I decided to replace my old thermax and expedition weight polarfleece long underwear with something more high tech and a size larger to accomodate my gradual bulking up (amost entirely muscle thanks to use of the internet). I bought a top made by Columbia (the Bugaboo) that is supposed to wick away perspiration. It is polyester (a good start) has a smooth silk-like interior surface(??), slightly fuzzy exterior, was fairly expensive, and reviewed in glowing terms by several people on the Columbia website. I hate the stuff. When I overheat enought to sweat, it feels like I am wearing wet tin. Ther must be something better out there. Which, if any, of the new stuff actually wicks and yet still feels warm? Or is feeling cold and clammy the new way to stay warm?