How Marathon Running Reshapes the Heart—Temporarily or Permanently?

Marathon running has grown in popularity as a test of endurance and fitness. The sport places significant demands on the heart, but its long-term effects remain unclear. Researchers continue to study the balance between temporary changes and potential stress on the cardiovascular system. Endurance exercise like marathons pushes the cardiovascular system to its limits. Studies show that three key cardiac biomarkers—cTnT, cTnI, and NT-proBNP—rise sharply within the first hour after a race. These levels often exceed clinical thresholds, though structural heart damage is not consistently detected on MRI scans.

Echocardiography has revealed modest changes in heart chamber size and left ventricular ejection fraction post-marathon. These variations depend on factors such as finishing time, training level, age, and sex. Most research so far has focused on male runners, limiting insights into how women may be affected.

Scientists emphasise the need for longitudinal studies to track long-term cardiac health in endurance athletes. Such research would help clarify the impact of repeated extreme exertion on the heart. The acute cardiac responses to marathon running are complex and not yet fully understood. Findings highlight the need for personalised risk assessments and evidence-based exercise guidelines. Further research is required to determine the long-term implications for athletes.