Hypothermia and Frostbite

As I was walking through the neighborhood tonight, I realized that winter has finally come to east Tennessee. No longer do we have the wet and balmy weather as we did over the holidays. The clear, starry sky appears beautiful until I realize my cheeks sting. And though we live south of the Mason-Dixon line, we can still be struck by such winter hazards as hypothermia and frostbite. Whether playing in the backyard, hiking the local trails, or fishing in the nearby streams and lakes, the cold weather can cause our body temperature to drop from 98.6 degrees to 95 degrees or less. This temperature change can cause shivering, clumsiness, and poor hand coordination. In addition, cognitive functioning slips with confusion, memory loss, slurred speech, and exhaustion. This state of lower body temperature with some or all of these symptoms is called hypothermia.Frostbite is a localized injury to the body where the tissue starts to freeze. The signs start with redness and pain to skin which then can become numb, white and firm. See the following articles, “Winter Weather Frequently Asked Question” and “Cold Weather Injuries” for further information on hypothermia and frostbite including prevention and management:

http://emergency.cdc.gov/disasters/winter/faq.asp
and
http://www.aboutkidshealth.ca/En/HealthAZ/SafetyandtheEnvironment/OutdoorSafety/Pages/Cold-Weather-Injuries.aspx

Two other factors besides temperature increase the risk for hypothermia and frostbite: wind and water. Wind can make the ambient temperature drop significantly – causing exposed skin to develop frostbite and core body temperature to drop to 95 degrees (hypothermia). For example, a 40 degree day with 30 mph winds generates a windchill temperature of 28 degrees; a 15 degree day with 20 mph winds generates a windchill temperature of -2 degrees. Wind can make a day much colder than the thermometer indicates. Be sure to take wind into account when planning outdoor excursions. Have clothing to block the wind, and avoid exposed skin on very cold and windy days. See the following National Weather Service Windchill Chart:

http://www.nws.noaa.gov/om/winter/windchill.shtml

Water can also hasten temperature loss and increase the risk for hypothermia. Whether drenched by rain, by snow, or by accidental immersion in a stream or pond, our wet bodies will drop their temperature much more quickly than when they remain dry. Cold and water are not a good mixture. When outdoors during cold and wet weather, avoid cotton (as it absorbs moisture and loses its insulatory properties). Rather, dress in layers with a wicking base layer, an insulating middle layer of fleece or synthetic material, and a windproof, waterproof outer layer. Furthermore, even during a warm day, an unfortunate plunge or fall in very cold water like the Little River or Chilhowee Lake can lead to hypothermia. Review the following article, “”Hypothermia Prevention: Survival in Cold Water” for further information on hypothermia and water exposure:

http://www.seagrant.umn.edu/coastal_communities/hypothermia

Winter is a wonderful time of year to explore the outdoors at home and afield, but remember to practice these safety tips.