Initial Hydration Status And Fluid Balance During Exercise Of Coaches And Fitness Trainers

Abstract

Current hydration guidelines emphasize the need to personalize fluid replacement strategies due to the extent variation on sweat rates between individuals. Also, it is recognized the importance of begin exercise well hydrated. Coaches and fitness trainers are key advising athletes and fitness enthusiast about having adequate hydration habits during exercise. PURPOSE: To determine initial hydration status and fluid balance during an exercise bout on coaches and fitness trainers who were participating in a sports science course. METHODS: Data were collected from 217 subjects (131 males and 86 females; age 30.6 + 8.9 years) during one 45-60 min exercise bout. Data were obtained during 4 separate sessions carried out at morning with a mean WBGT in the range of 17.9-23.8°C. Exercise bout consisted of intermittent exercise that combines martial arts and kickboxing (Body Combat). Subjects collected a urine sample from their first void of the morning and urine specific gravity (USG) was measured to determine initial hydration status. Subjects were weighted nude before and after the exercise session. During exercise, all subjects had free access to sports drinks bottles, which were weighed before and after training. Urine output was also monitored. RESULTS: 112 subjects (51.9%) appeared to be inadequately hydrated before exercise because they showed USG ≥1.020; 20 of them (9.3%) with a USG ≥1.030. The sweat volume lost was 880+356 mL (200-2162 mL) and 518+177 mL (88-1010 mL) for men and women respectively; fluid intake was 733+293 mL (38-1356 mL) in men and 600+299 mL (0-1740 mL) in women. On average, men replaced 98+74% and women 129+81% of their sweat losses, but this ranged from none to 600%. 144 subjects (66.4%) maintained their body mass (BM) (range from -0.5 to 0.5%), while 34 subjects (15.7%) gained more than 0.5% of their BM and 39 subjects (18%) had a BM loss >0.5% (only one subject finished exercise with a BM loss >2%). CONCLUSIONS: There was a large variation between individuals in the sweat rate and drinking behavior. A significant percentage of the subjects arrived already hypohydrated to the exercise bout, even though they have knowledge about hydration. Coaches and fitness trainers should develop a personalize hydration strategy to help athletes and match their sweat losses. Supported by Gatorade Sports Science Institute®