According to a report in The New England Journal of Medicine (2012; 366, 130–40), about 2 million people participate in long-distance running events in the United States annually. Is the increased popularity of demanding events like marathons becoming a health hazard?

Study authors analyzed cardiac arrest outcomes of marathon and half-marathon races from January 2000 to May 2010. During that time, 59 out of 10.9 million runners suffered a cardiac arrest—in 42 cases, it was fatal. The majority of incidents involved men (51), the average age of those affected was 42 ± 13 years, and cardiovascular disease accounted for most of the cardiac arrests. Significantly more incidents occurred during marathons than during half-marathons.

Distance runners can breathe easily. Although study authors noted that “male marathon runners, the highest-risk group, had an increased incidence of cardiac arrest during the latter half of the study decade,” they also concluded that “marathons and half-marathons are associated with a low overall risk
of cardiac arrest and sudden death.”