Effect of competitive marathon cycling on plasma N-terminal pro-brain natriuretic peptide and cardiac troponin T in healthy recreational cyclists.

For a further depiction of exercise-induced cardiac dysfunction, N-terminal pro-brain natriuretic peptide (NT-pro-BNP) and cardiac troponin T (cTnT) were measured in recreational cyclists (n = 29) during the Otztal Radmarathon 2004. In all subjects, NT-pro-BNP significantly increased from 28 +/- 21 to 278 +/- 152 ng/L immediately after the race (p <0.001), decreased again on the following day, and returned to baseline values 1 week later. The mean percentage increase in NT-pro-BNP was 1,128 +/- 803%. CTnT, negative in all subjects before the race, increased transiently in 13 athletes (45%), with levels ranging from 0.043 to 0.224 mug/L in 8 of them (28%). One day after competition, cTnT had normalized in all athletes. Because of the typical release of kinetics, the deflection of NT-pro-BNP is considered to be the adequate volume regulatory response of a hemodynamically stressed heart to prolonged strenuous exercise. The observed kinetics of cTnT substantiate a release from the free cytoplasmatic pool due to the half-life of cytosolic cTnT. In healthy cyclists, transient increases in NT-pro-BNP and cTnT are more likely to reflect cardiac fatigue than injury.