Body weight changes and voluntary fluid intakes of beach volleyball players during an official tournament

The aim of this study was to calculate sweat rates (measured by weight changes), voluntary fluid intakes, and fluid balance of beach volleyball players during a tournament. Data was collected during the 3 days of the tournament for male players (n=47) age M=26.17 (S.D.=5.12) years old. Participants were weighed before the warm up and they reweighed immediately after the game. The differences in body weight were calculated in grams. The voluntary fluid intake of players during the game was also recorded by observers, whose inter and intra reliability were evaluated (inter r=.89 and intra reliability r=.93). Fifty matches took place with a M=42.2 min duration per match. A wide individual variation appeared in fluid intake and sweat loss. The calculated average sweat rate, fluid intake rate and fluid balance of players during each match were M = 1440 ml, M = 731 ml and M = -0.8%, respectively. Air temperature ranged from 26 to 38 degrees C (M = 33.58 degrees C, S.D. -2.8) and humidity from 42% to 75% (M = 56.04%, S.D. = 8.7) and both were measured in each day of tournament, at the beginning and at the end of each game. Although players' dehydration (-0.8%) was of mild level, it was more or less the same as it was reported in other team sports studies. ANOVA did not prove differences between elite and non-elite athletes in sweat loss and fluid intake (p >.01). Sweat rate was associated only with humidity (r=.99, p <.01) and with fluid intake (r=.315, p <.05). The athletes should be aware of the great significance of fluids and to intake greater quantities in order to prevent weight loss and at the same time loss of vital elements that would cause their performance to decline. (c) 2007 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.