Not that cold, huh?! I do think -30C or -40C is extreme :p
I always feel that white people in Canada, US, and AUS show just how adaptable humans and human bodies are.
All white people there have European roots and we don't have the extreme weather conditions here that you do have over there.
Somehow your European ancestors managed to survive and adept.
I never forget what my girlie told me when she lived in the US. She and her then US husband & family went rafting one day. For them it was nothing too extreme.
Halfway through they stopped and my daughter quit from doing the rest. Her husband found her childish for giving up.
But she was scared to death as the river was really grumpy -and she doesn't scare so easily- and for her it was physically way too much as well. None of the others, Americans, had a problem.
I think a few generations of hardship has altered people and their bodies? Made them tougher. They had to in order to survive.
Apart from that, The Netherlands is as flat as a pancake bar for a small part in the east. But we haven't got mountains or raging rivers, nor life-threatening wildlife etc. And no extreme weather.
Our fight is against water --> almost half of The Netherlands is below sea-level.
Nevertheless, nothing is impossible. I managed in Indonesia (stinking hot & humid), Australia (desert, at first freezing cold, then stinking hot & dry) and I manage to live with the sh*te weather we got here, haha. Lots of rain and always windy.
As long as I don't have to chop wood or shovel snow, hihi. I need a man for that