HARGREAVES, M., D. COSTILL, L. BURKE, G. McCONELL, and M. FEBBRAIO. Influence of sodium on glucose bioavailability during exercise. Med. Sci. Sports Exerc., Vol. 26, No. 3, pp. 365-368, 1994. To examine the influence of beverage sodium content on glucose bioavailability during exercise, six trained men were studied during 30 min of cycle ergometer exercise at 65% VO2max. Immediately prior to exercise, subjects ingested 400ml of a 10% glucose solution containing 100 [middle dot]Ci of D-(3-3]-glucose, with a sodium concentration of either 0, 25, or 50 mmol[middle dot]1-1. Trials were conducted in the morning after an overnight fast and in randomized order at least 1 wk apart. Blood samples were obtained from a forearm vein before and during exercise and subsequently analyzed for plasma glucose and 3H glucose activity and blood lactate. No differences in oxygen uptake, heart rate, or blood lactate were observed between trials. Resting plasma glucose levels were not different between trials. The increases in plasma glucose and the plasma accumulation of 3H-glucose-were similar in the three trials. These results indicate that alterations in beverage sodium content, from 0-50 mmol[middle dot]1-1, have no effect on glucose bioavailability, as measured by increases in plasma glucose and 3H-glucose activity during moderate intensity exercise.
(C)1994The American College of Sports Medicine