4. Discussion
Fluid retention, weight loss, Na-dose
FLUID RETENTION
The primary hypothesis, that the beverage with the higher Na content and lower CHO would promote greater completeness of rehydration than that of the beverage with lower Na and higher CHO, was not confirmed. Fluid retention did not differ for either the ORS or sports drink at the end of 3.5 h, but both promoted more complete rehydration than the water placebo. Comparing mean values, the ORS was 32% more effective and the sports drink was 27% more effective than the response to the water placebo. It was expected that Na might play the dominant role based on the literature supporting a Na-dose effect when CHO content was fixed [In contrast to the outcome after 3.5 h, the pattern of fluid retained within the recovery tends to support the ORS as promoting a more rapid recovery. The urine volume for the ORS was reduced significantly between 30 and 60 min (Our speculation is supported by prior research indicating beverage energy density [Sodium balance, not just the beverage Na content, is also a critical factor in the completeness of rehydration [The magnitude of acute weight loss (~2.6%) was consistent with prior rehydration studies [