Blood markers suggest heart damage in amateur marathoners
Some of the same blood markers that spike following a heart attack also skyrocket in amateur long-distance runners, especially those who do a full marathon, researchers say. The small study in Spain tested non-professional runners before and after 10K, half-marathon and full-marathon races and found that a protein called troponin, which indicates damage to the heart muscle, surges to many times its normal level after a full marathon. It's not clear if this represents long-term damage, however, the study team writes in the journal Circulation. While deaths in long distance races are relatively rare, we shouldn't forget that the runner who sparked the marathon competitions, the Greek herald, Pheidippides, who in 490 BC ran a distance of about 26 miles from Marathon to Athens with the news of the victory his people had over the Persians died shortly after delivering that news, said Dr. James Glazier, a cardiologist at Detroit Medical Center and a clinical professor of medicine at Wayne State University, who wasn't involved in the study. The increase in troponin levels "suggests that marathons put quite a strain on the heart," Glazier said. "Other studies that looked at MRIs of the hearts of runners showed that they can become very enlarged after a race and we worry that with competitive running you might get some scarring of the heart and then maybe some rhythm problems."