Wl. Mason et al., CARBOHYDRATE INGESTION DURING EXERCISE - LIQUID VS SOLID FEEDINGS, Medicine and science in sports and exercise, 25(8), 1993, pp. 966-969
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.