Extreme Cold (Hypothermia)

Hypothermia describes a state in which the body's mechanism for temperature regulation is overwhelmed in the face of a cold stressor. Hypothermia is classified as accidental or intentional, primary or secondary, and by the degree of hypothermia. The body's core temperature is tightly regulated in the "thermoneutral zone" between 36.5?C and 37.5?C, outside of which thermoregulatory responses are usually activated. The body maintains a stable core temperature through balancing heat production and heat loss.

Shivering is likely the first thing you'll notice as the temperature starts to drop because it's your body's automatic defense against cold temperature-an attempt to warm itself. Signs and symptoms of mild hypothermia include: Shivering, dizziness, hunger, nausea, faster breathing, trouble speaking, slight confusion, lack of coordination, fatigue etc. Seek immediate medical attention for anyone who appears to have hypothermia. 

Accurately estimating the incidence of hypothermia is impossible, as hospital encounters only represent the "tip of the iceberg" in that they reflect the more severe cases. Even so, the number of emergency department encounters for hypothermia is growing, as ever-growing numbers of people take to the outdoors in search of adventure. The overall mortality rate from hypothermia is similar between men and women.