Question: What Is the Chemical Composition of Human Sweat or Perspiration?
As you might imagine, human perspiration is mainly water. Have you ever wondered what else is in sweat? Here's a look at the chemical composition of perspiration and the factors that affect it.
Why Do We Sweat?
The main reason people perspire is so evaporation of water can cool the body. Therefore, it makes sense that the main component of perspiration is water. However, perspiration also plays a role in excretion of toxins and waste products. Sweat is chemically similar to the plasma, but certain components are selectively retained or excreted.
Variations in Perspiration Chemical Composition
The chemical composition of perspiration varies between individuals and also depends on what they have been eating and drinking, why they are sweating, how long they have been perspiring and several other factors.
Perspiration consists of water, minerals, lactate and urea. On average, the mineral composition is:
- sodium (0.9 gram/liter)
- potassium (0.2 g/l)
- calcium (0.015 g/l)
- magnesium (0.0013 g/l)
Trace metals that the body excretes in sweat include:
- zinc (0.4 milligrams/liter)
- copper (0.3–0.8 mg/l)
- iron (1 mg/l)
- chromium (0.1 mg/l)
- nickel (0.05 mg/l)
- lead (0.05 mg/l)
"Sweat mineral-element responses during 7 h of exercise-heat stress," Int J Sport Nutr Exerc Metab 2007 Dec;17(6):574-82.