runs a little large, but that's ok, because I like my sleeping gear roomy. I find even though I'm not crazy about the style, a little old fashioned, I like sleeping in nylon, it slides easily as I turn over in bed. My shoulder gives me problems so I often change position and the nylon helps me slide over in bed. Plus I need long sleeves because rarely can I keep my arms covered and they get cold at night. Also, with the sleeves, I can put the rub I put on my shoulder and not worry about it getting on the sheets.