"YOU already know that if you exercise outside on hot and humid days, you should drink plenty of water. And you are probably well aware of the risk of heat stroke given the countless reports about the warning signs.

But if you’re going to be out exercising anyway, you may have different questions: How long does it take to acclimate to the heat and humidity, and what is the best way to do it? How much does your performance time slow when it is sweltering and humid, and why? Does it help to douse your head with water?"