COMPARISON OF REHYDRATION EFFECTS OF COCONUT WATER VS. LOW CALORIE SPORTS DRINK ON REHYDRATION

T. M. Norton, B. Rockefeller, C. Curtis, & W. M. Silvers Whitworth University, Spokane, WA Hypohydration impairs exercise performance and causes adverse health effects. Compared to plain water (PW) coconut water (CW) and carbohydrate electrolyte beverage (CEB) are reportedly more effective for rehydration. PURPOSE: To compare the rehydration effects of CW and a low calorie CEB after exercise-induced hypohydration. The research hypotheses were 1) both beverages would effectively rehydrate and 2) CW would rehydrate more effectively than CEB. METHODS: A convenience sample of 13 recreationally active college-aged men and women volunteered for participation. Participants were initially weighed and then asked to provide a urine sample to determine a base line specific gravity (SG1). Participants then ran on a treadmill at a comfortable, self-selected pace in a temperature-controlled chamber (32oC) until 2% of their initial body weight was lost. After the desired weight loss was achieved the participants provided another urine sample to determine a hypohydrated specific gravity (SG2). Participants were then allotted 1 hour to drink 120% of the weight lost during exercise with either CW coconut water or CEB (randomly ordered). After the full amount of liquid had been consumed participants sat for 1 hour outside of the chamber, after which a final urine sample was taken to determine the rehydrated specific gravity (SG3). A factorial ANOVA with repeated measures was used to determine which beverages were able to produce significant rehydration and to compare the difference in rehydration outcome between beverage conditions. Statistical significance was set at an alpha level of p ≤ 0.05. RESULTS: Within beverages there was a significant difference between SG2 and SG3 (1.015±0.007 vs. 1.008± 0.005; p = 0.003). Between beverages there was no significant difference between CEB and CW (1.011±0.008 vs. 1.006± 0.005; p = 0.902). CONCLUSION: This data indicates that both drinks effectively rehydrated the participants following exercise-induced hypohydration, but there was no significant difference in rehydration between the two beverages