Chilled to the Bone: Cold Stress
When they’re unprepared and unprotected, humans are easy targets for winter weather. Hypothermia, frostbite, and a variety of other injuries related to cold temperatures are all part of the mix.
Hypothermia is an abnormally low core body temperature (95 degrees F or lower) that happens when the body is exposed to cold and loses heat faster than it can make heat. Wet clothing, wind, and cold temperatures (generally lower than 40 degrees F) play a key role in lowering skin temperatures and eventually lower core body temperature. Other factors, such as diabetes, thyroid conditions, some medications, severe trauma, drugs, and alcohol, can all increase the risk of hypothermia.
Prolonged low-core body temperature affects the brain, making it difficult to think clearly or move properly. This makes hypothermia especially dangerous because victims are less likely to know what’s happening to them. Initial symptoms include shivering in adults and older children; clumsy movements; apathy; poor judgment; and cold, pale, or blue-gray skin. Anyone who is not properly clothed or sheltered with adequate heat can become a victim. If the heat loss is not stopped, hypothermia can quickly lead to unconsciousness and death. The keys to preventing hypothermia are layering clothing to avoid sweating from overheating, staying fueled with high-energy food and fluids, moving to keep extremities warm, and taking frequent breaks out of the cold.
Frost Nip often an early stage of frostbite – may cause numbness or blue-white skin for a short time, but normal feeling and color return when the tissue is warmed; there is no permanent tissue damage.
Frostbite happens when the skin and the tissues under the skin freeze as temperatures fall below 32 degrees F. Commonly affected are the hands, feet, and face. Frostbitten skin begins to look pale or blue and feels cold, numb, and stiff or rubbery to the touch. Longer exposures will affect the top layers of skin, which will feel hard to the touch, then turn red and blister when warmed. When exposure continues, the skin becomes white, blue, or spotty, and feels hard and cold to the touch. As the skin thaws, blood-filled blisters form and turn into thick black scabs. It’s likely that some tissue will die; tendons, muscles, nerves, and bones may also be affected. Most frostbite can be prevented by staying dry and wearing clothing that protects the extremities; insulated boots, thick socks, mittens, and a warm, wind-resistant hat that covers the ears are best.