Sex is rarely the cause of a heart attack, and most heart disease patients are safe to resume sexual activity after a heart attack, according to a research letter published today in the Journal of the American College of Cardiology.

Sexual activity can be a concern for many heart attack patients who worry about exertion triggering another heart event, but data on the harms and benefits of sexual activity in heart disease patients is limited. According to the research letter, sexual activity generally involves moderate physical activity comparable to climbing two staircases or taking a brisk walk.

Researchers looked at 536 heart disease patients between 30 and 70 years old to evaluate sexual activity in the 12 months before a heart attack and estimate the association of frequency of sexual activity with subsequent cardiovascular events, including fatal heart attack, stroke or cardiovascular death.

In a self-reported questionnaire, 14.9 percent of patients reported no sexual activity in the 12 months before their heart attack, 4.7 percent reported sex less than once per month, 25.4 percent reported less than once per week and 55 percent reported one or more times per week. During 10 years of follow up, 100 adverse cardiovascular events occurred in patients in the study. Sexual activity was not a risk factor for subsequent adverse cardiovascular events.

Researchers also evaluated the timing of the last sexual activity before the heart attack. Only 0.7 percent reported sex within an hour before their heart attack. In comparison, over 78 percent reported that their last sexual activity occurred more than 24 hours before the heart attack.

"Based on our data, it seems very unlikely that sexual activity is a relevant trigger of heart attack," said Dietrich Rothenbacher, M.D., M.P.H., lead author of the study and professor and chair of the Institute of Epidemiology and Medical Biometry at Ulm University in Ulm, Germany. "Less than half of men and less than a third of women are getting information about sexual activity after heart attack from their doctors. It is important to reassure patients that they need not be worried and should resume their usual sexual activity."

Researchers said that despite the benefits of sexual activity outweighing risks, the potential of erectile dysfunction as a side effect from various cardiovascular protective medications and the risk of a drop in blood pressure from combining certain heart medications with erectile dysfunction medications should be clearly communicated to patients.