Background: Equivocal studies exist on the potential of cardiac damage following prolonged endurance exercise. Aims: The aim of the study was to examine humoral markers of cardiac damage in female athletes during a 2-day mountain endurance race. Methods: Venous blood samples were drawn from seven female competitors prior to, and immediately following day-1 and day-2 of the event. The serum was analysed for total creatine kinase (CK), creatine kinase isoenzyme MB (CKMB), and cardiac troponin T (cTnT). Results: Elevations in CK and CKMB were apparent following day-1 of the event (mean ± SD; CK 84.1±54.6 mg/L vs. 387±276.7 mg/L, CKMB 2±1.7 mg/L vs. 5.9±1.7 mg/L) and subsequently rose further following race completion (CK 743±500 mg/L, CKMB 11.9±4.9 mg/L). Elevations in cTnT were noted in three competitors following day-1 cTnT (range 0.013–0.044 mg/L) and remained elevated in two competitors following day-2 (range 0.014–0.017 mg/L). Conclusions: The elevations in cTnT likely represent release from the cytosolic fraction. The mechanism responsible for such release is yet to be elucidated.
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