Background: The universal definition of myocardial infarction requires a rise and fall of cardiac troponin (cTn) where at least one measurement is above the 99th percentile level, combined with symptoms of cardiac ischemia and/or changes in EKG. However, cTn(T or I) rise has also been reported after strenuous exercise. Less is known about cTn elevation after normal physical activity.Methods: The level of high sensitivity cardiac troponin T (hs-cTnT) before and following completion of a bicycle stress test was measured in Li-heparin plasma from 19 healthy subjects. The blood samples were drawn at rest, immediately post, and at 1 h, 2 h and 3 h post-exercise.Results: Nine of the 19 participants (47%) showed a rise in hs-cTnT after the stress test, where all of them had their highest value in the last sample drawn 3 hrs after the termination of the stress test.Conclusion: A standard exercise test is often associated with an increase in hs-cTnT in healthy subjects. Release of troponin after heavy strain of long duration appears in many healthy subjects. Our finding is that this phenomenon also occurs after short duration strain. The mechanism behind this is obscure. In a clinical context small changes in troponin must be interpreted with caution.