You don't have to be an Arctic explorer to suffer frostbite. Anyone exposed to below freezing temperatures can become a victim. Certain age groups are more susceptible to frostbite than others. For example, infants, children and the elderly suffer the effects of cold more rapidly than other age groups. Infants have a large skin surface area for their small sizes and therefore lose body heat quickly. The elderly often suffer from poor blood circulation, which can mean inefficient body-temperature regulation in the first place.

People spending time in the cold outdoors are prime targets for frostbite. These include skiers, outdoor workers, mountain climbers, hunters and street people who fall asleep during subfreezing temperatures.Frostbite in an extremity can go unnoticed because the cold anesthetizes (deadens sensation in) the nerves, and also because the victim may be concentrating on his or her winter activity.

Even though frostbite can occur in subfreezing temperatures, other factors can contribute. For example, wind has a drastic effect on heat loss. If the thermometer reads 20 degrees and the wind velocity is 20 mph, the windchill is equivalent to minus 10 degrees. Moisture from rain, snow or perspiration speeds up heat loss even faster than wind.

Factors such as fatigue, hunger, smoking, drinking alcohol, tight clothing or boots, contact with metal, injury and age all increase the potential for frostbite. Alcohol opens up the outer blood vessels and allows heat to escape more readily. Fatigue and hunger increase the chances of a person falling asleep in the snow.

Frostbite usually occurs in one of the body's extremities (nose, ears, chin, fingers, toes) because they get cold first, are the hardest to cover, and have the poorest blood circulation.

Frostbite is literally the freezing of tissue. Ice crystals form in the spaces between the body cells. This draws water from the cell. The circulatory system constricts the outer blood vessels which allow blood sludging. This can deprive the tissue of oxygen so that tissue damage results.

The affected area will initially be very painful and may tingle. Later, it becomes numb. The skin is cold to the touch and may feel hard. In severe cases, you will be unable to roll the skin over the bones.

Seldom will a person administering first aid have to thaw a frostbitten part since emergency medical facilities are usually nearby. Thawing will cause tenderness, throbbing and burning pain.

To treat frostbite, put the damaged body part in warm water - never rub it - and once it is thawed do not allow the part to become frostbitten again since the ice crystals formed are larger the second time and produce greater damage. Get proper medical care immediately to avoid gangrene.