Your body sweats all the time: It is constantly trying to regulate its temperature to maintain a core temperature of 37.5 °C. As I put clothing on, I create barriers. These barriers create a reduction in evaporation of water, or your sweat. The goal is to make those fabrics not reduce the evaporation rate; it is to make fabrics that work with your body so you can speed up the evaporation rate. The less moisture in your microclimate, the more comfortable you will be.