Pathophysiology of hypothermia

In response to hypothermia, the hypothalamus stimulates mechanisms to generate heat, including compensatory shivering and an increase in thyroid and catecholamine activity. In addition, peripheral vasoconstriction redirects blood flow away from the body surface where maximum heat loss occurs.

Shivering can increase metabolic rate up to 5 times, to generate more endogenous heat. However, shivering stops once glycogen stores are depleted or the body temperature falls below 30ºC.

As core body temperature falls below the normal range, organ dysfunction progresses and cardiac arrhythmias develop, leading to death.