CARBOHYDRATE INGESTION DURING EXERCISE - LIQUID VS SOLID FEEDINGS

Six trained men were studied during 2 h of exercise at 65% VO2max to e xamine the influence of the physical form of carbohydrate supplementat ion on blood glucose and insulin responses. Three exercise tests were performed in randomized order, at least 1 wk apart. Subjects ingested 25 g of carbohydrate or 500 ml of a sweet placebo (CON) at 0, 30, 60, and 90 min of exercise. Carbohydrate was ingested as 500 ml of a 5% ri ce-based liquid (L-CHO) or as a 31-g food bar (S-CHO). No differences in oxygen uptake, respiratory exchange ratio, or heart rate were obser ved between trials. Blood glucose levels were higher (P < 0.05) throug hout exercise when carbohydrate was ingested, compared with CON. No di fferences in blood glucose during exercise were observed between L-CHO and S-CHO. Plasma insulin levels were higher (P < 0.05) after 120 min of exercise when carbohydrate was ingested. The results of this study indicate that carbohydrate supplements with differing physical form ( liquid vs solid) but equal carbohydrate content produce similar blood glucose and insulin responses during exercise.