How Does Stress Affect the Heart?
When you think about the best ways to keep your heart healthy, what comes to mind? You probably think about exercising, eating healthy foods, not smoking, and controlling your blood pressure and cholesterol.
All of those things are important for good health. But experts have discovered that stress is a leading risk factor for heart disease and stroke.
“Chronic stress, depression, and other affective disorders have a very potent impact on cardiovascular disease. It’s not simply because of differences in lifestyle. Rather, there’s an impressively strong biological link between chronic stress and heart disease itself,” says Ahmed Tawakol, MD, a Mass General Brigham cardiologist. “It’s only recently that we’ve started to really appreciate the magnitude of this link and the mechanisms underlying it.”
Chronic stress is a strong risk factor for heart disease all on its own. It becomes surprisingly potent when combined with other risk factors. Understanding how stress affects the cardiovascular system and how to combat these effects can help protect your heart.
The body’s response to chronic stress
Stress is everywhere and affects everyone. Long-term, chronic stress can have long-term consequences. Common causes of chronic stress include work, socioeconomic pressures, family problems, mental health disorders, and even chronic noise exposure.
Stress activates a part of the brain called the amygdala, which helps process emotions. The amygdala sends stress signals to the hypothalamus, which is like the brain’s command center.
The hypothalamus communicates with other areas of the body to produce responses to stress. The responses include the release of chemicals such as cortisol (often called the stress hormone) and adrenaline. Your heart rate may go up, and your blood pressure may increase. Along with these changes, stress triggers chronic inflammation.
Inflammation’s role in stress and cardiovascular disease
Scientists are starting to understand another response that’s key to the link between stress and heart disease. When the brain senses stress, it communicates with the bone marrow, a sponge-like tissue in the center of most bones. The bone marrow releases immune cells that cause inflammation, in an effort to destroy foreign substances such as infections.
“These inflammatory cells are ready to destroy whatever they can find that they think is a threat. They’re not patrol officers — they’re more SWAT team,” Dr. Tawakol explains.
During times of stress, the bone marrow increases the production of pro-inflammatory immune cells. At the same time, the immune system reduces the effort given to patrolling for new diseases such as viral infections or cancer.
“These cells cause chronic inflammation, including inflammation of the blood vessels. That can lead to lumps and bumps in the blood vessel walls, which promote all kinds of problems that lead to heart attack and stroke, such as plaque buildup and clots,” Dr. Tawakol continues. “That long-term inflammation of the blood vessels leads to atherosclerotic disease and puts you at risk for heart attacks and strokes.” Atherosclerosis is the buildup of cholesterol and other substances in the arteries, like in coronary artery disease.
Lifestyle choices effect on heart disease
People who are stressed out also may participate in unhealthy behaviors in an attempt to cope, Dr. Tawakol says. They may:
“When you add the effects of stress on the cardiovascular system together with these lifestyle choices, it’s a two-fold blow,” he says.
Exercise for stress reduction and heart health
Dr. Tawakol encourages exercise to combat the effects of stress and boost heart health. He and colleagues recently published a study that found that exercise calms the stress signals in the brain.
“Exercise has long been known to improve the sensation of stress and reduce depression. And at the same time, is famously known for its beneficial impact on heart health,” Dr. Tawakol says. “One of the questions we had was: Could exercise also impact these stress-related brain pathways that lead to cardiovascular disease?”
The researchers evaluated data on patients in the Mass General Brigham Biobank. The large database houses genetic, lifestyle, and environmental information about individuals who agree to participate. Researchers can use the data to better understand how these factors interact and affect health.
“The first thing we saw is that exercise has a very nice impact on heart health — no surprise there. That impact was strong even after we adjusted for other cardiovascular disease risk factors, other lifestyle factors, and other medical conditions,” he says. “The interesting part, though, is when we looked at brain imaging in roughly 700 patients, exercise decreased stress signaling in the brain. And the more exercise people did, the less stress signaling they had.”
Dr. Tawakol and his colleagues found that exercise increased brain activity in the pre-frontal cortex, which controls mental processes like memory, planning, and the ability to focus. “It is also well-known for its role in quieting down the stress centers of the brain. In other words, exercise appears to reduce stress by strengthening the cortex,” he says.
The researchers also examined whether people with more stress would benefit even more from exercise for heart disease risk reduction. They found that people with depression had more than double the benefit of exercise in terms of heart attack reduction compared to people without depression.
Ways to combat stress and heart disease
“Think of chronic stress as something that’s not only going to increase your heart disease risk, but it’s going to increase the rate of your aging,” Dr. Tawakol says. “The earlier you act on it, the better off you'll be.”
In addition to exercise, he suggests these key strategies:
Get enough sleep.
Practice stress-reduction techniques, such as yoga, mindfulness, and meditation.
Talk to your physician about other ways to reduce stress and anxiety, particularly if you have concerns about your mental health.
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