There may be something to those anecdotes about people suffering a heart attack during a bout of uncharacteristic physical activity-including sex. Tufts researchers who analyzed 14 studies of the cardiac effects of episodic physical activity found that it was associated with a short-term more than three-fold increase in heart-attack risk and five-fold increase in the risk of sudden cardiac death.
Issa J. Dahabreh, MD, of Tufts Medical Center and Jessica K. Paulus, ScD, of Tufts School of Medicine concluded, however, that given the infrequency and transience of such sporadic activity, the absolute risks are small.
The researchers systemically reviewed the medical literature and identified 14 relevant studies. Of those, 10 looked at heart attacks, three considered sudden cardiac death, and one measured risk of acute coronary syndrome.
There is a link between episodic physical activity and sexual activity with the risk of heart attack and death from sudden cardiac events within one or two hours after the activity, Paulus said. This risk was sharpest for those individuals who were unaccustomed to regular exercise.
Episodic sexual activity was linked to nearly triple the risk of heart attack in a short window of time during and after the sexual activity as compared to time periods in which the individual was not sexually active. But such risks declined with regular physical activity (exercise, that is, not necessarily more-frequent sex), emphasizing the importance of staying in shape. For each additional time per week a person was habitually active-such as a regular workout session-the relative risk of a heart attack triggered by episodic physical activity dropped by about 45%. Risk of sudden cardiac death associated with episodic physical activity similarly fell by 30% for each weekly workout.
Overall, Dahabreh and Paulus estimated that the absolute increased risk for a heart attack associated with an hour of sporadic activity per week was only two to three additional coronary events per 10,000 person-years. So the danger that a sudden burst of activity will put you in the hospital is still quite remote.
Just in case, though, the takeaway is to make your physical activity more frequent and regular than episodic. The researchers cautioned that their results should not be interpreted as indicating a net harm of physical or sexual activity. Those in the groups with the highest levels of habitual exercise, they pointed out, had much smaller increases in risk, if any at all.
TO LEARN MORE: Journal of the American Medical Association, March 23/30, 2011; abstract at jama.ama-assn.org/content/305/12/1225.abstract.