Wilderness: Hypothermia

Black Widow vs. Brown Recluse Slideshow

• Hypothermia Overview
• Hypothermia Symptoms
• Hypothermia Treatment
• When to Seek Medical Care
• Prevention
• Synonyms and Keywords
• Authors and Editors

Hypothermia Overview

Hypothermia is the medical name for a drop in the body's core temperature (hypo=less, thermia=temperature). The core temperature is best measured rectally, since temperature measurements from under the tongue or in the armpit may be unreliable. Hypothermia is defined as a body temperature below 35°C (95°F).

The body normally produces heat by routine cellular metabolism. As the body is exposed to the cold, more than half of heat loss is through radiation. However, if the body is immersed or wet, conduction heat loss can become the most important problem.

The body generates heat by increasing activity and by shivering. The body protects its core organs by shunting blood flow away from the skin and towards the center of the body. This saves the blood from being cooled as it passes close to the surface, but it also decreases the blood supply to the tips of the body: hands and fingers, feet and toes, nose and ears. This loss of blood flow and exposure to cold leads to frostbite in these peripheral areas.