A decade-long study of 152 recreational marathon runners, published in Jama Cardiology, suggests that running marathons does not cause lasting heart damage. While blood tests show temporary increases in troponin, a marker for heart strain, and the right ventricle's pumping ability drops short-term after races, these effects recover within days. Crucially, the ten-year follow-up revealed no permanent damage to heart function, addressing earlier concerns about long-distance exercise potentially harming the heart.