Fact: "It sounds counterintuitive, but the fitter you are, the sooner your body begins to sweat, so a person who's in extremely good shape will produce more sweat than somebody who isn't," says Beth Stover, M.S., C.S.C.S., a senior scientist at the Gatorade Sports Science Institute in Barrington, Illinois. "With each workout, you become a more and more efficient sweating machine."