This study investigated the hypothesis that addition of ${\text{Na}}^{+}$ to a rehydration beverage would stimulate drinking and augment restoration of body water in individuals dehydrated during 90 min of continuous treadmill exercise in the heat. Following a 3.0 ± 0.2% decrease in body weight (BW), 6 subjects sat in a thermoneutral environment for 30 min to allow body fluid compartments to stabilize. Over the next 3 hr, subjects rehydrated ad libitum using either flavored/artificially sweetened water (H₂0-R) or a flavored, 6% sucrose drink containing either $25({\text{LNa}}^{+}-\text{R})$ or 50 ${\text{HNa}}^{+}-\text{R}$ mmol/L NaCl. Results demonstrated that rapid removal of the osmotic stimulus, during ${\text{H}}_2$0-R, and the volume-dependent dipsogenic stimuli, during ${\text{HNa}}^{+}-\text{R}$, are important factors in limiting fluid intake during rehydration, compared to ${\text{LNa}}^{+}-\text{R}$. It was also found that the pattern of fluid replacement and restoration of fluid balance following dehydration is influenced by the dehydration protocol used to induce the loss in total body water and the sodium content of the rehydration beverage.