The most concentrated area of the body with sweat glands is on the bottom of a person's feet. Sweat is the body’s cooling system. It’s evaporation serves to cool the body off. But, it’s not all the same. A person's body has two to four million sweat glands divided into two types: eccrine and apocrine. Eccrine glands are the most numerous and release only water and salt, while apocrine glands begin functioning after puberty and release water containing proteins and carbohydrates.
Sweat glands are found all over the body, except on the nails, ears and lips. With human feet, there are normally about 250,000 sweat glands. Accordingly, a pair of feet can produce up to a pint of sweat per day. The sweat is oily, cloudy, viscous, and originally odorless; it gains odor upon decomposition by bacteria.