Several reports have emerged over the past few years linking endurance exercise with heart problems. Most recently, researchers from Australia and Belgium studied 40 trained athletes who were to participate in one of four events: an endurance triathlon, alpine cycling, an ultra triathlon or a marathon. The athletes presented with no known heart problems. The researchers obtained magnetic resonance imaging (MRI) from each athlete 2–3 weeks before the race, 1 hour post­-race and 6–11 days postrace. When examining the results, the researchers noted that 1 hour after the race the athletes’ right ventricles had changed shape, volume had increased and function had decreased. Fortunately, in most of the subjects heart shape and function returned to prerace condition after a week. However, the five athletes with the most experience in endurance racing presented with more permanent scarring.

“Intense endurance exercise causes acute dysfunction of the right ventricle, but not the left ventricle,” the researchers noted. “Although short-term recovery appears complete, chronic structural changes and reduced right ventricle function are evident in some of the most practiced athletes, the long-term clinical significance of which warrants further study.”

The study authors were careful to point out that the results of this study do not necessarily indicate that participation in endurance activities is unhealthy.

The report was published in the European Heart Journal (2011; doi:10.1093/eurheartj/ehr397).