Case report—very high cardiac troponin I concentrations following endurance exercise: a complex finding

Background: Exercise is known to increase cardiac troponin I (cTnI) concentrations, whereas the magnitude of exercise-induced elevations shows large inter-individual variability. Severely elevated cTnI concentrations post-exercise may be indicative of increased cardiac vulnerability and subclinical cardiovascular pathology. Case summary: We present the case of a 66-year-old male recreational endurance athlete who showed remarkably high post-exercise cTnI concentrations after a long-distance walking event, but not after a cycling event. He did not experience any signs or symptoms of cardiac distress. Independent of his cTnI assessments, he underwent cardiac assessment, which revealed an intermediate stenosis of the proximal left anterior descending coronary artery, whereas functional testing did not reveal ischaemia or infarction. Discussion: There is currently no consensus on the clinical interpretation of exercise-induced cTn elevations. Our athlete showed a very high cTnI concentration post-exercise, without evidence of ischaemia or myocardial infarction. Accordingly, we summarize other explanations that may have caused the elevated cTnI concentrations, including (1) progression of coronary atherosclerosis, (2) other underlying cardiac conditions, (3) exposure to exercise-related cardiac stress, (4) dehydration, and (5) cardiac vulnerability. This case with a large intra-individual difference in post-exercise cTn concentrations illustrates the challenging interpretation of exercise-induced cTn elevations. Future studies examining the underlying mechanisms of exercise-induced cTn release and its clinical sequelae are warranted to improve differentiation between physiological and pathological cTn elevations in athletes.