Fluid balance and electrolyte losses in collegiate male soccer players in practice and game under different environments.

The environment poses significant physiologic challenges to athletic performance. The purpose of this study was to investigate fluid balance and electrolyte losses in Chinese collegiate male soccer players during practices and games under different environments. Twelve male players were recruited across 38 practices (P) and 17 games (G) over a 9-month period, conducted in hot (H) and cool (C) environments, yielding four experimental conditions: G + H, P + H, G + C, and P + C. Fluid balance parameters comprised body mass loss (BML), urine specific gravity (USG), and sweat compositions. On-field running characteristics were collected only in games, including total distance covered (TD), number of sprints, fast run distance, accelerations, and decelerations. Pre-exercise USG indicated that > 50% of players began exercise in a hypohydrated status across four conditions. Players in G + C showed a higher proportion of ≥ 2% hypohydration, whereas players were overhydrated in G + H. Fluid balance parameters were significantly influenced by both exercise conditions and environments. Better running performance was found in G + C than G + H (p < 0.001). Both TD (r = -0.56, p < 0.001) and fast run distance (r = -0.54, p < 0.001) was inversely associated with %BML. Pre-exercise hypohydration remains a significant concern, regardless of exercise conditions or environments. TD and fast run distance may serve as practical indicators of post-game hydration status. Future guidelines aim at modifying drinking behaviors could help players maintain optimal hydration.