The intent of this study was to determine whether adding carbonation to either water or a low calorie sport drink would affect gastric emptying (GE). Fifteen subjects rode for 20 minutes on a cycle ergometer at 55% of max . After 5 minutes of exercise, the subjects ingested 5.5 mllkg body weight of a test solution: water (W), carbonated water (CW), and a low calorie sport drink in both a carbonated (C2C) and noncarbonated (2C) form. At the end of each ride, the stomach was emptied through gastric aspiration. The results indicate that carbonation has no effect on GE. However, the type of drink did have an effect on GE, as both 2C and C2C emptied from the stomach at a slower rate than either W or CW. Subjective ratings of gastrointestinal comfort were similar for both carbonated and noncarbonated forms, and at no time did the subjects report discomfort. The results were independent of the exercise challenge, as exercise intensity, heart rate, and ratings of perceived exertion did not differ between experimental trials. It is concluded that carbonation does not affect the GE characteristics of a drink taken during submaximal exercise, but the flavoring system of the low calorie beverage decreased the rate of GE by as much as 25% when compared to water.
The authors are with the Human Performance Laboratory, Ball State University, Muncie, IN 47306. Request reprints from D.L. Costill, Director.