Hypothermia occurs when a person's body temperature falls below 95 degrees Fahrenheit or 35 degrees Celsius (centigrade).
The most obvious sign of hypothermia is a low core (internal) temperature. The person with hypothermia may not realize that his or her prolonged exposure to cold requires emergency medical care. Other signs and symptoms include: apathy or loss of interest in surroundingslethargy or difficulty movingslow pulse and slow respirationconfusion drowsiness loss of coordinationcold skinshock caused by decreased blood flowslurred speechuncontrollable shiveringweakness
Hypothermia is most likely in those who: are very old or very youngare very thinhave heart disease or circulatory problems
Hypothermia occurs when more heat is lost from the body than the body can produce. Although it usually happens at extremely cold temperatures, it can occur even at moderate temperatures. It does not have to be freezing outside for a person to become hypothermic. For example, falling into cold water or wearing wet clothing in cold weather can bring on hypothermia. Failing to wear a hat in cold weather can also lead to hypothermia, since a large amount of body heat escapes through the head.
Extreme fatigue, hunger, or lack of fluids can also lead to hypothermia. Excessive wind can increase the amount of heat lost and cause hypothermia as well.
The key to preventing hypothermia is to avoid extremely cold temperatures. If this is not possible, a person should try to stay away from windy areas where the windchill factor will be higher, such as open spaces with no shelter. Poor circulation can also worsen the condition, so very tight clothing and boots should be avoided.
Several medications and drugs can worsen the effects of hypothermia. Drinking alcohol and smoking tobacco can also aggravate the condition. When in a cold area, a person must get adequate amounts of food and liquid to maintain a healthy temperature.
Proper cold weather garments are also important. Windproof, water-resistant, layered clothing should be worn. All body parts should be protected, especially the hands and feet and ears. A hat should always be worn in cold temperatures, since much heat is lost through the scalp.
Hypothermia is diagnosed by taking a person's temperature. The condition can also be identified by observing the person's symptoms and taking a medical history.
If a person is suspected of having hypothermia, the following steps should be taken: Check for signs of circulation, such as normal breathing, coughing, or movement in response to stimulation.Contact the emergency medical system immediately.Start cardiopulmonary resuscitation, or CPR, if the person stops breathing. Use 30 chest compressions for every 2 mouth-to-mouth rescue breaths.A person lying in a very cold area should not be assumed dead. He or she may be unconscious but alive.The person should be handled very gently, since there is an increased risk of cardiac arrest when body temperature is very low. Do not rub or manipulate the person's arms and legs.The person should be removed from the cold. If this is not possible, he or she should be moved out of the wind. The person's head and neck should be covered, and the individual should be insulated from the cold ground. As soon as possible, move the person to a warm room and cover the individual with blankets. Any wet or constricting clothing should be removed and replaced with dry clothing.If necessary, another person can cover the victim with his or her body. Warm compresses should be applied to the neck, chest wall, armpits, and groin.If the person is alert and can protect his or her airway, he or she should be fed warm fluids.Warm baths and direct heat from heating pads or lamps should be avoided.The person should not be given alcohol, because alcohol causes blood vessels to dilate, leading to further heat loss..Stay with the affected person until medical help arrives
A person can be warmed too quickly. This may cause overheating, or hyperthermia. Changes in heart rhythms, called arrhythmias, can often occur during warming. Whenever possible, medical advice should be sought before a person is warmed.
The person usually recovers well after treatment. It is important for the individual to avoid exposure in the future.