Abstract

Carbohydrate containing drinks are commonly consumed as an ergogenic aid during endurance sports activities. The efficacy of a given drink is limited by the rate of absorption, which is in turn limited by gastric emptying. A myriad of factors influence gastric emptying. The influence of several of these factors (training status, exercise intensity, and carbohydrate composition) was investigated by repeated experiments using a nasogastric tube and a modification of the technique of George. A group of well-trained bicyclists and a group of untrained subjects performed similar experiments. Three different carbohydrate containing drinks (15 g/100 ml glucose (G), 15 g/100 ml maltodextrin plus 3 g/100 ml fructose (MD), 7 g/100 ml sucrose (I)) and artifically sweetened water were compared during rest and 50 and 70 Wmax bicycling. Experimental design was crossover. There was a trend for the carbohydrate drinks to empty initially more slowly under the influence of exercise. Differences in drink volume remaining in the stomach were significant with I at 10 min (70, mean = 48.9; rest, mean = 30.5) and at 20 min (70, mean = 28.9; rest, mean = 23.8) and with MD at 10 min (70, mean = 71.1; rest, mean = 55.9). A similar trend was also seen with 50 Wmax exercise; this trend was only significant with MD at 10 min (50, mean = 72.1; rest, mean = 55.9). Drink composition was a much stronger inhibitor of gastric emptying. No differences in gastric emptying were found between trained and untrained subjects. Verf.-Referat