Cardiac Biomarkers Release in Preadolescent Athletes After an High Intensity Exercise.

INTRODUCTION: An elevation of cardiac troponins has been described in healthy athletes after endurance exercises. The clinical significance of this increase is unclear and the lack of awareness of this phenomenon may lead to inappropriate management of these subjects. AIM: We sought to determine wether an intensive cycling training could determine a biomarkers elevation.
METHODS: We evaluated serum high sensitivity cardiac troponin T, NH(2)-terminal pro-brain natriuretic peptide, CK-MB and CK in 21 healthy male preadolescent athletes (age 9.2 ± 1.7 years) after an intensive cycling training prolonged until muscular exhaustion (mean duration 16'41″). During exercise heart rhythm and rate were monitored with Holter.
RESULTS: 62% of the group had an elevation of cardiac biomarkers: specifically, 6 children had an increase in troponin levels; 3 of them had an elevation of pro-brain natriuretic peptides as well. Pro-brain natriuretic peptides resulted increased in 9 subjects. There was no relation between troponin elevation and heart rate, age or exercise duration; subjects with increased pro-brain natriuretic peptides had mean and maximal heart rates lower than children with normal natriuretic peptides levels. Other sports were performed in 50% of subjects with normal troponins and only in 17% of those with increased values.
CONCLUSIONS: A short, high-intensity exercise caused an elevation of cardiac biomarkers in 62% of our subjects. The grade of training may influence the release of troponin and this increase is probably related to a temporary discrepancy between O2 delivery and consumption. Increases in natriuretic peptides levels are possibly expression of different adaptations to exercise.