A ten-year study of 152 recreational marathon runners, published in Jama Cardiology, suggests that running marathons does not cause lasting heart damage. While the heart's right ventricle shows a temporary drop in pumping ability post-race, it recovers within days. The study found no long-term functional damage over the decade. Earlier concerns about marathon strain were partly due to elevated troponin levels in runners' blood, a marker typically associated with heart attacks, but this rise appears to reflect temporary strain rather than permanent injury in healthy athletes.