Rehydration with a caffeinated beverage during the nonexercise periods of 3 consecutive days of 2-a-day practices.

The purpose of this study was to assess the influence of rehydration with a caffeinated beverage during nonexercise periods on hydration status throughout consecutive practices in the heat. Ten (7 women, 3 men) partially heat- acclimated athletes (age 24 +/-1y, body fat 19.2 +/- 2 %, weight 68.4 +/- 4.0 kg, height 170 +/- 3 cm) completed 3 successive days of 2-a-day practices (2 h/practice, 4 h/d) in mild heat (WBGT = 23 C). The 2 trials (double-blind, random, cross-over design) included; 1) caffeine (CAF) rehydrated with Coca-Cola and 2) caffeine-free (CF) rehydrated with Caffeine-Free Coca-Cola. Urine and psychological measures were determined before and after each 2-h practice. A significant difference was found for urine color for the post-AM time point, F = 5.526, P = 0.031. No differences were found among other variables (P > 0.05). In summary, there is little evidence to suggest that the use of beverages containing caffeine during nonexercise might hinder hydration status.