The effect of water temperature and carbohydrate drink on intestinal epithelial injury, endotoxemia, splanchnic perfusion, and core temperature, during running in the heat

Abstract

Background: Prolonged exercise can result in splanchnic hypoperfusion and elevated core body temperature (Tcore), which can contribute to gastrointestinal injury and endotoxemia. The effects of fluid temperature and carbohydrate consumption during exercise on these variables are less clear. Objectives: The study aimed to determine the effects of the temperature of water and carbohydrate drinks on intestinal epithelial injury, endotoxemia, splanchnic perfusion, and Tcore during 60-minute of moderate-intensity running. Methods: Ten participants completed four 60-minute running trials at 70% VO2max with different types of hydration: no water (NW), ambient temperature water (ATW), cold water (CW), and cold carbohydrate water (CW+CHO). Doppler ultrasound of the superior mesenteric artery (SMA) and portal vein (PV) and blood for intestinal fatty acid binding protein (I-FABP) and lipopolysaccharide (LPS) levels were assessed before and after exercise. Tcore was continuously monitored during exercise. Results: I-FABP significantly increased in all trials (NW: 1045.85 ± 1571.73 pg/mL; ATW: 1940.83 ± 910.65 pg/mL; CW: 1567.87 ± 1069.36 pg/mL; and CW+CHO: 779.92 ± 654.40 pg/mL; p < 0.05 for all). LPS showed no significant differences within each trial and between all trials (p >0.05 for all). All fluid replacement trials exhibited a significant reduction in splanchnic hypoperfusion in both SMA and PV compared to NW (p