Cardiac troponin patterns in athletes completing Norseman Xtreme Triathlon

Cardiac troponins (cTns) are frequently measured in patients when suspecting coronary artery disease (CAD). However, recent studies suggest that elevated cTns following exercise may predict CAD and increased mortality. Although the mechanisms underlying postexercise cTn increase remain unclear, the cardiac troponin I (cTnI)/cardiac troponin T (cTnT) ratio shows promise for distinguishing cardiac pathologies. This study assesses the dynamics of cTnI and cTnT concentrations and the cTnI/cTnT ratio in serum samples collected 1-2 days before, within 1 hour after and 11-24 hour after completing Norseman Xtreme Triathlon.

Using Abbott's STAT High Sensitive Troponin-I assay and Roche's Elecsys Troponin T hs assay, we measured cTnI and cTnT in venous serum of 93 adult triathletes.

Concentrations of cTnI, cTnT and cTnI/cTnT ratio increased from baseline to immediately after the race (cTnI median (25-75 percentile) from (3 (2-6) ng/L) to 69 (37-156) ng/L, cTnT from (6 (5-8) ng/L) to 40 (24-55) ng/L and cTnI/cTnT from (0.5 (0.3-0.8)) to 2.1 (1.5-2.9), all p<0.001). Serum cTnI and cTnT concentrations remained elevated the day after the race, whereas the cTnI/cTnT ratio declined the day after the race compared with baseline levels. Three participants displayed higher cTnI levels, and 14 participants showed higher cTnI/cTnT ratios the day after the race compared with immediately after.

Serum concentrations of cTnI, cTnT and the cTnI/cTnT ratio increase immediately after a long-distance triathlon, and concentrations trend towards normalisation the next day. The clinical implications are unknown and warrant further investigation.