Wearing clothes made of fabrics such as polyester and acrylic can trigger sweating, so avoid them when you have something important to do, like a work presentation or girls’ night out. "The main purpose of sweating is to cool our body temperature. Synthetic fabrics prevent sweat from evaporating, which in turn increases the body's efforts to cool itself," explains Liz Lyster, M.D. of Holtorf Medical Group in Foster City, Calif. She recommends swapping out synthetic material for natural fabrics, like cotton or silk, to keep you dry. The exception is synthetics made with moisture-wicking materials, usually athletic apparel, which are designed with a special weave that lets the skin breathe and sweat evaporate.