Exercise, Sex Can Boost Heart Attack Risk

Overall, Increased Heart Risk Is Small, Especially for Regular Exercisers, Experts Say

By Kathleen Doheny
WebMD Health News

Reviewed by Laura J. Martin, MD

March 22, 2011 -- Exercise and sex can boost the risk of heart attack and sudden cardiac death, according to a new report, although the increased risk is small and transient, the researchers say.

The risk is higher for those who are occasional exercisers compared to habitual exercisers, says researcher Issa Dahabreh, MD, a research associate at the Center for Clinical Evidence Synthesis, Institute for Clinical Research and Health Policy Studies at Tufts Medical Center in Boston.

"For those individuals habitually physically active, they are less susceptible to the triggering effects of physical activity and sexual activity," he tells WebMD.

His report, which analyzed previously published studies looking at the link between exercise, sex, and heart attack or sudden cardiac death, is published in The Journal of the American Medical Association.

The new findings echo those of previous research, says Barry Franklin, PhD, a spokesman for the American Heart Association and director of Cardiovascular Rehabilitation and Exercise Laboratories, Beaumont Hospital, Royal Oak, Mich.

Overall, the bottom line? For susceptible people who engage in vigorous activity -- whether exercise or sex -- ''yes, the transient risk of a catastrophic cardiac event increases during and immediately after that period," Franklin says. However, when people are in good physical condition, ''the risk is essentially non-existent or very, very slightly increased."

Exercise, Sex, and Heart Attacks: Study Details

Dahabreh and his co-author, Jessica Paulus, ScD, an assistant professor of medicine at Tufts University School of Medicine, combed the medical literature for published studies looking at the link between exercise, sex, and heart attack or sudden cardiac death.

Many previous studies were limited by small numbers of participants, the researchers say; so they pooled the results, hoping to get stronger statistics and possibly identify a pattern not evident in smaller studies.

They focused on 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 exposed to physical activity and engaged in sexual activity to times when they were not, and the effect on cardiac health.

''These [types of] studies are particularly useful for [assessing] transient or short-term risks," says Paulus, who is also an adjunct assistant professor of epidemiology at the Harvard School of Public Health.

Overall, they found:

  • Episodes of physical activity boosted heart attack risk 3.5 times and risk of cardiac death nearly 5 times.
  • Sexual activity increased heart attack risk 2.7 times; no statistic is available for the link between sex and sudden cardiac death risk, Dahabreh says.

Paulus puts the risk in perspective this way: ''Physical activity and sexual activity are triggers of heart attack and sudden cardiac 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."

The increased risk, expressed as a relative risk, is a comparison of the risk when participants are exercising or having sex compared to the risk when they are not.

The absolute risk -- the probability of the heart attack or sudden cardiac death actually occurring to an individual -- was small. "If you look at the individual levels, look at the risk in absolute terms, this is a very small effect," Dahabreh says.

And regular exercisers can count on an even lower risk, it appears. Participants were asked how many times a week they exercised, and for every additional time, the relative risk for heart attack decreased by about 45%; for sudden cardiac death it decreased by 30%.

Although 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 a variety of other good habits, such as eating healthfully.

Up to a million heart attacks and 300,000 cardiac arrests occur annually in the U.S., the authors write.

Paulus cautions that ''for those who are going to initiate an exercise program, they need to do so under the care and supervision of a clinician."

The study was funded by the National Center for Research Resources of the National Institutes of Health.

Exercise, Sex, and Heart Attacks: More Perspective

Franklin, who has also researched the topic, has published similar findings.

He points, too, to a study published in 1996 in The Journal of the American Medical Association, in which the researchers looked at more than 1,700 heart attack patients, asking what they did in the two hours before their attack.

Although the researchers found recent sexual activity could trigger a heart attack, they said the relative risk was low and the increase in absolute risk from sexual activity is extremely low: ''one chance in a million for a healthy individual."

Of the latest analysis on exercise, sex, and heart attacks, Franklin says: "They aren't saying this is dangerous stuff, just to realize there is a transient increased risk with vigorous activity in susceptible individuals."

"If you want to protect yourself, you ought to be regularly physically active," he says. "Regular exercise does not completely eliminate the risk, but it markedly reduces the likelihood of an exertion-related cardiovascular event."



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SOURCES: Issa J. Dahabreh, MD, research associate, Center for Clinical Evidence synthesis and Evidence-based Practice Center, Tufts Medical Center's Institute for Clinical Research and Health Policy Studies, Boston.Jessica K. Paulus, ScD, assistant professor, Tufts University School of Medicine; adjunct assistant professor of epidemiology, Harvard School of Public Health, Boston.Dahabreh, I. The Journal of the American Medical Association, March 23-30, 2011; vol 305: pp 1225-1233.Barry Franklin, PhD, American Heart Association spokesperson; director, Cardiac Rehabilitation and Exercise Laboratories, Beaumont Hospital, Royal Oak, Mich., professor of physiology, Wayne State University School of Medicine, Detroit.Muller, J. The Journal of the American Medical Association, May 8, 1996: vol 275: pp 1405-1409.

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