Changes In Endothelium Markers During A Summer Ultra-endurance Road Cycling Event In The Heat

Abstract

PURPOSE: To assess the impact of completing a 164-km road cycling event performed in a hot environment (Wichita Falls, TX in August), on endothelium markers in men and women. METHODS: A total of 37 participants, 28 men and 9 women, mean age of 51.8 ± 9.5 y completed the ride. Plasma samples were collected the morning before (Pre) and immediately after (IP) completing the ride. We examined associations between changes in pre- and post-ride concentrations of endothelial cell markers - endothelin-1 (ET-1), p-selectin, and intercellular adhesion molecule 1 (I-CAM1) - as a function of race time and participant characteristics. RESULTS: All of the endothelial cell markers (ET-1, p-selectin, and I-CAM1) increased significantly from Pre to IP. Controlling for Pre values: completion time was positively correlated with ET-1 (r=0.42, p<0.01) and negatively related to p-selectin (r=-0.42, p<0.001); percent body fat was negatively correlated with p-selectin (r=-0.40, p<0.01) and I-CAM1 (r=-0.35, p<0.05)). In addition, males had greater concentrations of I-CAM1 (d=1.32, p<0.01) and p-selectin (d=0.84, p<0.05) than females. CONCLUSION: Completing a 164-km ride in the heat resulted in increased concentrations of selected endothelial cell markers in both men and women. Whereas this may suggest endothelial cell injury, it is unclear whether this activation leads to an increased risk of blood clot formation.