Improving rehydration in thermally dehydrated rats with sucrose solution

After heat exposure, rats do not consume enough water to rehydrate completely. We investigated the potential of providing access to both water and sucrose solution to improve rehydration in rats. A secondary goal was to determine if thermal dehydration alters the preference rats exhibit for sucrose solution. During the experiments, male Sprague‐Dawley rats had access to either water, 10% sucrose solution, or both water and 10% sucrose solution. Experiments were carried out on rats at 25°C for four hours with access to fluids and rats exposed to 37.5°C for four hours without access to fluids (thermal dehydration) and then allowed access to fluids for 4 hours at 25°C. At 25°C, rats allowed access to sucrose solution alone or with water drank over 10 times as much fluid as rats allowed access to water alone and produced 4 times more urine. Rats allowed access to fluid following heat exposure had increased water intake but not sucrose solution intake and had reduced urine output compared to the rats at 25°C. Thermally dehydrated rats allowed access to sucrose solution alone or water and sucrose solution had significantly higher levels of rehydration than rats allowed access to water alone. Thermal dehydration greatly reduced the preference for sucrose solution. Although rehydration is improved by providing rats with access to sucrose solution, this benefit may be offset by hyponatremia. Supported by NSF‐REU grant DBI‐0139035.