Systemic effects of ingesting varying amounts of a commercial carbohydrate beverage postexercise.
Glace BW, Gleim GW, Zabetakis PM, Nicholas JA.
Nicolas Institute of Sports Medicine, Lenox Hill Hospital, New York, NY 10021.
OBJECTIVE: Although the role of postexercise carbohydrate intake in the replenishment of muscle glycogen is well established, large amounts of carbohydrate may affect other systems which are recovering from exercise as well. METHODS: We varied the timing and amount of a commercial glucose polymer/fructose (CHO) beverage ingested postexercise in 2 groups of 8 normotensive men following 1 hour of cycling exercise. In Study A the subjects ingested 1 L of a 200 g CHO solution or 1 L of water (W) immediately postexercise. The participants in Study B consumed 1 L of a 1.5 g/kg CHO solution, or W, immediately and 2 hours postexercise. RESULTS: Recovery systolic blood pressure was elevated after 200 g CHO as compared to water, but not after 1.5 g/kg CHO. Diastolic blood pressure was decreased, while heart rate, insulin and glucose increased following both doses of CHO. Despite the potassium (K) content of the beverages, serum K decreased in Study A and B, while a trend was noted following CHO for decreased urinary K excretion at 2 hours and for increased sodium excretion at 4 hours in Study B. Post CHO aldosterone declined more rapidly than after W, and urine volumes were decreased compared to W in both studies 2 hours after CHO. CONCLUSIONS: We speculate that hyperinsulinemia contributed to the rapid decline in K and aldosterone by creating a flux of K to the intracellular space. It appears that CHO ingestion postexercise results in systemic effects that are related to the amount and timing of CHO consumed.