Recreational marathoners take note: Strenuous exercise such as running a long-distance race can damage the heart muscle, new research shows.
Although the damage can be reversible for some, researchers from the Institut Universitaire de Cardiologie et de Pneumologie de Québec warn it is more widespread in less fit distance runners and recreational distance runners who don't properly prepare for marathons may be in danger.
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Their study, published in the Canadian Journal of Cardiology, evaluated 20 amateur distance runners who were scheduled to take part in the Quebec City Marathon and who had no known cardiovascular disease or drug treatment.
The runners were tested for heart health and function six to eight weeks before the marathon, on the day of the race, and within 48 hours after completing the competition. Some also underwent a third round of testing after three months.
The findings indicated the race induced a decrease in left and right ventricular function of the heart — a key measure of cardiac health — in half of the amateur distance runners.
When a lot of the heart was affected, the heart also showed swelling and reduced blood flow.
Lead researcher Eric Larose said the results clearly showed that the endurance sport can affect heart function of recreational runners.
"We also found that heart muscle changes were more common and widespread in runners with lower fitness and less training," he said, adding: "We don't know whether such changes mean that recreational runners are at risk [but] these results emphasize the need for proper preparation before recreational distance runners engage in a marathon race."
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