Changes in serum cardiac troponins following a 21-km run in junior male runners

Aim. This study was designed to examine the appearance and clearance characteristics of serum cardiac troponin T (cTnT) and I (cTnI) in junior runners after an exhaustive 21-km run. The dependence of the alternations of the cardiac troponins on the runners' training status reflected in training years, running ability and physiological profile at ventilatory threshold (Th _vent) was also examined. Methods. Ten trained male adolescents (16.2±0.6 years) performed 21-km run and graded treadmill exercise with maximum effort on two different days. cTnT and cTnI immediately before and 2,4 and 24 hours after exercise were measured in the 21-km trial. The parameters at Thvent including the running speed (Th_vent-Speed) and V̇O ₂ (Th_vent-V̇O₂) were identified in the graded exercise trial. Results. Serum cTnT and cTnI in 6 of the 10 subjects measured 4 hours after the 21-km run were above the myocardial injury cutoffs of 0.03 and 0.09 ng·mL^-1, respectively, but returned towards pre-exercise levels within 24 hours that were not in the same manner observed in the clinical situation of myocardial infraction. The 6 subjects' training status was generally lower than that of the rest 4. Further, subjects' 4-h serum cTnT and cTnI were negatively related to their training years, Th _vent-Speed and Th_vent-V̇O₂, and positively related to their personal best in half- and full-marathon races (r ²≥36%, n=10). Conclusions. Such findings implied that clinicians based the diagnosis of long-distance run-induced myocardial infraction in novice junior runners upon the transient postexercise elevations of cardiac troponins alone should be with caution.