During exercise and/or heat exposure sweat losses must be replaced by the appropriate amount of ingested fluids. Underestimating fluid requirement may result in hypohydration and overestimating them may lead to hyponatremia. However, the temperature of ingested beverages may also disproportionately reduce sweating responses due to cooling of internal thermosensors in the stomach.
We are presently performing research investigating the relative sensitivity of different skin body regions to reduction in sweat output in response to cold beverage ingestion. We also aim to determine the optimal beverage temperature for different environmental conditions to ensure maximum conductive cooling and hydration through ingestion of fluids while maintaining sweat output and subsequent evaporative cooling.