When You Sweat, This Is What Happens To Your Body
As it turns out, sweating is actually your body's way of cooling itself down. When your core body temperature increases from either heat or exercise, the sympathetic nervous system triggers the secretion of sweat through your eccrine glands, which are sweat glands located all over your body (via Popular Mechanics). When your sweat reaches the surface of your skin, it evaporates, removing excess heat from your body. Known as heat of vaporization, this process results in a cooling effect, which can help lower and regulate your body's internal temperature.
Not all sweat pertains to heat regulation, however. You can also sweat when you're stressed or nervous. When this occurs, sweat is secreted through your apocrine glands, which are located in the armpits and groin area. Since apocrine glands are also scent glands, your sweat is more likely to smell when you're nervous than when you're working out or sitting outside in the heat.
What causes sweat to smell?
It's not the sweat itself that produces an odor, however. In fact, sweat is virtually odorless. Body odor is actually caused by bacteria (via Medical News Today). When bacteria on the skin break down protein molecules in your sweat into acids, it releases a foul or unpleasant odor. Since bacteria thrives in moist environments, or areas of the body that produce the most sweat, body odor is most likely to occur in the armpits, feet, groin, belly button, genitals, anus, and behind the ears.
Although the human body generally produces a variety of potential odorants, large quantities of these compounds are required to produce any pungent or noticeable smells. While everyone is born with these substances on their skin, it is not until puberty that sweat glands and hormones become active enough to accumulate bacteria and emit a more distinctive odor. For people with hyperhidrosis, who tend to sweat more excessively, body odor may occur more frequently. Applying deodorant and antiperspirant at night can help get rid of any excessive body odor.