Too much prolonged high-intensity exercise risks heart health

http://www.eurekalert.org/pub_releases/2014-05/bmj-tmp051214.php

PUBLIC RELEASE DATE: 14-May-2014
Contact: Stephanie Burns
BMJ-British Medical Journal
Too much prolonged high-intensity exercise risks heart health

Two studies indicate J-shaped curve for benefits of physical activity: More doesn't always mean better

Overdosing on high intensity exercise may actually increase the risk of death from a heart attack or stroke in those with existing heart disease, suggests German research published online in the journal Heart.

Similarly, a second Swedish study in the journal suggests that young men undertaking endurance exercise for more than five hours a week may increase their risk of developing an irregular heart rhythm in later life.

Both sets of findings indicate a J-shaped curve for the health benefits of exercise, with more not always meaning better, and raise questions about the intensity and duration of physical activity at different times of life, says a linked editorial.

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