Most of us know that our normal body temperature is 98.6°F (37°C), and that if an adult’s temperature goes above about 104°F (40°C) there is a serious risk of brain damage or death. However, many often do not realize that a core body temperature lower than 95°F (35°C) can have equally devastating consequences. When this happens due to a person being exposed to cold temperatures or when their metabolism does not produce enough heat, they have what is called hypothermia.
The hypothalamus is the part of the brain responsible for regulating body temperature. When it recognizes that there has been a change in the temperature of the external environment, the hypothalamus sends the necessary signals to either heat or cool the body in order to maintain a core temperature of around 98.6°F. Many people consistently have a somewhat higher or lower body temperature than this, but a degree or so in either direction is not considered abnormal. If the body is getting too hot, the hypothalamus sends the signal to sweat, whereas if the body is losing too much heat, it commands our muscles to shiver in order to generate more heat.
However, there are conditions in which the body cannot generate enough heat to keep itself warm. Infants and the elderly are at greater risk of hypothermia, as they have less of an ability to generate heat. When hypothermia happens, blood is shunted away from the extremities in an attempt to keep the organs warm. If the body temperature continues to fall, organs such as the liver and kidneys begin to shut down as the blood is redirected to protect the heart and brain. With no outside intervention to warm the body, death will eventually occur.
One of the main problems with hypothermia is that the person experiencing it may not be aware of the problem until it is too late. Hypothermia is a condition that develops gradually, with thinking and reasoning slowing to a point where the person experiencing it is not aware that their mental function is impaired.
All body processes begin to slow down as the body’s temperature drops. Some of the first symptoms are hunger and nausea. Apathy soon follows, followed by lethargy, confusion and slurred speech. The person may then lie down, lose consciousness and fall into a coma. One of the most unusual symptoms of hypothermia is that the affected person may remove all of his or her clothes before losing consciousness. Brain function ceases when the body reaches a core temperature of 68°F (20°C).
Most hypothermia is a result of prolonged exposure to cold temperatures with inadequate protection. Being immersed in cold water brings on hypothermia very quickly. If a person with hypothermia has been found, move the person into a warm sheltered place out of the wind, remove any wet clothing and call emergency services. Give the person warm, dry clothing that preferably also covers the head. Apply warm (not hot!) compresses to the neck, chest and groin area, and cover the person with blankets or use body-to-body contact to begin the process of re-warming.