Abstract
BACKGROUND/OBJECTIVES: Hypo-hydration is a major health concern that affects performance and is associated with increasing morbidity and growing health care costs. There is an emerging interest in optimizing hydration and identifying how factors such as ingestion rate and beverage composition affect hydration. This study examined three beverages with varying ingestion rates and measured markers of hydration. METHODS: Thirty healthy, active participants between the ages of 18 and 45 years were given three different beverages on three separate days. The beverages were of identical volumes (1 L), but differed in the rate of ingestion, carbohydrate content and electrolyte content. Beverage 1 and water alone were both consumed at a metered rate of one liter over four hours, whereas Beverage 2 was used as a positive control and was consumed at a bolus rate of one liter in 30 min. RESULTS: After six hours, Beverage 1 significantly improved markers of hydration compared to water alone or Beverage 2. Beverage 1 decreased cumulative urine output vs. water alone by 32% (absolute difference -0.33 L; CI ± -0.16 to -0.51) and vs. Beverage 2 by 26% (absolute difference -0.26 L; CI ± -0.13 to -0.38). Beverage 1 increased the beverage hydration index vs. water alone by 64% (absolute difference +0.64 L; CI ± 0.36 to 0.92) and vs. Beverage 2 by 48% (absolute difference +0.53 L; CI ± 0.30 to 0.76). CONCLUSIONS: Beverage 1 is superior to water alone at improving hydration when it is ingested at similar rates. Moreover, metered ingestion of Beverage 1 improved hydration compared to a bolus ingestion of Beverage 2, this could be due to the dissimilar ingestion rates and/or beverage composition.