A new study published in the European Heart Journal suggests that athletes who participate in extreme endurance exercise may incur damage to the right ventricle of the heart, according to a press release.
The study, conducted by André La Gerche, MD, PhD, a postdoctoral research fellow at St. Vincents Hospital, University of Melbourne, Australia, and based at the University Hospitals Leuven, Belgium, recruited 40 elite athletes in Australia who were planning to compete in one of four endurance events marathon, endurance triathlon, alpine cycling or ultra triathlon. They each trained intensely for more than 10 hours a week, finished within the top 25% of the field in a recent event and had no known heart problems.
La Gerche and colleagues studied the athletes using echocardiography, magnetic resonance imaging (MRI) and blood tests 2 to 3 weeks prior to the race, within 1 hour of finishing the race and 6 to 11 days after the race. The results showed that the athletes hearts changed shape, with the volume increasing and the function of the right ventricle decreasing. Also, the level of B-type natriuretic peptide, a chemical secreted by the ventricles in response to excessive stretching of the heart muscle cells, increased.
The right ventricle function recovered within a week for most of the athletes, but five (13%) who had competed in longer endurance challenges showed evidence of more permanent damage. In those, the MRI detected signs of scarring of the heart muscle. The researchers also found that the post-race damage to the right ventricle increased with the duration of the race.
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, La Gerche stated in the release. The question from our research is whether there are some athletes in whom extreme exercise may cause injury from which the heart does not recover completely. If this occurs, affected athletes may be at risk of reduced performance a cardiac over-training syndrome or it may cause arrhythmias. If this occurs, 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.
The left ventricle, which until recently has been most studied in athletes, showed no change. Now there is sufficient evidence to invest in the long-term prospective studies that are required" for study of the right ventricle, he said.