Hypothermia, << hy puh THUR mee uh, >> is a condition in which the temperature of the human body falls abnormally low, generally below 95 °F (35 °C). The normal human body temperature is 98.6 °F (37 °C). Hypothermia usually results from prolonged exposure to cold.
Hypothermia commonly occurs among individuals who frequent the outdoors, such as hunters and skiers, and among people who accidentally become immersed in cold water, such as when a boat overturns. However, even prolonged exposure to indoor temperatures as high as 65 °F (18 °C) can bring on hypothermia. Such cases occur chiefly among elderly people. Others at a greater than average risk of developing hypothermia include children, people who are ill or injured, and people with poor blood circulation.
Signals of hypothermia include shivering, numbness, loss of vision, drowsiness, dizziness, or confusion. If body temperature falls below 90 °F (32 °C), the victim may lose consciousness. In deep hypothermia–below about 80 °F (27 °C)–abnormal heart action may cause blood flow to slow or stop, leading to death.
A victim of hypothermia should be removed from the cold as soon as possible. Call for medical help immediately. Remove wet clothes and cover the body with dry clothing or blankets. The victim should be warmed slowly. Do not give anything to eat or drink unless the victim is fully conscious. Never give beverages that contain alcohol or caffeine. If the victim becomes unconscious and stops breathing, give artificial respiration. If the pulse stops, give cardiopulmonary resuscitation (see Cardiopulmonary resuscitation).
Doctors may bring on hypothermia to perform operations in which the circulation of blood must be stopped, such as brain surgery or heart surgery. At normal body temperature, many organs would be permanently damaged if they did not receive oxygen from the blood for more than a few minutes. During hypothermia, the activity of organs and tissues slows down, reducing the need for oxygen. In deep hypothermia, blood flow may be stopped for more than an hour without damaging body organs.
