In another thread I briefly mentioned my efforts regarding cold adaptation, but since it isn't directly related to training and fitness, I did not go into detail. Here's information on that topic in a little more appropriate location.
The last couple of winters I have made a deliberate and consistent effort to expose myself to increasingly cold conditions. This is partly just to harden myself to cold for SAR and/or potential survival situations in our extremely remote rural area, and partly to increase and activate my brown adipose tissue (BAT). I find the science of BAT fascinating, and like the concept of burning fat for non-shivering thermogenesis. I don't know how much the cold adaptation process has contributed to my overall fat loss, as I have no way to measure that, but it has certainly had impressive results regarding my ability to tolerate extreme conditions.
In the fall I started driving to and from work with my window rolled down and no heat or coat, even as it began to drop below freezing. I also worked out in my unheated barn, always in shorts, and usually barefoot and shirtless. By the time winter truly set in I was comfortable wearing a t-shirt in conditions where most people were wearing coats and complaining about the cold. In really extreme conditions (like the morning it was -10 Fahrenheit) I only rolled down my window a few inches and I wore thin glove liners and a stocking cap, but I made the 15-20 minute drive to work in a polo shirt and cargo pants without heat and never shivered at all. On regular winter days in the single-digits to mid-twenties I went with the window wide open and no gloves or hat. In fact, on any days below about 20 degrees I found that I had to drive with my elbows held out from my sides in order to avoid sweaty armpits, as my torso began radiating a great deal of heat within a few minutes.
After lots of extreme exposure for short durations I found that I also could manage milder conditions for much longer without discomfort. For our annual Winterfest celebration in January the temperature soared into the mid- to upper-30s for the whole day. I spent about five hours in a t-shirt, kilt, and tactical boots (no socks), slogging around in the slush and helping organize events. By the end of the day I was just starting to feel cold and shiver occasionally, but I think that was mainly due to inadequate food intake during all the activities. As long as I provide enough fuel it seems that my body is now very efficient at generating heat.
If anyone is interested in more about this topic I have made a few videos discussing it. You can view my BAT Man playlist at: https://www.youtube.com/playlist?list=PLztXQ9N4kzLOhUyVmUtwbI0CZ8NkfcKtJ