I really blame myself for not reading the details before buying 3 of these. 100% polyester is not the most comfortable material for my skin. Today was a typical hot and muggy summer day in Philadelphia, and I've ever been uncomfortable with the sweat that plastic fibers leave on my skin! I've read so many reviews from people who thought the fabric was perfect in their heat... of course you don't sweat in Arizona as it evaporates as soon as you think about coming out of your pores. With the humidity here, we need a little more to survive. A good cotton shirt would soak up and evaporate (maybe half?) it all. But sweat hits that plastic shirt like a brick wall and runs down his chest into his pants. Although the shirt is surprisingly dry, I get soaked underneath with my own saline solution and look like I have urinary incontinence (which I AM NOT because my kidneys have nothing to do with all the sweating). Give me cotton every day for this abomination. Maybe these are my winter shirts (they're too thin for that, but I've already bought them, so I'm not wearing them yet)?