Introduction: Strenuous exercise induces significant increases in cardiac biomarkers. However, it is still unclear whether this is caused by cardiomyocyte necrosis or secondary mechanisms such as ischemia, cardiac energy deficiency, increased inflammation, or renal dysfunction.
Methods: Therefore, we investigated cardiac biomarkers (high-sensitive cardiac troponin T (hs-cTnT), N-terminal pro-brain natriuretic peptide (NT-proBNP), heart-type fatty acid-binding protein (h-FABP)), inflammation markers (high-sensitive C-reactive protein (hs-CRP), interleukin-6 (IL-6), interleukin-10, tumor necrosis factor-α), and renal function (cystatin C) in 102 healthy men age 42 ± 9 yr before and 0, 24, and 72 h after a marathon.
Results: Kinetics of hs-cTnT revealed a peak immediately after the race (V3) that decreased rapidly to pretest values within 72 h (V5) (median (interquartile range) = 31.07 (19.25-46.86) ng·L(-1) at V3 and 3.61 (3.20-6.70) ng·L(-1) at V5, P < 0.001). NT-proBNP and h-FABP kinetics showed a similar pattern (NT-proBNP = 92.6 (56.9-149.7) ng·L(-1) at V3 and 34.9 (21.7-54.5) ng·L(-1) at V5; h-FABP = 44.99 (32.19-64.42) μg·L(-1) at V3 and 7.66 (5.64-10.60) μg·L(-1) at V5; always P < 0.001). Proinflammatory markers, such as IL-6 and hs-CRP, and renal dysfunction were significantly augmented immediately after the race (before the race compared with maximum after the race: IL-6 = 15.5-fold, hs-CRP = 28-fold, cystatin C = 1.22-fold, all P < 0.001). These increases were not related to the increase of hs-cTnT. Similarly, training history, finishing time, and exercise intensity were not associated with changes of hs-cTnT.
Conclusions: Cardiac biomarkers were increased immediately after a marathon race. Interestingly, values returned to normal levels within 72 h. These kinetics with a sharp peak indicate that cardiac necrosis during marathon running seems very unlikely but may be explained by altered myocyte metabolism.
Trial registration: ClinicalTrials.gov NCT00933218.