ANDY'S ANSWER: Your hormones start going into overdrive during puberty and one of the results is that your body will heat up and in turn, you will sweat more. Sweating is your body's natural way to help cool you. (The moisture evaporates from your skin producing a cooling effect.) You actually sweat from up to 5 million sweat glands which are distributed over your whole body. Sweat itself is mostly water and doesn't smell bad. The reason that your feet stink and your underarms can get rank is because evaporation doesn't happen as efficiently there.