Cold adaptation is found among Australian aborigines and Inuits in Greenland. Inuits have relatively more sweat glands in the face and less on the body.
Aborigines can sleep naked on the ground even at low temperature. Inuits have a basal metabolic rate 50% higher than persons living in a temperate climate do. The threshold for shivering is shifted towards the left in cold-adapted persons, but they maintain normal function at the new set point. Very old people may show the same phenomenon, and live with a core temperature of 35 oC without shivering. Obviously, cold adaptation implies non-shivering thermogenesis, which is oeconomic metabolic heat liberation