Influence of maturational status in the exercise-induced release of cardiac troponin T in healthy young swimmers.

Objectives: To determine the influence of maturational status on the release of cardiac troponin T (cTnT) induced by a bout of 30min, high-intensity, continuous exercise.

Design: Quasi-experimental, cross-sectional study.

Methods: Seventy male, young, well trained swimmers (age range 7-18 years, training experience 1-11 years) were classified by maturational stages: Tanner stage I (n=14), II (n=15), III (n=15), IV (n=13), and V (n=13). Participants underwent a distance-trial of 30min continuous swimming, and cTnT was measured before, immediately after and 3h after exercise. Changes in cTnT over time were compared among groups, and associated with exercise load.

Results: Basal cTnT was higher in Tanner-V (3.8-8.1ng/L) compared with I (1.5-5.5ng/L, p<0.001), II (1.5-4.5ng/L, p<0.001) and III (1.5-6.8ng/L, p=0.003), and in IV (1.5-6.3ng/L) compared with II (p=0.036). Maximal elevations of cTnT from baseline were notable (p<0.001) and comparable among maturational stages (p=0.078). The upper reference limit for myocardial injury was exceeded in 35.7% of the participants, without differences among groups (p=0.18). Baseline cTnT correlated with participant characteristics, and maximal cTnT elevations from baseline with exercise internal load (%HRpeak, r=0.34, p= 0.003; %HRmean, r=0.28, p=0.02).

Conclusions: Maturational status influences positively absolute pre- and post-exercise cTnT but not its elevation after a bout of 30min, high-intensity, continuous exercise.