Exercise-induced cardiac troponins in long-distance walkers: a preliminary observation.

Abstract Background Elevated concentrations of cardiac troponin (cTnT and cTnI), the preferred biomarker to diagnose myocardial infarction, can be detected in other (cardiac) conditions and even post-exercise. Whether these exercise-induced elevations reflect a (patho)physiological process, as well as their clinical implications, is unknown. In this preliminary study, pre- and post-exercise high-sensitivity cTn (hs-cTnT and hs-cTnI) concentrations were investigated in long-distance walkers. Purpose Gain insight of elevated cTnT and cTnI concentrations post-exercise in long-distance walkers. Methods From 478 participants, walking 30-50 km on the first day of the 4Daagse 2023, blood-samples were collected pre- and <6h post-exercise. In addition, health and exercise questionnaires were conducted. Hs-cTnT (Roche) and hs-cTnI (Abbott) concentrations were determined and the unisex, female and male Upper Reference Limit (URL) were according to package inserts (Roche: 14 ng/L, 9 ng/L, 16 ng/L, Abbott: 26 ng/L, 16 ng/L, 34 ng/L). Results Participants (51% female) were 57±7.6 years (mean±SD). At baseline, median [IQR] hs-cTnT and hs-cTnI were 5.9 [4.5-8.0] and 1.7 [1.1-2.9] ng/L, which increased significantly post-exercise to 8.7 [6.4-12.4] ng/L (P<0.001) and 5.2 [3.1-9.5] ng/L (P<0.001). Pre-exercise, the unisex-URL for hs-cTnT was exceeded by 4.4% walkers and for sex-specific URLs, this resulted in 6.6% females and 3.8% males. For hs-cTnI, the unisex-URL was exceeded by 0.6%, as for sex-specific URLs, 0.8% females and 1.3 % males surpassed. Post-exercise, hs-cTnT URLs were exceeded by 18.2%, 35.1%, 16.5% and as for hs-cTnI post-exercise, 7.3%, 11.6%, 3.8% for unisex, female and male. Alternatively, the absolute median delta difference was 2.4 [0.9-4.6] ng/L for hs-cTnT and 3.0 [1.6-5.7] ng/L hs-cTnI. Conclusion Post-exercise long-distance walkers had significantly increased hs-cTnT and hs-cTnI concentrations, in particular in women when using sex-specific cutoffs. In order to understand clinical implications of these findings, status of cardiac vascular diseases, risk-factors and exercise characteristics will be analyzed in the future.