(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.
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.