Adaptive mechanisms help humans survive extreme cold

2015-05-13 7

Originally published on January 8, 2014

Parts of the United States have experienced record-breaking cold weather this week caused by a polar vortex that saw temperatures fall to as low as -70 degrees Fahrenheit.

Although certain human populations such as the Inuit in Canada and the Nenets in Russia have adapted certain traits to help them better survive in polar climates, humans as a species are not designed to survive such in subzero temperatures.

However, humans do posses a number of mechanisms for adapting to extreme cold.

The hypothalamus registers cold and triggers vasoconstriction at the skin surface, concentrating blood flow to the body's core to keep internal organs warm. Cutting off blood supply to the limbs can cause frostbite when bare skin is exposed to the cold. With reduced blood flow, tissue is susceptible to freezing and damage.

Goosebumps are also caused by contracted hair follicles. Risen hairs capture heat radiating from the body. The metabolic rate also rises in cold temperatures to generate warmth for the body. People living in extreme subarctic regions, such as the Inuit, have much higher basal metabolic rates to help them survive the cold.

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