Causes

Hypothermia occurs when your body loses heat faster than it produces it. The most common causes of hypothermia are exposure to cold-weather conditions or cold water. But prolonged exposure to any environment colder than your body can lead to hypothermia if you aren't dressed appropriately or can't control the conditions.

Specific conditions leading to hypothermia include:

• Wearing clothes that aren't warm enough for weather conditions
• Staying out in the cold too long
• Being unable to get out of wet clothes or move to a warm, dry location
• Falling into the water, as in a boating accident
• Living in a house that's too cold, either from poor heating or too much air conditioning

How your body loses heat

The mechanisms of heat loss from your body include the following:

• Radiated heat. Most heat loss is due to heat radiated from unprotected surfaces of your body.
• Direct contact. If you're in direct contact with something very cold, such as cold water or the cold ground, heat is conducted away from your body. Because water is very good at transferring heat from your body, body heat is lost much faster in cold water than in cold air. Similarly, heat loss from your body is much faster if your clothes are wet, as when you're caught out in the rain.
• Wind. Wind removes body heat by carrying away the thin layer of warm air at the surface of your skin. A wind chill factor is important in causing heat loss.