The kinetics of cardiac troponin T release during and after 1- and 6-h maximal cycling trials

Objectives: In this study, the effects of short-duration high-intensity exercise and long-duration exercise on highsensitivity cardiac troponin T (hs-cTnT) levels were compared.Methods: Twelve male amateur cyclists performed 1-and 6-h cycling trials.In both exercise trials, hs-cTnT was assessed at rest, immediately postexercise and at 1, 3, 6, 12, and 24 h postexercise.Additionally, hs-cTnT levels were assessed every hour during the 6-h trial.Results: Exercise resulted in an increase in hs-cTnT levels in all subjects.Circulating hs-cTnT levels increased in both exercise trials (p < 0.001), with higher peak values occurring after the 1-h trial compared with those of the 6-h trial (p = 0.023).The upper reference limit (URL) exceeded 83 % of the participants in the 1-h trial and 42 % of the participants in the 6-h trial.There was substantial individual variability in peak hs-cTnT in both trials.Values of hs-cTnT were greater after exercise than during exercise for the 6-h trial.For both exercise trials, the maximum postexercise hs-cTnT values correlated with the %HR MAX (r = 0.906 for the 1-h trial, r = 0.735 for the 6-h trial).For the 1-h trial, the maximum postexercise hs-cTnT values were observed at 3 h in all subjects.No significant difference in the hs-cTnT values was observed for the 6-h trial during the first 12 h postexercise.Conclusions: Our results demonstrated greater hs-cTnT levels in young male participants after a 1-h cycling trial than after a 6-h cycling trial, despite a substantially greater energy expenditure and total external work completed in the 6-h trial.Postexercise hs-cTnT values are associated with relative exercise intensity.