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Untrained Runners Risk Stressing Heart

Running a marathon with less than 35 miles a week of training may endanger heart

Couch potatoes should think twice before running marathons, according to a Harvard researcher who found that under-trained runners who take on the 26.2-mile challenge are putting their hearts at risk.

Individuals who trained for 35 miles per week or less before running a marathon exhibited temporary changes in both cardiac function and biochemistry indicating heart stress, according to the study by Harvard Medical School Instructor Malissa J. Wood.

“The average person who runs is not doing themselves any favors by under-training for the marathon,” Wood said.

Wood’s study tracked the hearts of 60 marathoners using echocardiography, which produces an image of the heart by means of sound waves.

That method, along with blood sample tests, revealed that under-trained marathon runners suffered from a host of abnormalities—including decreased right ventricular function and elevated levels of two enzymes linked to heart stress.

These negative symptoms were much less pronounced in those who ran at least 45 miles per week before the marathon according to the study. For example, under-trained marathoners exhibited levels of one stress-linked enzyme that were nine times higher than those found in the runners whose weekly regimen included more than 45 miles.

“The biggest message of our study was that no matter how old you are, you should train well before taking on a marathon,” said Wood, who is herself a marathoner.

Of her own strategy, Wood said, “I just go really slow and drink a lot of water”—though she boasts an impressive sub-four-hour best time herself.

Wood’s study has not dimmed the optimism of members of the Harvard College Marathon Challenge, which is entering its second year.

The group recruits College students—including non-athletes—to run the Boston Marathon in April and raises money for charity.

“Having conquered the marathon, you have the feeling that you can pick up and go full speed at anything,” said Matthew R. Conroy ’07, who is in charge of training for the group.

But as Wood’s study demonstrates, it’s not a challenge to be taken lightly.

“We want people to understand that we want them to keep running, but running wisely,” she said.
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