Highly increased Troponin I levels following high-intensity endurance cycling may detect subclinical coronary artery disease in presumably healthy leisure sport cyclists: The North Sea Race Endurance Exercise Study (NEEDED) 2013

Background: Circulating cardiac troponin levels increase following prolonged intense physical exercise. The aim of this study was to identify participants with highly elevated cardiac troponins after prolonged, high intensity exercise, and to evaluate these for subclinical coronary artery disease. Methods and results: Ninety-seven recreational cyclists without known cardiovascular disease or diabetes, participating in a 91km mountain bike race were included, 74 (76%) were males, age: 43 +/- 10 years, race duration: 4.2 (3.6-4.7) h. Blood samples, rest electrocardiogram and physical examination were obtained 24h prior to, and at 0, 3 and 24h following the race. Median cardiac troponin I level at baseline: 3.4 (2.1-4.9) ng/l (upper limit of normal: 30.0ng/l). There was a highly significant (p < 0.0001) increase in circulating cardiac troponin I in all participants: immediately following the race; 50.5 (28.5-71.9) ng/l, peaking at 3h 69.3 (42.3-97.7) ng/l and declining at 24h: 14.2 (8.5-27.9) ng/l. No cyclist had symptoms or rest electrocardiogram changes compatible with coronary artery disease during or following the race. Coronary artery disease was detected by coronary angiography in the three cyclists with the three of the four highest cardiac troponin values (>370ng/l) at 3 and 24h following the race. Computed tomographic coronary angiography was performed in an additional 10 riders with the subsequently highest cardiac troponin I values, without identifying underlying coronary artery disease. Conclusions: This study suggests that there is a pathologic cardiac troponin I response following exercise in individuals with subclinical coronary artery disease. This response may be associated with an excessive cardiac troponin I increase at 3 and 24h following prolonged high-intensity exercise.