We start to sweat when we exercise, or when we’re anxious because we get really warm. But why and how do we sweat? And what’s in our sweat? As gross as we think sweating may be, it’s important for our bodies to maintain its regular temperature.
Why do we sweat?
Sweating is a mechanism that our bodies use in an attempt to cool us down when it feels too warms (when our body temperature goes over 98.6° Fahrenheit/37° Celsius). If we didn’t sweat, we wouldn’t be able to cope with high temperatures in the environment or created by our bodies.
The sweat that we release via our sweat glands when we’re warm spreads across the surface of our skin and evaporates, which in turn allows the skin to cool; the evaporation of sweat generates a breeze-like effect.
How do we sweat?
We have little structures in our skin called thermoreceptors that allow us to detect changes in temperature. These thermoreceptors are found at the end of nerves. These thermoreceptors will detect a change in the temperature of our bodies and convey this message to the hypothalamus, which is the part of the brain that controls the sweat glands. The hypothalamus then sends a signal to the sweat glands, via the nervous system, to produce sweat in an effort to bring the body temperature back to 98.6°F/37°C.
We have two different types of sweat glands in our bodies, eccrine (aka merocrine) and apocrine. Apocrine sweat glands don’t partake in the cooling of the body. Eccrine sweat glands are found in our skin, including our palms and the soles of our feet. They open directly onto our skin’s surface through sweat pores. These glands, in addition to releasing sweat, also produce the sweat when the hypothalamus sends a signal through the nervous system!
What’s in our sweat?
Sweat consists of a lot of water, some salts and extremely small amounts of waste products. These waste products, urea, uric acid & ammonia, are also components of our urine. Hence the justification to saying ‘Pee-You!’ when someone sweaty walks by; they literally have a tiny bit of pee on them.
Seeley, R.R., Stevens, T.D., and Tate, P. 2008. Anatomy and Physiology (8th ed.). pp. 162, 164-165, 1012. New York: McGraw-Hill.