Tuesday, March 22, 2011

Exercise Too Much of a Good Thing?

Photo courtesy of NYTimes.com; Jonathan Knowles/Getty Images

Researchers in Britain have recently began studying the heart health of older athletes.  The scientists included only men who had been part of a British national or Olympic team in distance running or rowing, as well as members of the 100 Marathon club, which admits runners who have completed at least a hundred marathons.  All the men have been athletic, training and competing, for most of their lives.  Twelve were age 50 or older, with the oldest age 67; another 17 were relative striplings, ages 26 to 40.  The scientists also gathered a group of 20 healthy men over 50, none of them endurance athletes, for comparison.

The scientists subjected the participants to a new kind of magnetic resonance imaging (MRI) of their hearts that "identifies very early signs of fibrosis, or scarring, within the heart muscle,"  according to the New York Times.  Fibrosis can lead to siffening or thickening of the heart and eventually heart failure.

The results of the study, which were released only a few weeks ago in The Journal of Applied Physiology, showed that none of the younger atheletes and older non athletic athletes had fibrosis in their hearts.  On the other hand, about half of the older lifelong athletes showed some sign of heart muscle scarring.  "The affected men were, in each case, those who’d trained the longest and hardest. Spending more years exercising strenuously or completing more marathon or ultramarathon races was, in this study, associated with a greater likelihood of heart damage."

There have been other studies like this one in Germany and with lab rats.  The bottom line is, the question of whether intense, lifelong endurance exercise is harmful to the heart has been around for ages.  As the Times points out, it most often arises whenever a lifelong athglete who is supposedly healthy suffers a major heart attack.

After reading the article, it appears to me there is some small, but significant, link between lifelong endurance training and damage to the heart.  That does not mean that everyone should just quit exercising.  This study targeted people who exercised vigorously every day and ran/cycled/swam countless marathons, triathalons, etc...

Because the study has been done before (with some loopholes that were covered in this most recent study) and the results have been mildly consistent, I believe that there is a connection between endurance training and heart damage, and that lifelong athletes should be aware of these risks.  For now, however, until the science of excessive exercise is better perfected, we should all keep exercising regularly, but with a little more caution.  Pay attention to what your body is telling you, and see a doctor if your heart starts acting up during or after exercise.  Otherwise, just keep swimming! (Or running, or bicycling... you get the gist.)

Read more at http://well.blogs.nytimes.com/2011/03/09/when-exercise-is-too-much-of-a-good-thing/?hp.

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