Oh, I know they gave "Luke" the head-start. But I don't think I've ever heard/been told that "staying active" stays off hypothermia at some point your body can't create heat faster than it's losing it. I would think being in arctic temperatures of 30 or 40 below zero Celsius it doesn't matter how active and healthy you are your body can only make so much heat so fast. At even starting to get cold is going to have an impact on finer motor skills and concentration.
True but staying active can help delay things.
I was out in -30C yesterday morning and can tell you that it's worse just being then when you're moving about.