March 22, 2011 -- A new analysis finds that both physical and sexual activity may boost heart attack risk, but for most people, the increased risk is slight and fleeting. For regular exercisers, the risk is even lower.
"Physical activity and sexual activity are triggers of heart attack and sudden death, but that risk occurs over a very short period of time, on the order of one to two hours, during and after the activity," says researcher Jessica Paulus, ScD, assistant professor of medicine at Tufts University School of Medicine and adjunct assistant professor of epidemiology at Harvard University School of Public Health.
Her co-researcher, Issa Dahabreh, MD, a research associate at Tufts Medical Center, puts the risk in perspective. "If 10,000 people increased their physical activity or sexual activity by one hour per week, you would expect two or three additional heart attacks or sudden cardiac deaths [in that group] per year," he says.
That risk estimate doesn't take into account the benefits of exercise, he says, and applies to people about 50 to 64.
The new analysis is published in The Journal of the American Medical Association.
Looking for Links Between Exercise, Sex, and Heart Attack
The researchers scanned the medical literature for studies that looked at the link between exercise, sex, and heart attack or sudden cardiac death.
They found 10 studies that looked at physical activity, three that focused on sexual activity, and one that looked at both. The studies compared the risk of heart attacks and sudden death when participants were either exercising or having sex to times when they were not.
They pooled the results hoping to get stronger statistics. They wanted to see if they could identify a pattern not seen in the smaller studies.
Overall, the researchers found:
- Exercising boosted heart attack risk 3.5 times. It increased risk of cardiac death nearly five times.
- Having sex increased heart attack risk 2.7 times. No statistic is available for the link between sex and sudden cardiac death risk.
While the increase in risk may seem high, the researchers say, the actual chance of the heart problem happening is still low because the initial risk is low.
Low Risk for Regular Exercisers
Regular exercisers have an even lower risk, the researchers found. Participants told how many times a week they exercised. For every additional session, the risk of heart attack decreased by about 45% and for sudden cardiac death by 30%.
While it points to a reason to exercise, Dahabreh cautions that the regular exercise may simply be a marker for a healthy lifestyle that also includes other good habits.
Up to a million heart attacks and 300,000 cardiac arrests occur annually in the U.S., the researchers write.
Paulus cautions those who haven't exercised regularly to see a doctor before starting.
The study was funded by the National Center for Research Resources of the National Institutes of Health.
The new findings echo those of other studies, says Barry Franklin, PhD, a spokesman for the American Heart Association and director of Cardiovascular Rehabilitation and Exercise Laboratories, Beaumont Hospital, Royal Oak, Mich.
''In a nutshell, it's saying that physical exertion is a double-edged sword," Franklin tells WebMD. While it protects against getting heart disease and having heart attacks, it can also slightly boost the risk of heart problems. The risk of heart problems is higher in occasional exercisers than regular ones, he says.
"One way to diminish the risk is to be a regular exerciser," he says. Regular exercisers, he says, are used to the increase in blood pressure and heart rate that goes along with exertion.