I was always warm too, but last winter was the first that I found I needed to dress warmer than before. I know circulation begins to gradually slow down with age, but I was hoping for another decade before I experienced it. Alas, that was not the case. I also know it's not a fat things in terms of percentage of body weight, because I've been at a steady state for about four years. So, it's most likely the circulation. I'll be damned if I'm going to let it stop me from doing the things I want to do. I'll wear more base layers, buy better wind-proof garments, etc. before staying inside all winter long.