A strongly increased troponin value after strenuous sports activities could be an early indication of a heart attack risk, a study from the Netherlands finds.
Long-distance runners, cyclists that underwent a strenuous mountain route stage, and other high endurance athletes often show increased troponin levels. It is unclear however whether this finding is clinically relevant, and it is still the subject of discussion. A recent study looked into whether there is actually a connection between exercise-induced troponin and cardiovascular diseases.
The Dutch study recruited a total of 725 subjects, 62% of whom were men. The participants were on average 61 years old. All of them had to walk between 30 and 55 kilometers. Before the march and immediately afterward, the researchers determined troponin I level in the participants’ blood.
About 1% of the test subjects had troponin values > 0.040 μg/l before the walk, while after the activity, this number rose to 9% (p < 0.001). The participants were followed up for a mean duration of 43 months. In 62 subjects a cardiovascular event occurred; 29 died and there was at least one severe cardiovascular event (MACE: major adverse cardiovascular event) in 33 cases. In those subjects who had a troponin value of ≤ 0.040 μg/l before the start of the study, 7% suffered a cardiovascular event. The hazard ratio (HR) was 2.48 (95%-KI: 1.29-4.78) after adjustment of age, gender, and cardiovascular risk factors as well as cardiovascular pre-existing conditions. The observed correlation between increased troponin levels after exercise and MACE was particularly observed in those subjects who did not have any cardiovascular disease prior to the start of the study.
The results suggest that an elevated troponin level after exercise may be an early marker for future cardiovascular events in both exercised and unexercised individuals. However, the significance of the work is limited above all by the fact that the troponin tests used were not highly sensitive. Furthermore, the short duration of the study and the small number of subjects reduce the significance of the study. The authors also emphasized that their results were not valid for other sports or in general.
Original study:
Aengevaeren VL et al., Exercise-Induced Cardiac Troponin I Increase and Incident Mortality and Cardiovascular Events; Circulation 2019; doi:10.1161/CIRCULATIONAHA.119.041627