In broad strokes, however, thermogenic research has showed four main strategies that the body can use to resist the cold: Humans can increase their metabolic rate by shivering; they can stay warm through some passive metabolic mechanism; or they can shunt blood to their core by closing off the arteries in their extremities. Lastly, as in most cases of people who live in colder climates, the human body can also accumulate higher levels of ordinary white fat as an insulation to help stem heat loss in the first place.
