Impact of training specificity on exercise-induced cardiac troponin elevation in professional athletes: A pilot study

BACKGROUND: Release of cardiac biomarkers is common after strenuous endurance exercise, but data on intermittent exercise are scarce. It has not been investigated whether cardiac troponin elevation is influenced depending on the type of exercise that an athlete is adapted to perform. We hypothesized that intermittent but not continuous exercise induces cardiac troponin elevation in professional athletes adapted to high-intensity intermittent exercise. AIM: To examine how training specificity impacts high-sensitivity cardiac troponin T (hs-cTnT) release. METHODS: Nine professional floorball players participated in the study, which comprised two different exercise tests: a continuous incremental cycle ergometer test and a Yo-Yo Intermittent Recovery 2 (Yo-Yo IR2) test. Serial assessment of hs-cTnT was performed after the cycle ergometer test and the Yo-Yo IR2 test (baseline, 0, 2, 6, and 24 h). RESULTS: No hs-cTnT elevation above the myocardial damage cutoff (≥ 14 ng/L) was shown after the cycle ergometer test, whereas hs-cTnT levels rose over the cutoff in three of nine participants after the Yo-Yo IR2 test. The hs-cTnT levels peaked at 6 h after both tests, but were significantly higher after the Yo-Yo IR2 test compared to the cycle ergometer test (median hs-cTnT concentration 10.6 ng/L vs 7.8 ng/L, P = 0.038). All levels returned to baseline within 24 h. CONCLUSION: In professional athletes adapted to high-intensity intermittent exercise, hs-cTnT was significantly elevated after intermittent but not continuous exercise. This principle of specificity training should be considered when designing future studies to avoid misinterpretation of hs-cTnT elevation.