Here's some research of cold adaptation (although the main topic is about fat loss).. I find it interesting how little it requires to adapt a little bit - just ten days. Knowing it is this fast progress without any extreme exposures probably makes it a lot easier to keep motivated long enough. http://www.runnersworld.com/weight-loss/stay-cool-stay-thin In the first study, researchers in the Netherlands showed that relatively mild bouts of cold exposure for as little as 10 days cause brown fat activity to ramp up, making you more resistant to cold temperatures and burning more calories in the process. The protocol: sitting in shorts and T-shirts in a room kept at 15-16 C (59-61 F) for 2 hours on the first day, 4 hours on the second day, and 6 hours for the following eight days. In the second study, a similar cold exposure protocol (2 hours at 17 C / 62.6 F daily for 6 weeks) increased resting energy expenditure and actually led to a decrease of 5.2% in body fat mass. A control group exposed to 27 C / 80.6 F didn't show any fat loss. For a much more detailed explanation of how this all works and what it means,check out Stephan's report. For me, the takeaway isn't that bad thermostat setting are causing an obesity crisis -- nobody is claiming that. Instead, the most interesting wrinkle is the finding in the first study that, after 10 days, the subjects reported much higher comfort ratings in the cool temperatures. Yes, modern conveniences like heating and elevators make our lives more comfortable, and yes, these conveniences increasingly seem to come at a cost to physical health. But doing without some of these comforts isn't as much of a hardship as you might think, because of the body's extraordinary ability to adapt. Taking the stairs or turning down the thermostat a few degrees might seem like a shock at first -- but if you stick with it, you won't even notice it after a while. While Wim Hof's iceman stuff has more impressive outcomes, it's also much harder, I tried it a little last winter, my motivation didn't quite last long enough. Maybe I was trying to reach too high, because for me it would be very cool to be able to comfortably sit in shorts and t-shirt at +19°C.. That would lengthen my indoors shorts and t-shirt season something like 10 months. I can run shirtless at +5°C, but sitting and being still is quite different for me. I would guess that whole body cold adaptation would be good for barefooting at cold weather. If you are able to produce more heat, there's more heat to distribute to feet..