After a bad day at work, do you ever complain to your friends that your high-pressure job or demanding boss is giving you a heart attack? It's just a figure of speech, but you might actually be on to something.
According to a new study of more than 22,000 female doctors and nurses, being in a stressful work situation increases a woman's risk of heart attacks and related problems, possibly because the stress contributes to high blood pressure and other hazards.
Women who reported high levels of job strain were two-thirds more likely to have a heart attack during a 10-year period compared with women in easygoing jobs, the study found. Women in high-strain jobs were also 41% more likely to require a heart procedure such as bypass surgery.
Job strain isn't exactly the same as job stress. When researchers talk about job strain, they're referring to a specific type of psychological stress that's "basically a combination of how demanding one's job is and how much control one has over one's job," says Michelle Albert, M.D., the senior author of the study.
Challenging, fast-paced jobs aren't necessarily straining. High-strain jobs are very demanding, yet they also involve little control or authority (picture working 12-hour days while being micromanaged). Low-strain jobs, on the other hand, feature relatively few demands and high levels of day-to-day control.
Chronic stress can lead to anxiety and depression, both of which have been linked to heart disease. In this study, though, anxiety and depression—along with other risk factors, such as smoking and body mass index—contributed only slightly to the relationship between job strain and heart attacks, suggesting that other factors were at play.
One likely explanation, Albert says, is that job strain leads to over-activation of the body's stress system, including the release of stress hormones. This can lead to higher blood pressure, insulin resistance, and other processes that damage the blood vessels and heart.
"Stress is normal, except when it overpowers our body's ability to adapt to the stressor—and that's what we're talking about here," says Albert, a Harvard Medical School professor and cardiologist at Brigham & Women's Hospital, in Boston.
Albert and her colleagues were somewhat surprised to find that women with high-demand, high-control jobs had elevated heart risk, too. This type of job—managerial positions, for instance—aren't considered high-strain, so it could be that they breed a different kind of stress.
It can be lonely at the top, and women who find themselves with a lot of responsibility and authority may be more isolated, Albert says. Feelings of loneliness and a lack of social support have both been shown in previous studies to contribute to a higher risk of heart disease.
Interestingly, worrying about losing your job—a common source of work-related stress—wasn't linked at all with heart disease in the study. But that could just be a quirk of the study population, and may not be true across all industries.
"The group of women studied here are health care professionals," Albert says. "In the current economic climate, health care jobs tend to be a little bit more stable."
The findings may not apply to everyone, in other words, and they don't necessarily capture the myriad other sources of stress that can affect health, such as owing money or losing a loved one. All that remains to be worked out in future research.
"We live in an environment where you just don't have one type of stressor," Albert says. "You have multiple types of stress, so there's a great need to look at the joint impact of different stressors on cardiovascular disease."