What causes hypothermia?

When exposed to cold temperatures, your body begins to lose heat faster than it can be produced. Prolonged exposure to cold will eventually use up your body's stored energy. The result is hypothermia, or abnormally low body temperature. Body temperature that is too low affects the brain, making the victim unable to think clearly or move well. This makes hypothermia particularly dangerous because a person may not know it is happening and won't be able to do anything about it.

Hypothermia is most likely at very cold temperatures, but it can occur even at cool temperatures (above 40 degrees F) if a person becomes chilled from rain, sweat, or submersion in cold water.

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Exposure to cold temperatures: Hypothermia is typically caused by prolonged exposure to cold temperatures. It does not always occur in the winter months. It may occur if the weather is exceptionally cold in the fall or early spring. The wind chill factor should also be taken into consideration.

In some cases, exposure does not have to be prolonged. For instance, if an individual falls through the ice on a body of water he/she may develop hypothermia within minutes to hours (depending on the temperature of the water). The body loses heat more quickly in water than it does in the air. Exposure to water that is colder than the body can potentially decrease the body temperature.

Prolonged exposure to cool or damp temperatures: Hypothermia may be caused by prolonged exposure to cool, damp environments. When water is on the skin and starts to evaporate, a person's body temperature falls. If wind blows over wet skin it increases evaporation and cools the body even faster. For instance, if an individual is outside during a rain shower on a cool day, hypothermia may result if the person does not quickly move inside to warm up and dry off.

Inadequate protective clothing: Not wearing enough protective clothing, such as jackets, hats, mittens/gloves, and scarves, increases the risk of hypothermia. It is especially important to cover the head because it contains a large proportion of the body's blood volume and loses heat more quickly than the rest of the body.

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