Evening Herald
Friday 30 November 2012
By Stephen Adams
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.
OVERSTRETCHING
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 signaling. These could trigger potentially dangerous heart rhythm problems. “In addition, long-term excessive exercise may accelerate aging in the heart, as evidenced by increased coronary artery calcification, diastolic ventricular dysfunction, and large-artery wall stiffening,” they write in the journal Heart.
Dr James O’Keefe and Carl Lavie, from St Luke’s Mid America Heart Institute in Kansas City, and the Pennington Biomedical Research Centre in Baton Rouge, US, say the heart is only designed for “short bursts” of intense activity. They cite the example of Micah True, the hero of the book Born to Run about ultra endurance running. He died in March, aged 58, on a 12 mile training run in New Mexico.
He routinely ran a marathon a day, sometimes more.
They believe that decades of such exertion led True to develop Phidippides cardiomyopathy.
Named after the original runner, who died delivering news of the Greeks’ victory at Marathon, it is “the constellation of cardiac pathology that has been observed in the hearts of some veteran extreme endurance athletes”.