The Effects of Marathon Running on the Heart
Some Recent Studies Say Endurance Athletes Risk Cardiac Damage
Jun 26, 2009
Many people probably recall the 58-year-old man who died of a heart attack while running the 2008 New York Marathon. The risk of having a fatal heart attack during, or in the 24-hour period following a marathon is about 1 in 50,000, according to a 1996 study. But does running a marathon damage the heart? Here’s what experts have to say.
A Temporary Change of Heart …
Running a marathon may be hard on the heart, but it does not cause any long-term damage. That’s what some researchers found, after examining the hearts of amateur marathon runners shortly after competition.
Researchers from Harvard Medical School examined the hearts of 60 recreational runners before and 20 minutes after the 2004 and 2005 Boston Marathon. Scans and blood tests revealed signs of heart stress, including difficulty refilling chambers after pumping blood out and impaired ability to pump blood to the lungs. The biggest finding was that runners who had averaged fewer than 35 miles per week showed much greater heart abnormalities than those who had run at least 45 miles per week. However, there was no evidence to show that any long-term effects were caused by the changes.
A 2009 Canadian study used cardiac magnetic resonance imaging (CMR) to assess whether running a marathon creates permanent heart damage. Researchers from the University of Manitoba in Winnipeg examined the hearts of 14 non-elite runners of the Manitoba Marathon in immediately after the race. Results were similar to those of the Harvard study. Heart chambers had some difficulty refilling, and there was a decrease in the heart’s ability to pump blood to the lungs. However, when researchers repeated the imaging a week later, everything was back to normal.
… Or in It for the Long Run?
The heart-pumping dysfunction brought on by running 26.2 miles might disappear with time, but years of frequent marathon running can lead to signs of coronary artery disease, some studies have found.
A 2006 German study of 108 men age 50 and older who had done at least five marathons in the past three years found that the men were more likely than non-runners to have significant levels of calcium deposits in their arteries, which is linked to a higher risk of heart attack.
Researchers in Minnesota are conducting similar studies on the hearts of local marathoners. William Roberts, medical director of the Twin Cities Marathon, and his colleagues have recruited about 50 men who have done at least one marathon year for the past 25 years or more. According to an article on TwinCities.com, the doctors are finding calcium deposits in the runners’ hearts. They are still collecting data to compare the study subjects to non-runners.
A 2009 study conducted by researchers at the West German Heart Center in Essen, Germany found that the hearts of 102 male marathoners age 50 and older were more likely to show signs of coronary artery disease than those of non-runners. It should be noted that 51.8 percent of runners were former smokers and 4.6 percent were current smokers.
To Run or Not to Run?
While the controversy remains as to whether marathon running is harmful to the heart, one thing is for certain. Running, in general, has massive health benefits.
An editorial, “Is Marathon Running Hazardous to Your Cardiovascular Health? The Jury Is Still Out,” appeared in the journal Radiology, following the Essen study. Authors Kibar Yared, M.D., and Malissa Wood, M.D., point out:
“While the sedentary community has been eager to highlight the detrimental long-term effects of endurance exercise, to our knowledge, there has been no conclusive evidence to directly support this claim. There is, however, an abundant body of literature to support the positive physiologic and biochemical response of healthy myocardium after exposure to prolonged exercise.”
