Effects of commercial isotonic sports drinks during intermittent exertion

Abstract

Background: Carbohydrate-electrolyte drinks support performance and recovery during athletic activities. The impact of these isotonic drinks is usually verified by means of placebos without energy. Objective: We checked the extent to which commercial sports drinks may be superior to a syrup–water mixture, similar in calorific value, during an intermittent exertion. Method: In a cross-sectional study, three homogeneously parallelized groups, including a total of 35 test subjects, performed full-strain endurance and speed tests (5,000 m, 3,000 m, 1,500 m, 800 m, 400 m, and 200 m). During the rest intervals, isocaloric drinks with the same CHO (6,66–7,0 g), but different sugar (ISO1: 2,46 g; ISO2: 5,6 g; syrup: 6,7 g) and electrolyte content were given in a randomized way. The parameters of running performance, body weight, rating of perceived exertion, heart rate, and blood lactate concentration were analyzed. Results: Over the distances (p≥0.10), the results did not show any ergogenic effect of the isotonic drinks in comparison with the syrup–water mixture. There were also no significant differences in terms of rates of perceived exertion (p≥0.26) and the physiological parameters of heart rate (p≥0.30) and blood lactate (p≥0.18) among the groups. Conclusion: During intermittent and repetitive exertion below 30 minutes, homemade energy drinks exhibited the same effects as commercial sports drinks.