Effect of Rehydration with Mineral Water on Cardiorespiratory Fitness Following Exercise-Induced Dehydration in Athletes

Background: The aim of the present study was to examine the effect of rehydration with mineral water on cardiorespiratory fitness in athletes. Methods: Twenty athletes (age 21.7 ± 3 years) underwent a random, crossover design experimental trial. Three visits were arranged, with the first for baseline measurement. The second visit included three phases (pre-dehydration, post-dehydration, and post-rehydration), with either Zamzam (mineral water) or bottled water (control water) used. The third visit was similar to the second visit, but with an exchange of the type of water used. Cardiorespiratory fitness and blood parameters were evaluated. Results were compared between Zamzam water and bottled water, and between the phases for each type of water. Results: No significant difference was found between Zamzam and bottled water for the cardiorespiratory fitness markers. However, Zamzam water maintained cardiorespiratory functions including VO_2peak, VT1, VT2, and VE_peak, even with rehydration equivalent to 100% of the loss in body weight following exercise-induced dehydration (>2% loss in body weight). Rehydration with bottled water was associated with a significant reduction in both the VO_2peak and VE_peak. Conclusions: Rehydration with mineral water such as Zamzam is unlikely to impair cardiorespiratory fitness, even with an intake equal to 100% of the loss in body weight.