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Sweat: Smelly and Clean

Sweat rids the body of water, but also of trace amounts of toxins. Read on for a quick look at the science of sweat.

The sweat glands are the body’s own fire-sprinkler system. They keep the temperature inside our skin livable by releasing water, which cools the body as it evaporates. Though mostly water and salt is excreted, some studies suggest that sweat glands—like the kidneys, liver, and colon—might rid the body of unwanted elements, such as toxic metals. A 2012 meta-review published in the Journal of Environmental and Public Health found reason for further investigation into sweat as a detoxification method. One study reviewed found that levels of arsenic, lead, and mercury in test subjects’ sweat went down after repeated sessions in a sauna.

Sweating in the Old Days

Regardless of how much sweat can actually aid detox efforts, humans have long felt that sweating has a cleansing or curative effect. Saunas have been a Finnish tradition since the 12th century, and healers often worked within them. (Finland still has about two saunas for every five people). Many tribes throughout the Americas have used sweat lodges for practical and spiritual purposes, from enhancing a shaman’s purification rituals to marking puberty to preparing for battle.

Bonus Points

• Sweat comes from two sources: eccrine glands, scattered across the body for cooling, and apocrine glands, which are most concentrated in bacteria-rich regions such as the armpits and crotch. Apocrine glands are activated by stressful emotions, meaning that running from a bear will make you smell worse than running on a treadmill.
• The ability to sweat varies wildly across the animal kingdom. For instance, horse sweat contains a foamy, soapy substance called latherin, which helps the sweat spread over horses’ large, oily bodies.