Review Examines How Marathon Running Affects Heart Health
A recent review published in BMJ Open Sport & Exercise Medicine investigated how marathon running influences heart health and whether the changes observed after endurance events are temporary physiological responses or signs of long-term cardiac adaptations.
Researchers analyzed data from studies comparing heart function before and after marathon races. The review included 69 studies involving 3,274 participants, most of whom were men aged between 27 and 63 years. Of these, 49 studies were included in a pooled statistical analysis.
The study focused on three important cardiac biomarkers—cardiac troponin T (cTnT), cardiac troponin I (cTnI), and N-terminal pro-B-type natriuretic peptide (NT-proBNP)—which are commonly used to assess heart stress, injury, or heart failure. Results showed that levels of all three biomarkers increased significantly within one hour after completing a marathon, often exceeding standard clinical thresholds associated with heart damage.
Researchers also examined echocardiography and cardiac MRI findings. Several temporary changes in heart chamber size and pumping function were observed, including alterations in left ventricular ejection fraction, which measures how effectively the heart pumps blood. However, these changes were generally small and not considered clinically significant. MRI scans did not reveal evidence of structural heart damage or lasting injury to the heart muscle.
The review found that responses varied according to factors such as age, sex, training status, and marathon performance time. Nevertheless, the researchers highlighted several limitations, including the underrepresentation of women and inconsistent reporting of participants’ training backgrounds. Many of the included studies also carried a relatively high risk of bias.
Overall, the findings confirm that marathon running causes short-term increases in cardiac biomarkers and temporary changes in heart function. However, it remains uncertain whether these effects are harmless adaptations to intense exercise or early signs of potential long-term cardiac remodeling. Further long-term research involving diverse populations is needed to better understand the cardiovascular impact of extreme endurance exercise.
