The effects of preceding exercise on myocardial damage in rats.

[Purpose] The purpose of this study was to investigate the effects of exercise on myocardial injury in male Sprague-Dawley rats. Two groups of rats were trained with either moderate- or high-intensity treadmill running for four weeks. Subsequently, the concentrations of cardiac troponin and the N-terminal of prohormone brain natriuretic peptide (NT-proBNP) were examined following a single bout of prolonged intensive exercise (lasting 3 h). [Subjects and Methods] The study included 40 six-week-old male Sprague-Dawley rats weighing 150-180 g each. The aerobic exercise group was divided into high-intensity (28 m/min) and moderate-intensity (15 m/min) subgroups. Both subgroups were trained for 35 min daily for six days per week (excluding Sunday) over a four-week period. Following training, the high- and moderate-intensity exercise groups and a nonexercise group performed one bout of prolonged treadmill exercise for 3 h at a speed of 15 m/min. [Results] The cardiac troponin and NT-proBNP levels differed significantly between the groups. [Conclusion] The exercise groups showed lower levels of cardiac troponin and NT-proBNP than the nonexercise group after the bout of prolonged intensive exercise.