Saturday, December 09, 2006

Is Marathoning Too Much of a Good Thing for Your Heart?

This New York Times article starts with a story of a runner that had a heart attack during the Marine Corps Marathon. Another runner also died of a heart attack in the same race.

This has been an unusual season for the cardiac health of marathoners. After years in which almost no deaths were attributed to heart attacks at this country’s major marathons, at least six runners have died in 2006.

So there is renewed scrutiny. This topic comes and goes but what makes this article noteworthy is that has the findings of two studies.

Here is the first study:

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.
The second study finds that:

More than a third of the runners (in the study) had significant calcium deposits, suggesting they were at relatively high risk for a heart attack. Only 22 percent of a control group of nonrunners had a comparable buildup.

Last year a nonmarathoner cousin of mine in his late thirties who had no symptoms and was fit was struck by a heart attack but survived so frankly this article has put a bit of a scare in me. One suggestion is for a visit to a cardiologist for marathoers over 40 to get a Spiral CT scan which is one of the best ways to detect any heart abnormalities. The other suggestion was to do the training and on marathon day watch the marathon on TV. I am not sure the last suggestion will work.