To determine the prevalence of elevated troponin levels after a marathon, and test for an association with reduced renal clearance.

Prospective observational study of entrants running the full (42 km) 2007 Perth Marathon, Western Australia.

Elevated troponin levels (≥ 0.1 μg/L) after the race; pre- and post-race survey data, and biochemical parameters.

27% of runners (92/346) enrolled in the study, of whom 88 (96%) completed it. Most were men (71%; 65/92); mean age was 43.1 years (SD, 9.8 years; range, 25–64 years) and mean body mass index (BMI) was 24.1 kg/m2. Raised troponin levels were seen in 32% of participants (28/88), the highest being 1.4 μg/L. The strongest predictor for developing elevated troponin levels was a decrease in weight (odds ratio [OR], 2.15; 95% CI, 1.27–3.65). Creatinine increase was also associated with elevated troponin levels (OR, 1.03; 95% CI, 1.01–1.06), but pre-race estimated glomerular filtration rate, age, sex, BMI, training factors, marathon experience and race time were not. Most runners (99%; 87/88) had elevated levels of ischaemia-modified albumin after the race.

Troponin level increases were common among marathon finishers. The strongest predictors were weight loss and an increase in creatinine levels, suggesting that reduced renal clearance is an associated factor. Further study is needed to determine the clinical significance of these findings, and to understand the mechanism.