(TELEGRAPH) — Doing too many marathons could kill you, doctors have said in a stark warning about the dangers of taking too much vigorous exercise.
Fitness fanatics should do “just one or a few” marathons or full-distance triathlons, say the cardiologists, because over-exerting the heart for years can lead to long-term damage.
There is now convincing evidence that repeatedly asking the heart to pump “massive” volumes of blood, for hours at a time, can lead to an array of problems, they say.
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These include overstretching of the organ’s chambers, thickening of its walls and changes to electrical signalling. These could trigger potentially dangerous heart rhythm problems.