Immediate and 24-h post-marathon cardiac troponin T is associated with relative exercise intensity.

PURPOSE We aimed at exploring whether cardiopulmonary fitness, echocardiographic measures and relative exercise intensity were associated with high-sensitivity cardiac troponin T (hs-TNT) rise and normalization following a marathon. METHODS Nighty-eight participants (83 men, 15 women; 38.72 ± 3.63 years) were subjected to echocardiographic assessment and a cardiopulmonary exercise test (CPET) before the race. hs-TNT was measured before, immediately after and at 24, 48, 96, 144 and 192 h post-race. Speed and mean heart rate (HR) during the race were relativized to CPET values: peak speed (%VVMAX), peak HR (HR%MAX), speed and HR at the second ventilatory threshold (HR%VT2 and %VVT2). RESULTS Hs-TNT increased from pre- to post-race (5.74 ± 5.29 vs. 50.4 ± 57.04 ng/L; p < 0.001), seeing values above the Upper Reference Limit (URL) in 95% of the participants. At 24 h post-race, 39% of the runners still exceeded the URL (High hs-TNT group). hs-TNT rise was correlated with marathon speed %VVT2 (r = 0.22; p = 0.042), mean HR%VT2 (r = 0.30; p = 0.007), and mean HR%MAX (r = 0.32; p = 0.004). Moreover, the High hs-TNT group performed the marathon at a higher Speed %VVT2 (88.21 ± 6.53 vs. 83.49 ± 6.54%; p = 0.002) and Speed %VVMAX (72 ± 4.25 vs. 69.40 ± 5.53%; p = 0.009). hs-TNT showed no significant associations with cardiopulmonary fitness and echocardiographic measures, except for a slight correlation with left ventricular end systolic diameter (r = 0.26; p = 0.018). CONCLUSION Post-race hs-TNT was above the URL in barely all runners. Magnitude of hs-TNT rise was correlated with exercise mean HR; whereas, its normalization kept relationship with marathon relative speed.