Sweating maintains homeostasis by helping the human body cool down when it is warmer than its normal healthy temperature. The water sweating puts on the skin absorbs a large amount of heat from the body as it evaporates. While sweating is common in mammals, sweating primarily for cooling is rare.
Sweat is released by glands embedded in the skin that are located all over the body, but are particularly concentrated in areas such as the armpits. Women have more sweat glands than men, but those of men tend to be more active. High skin temperature makes the glands more likely to release sweat, but the real determinant of whether the skin releases sweat is changes in core temperature. Body temperature is monitored, and sweating is controlled, in the hypothalamus, a structure in the brain.
Water is the most important ingredient in sweat, but there are many other components dissolved in the water, which can sometimes give it an odor. Urea, the main waste product dissolved in urine, is one. Lactate is another waste chemical often released. Many minerals and mineral ions are also released, including sodium, potassium and calcium. Including these and trace elements also released, sweat can be composed of as much as 1 percent dissolved materials.