care generally, but not always, leads to
recovery of heart function.
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Beyond single, severely stressful events, living day-to-day with stress is clearly associated
with increased risk of heart attack and stroke. We have only recently begun to understand
the neurochemical pathways that generate atherosclerosis and cardiovascular disease. They
include close communication between the central nervous system, heart, adrenal gland, and
kidneys involved in the activation and release of stress hormones such as cortisol and heart
damaging neuropeptides.
On another level, we have come to appreciate that chronic psychosocial or mental stress
accelerates cardiovascular disease by promoting inflammation, oxidative stress, and
abnormal function of the endothelium, the protective inner lining of our blood vessels.
The association between high levels of social connectivity and favorable cardiovascular
effects, including better outcomes after stroke, raises the possibility that a larger amygdala
may afford cardioprotection. The Leiden Longevity Study supports this concept: large left
amygdala volumes were not only associated with a high level of emotional health, but also
correlated with familial longevity. By contrast, reduced social interactions caused by panic
disorders have been associated with reduced amygdala volumes in the lateral and basal
regions believed to process fear and anxiety. These disorders correlate with reduced
parasympathetic tone, a known contributor to cardiovascular disease risk.
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Amygdala activity has also been suggested to play a role in cardiovascular disease risk
prediction. For example, residing in high-paced, crowded, noisy, and polluted cities leads to
activation of the perigenual anterior cingulate cortex, a brain region that regulates
amygdala activity and response to psychosocial stress. Chronic exposure to stress results in
allostatic load that adversely impacts brain plasticity and cardiovascular risk factors,
including an exaggerated blood pressure response owing to activation of the perigenual
cingulate cortex.
Does counteracting negative stressors reduce cardiovascular risk? While no clinical outcome
trials have been conducted to date, adoption of lifestyle strategies aimed at improving
positive emotions seems to improve biomarkers of cardiovascular health, such as
inflammation, arterial stiffness, and endothelial function. In my cardiology practice and as
elaborated upon below, I recommend that my patients employ these five strategies to
reduce day-to-day stressors:
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Relaxation Practices
There are several mechanisms by which relaxation strategies such as these improve
biomarkers of cardiovascular risk. The first is improvement in parasympathetic tone, the
heart’s ability to maintain blood pressure and/or heart rate in the face of daily stressors.
(This contrasts with the “fight-or-flight” response described earlier, an adaptive
physiological mechanism characterized by increased sympathetic tone with associated rise
in blood pressure and heart rate). Examples include the inordinate or “hysterical” strength
that arose in a daughter attempting to save her father who was pinned under a car and a
mother fighting off a lion that attacked her son.
Such isolated “spring into action” situations have no lasting cardiovascular consequences in
otherwise healthy individuals. But regularly occurring stressful situations can result in
persistently heightened sympathetic tone. Under these conditions, the heart is chronically
stressed by exaggerated blood pressure and heart rate responses that endure after the
stressful situation is resolved. A persistent increase in sympathetic tone, moreover, raises
the likelihood of inflammation, abnormal heart rhythms, and increased risk of sudden
cardiac death.
One recent study, for example, found that in a group that had practiced meditation on a
regular basis, the expression of pro-inflammatory genes was reduced compared to those
who had never mediated. In the second stage of the study, one half of the non-meditating
group was randomly assigned to relaxation training sessions incorporating meditation,
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prayer, and yoga. After two months, genetic expression of pro-inflammatory genes
resembled that of long-time meditators. Practicing relaxation also reduced the expression of
genes promoting insulin resistance, the forerunner of Type 2 diabetes. The results of this
study not only affirmed the importance of brain-heart connections on a molecular level but
found that relaxation can have a robust effect in a very short time, supporting the adage
“never too late to start.”
Mindfulness meditation, which has become one of the most popular relaxation practices
over the past decade, combines heightened, non-judgmental awareness of one’s
surroundings and feelings with slow deep breathing exercises. A stress-reduction program
based on mindfulness has been associated with improvement in hypertension and
depression, while strengthening the immune system and raising activity of telomerase, an
enzyme that slows biological aging.
Researchers have also studied the cardiovascular impact of practices that incorporate
relaxation and movement. Yoga and Tai Chi, for example, improve balance and coordination
to help the elderly prevent falls and fractures, and bolster strength and stabilization. In
cardiovascular terms, yoga is associated with reduced systolic blood pressure and
cholesterol: a recent meta-analysis of 49 trials found that three sessions of yoga weekly
reduced systolic blood pressure as much as low-dose antihypertensive medication. Tai Chi
has been shown to help suppress inflammation and depression, both cardiovascular disease
risk factors. Finally, yoga may also raise brain levels of γ-aminobutyric acid (GABA), a
neurotransmitter involved in mood stabilization and stress reduction and both yoga and
meditation practices lead to the release of serotonin, another important neurotransmitter
involved in mood regulation.
Comic Relief
While it has long been thought that laughter can induce a sense of well-being through the
release of endorphins, its connection to cardiovascular health has only become apparent in
recent years. Specifically, the β-endorphins released by a hearty belly laugh bind to
receptors on the surface of the vascular endothelium to release nitric oxide, a molecule with
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multiple cardioprotective properties. Recent studies have, in fact, found the risk of heart
attack and stroke is reduced in individuals who laugh on a regular basis, compared to those
who never or rarely laugh. Laughter also reduces stiffness and aging of blood vessels,
including those in the brain.
A popular way to combine laughter with deep breathing techniques is through laughter
yoga. The origins of this practice date back to 1995 when Dr. Madan Kataria, a family
physician, assembled a small group in a public park in Mumbai, who met each morning to
laugh together through a series of funny expressions and movements that Dr. Kataria
devised. Nearly 25 years later, more than 15,000 laughter yoga clubs exist in more than 70
countries worldwide.
A typical session lasts from 30 to 60 minutes, during which a leader engages participants in
exercises designed to elicit forced laughter that converts to emotional laughter as the
session wears on. One popular exercise is “milkshake or cocktail laughter,” where
participants pretend to pour a glass of milk (or cocktail) into one hand saying “here” then
into the other hand repeating “here” and then pretending to drink it or discard it behind
their shoulder with repeated laughter.
The benefits of laughter yoga include decreased cortisol levels and systolic blood pressure,
as well as improvement in indices of depression and overall life satisfaction. While research
in this field remains sparse, the encouraging results from these small-scaled studies support
the development of a clinical trial in which laughter therapy is one component of an
integrated therapeutic lifestyle designed to reduce cardiovascular events.
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pleasurable music. A pilot study suggested that focusing on this sensation (i.e., mindful
music) may be a useful intervention to speed recovery following stroke.
More work needs to be done to pinpoint the impact of many of the practices mentioned
above. But there is already enough research to conclude that effective management of day-
to-day psychosocial stressors is vital to good overall heart and brain health. Beyond good
nutrition and regular physical activity, then, consider practicing meditation or yoga on a
routine basis. Laugh, listen to music, and hug your favorite people and pets. Such are the
keys to a longer, happier life.
Bio
Michael Miller, M.D., is Professor of Cardiovascular Medicine at the University of Maryland
School of Medicine and serves on the American Heart Association Leadership Council for
Lifestyle and Cardiometabolic Health. He is past president of the American Society of
Preventive Cardiology, serves as consultant for the National Library of Medicine and assisted
the US Postal Service in developing the “Heart Health Stamp.” Miller earned his medical
degree at Rutgers Medical School and completed residency at the University of Cincinnati
Hospital and fellowships in metabolism and cardiovascular diseases at the Johns Hopkins
Hospital. He has published more than 250 original scientific publications, book chapters and
three books. His most recent book is Heal Your Heart, The Positive Emotions Prescription to
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Prevent and Reverse Heart Disease (Random House, 2014). Miller’s twitter feed is
@mmillermd1