Sweat Basics

The average person has 2.6 million sweat glands. Sweat is made up of water and electrolytes such as sodium, chloride, and potassium. When the hypothalamus senses an increase in core temperature it will act by increasing blood flow to the skin, stimulating the sweat glands. The result is an increase in the rate of water lost through sweating.

During low- to moderate-intensity exercise of less than one hour, there are minimal electrolyte losses because the body reabsorbs most of the electrolytes from the sweat. However, during moderate- to high-intensity exercise of greater than one hour, the electrolyte loss in sweat becomes significant and the sweat rate is too fast for re-absorption of electrolytes