Fuse

There’s no denying that regular physical activity and a healthy sex life are good for your heart. But if you’ve ever huffed and puffed your way through a jog or a particularly strenuous bout of lovemaking, you might have wondered whether the exertion was actually stressing, rather than strengthening, your heart.

The question is a valid one. Doctors have long known that extreme strain in the form of physical (or psychological) stress can trigger heart attacks. Now, the latest study on the matter — a review paper analyzing 14 previous studies — confirms that the risk of heart attack does indeed spike in the hour or so after an episode of physical or sexual activity.

In the new meta-analysis, which included data on heart attack rates and occasional physical activity — everything from having sex to running to climbing stairs — researchers found that during exercise, heart attack risk can rise 3.5 times higher than during periods of non-activity. During sex, the risk is 2.7 times higher than at other times. And the risk of dying from a heart-related event during or immediately after bouts of physical activity is five times that when you’re not active.

But before you hang up your running shoes or take a vow of celibacy, the authors of the study, published in the Journal of the American Medical Association, point out that the absolute heart-attack risk posed by physical activity is very low. “We don’t want anyone to misinterpret our findings to mean there is an overall harm from exercise,” says the study’s co-author Dr. Issa Dahabreh of the Institute for Clinical Research and Health Policy Studies at Tufts Medical Center.

He says it’s important to distinguish between triggering effects, such as his study did, and overall effects of exercise. The triggering effect of physical exertion, he says, is short-lived, and is limited to the time of exercise and up to two hours afterward. Taken in the broader context of a day, or even a week or year or lifetime, the amount of time you spend exercising is very small, so the small increase in risk posed by episodes of physical activity is outweighed by the larger benefit of regular exercise — which some studies say is as much as a 30% reduction in heart disease risk.

It may seem contrary that a behavior that poses a short-term risk after each episode actually confers benefit when its effects are added together over the course of a year or longer, but that’s exactly what’s happening with exercise and heart disease. “There are two competing forces operating when a person is exercising,” says Dahabreh. “There is a significant force we estimated that tends to increase heart-attack risk during exercise. But once you stop, studies suggest that within one to two hours that transient effect goes away.”

Even more important, he says, the study found that people who were regular exercisers experienced a relatively smaller rise in heart-attack risk during or immediately after periods of exertion, compared with people who didn’t get as much regular physical activity. For every additional bout of physical activity a person regularly got each week, his risk of heart attack dropped by about 45%.

In other words, the fitter you get, the lower your risk of succumbing to a heart attack triggered by physical activity. “Everyone experiences spikes in risk when they exercise,” says study co-author Jessica Paulus of Tufts University and Harvard School of Public Health. “But our analysis suggests that the magnitude of the spike is lower for regular exercisers.”

Which means that if you’re thinking about getting more active, you should do so gradually, especially if you have been sedentary and aren’t used to physical activity. For such individuals, even climbing a set of stairs or taking a long walk may qualify as sufficient physical activity to increase heart-attack risk, so it’s important to adopt an exercise program under the supervision of a doctor, says Paulus.

Even though physical exertion can put some strain on your heart, sticking to a regular program of exercise, it turns out, can help you to overcome that small risk. And what better reason to start getting in shape than the promise of better sex?