What stress can do to your heart

Divorce, work and money worries take a bigger toll than we might imagine.

When someone is exposed to repeated levels of stress there are changes in regions of the brain that affect the way we perceive stress. Picture: Istock

Saturated fat, salt, inactivity and, of course, smoking are all things we are well aware we need to reduce or stop to cut our risk of heart disease and ward off a heart attack or stroke. But there is an overlooked risk factor that scientists are beginning to take more seriously when it comes to preserving cardiovascular health. Emotional stress might be more damaging to the health of your heart, particularly when the psychological burden of it is chronic.

According to a growing body of research, divorce and relationship difficulties, work stress, money worries and loneliness are taking their toll on our hearts to a far greater degree than we might imagine. In the latest study to examine the effects of chronic psychological stress, researchers from Emory University in Atlanta and other institutions showed that, in patients with underlying but stable heart disease, meaning it was not an immediate threat, mental stress was more of a risk to their hearts and lives than physical stress. Reporting in the Journal of the American Medical Association, the team came to this conclusion after assessing the responses of 918 people to varying loads of physical and emotional stress.

Viola Vaccarino, a professor of cardiovascular research at Emory University and the lead author on the paper, says standardised stress tests were used to assess whether a participant’s heart responded by developing myocardial ischemia - reduced blood flow to the heart muscles that can trigger events such as heart attacks and strokes - when they were emotionally or physically stressed. After tracking them for four to nine years, Vaccarino and her team discovered that it was the participants who experienced myocardial ischemia after being mentally stressed who were more likely to suffer a heart attack or to die of cardiovascular disease in the years that followed. “Our findings are significant because they highlight the importance of emotional factors on the clinical course of patients with heart disease, providing compelling evidence to include stress and mental health indicators in the risk assessment of these patients,” Vaccarino says.

In patients with underlying but stable heart disease, meaning it was not an immediate threat, mental stress was more of a risk to their hearts and lives than physical stress. Picture:istock image

Not everybody who experiences emotional stress has the same cardiovascular response. “There is a gradient of susceptibility to the effects of stress on your heart and some people are more resilient than others,” says Michael Osborne, a cardiologist at Massachusetts General Hospital and an instructor in medicine at Harvard Medical School. “The impact depends on the type and level of stress as well as the individual who is being stressed.”

If you have personality traits such as impatience, a competitive nature, getting upset easily and associating self-worth with achievement, or you get easily anxious and frazzled, the chances are you are more likely to experience a rise in risk factors such as high blood pressure. “We still need more work to understand the exact mechanisms of why some are more vulnerable to emotional stress than others,” Vaccarino says.

Emotional stress causes acute and chronic inflammation, increases in blood pressure and heart rate, constriction of blood vessels and long-term metabolic effects such as insulin resistance, obesity and diabetes, all of which are bad for the heart. “Another way that stress can be harmful is through causing mental disturbances like depression and post-traumatic stress disorder that have also been related to cardiovascular disease risk,” Vaccarino says.

Hormones released when we are stressed undoubtedly play a role. Acute stress that occurs when witnessing an accident, for example, activates the body’s “fight or flight” response. “This prompts the release of hormones such as adrenaline that increase the physical activity of the heart and other organs,” says Rahul Potluri, a consultant cardiologist at the Royal Devon and Exeter Hospital. “It’s when this surge of hormones occurs that blood pressure and heart rate rise, leading to increased demands being placed on the heart that are similar to physical stresses such as very intense exercise.” Osborne says these stress hormones have other effects. “Their release increases inflammation and oxidative stress in the body, both of which can culminate in cardiovascular disease.”

For a study published in the European Heart Journal, Osborne looked at how the body responded to chronic psychological stress in 498 healthy people. He found that repeated stressful events - in this case exposure to traffic noise - led to the prolonged activation of stress responses, such as raised hormones and blood pressure, and also to changes in the brain. “When someone is exposed to repeated levels of stress there are changes in regions of the brain that affect the way we perceive stress,” Osborne says. “As a result stress response pathways become chronically activated, which contributes to a higher risk of cardiovascular and metabolic disease.”

Although her study focused on people already at risk of a heart attack, Vaccarino says anyone can be affected by the adverse effects of stress, even those of us who assume our hearts are healthy. “People with underlying heart disease tend to show larger harmful effects of stress than those without heart disease,” Vaccarino says. “But people without cardiovascular disease can also be affected. Research has shown that even perceived stress - believing we are stressed - is associated with an increased incidence of cardiovascular events.”

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HOW TO REDUCE STRESS - FIVE EASY THINGS TO TRY

1. Get at least seven hours of sleep a night

“Levels of stress hormones such as cortisol fall when we are asleep,” Rahul Potluri, a consultant cardiologist says. “And recent studies have shown that erratic sleeping, as with shift workers, holds increased cardiovascular risk and in some people can cause irregular heart rhythm [atrial fibrillation].” Getting at least seven hours of sleep a night is key.

2. Exercise for 150 minutes a week to reduce stress

According to the European Society of Cardiology, we should aim for 150-300 minutes of moderate-intensity activity - fast walking, jogging, moderate cycling - or 75-150 minutes of vigorous aerobic exercise such as hard running or swimming each week.

3. Try t’ai chi, yoga and meditation

Mind-body relaxation techniques are hugely effective at reducing damaging stress levels. “They can help clear the mind and, in turn, reduce levels of catechomalines, hormones in the body such as adrenaline that are released when we are stressed,” Potluri says.

4. Have a laugh every day

According to a study of 20,934 people published in the Journal of Epidemiology, laughter can improve vascular health in the short term by immediately improving arterial stiffness and blood vessel function, but also in the long term. Researchers found that the prevalence of heart disease among people who laughed most days was lower than among those who said they rarely laughed.

5. Drink a mug of cocoa

Researchers at the University of Birmingham, reporting in the journal Nutrients, found that blood vessels functioned better during periods of emotional stress when people were given a drink of cocoa. The drink contains flavanols, chemicals with proven cardiovascular benefits. The study found that drinking cocoa reduced temporary impairments in blood vessel function and improved blood flow during mentally stressful episodes.

The Times