I can assure you, we aren't a sado-maso club!
Some of us try out the limits and that is survival training.
Survival means that you get in the situation in the woods, for example because your car breaks in the middle of nowhere, or even Norway
and you have to try to get out and reach the civilisation.
Most of us would easily manage such a situation, but that isn't the main point why most of us are doing all that.
Using the same techniques, we are doing the opposite of survival: We train to go into the woods and to live there comfortable!
I am a very experienced bushcrafter and I did a lot of trekking and camping all my life, but in the last years I changed my clothing system from a traditional German old school boy scout system with leather knickerbockers and woolen and cotton clothing to a modern outdoor clothing layering system.
You will be very surprised, where I mainly tried it out and used the time to think about it: I did it mainly at the bus stops and the main railway station of Colone!
The railway station is located next to the Rhine, there it becomes very unpleasant if it is cold, the wind comes along the Rhine and the rails. Standing in this whet and windy weather on the platform under the cathedral and waiting for the train I looked up in my smartphone the current temperature, played with the zippers, putting parts of my new layering system on and off and concentrated in what I feel.
In between I payed attention about my feeling on little or longer walks in the town.
And after I understood exactly what's going on, I took that clothing equipment with me to test it in between 45*C in southern France during the days of the summer and minus 20*C in the nights of the north east German January in the open field around my brother farm.
And now I know exactly which clothing I have to use in which situation and never get the problem that it becomes uncomfortable to me.
Additional to that I use the in my opinion best military sleeping bag system that is currently available, the Snugpak Special Forces Sleeping bag System with its bivvy bag, of course in olive green, because I want to be invisible if I sleep in Forest and field. That system never becomes to cold or to hot in every European weather conditions except winters in northern Scandinavia and Russia, and even there it would work well if I would use additional warm clothing and my Hilleberg two persons tent Nallo 2 or if I would use my bushcraft know how and would heat a lean to poncho shelter with a long log fire.
I wear custom made leather hiking boots, I own a trekking air mat for stony or frozen ground. All my other modern equipment is long lasting and durable but very very light, but most of it isn't especially expensive.
I own the best stuff in the world but I usually let my most expensive stuff at home, because I don't really need it in most conditions.
Military surplus stuff offers superior qualities but used at very low prices, and I use a lot of it.
Equipped with stuff that works well at minus 20*C I feel very comfortable in normal soft winter conditions off course!