Drink more fluids in hot climates, hot weather, or during activity in hot environments to help prevent dehydration and decrease the risk of a heat-related illness. Water or commercial sports drinks are good choices.
Drinking sports drinks containing electrolytes and carbohydrates may help support athletic performance during very strenuous activities. The electrolytes provided in sports drinks may prevent muscle cramps caused by loss of salt.
The temperature of the fluid can be cold as long as this does not cause stomach cramps.
WebMD Medical Reference from Healthwise