Recent research has shown that endurance athletes suffer cardiac fibrosis — scarring in the heart muscle. When scientists look at heart tissue from marathon runners, rowers and Ironman competitors, they often find signs of fibrosis, while sedentary subjects usually have no fibrosis at all. In non-athletes, fibrosis is an indicator for arythmias, but medical researchers don’t know how how this heart muscle fibrosis effects the longevity of endurance athletes.
To answer this question, Spanish researchers compare longevity of Tour de France racers against the general population. From the Globe & Mail:
Given the number of cyclists in this year’s Tour de France who have skidded off mountain passes, been sideswiped by passing cars or catapulted into barbed-wire fences, it’s obvious that riding in the Tour can be hazardous to your health.
Researchers at the University of Valencia in Spain compared [Tour racers] to average figures for people from France, Italy and Belgium. The finding: Median age of death was 73.5 years for the controls compared to 81.5 years for the cyclists, and the mean lifespan was 17 per cent longer for the cyclists.