Cardiac arrest rate low for marathoners


About 1 in 184,000 runners goes into cardiac arrest while participating in a long-distance race, a study finds, which may make marathons no more dangerous than other vigorous activities.

Data on about 10 years of marathons and half-marathons in the U.S. were analyzed for the study, released Wednesday in the New England Journal of Medicine. Out of 10.9 million runners, there were 59 instances of cardiac arrest, 42 of them fatal.

More cases of cardiac arrest happened during marathons than half-marathons, and more deaths occurred during marathons. More men than women experienced cardiac arrest, and those who survived the episode tended to be older.


Researchers were able to get comprehensive clinical information on 31 of the runners who experienced cardiac arrest; among those, 23 died. The most common causes of death were hypertrophic cardiomyopathy and possible hypertrophic cardiomyopahty; that’s a condition in which the heart muscle thickens, making it more difficult for the heart to pump blood.

Among those who survived, ischemic heart disease was the main cause of cardiac arrest; in that condition, the heart can’t pump enough blood to the body, usually because of coronary artery disease. Survivors also tended to reap the benefits of getting early CPR from bystanders as well as from being on the receiving end of a defibrillator.

The authors noted that the number of cardiac arrests during races has gone up in the last decade, probably because more people are participating. But the fact that rates went up could mean the sport is attracting more men at higher risk for cardiovascular disease who are running for health benefits.