A lot of people assume that sweat is just water, but it's more than that! OK, so it's actually 99% water--but let's not discount the remaining 1%, which is comprised of carbs, protein, and urea (a vessel for excreting nitrogen from our bodies).
Did you know that there are two kinds of sweat glands, and they both produce a unique type of sweat? First, we have the eccrine sweat glands--these are found throughout the body and their primary function is to regulate your body temperature by continuously delivering water to the surface of your skin. That's right, they don't even stop. They're always working! The second type of sweat glands are primarily found in the underarm area. These are the apocrine glands, and they secrete the "milky" sweat that interacts with bacteria responsible for body odor. Contrary to the eccrine glands, they only work part-time.
PRO TIP: Change the way you think about sweat. Your body is constantly expelling and replenishing its supply of water to fulfill necessary functions that keep your body temperature regulated and eliminate toxins!