Why was this study done?

Proper hydration is of key importance to athletes and is closely tied to athletic performance and time to fatigue. Water is a good hydration source, but hydration occurs faster when electrolytes (primarily sodium) and carbohydrates are included in drinks. This study was designed to investigate varying concentrations of sodium and carbohydrate in rehydration formulas for athletes.

What did the study find?

Athletes were provided a rehydration formulas containing sodium to carbohydrate in the following ratios: 122 mg/27g, 214 mg/27g, 122mg/14g, and water (as a control). The rehydration formula containing 122 mg/27g appeared to be the best at maintaining plasma glucose and osmolality, while also being well-tolerated by the athletes.

The Effects of Sodium: Carbohydrate (Na: Carb) Ratios in Rehydration beverages (RB) on Plasma (PG), Osmolality (PO), Volume (PV), and Subject Tolerance (ST)
Authors: Wong L, Jensen C, Whittam J. FASEB J, 1990. 4(3):A381
PDF Abstract: FASEB J, 1990.