Hypothermia is dangerously low body temperature, below 95°F (35°C).

Low body temperature; Cold exposure

People most likely to experience hypothermia include:

• Very old or very young
• Chronically ill, especially with heart or circulation problems
• Malnourished
• Overly tired
• Under the influence of alcohol or drugs

Hypothermia occurs when more heat is lost than the body can generate. It is usually caused by extended exposure to the cold.

Common causes include:

• Being outside without enough protective clothing in winter.
• Falling overboard from a boat into cold water.
• Wearing wet clothing in windy or cold weather.
• Heavy exertion, not drinking enough fluids, or not eating enough in cold weather.

As people develop hypothermia, their abilities to think and move are often lost slowly. In fact, they may even be unaware that they need emergency treatment. Someone with hypothermia also is likely to have frostbite.

The symptoms include:

• Drowsiness
• Weakness and loss of coordination
• Pale and cold skin
• Confusion
• Uncontrollable shivering (although at extremely low body temperatures, shivering may stop)
• Slowed breathing or heart rate

Lethargy, cardiac arrest, shock, and coma can set in without prompt treatment. Hypothermia can be fatal.