The Effect Of Sodium And Carbohydrate In A Rehydration Food On Subsequent Exercise Performance

The purpose of this study was to determine the effectiveness of two rehydration beverages on fluid restoration and metabolism on subsequent exercise following exerciseand heat-induced dehydration. Twelve male subjects were dehydrated by ~3 % of body mass with exercise and heat exposure. In a randomly assigned, counterbalanced design, subjects were rehydrated at room temperature with either 175 ml of chicken noodle soup (SOUP: Campbell Soup Company, Camden, NJ) or an artificially sweetened placebo (CON) at the beginning of the 120 min rehydration period and 20 min later. Water was ingested every 20 min during the remaining 100 min of rehydration. Soup contained 161.0 mmol/l Na, 5.3 mmol/l K, and 32.6 g total carbohydrate. CON contained 14.4 mmol/l Na, 16.0 mmol/l K, and no carbohydrate. Total fluid ingestion was matched with body fluid loss during dehydration. After rehydration, subjects performed 30 min of steady state exercise at 68% VO2peak. Subjects then performed a time trial in which they accumulated as rapidly as possible the amount of work equal to 30 min of exercise at 70% VO2peak in a thermo-neutral environment (25 C and 40% relative humidity). There was no significant difference in percent recovery of body mass during rehydration (CON: 79.4 ± 3.3%; SOUP: 80.9 ± 3.4%). Time trial performance was significantly improved in SOUP (30.6 ± 0.8 min) compared with CON (33.2 ± 1.4 min; p=0.031). The rate of carbohydrate oxidation tended to be higher in SOUP (2.33 ± 0.09 g/min) compared with CON (2.18 ± 0.11 g/min; p=0.076). No differences in heart rate or ratings of perceived exercise were found during post-rehydration exercise. These results