During play, ice hockey goaltenders routinely dehydrate through sweating and lose ≥2% body mass, which may impair thermoregulation and performance. 

Purpose: This randomized, crossover study examined the effects of mild dehydration on goaltender on-ice thermoregulation, heart rate, fatigue, and performance. 

Methods: Eleven goaltenders played a 70-minute scrimmage followed by a shootout and drills to analyze reaction time and movements. On ice, they either consumed no fluid (NF) and lost 2.4% (0.3%) body mass or maintained body mass with water (WAT) or a carbohydrate-electrolyte solution (CES). Save percentage, rating of perceived exertion, heart rate, and core temperature were recorded throughout, and a postskate questionnaire assessed perceived fatigue. 

Results: Relative to NF, intake of both fluids decreased heart rate (interaction: P =.03), core temperature (peak NF = 39.0°C [0.1°C], WAT = 38.6°C [0.1°C], and CES = 38.5°C [0.1°C]; P =.005), and rating of perceived exertion in the scrimmage (post hoc: P <.04), as well as increasing save percentage in the final 10 minutes of scrimmage (NF = 75.8% [1.9%], WAT = 81.7% [2.3%], and CES = 81.3% [2.3%], post hoc: P <.04). In drills, movement speed (post hoc: P <.05) and reaction time (post hoc: P <.04) were slower in the NF versus both fluid conditions. Intake of either fluid similarly reduced postskate questionnaire scores (condition: P <.0001). Only CES significantly reduced rating of perceived exertion in drills (post hoc: P <.05) and increased peak movement power versus NF (post hoc: P =.02). Shootout save percentage was similar between conditions (P =.37). 

Conclusions: Mild dehydration increased physiological strain and fatigue and decreased ice hockey goaltender performance versus maintaining hydration. Also, maintaining hydration with a CES versus WAT may further reduce perceived fatigue and positively affect movements.