The effect of two different acute running exercises on markers of cardiac injury

The positive effects of regular exercise and physical activity on health are well known. Running exercises increase cardiovascular endurance and reduce the risk of mortality. However, it is reported that high-intensity exercises can cause cardiac damage and therefore carry health risks. In recent years, high-intensity interval training (HIIT), which consists of short periods of intense activity combined with long rest periods, has gained popularity to increase cardiovascular endurance. This study was conducted to evaluate whether acute HIIT training in recreational runners would lead to a greater increase in cardiac biomarkers (cTnI, NT-proBNP, BNP, CKMB, myoglobin) than moderate-intensity long-term endurance running performed for the same duration and volume. 15 male athletes who train for recreational running at least three days a week completed one hour of HIIT, which consisted of one minute of intense running followed by four minutes of jogging, and one hour of continuous moderate intensity endurance running at 1-2-week intervals. Participants' VO2 maximum values and maximum heart rate were evaluated before the running trials. The average intensity of both running exercises was roughly 70% of maximum VO2 capacity. Blood samples were taken for cardiac biomarkers analysis before, immediately after and three hours after the running exercises. Both types of running led to increases in serum concentrations of cTnI, NT-proBNP, CKMB, myoglobin. However, no significant difference was found between the concentrations of cardiac biomarkers and the percentage changes caused by HIIT and moderate intensity running in blood samples collected immediately after exercise or three hours later. These findings show that HIIT exercise, which includes high-intensity bouts, does not lead to an increase in cardiac biomarkers compared to moderate-intensity exercise performed at the same volume and duration. Keywords: HIIT, moderate intensity endurance running, cTnI, NT-proBNP, CKMB