Frostbite is the freezing of parts of the body. Your cells are mostly water; when water freezes it forms crystals. The crystals are sharp and are larger than the same amount of water (ie. water expands when it freezes). This leads to punctures in the cell membranes; the affected parts of the body sort of digest themselves due to the release of enzymes from the broken cells. Frostbite usually affects the extremities - toes, fingers, nose, ear lobes, private parts for men - because they have less blood flow and are harder to keep warm. Your body also sacrifices these body parts in an effort to keep warm by constricting blood vessels to keep the majority of blood from cooling and carrying the cold back to the center of the body. […]

Hypothermia is the bone-chilling cold you feel when your entire body’s temperature is dropping. Your normal body temperature is 98.6 ˚F (37 ˚C) or thereabouts. At 95 ˚F (35 ˚C) hypothermia begins. At 91 ˚F (32.7 ˚C) you get amnesia, and below 85 ˚F (29.5 ˚C) you lose consciousness. […] Hypothermia can kill you in several ways, two of which have to do with electricity. Your heart beats because it supplies itself with a chemico-electrical jolt every second or so. This is what occurs in the sinus and AV nodes of the heart and is based on an electrical charge difference across the cells’ membranes in the node. Low body temperature messes with the membrane potential, so the heartbeat is slow and erratic. Too slow (bradycardia) or too erratic (arrhythmia) leads to a heartbeat so dysfunctional that it won’t push the blood through your body and you die from cardiac failure.

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photo { Stephen Shore }

health | December 10th, 2014