Schleh MW, et al. - Researchers performed a comparison of 2 commercially available beverages, an oral rehydration solution (ORS; 60.9 mM Na+; 3.4% carbohydrate) and a sports drink (SDS; 18.4 mM Na+; 5.9% carbohydrate), on hydration and metabolism during submaximal exercise in the heat. It was noted that ORS and SDS did not differ in fluid retention when supplemented during exercise in the heat. Thereby suggesting a higher significance of fluid volume rather than drink contents, when ingested during exercise in a hot environment.