Effects of a moderate intake of beer on markers of hydration after exercise in the heat: a crossover study

Background: Exercise in the heat causes important water and electrolytes losses through perspiration. Optimal rehydration is crucial to facilitate the recuperation process after exercise. The aim of our study was to examine whether a moderate beer intake as part of the rehydration has any negative effect protocol after a short but dehydrating bout of exercise in the heat. Methods: Sixteen active male (VO2max, 56 +/- 4 mL/kg/min), were included in a crossover study and performed a dehydrating exercise (<= 1 h running, 60 %VO2max) twice and 3 weeks apart, in a hot laboratory setting (35 +/- 1 degrees C, humidity 60 +/- 2 %). During the two hours following the exercise bouts participants consumed either mineral water ad-libitum (W) or up to 660 ml regular beer followed by water ad-libitum (BW). Body composition, hematological and serum parameters, fluid balance and urine excretion were assessed before, after exercise and after rehydration. Results: Body mass (BM) decreased (both similar to 2.4 %) after exercise in both trials. After rehydration, BM and fat free mass significantly increased although BM did not return to baseline levels (BM, 72.6 +/- 6.7 to 73.6 +/- 6.9; fat free mass, 56.9 +/- 4.7 to 57.5 +/- 4.5, no differences BW vs W). Beer intake did not adversely affect any measured parameter. Fluid balance and urine excretion values did not differ between the rehydration strategies. Conclusions: After exercise and subsequent water losses, a moderate beer (regular) intake has no deleterious effects on markers of hydration in active individuals.