The Health Blog’s chief safety worry about running has always been evading the cellphone-wielding drivers making right turns with no regard to who might be in the crosswalk.
But anecdotal reports of deaths during marathons and half-marathons over the past few years have raised public concern over whether running — or at least racing — long distances is hazardous for the heart.
As the WSJ reports, a new study should ease worries about long-distance racing and the most critical heart problem — cardiac arrest, which an author of the study calls “the worst of the worst.” The study, published in the New England Journal of Medicine, found that of 10.9 million participants in U.S. full and half-marathons over more than a decade, there were just 59 cases of cardiac arrest, when the heart actually ceases to pump blood through the body.
Of course, for the loved ones of the 42 people who actually died from cardiac arrest during the races, this study won’t come as any comfort. So are there any ways to know if you’ll be one of the unlucky few?
Racing a marathon or half-marathon doesn’t cause a perfectly good heart to go into cardiac arrest, but it can be the catalyst for people with underlying problems.
Researchers were able to get complete medical records for 31 of the 59 cases of cardiac arrest. Most of the fatalities for which researchers had complete data were the result of hypertrophic cardiomyopathy, a thickening of the left ventricle of the heart. (That’s also the condition that prompts most deaths in young athletes, prompting a debate over whether student athletes should be screened for that and other potentially dangerous problems.)
And in survivors, the most common problem was underlying coronary artery disease — the narrowing of the arteries that is associated with aging and other risk factors. When the demands of the race call for more oxygen to the heart than those clogged vessels can deliver, cardiac arrest can occur, the researchers said.
That was surprising, Aaron Baggish, director of the cardiovascular performance program at Massachusetts General Hospital in Boston and senior author of the study, tells the Health Blog. Previously it was thought that acute heart problems during exercise occur from a rupture of arterial plaque, but that wasn’t the case in the records examined by researchers.
The good news is that while plaque ruptures can’t be predicted by a stress test or echocardiogram, various tests can help identify patients with both previously undetected hypertrophic cardiomyopathy and the problem seen in survivors in the study, says Baggish. More research needs to be done to determine whether pre-race testing is appropriate, and for whom.
For now, it’s a good idea to have a conversation with a physician before starting a marathon training program, particularly if you are not in particularly good cardiovascular shape to begin with or you are a middle-aged man. (Men constituted 86% of the cardiac-arrest cases in the study.)
“One of the big take-home messages for the middle-aged runner is that while [running] is without question a way to stay healthy, it’s not completely protective,” says Baggish.
And, as the Boston Globe points out today, heart attacks — which usually involve a ruptured plaque and don’t typically cause the heart to stop beating entirely — are a more common finish-line occurrence for runners. So race participants should know the symptoms of a heart attack, including discomfort or pain in the chest or upper body, shortness of breath, nausea and excess sweating, and be on the lookout for them.
Bonus: Why is the Swim the Most Deadly Leg of the Triathlon?
Image: Bloomberg News
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