Valentine, R. J., St. Laurent, T. G., Saunders, M. J., Todd, M. K., & Flohr, J. A. (2006). Comparison of responses to exercise when consuming carbohydrate and carbohydrate/protein beverages. Medicine and Science in Sports and Exercise, 38(5), Supplement abstract 1996.

The purpose of this study was to compare exercise responses after consuming >1 g/min of carbohydrate in a CHO+P beverage (7.3%+1.8%) versus isocarbohydrate and isocaloric carbohydrate beverages. Male cyclists (N = 10) completed prolonged bouts of cycle ergometry at 75% VO2peak while consuming 250 ml of beverage every 15 min. During the three trials (5-10 days apart), beverages were administered in a randomly counter-balanced double-blind design. Metabolic measures were assessed following 30 minutes of exercise.

Oxygen uptake did not differ among trials or conditions. Blood lactate and heart rate were significantly lower in the CHO+P trial compared to the other two conditions. RPE in the CHO+P trial was significantly lower than in the isocarbohydrate condition but not in the isocaloric condition. Plasma glucose concentrations did not differ between trials.

Implication. A CHO+P beverage consumed during exercise reduces lactate accumulation, heart rate, and perceived exertion compared to CHO beverages, despite no differences in blood glucose levels. There are metabolic and performance advantages of CHO+P beverages over both isocarbohydrate and isocaloric CHO beverages.

Return to Table of Contents for this issue.