Thursday, December 07, 2006

Running marathons: Bad for the heart?

Maybe I should stay home on the couch and eat potato chips.

From the New York Times:

But some physicians, including Dr. Siegel, an author of more than two dozen studies of racers at the Boston Marathon, wonder if there is more to the deaths than mathematical inevitability: Does racing 26.2 miles put a heart at risk?

A new study by Dr. Siegel and colleagues at Massachusetts General Hospital and other institutions is at least suggestive. Sixty entrants from the 2004 and 2005 Boston Marathon were tested before and after the race. Each was given an echocardiogram to find abnormalities in heart rhythm and was checked for blood markers of cardiac problems — in particular for troponin, a protein found in cardiac muscle cells. If the heart is traumatized, troponin can show up in the blood. Its presence can determine whether there has been damage from a heart attack.

The runners (41 men, 19 women) had normal cardiac function before the marathon, with no signs of troponin in their blood. Twenty minutes after finishing, 60 percent of the group had elevated troponin levels, and 40 percent had levels high enough to indicate the destruction of heart muscle cells. Most also had noticeable changes in heart rhythms. Those who had run less than 35 miles a week leading up to the race had the highest troponin levels and the most pronounced changes in heart rhythm.

I've run 28 marathons and haven't died yet. But then again, there are smokers out there who say "I've been smoking all my adult life..."

Related post: Marathon runners face higher skin cancer risk--especially this one

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