This is a comfortable and comforting, well-made expedition-weight thermal shirt warmer than the mid-weight styles more popular in local sporting goods stores now that the winter season has been left behind (except for high altitudes in the Arizona desert at night). However, Duofold sizes tend to run small. My chest measures 36" but the Medium-size shirt fit snugly and the sleeves stopped two inches short of the wrists. Amazon obligingly rushed a Large-size exchange to me on the very next day with no charge for postage, including the prepaid return authorization. It is the right fit for me, not so tight that I feel squeezed. When warmth is required, a little extra material with a more relaxed fit is my recommendation.