Psychological stress activates the fear center in the brain, setting into motion a cascade of reactions that can lead to heart attacks and strokes.
You’re probably familiar with these major risk factors for heart disease: high blood pressure, high cholesterol, smoking, diabetes, obesity and physical inactivity. And chances are your doctor has checked you more than once for these risks and, I would hope, offered advice or treatment to help ward off a heart attack or stroke.
But has your doctor also asked about the level of stress in your life? Chronic psychological stress, recent studies indicate, may be as important — and possibly more important — to the health of your heart than the traditional cardiac risk factors. In fact, in people with less-than-healthy hearts, mental stress trumps physical stress as a potential precipitant of fatal and nonfatal heart attacks and other cardiovascular events, according to the latest report.
The new study, published in November in JAMA, assessed the fates of 918 patients known to have underlying, but stable, heart disease to see how their bodies reacted to physical and mental stress. The participants underwent standardized physical and mental stress tests to see if their hearts developed myocardial ischemia — a significantly reduced blood flow to the muscles of the heart, which can be a trigger for cardiovascular events — during either or both forms of stress. Then the researchers followed them for four to nine years.
Among the study participants who experienced ischemia during one or both tests, this adverse reaction to mental stress took a significantly greater toll on the hearts and lives of the patients than did physical stress. They were more likely to suffer a nonfatal heart attack or die of cardiovascular disease in the years that followed.
The study, known as Interheart, showed that psychological stress is an independent risk factor for heart attacks, similar in heart-damaging effects to the more commonly measured cardiovascular risks, explained Dr. Michael T. Osborne, a cardiologist at Massachusetts General Hospital.
But what about the effects of stress on people whose hearts are still healthy? Psychological stress comes in many forms. It can occur acutely, caused by incidents like the loss of a job, the death of a loved one, or the destruction of one’s home in a natural disaster. A recent study in Scandinavia found that in the week following a child’s death, the parents’ risk of a heart attack was more than three times the expected rate. Emotional stress can also be chronic, resulting, for example, from ongoing economic insecurity, living in a high-crime area or experiencing unrelenting depression or anxiety. Bereaved parents in the Scandinavian study continued to experience an elevated cardiac risk years later.
How stress damages the heart
Dr. Osborne participated with a team of experts led by Dr. Ahmed Tawakol, also at Massachusetts General, in an analysis of how the body reacts to psychological stress. He said the accumulated evidence of how the brain and body respond to chronic psychological stress strongly suggested that modern medicine has been neglecting a critically important hazard to heart health.
Dr. Tawakol’s team explained that advanced neuroimaging made it possible to directly measure the impact of stress on various body tissues, including the brain. A prior study of 293 people initially free of cardiovascular disease who underwent full-body scans that included brain activity had a telling result. Five years later, individuals found to have high activity in the amygdala were shown to have higher levels of inflammation and atherosclerosis.
Translation: Those with an elevated level of emotional stress developed biological evidence of cardiovascular disease. In contrast, Dr. Osborne said, “people who are not tightly wired” are less likely to experience the ill heart effects of stress.
The researchers are now investigating the impact of a stress-reducing program called SMART-3RP (it stands for Stress Management and Resiliency Training-Relaxation Response Resiliency Program) on the brain as well as biological factors that promote atherosclerosis. The program is designed to help people reduce stress and build resilience through mind-body techniques like mindfulness-based meditation, yoga and tai chi. Such measures activate the parasympathetic nervous system, which calms the brain and body.
Defusing stress and its effects
Even without a formal program, Dr. Osborne said individuals could minimize their body’s heart-damaging reactions to stress. One of the best ways is through habitual physical exercise, which can help to tamp down stress and the body-wide inflammation it can cause.
Given that poor sleep increases stress and promotes arterial inflammation, developing good sleep habits can also reduce the risk of cardiovascular damage. Adopt a consistent pattern of bedtime and awakening, and avoid exposure at bedtime to screens that emit blue light, like smartphones and computers, or use blue-light filters for such devices.
Practice relaxing measures like mindfulness meditation, calming techniques that slow breathing, yoga and tai chi.
By Jane Brody a Personal Health columnist, a position she has held since 1976. She has written more than a dozen books including the best sellers “Jane Brody’s Nutrition Book” and “Jane Brody’s Good Food Book.”