Is drinking water ad libitum sufficient to stay euhydrated throughout an hour of ice hockey practice

Introduction: The effects of carbohydrate and electrolyte containing sports drinks on hydration status has been investigated in ice hockey players. Unfortunately, no study has yet examined if a change in any hydration markers occur during an ice hockey practice or game when subjects are allowed to only drink water. Aim: The aim of this study was to determine how hockey players’ hydration level, measured as plasma sodium concentration, is affected by an hour of on-ice practice whilst exclusively drinking water to thirst. Subjects: Twenty- one male competitive hockey players (18.5 ± 1.4 years of age), playing in the second highest division of the Swedish junior J20 hockey league. Method: Subjects were tested during two sessions. During the first session a baseline plasma sodium value was measured using a capillary blood sample. For the second session subjects were measured for weight and plasma sodium concentration before and after an hour of on-ice practice. Subjects were instructed to drink water ad libitum during the practice session and intensity was measured using heart rate monitors. Sweat loss could be calculated using the change in body weight added to the measured drinking quantity. Results: No statistical difference was found for the plasma sodium values between baseline, pre and post measures. No correlation was found between difference in sodium concentration (pre-post) and water consumed as well as between difference in sodium concentration and sweat rate. Conclusion: It is sufficient during intermittent sports practices lasting one hour to drink water ad libitum in order to not affect hydration status in the form of plasma sodium concentration. KEYWORDS: Hydration, dehydration, drinking, fluid, water, electrolyte, ad libitum, ice hockey.