Higher levels of cardiac troponins were measured in amateur endurance runners who competed in a full marathon, as compared to completing a half-marathon or a 10 kilometer race, despite a higher training volume in the marathon runners. A study compared 63 healthy nonprofessional runners, who trained for and competed in a 10-km race, half-marathon race or a full marathon race. The training volume was adapted to the aimed distance.

The study was performed because it is controversial whether the marathon distance is healthy or potentially harmful to the amateur athlete’s cardiovascular system. While cardiac arrest in marathoners is rare, a high proportion of all exercise-induced cardiac events occurs during marathon competitions. Competing in a marathon leads to an acute increase in the concentration of cardiac biomarkers, which is considered benign because the markers generally normalize within days. Still, the clinical relevance of the elevated cardiovascular strain imposed by the marathon is unclear and remains topic of debate.

In this study, expectedly the time spent to complete the race and body mass loss (as measure of dehydration) increased with distance, but self-reported perceived exertion was similar for all distances. Cardiac biomarkers were measured after the races. Cardiac troponins I and T were significantly higher with longer distances, while NT-proBNP and cardiac creatine kinase were only elevated in the runners who completed a full marathon. Skeletal muscle isoenzymes of creatine kinase and myoglobin also increased with distance run.

This suggests that the strain imposed on the myocardium by competing in a full marathon is greater compared with competing in shorter distances. While the observed release of cardiac troponins may not be indicative of any cardiovascular dysfunction, the elevated levels do reflect a superior cardiac stress at the longest distance evaluated, as compared to the shorter distances.

Elevation of Cardiac Troponins After Endurance Running Competitions

Originally published 3 Dec 2018. Circulation. 2018;0

Find the article online at Circulation