Effects of Ingesting a Large Volume of Carbohydrate-Electrolyte Solution on Rehydration during Recovery and Subsequent Exercise Capacity

This randomized, double-blind study examined the effects of rehydration per se and rehydration plus carbohydrate (CHO) ingestion during recovery (REC) on subsequent endurance running capacity. Nine men ran at 70% VáO2max on a level treadmill for 90 min (T1) on two occasions, followed by a 4 hour REC and a further exhaustive run at the same speed (T2). During the first 3 hours of REC, subjects drank either a 6.9% CHO-electrolyte solution (CE) or a CHO- and electrolyte-free sweetened placebo (PL) every 30 min. Volumes prescribed were 200% of the fluid lost after T1, but the actual volume of fluid ingested during the REC ranged from 113-200% and 88. 5-200% of the body mass lost for the CE and PL trials (NS). However, positive fluid balance was found in both trials after REC. During T2, run time was 24.3 +/- 4.4 min longer in the CE trial (69.3 +/- 5.5 vs. 45.0 +/- 4.2 min; p <.05). Higher blood glucose concentrations were observed throughout REC in the CE trial. These results suggest that ingesting a CHO-electrolyte solution is more effective in restoring endurance capacity compared to the same large volume of placebo, even though complete rehydration was achieved in both trials.