Gut Leakage and Cardiac Biomarkers after Prolonged Strenuous Exercise

Transient increase in the cardiac biomarkers troponin T (cTnT) and NT-proBNP are observed during strenuous exercise, even in healthy athletes. Gut leakage, the translocation of bacterial lipopolysaccharide (LPS) into the circulation, is associated with atherosclerosis and cardiovascular disease but has also been reported after prolonged endurance exercise. We aimed to explore the link between exercise-induced gut leakage and cardiac biomarker release.

Participants in Norseman Xtreme Triathlon (Norseman) were included ( n = 44, age 43 ± 9 yr, 9 [21%] women). Blood samples were taken before and immediately after the race for the determination of biomarkers. cTnT and NT-proBNP were measured by conventional methods. Gut leakage marker LPS was measured by the kinetic, chromogenic limulus amebocyte lysate assay method, whereas LPS-binding protein (LBP), soluble cluster of differentiation 14 (sCD14), and intestinal injury marker intestinal fatty acid-binding protein (I-FABP) were measured by enzyme-linked immunosorbent assay.

Median (25, 75 percentiles) finish time was 14 h 33 min (13 h 42 min, 15 h 29 min). TnT and NT-proBNP increased significantly to 38 ng·L -1 (27, 56) and 495 ng·L -1 (310, 828) after the race ( P < 0.001, both). LBP and sCD14 also increased significantly ( P < 0.001, both), as did I-FABP ( P = 0.003), whereas LPS remained unchanged ( P = 0.13). No significant correlations between changes in gut leakage markers and changes in cardiac biomarkers were observed after adjusting for multiple testing.

Cardiac and gut leakage biomarkers increased after Norseman Xtreme triathlon. However, changes in these biomarkers were not intercorrelated, suggesting that the exercise-induced increase in cardiac and gut leakage biomarkers occurs independently of each other.