How can anyone get used to -50?
Perhaps conditioned is a better word. Without a heated suit, nobody will stay out working for long stretches at that temperature, so people will rotate out to work for short stretches, then back into a heated enclosure.
Enough good food, and really good gear are mandatory. What surprises some is the dehydration risk in the extreme cold, it's higher than you might think.
Some people can't deal with it, period. I guess it's no different than any other type of work with high physical stresses - while it's not for everybody, some people adapt to it fairly quickly.
I remember jogging in Phoenix at 5:30am - construction crews already working. This is the flip-side of AZ.
Rgds, D.