Marathons 'could damage heart'

10 Dec Daily Telegraph

Taking part in extreme endurance events like triathlons and marathons could damage the heart, researchers warn today

Putting the heart under heavy strain for long periods causes scarring of the heart muscle, known as fibrosis. This damage is normally reversed within a week of an event, the repairal process serving to make the heart fitter.

However, academics who followed 40 elite Australian athletes found evidence of "more permanent damage" in five of them. The results are published in the European Heart Journal. Fibrosis can impair how well the heart performs when a person is exercising intensively. It can also lead to irregular heartbeats, called arrhythmias.

Dr André La Gerche, currently based at the University Hospitals Leuven, in Belgium, said:

"It is likely to affect only a minority of athletes, particularly those in whom more intense training fails to result in further improvements in their performance."

He noted that the five who saw longer-term damage had been training and competing for longer than the others. He also emphasised:

"It is most important that our findings are not over-extrapolated to infer that endurance exercise is unhealthy. Our data do not support this premise."

The researchers found damage in the right ventricle, one of the four chambers of the heart, using MRI scanning. They found no damage in the left ventricle.

Professor Sanjay Sharma, a consultant cardiologist and medical director of the London Marathon, said that while the study was small it provided "food for thought".

"I don?t believe that the human body is designed to exercise at full stretch for as long as 11 hours a day, so damage to the heart is not implausible.

"It is too early to say that taking part in endurance sports causes long-term damage to the right ventricle, but this study is an indication that it might cause a problem in some endurance athletes with a predisposition and, therefore, it should be studied further."