Effect of High-Sodium Beverage on Rehydration Following Exercise-Induced 2% Dehydration

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Watts, Amanda L
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Exercise-induced dehydration is dehydration that develops during exercise. Exercise-induced dehydration can markedly impair performance and many recommendations have been published to avoid this repercussion. Several beverages have been studied to gauge their effectiveness at rehydrating following exercise-induced dehydration. A new beverage recently introduced to the market is BANa, which has a high sodium content. In this study, BANa (BAN) was compared to plain water (PW), coconut water (CW), and a carbohydrate-electrolyte sports drink (SD) for their rehydrating abilities. Six volunteers (mean age and VO2peak of 21.5 ± 0.8 years and 35.1 ± 10.8 ml min kg-1 respectively) exercised at 60% of VO2peak in a room heated to 90° until 2% of their body weight was lost. After exercise the subject sat for 2 hours and drank a volume of PW, CW, SD and BAN on different occasions representing 120% of the fluid lost. Blood and urine samples, as well as body weight, were taken throughout. Each fluid was consumed in 3 portions representing 50%, 40%, and 30% of the 120% fluid loss at 0, 30, and 60 min of the 2-hour rehydration period. Urine and blood samples were collected to measure USG, hemoglobin and hematocrit. Hemoglobin and hematocrit were then used to calculate plasma volume. There were no significant differences found for any of the measured variables except for a time effect for USG, indicating that our dehydration-rehydration protocol was effective. Also, there was a trend toward BAN maintaining plasma volume the best. In conclusion, all tested beverages are capable of promoting rehydration and little difference is seen between the four tested conditions. However, BAN seems to be most effective at retaining plasma volume.
hydration, dehydration, rehydration, exercise, fluid balance, water, coconut water, sports drink, BANa