What Actually Happens To Your Heart After Running A Marathon? Here’s What A Study Found

June 12, 2026

Marathon running is known for its health and fitness benefits. Millions of people around the world participate in these long-distance races each year to improve endurance, challenge themselves, and maintain an active lifestyle. However, the high physical demand of running 42.2 kilometers puts extreme stress on the body, especially on the heart. A new study published in BMJ Open Sport & Exercise Medicine highlights how marathon running affects cardiac structure and certain biomarkers linked to heart injury. The findings suggest that these measurable changes happen immediately after a marathon, although the long-term relevance of these changes remains unclear.

Researchers conducted a systematic review and meta-analysis of 69 studies which involved healthy adult marathon runners. They combined data from multiple studies, they aimed to understand how the heart responds to the extreme physical effort required to complete a marathon. The study examined both blood biomarkers and imaging-based measurements of heart structure and function. While the results showed noticeable changes after races, the researchers emphasised that there is currently no strong evidence that these temporary changes lead to permanent heart damage in healthy athletes. NDTV