Hypothermia is defined as having a core body temperature less than 95 degrees F or 35 degrees C. It most often occurs because of prolonged exposure to cold weather.
Shivering is the body's automatic defense against cold temperature, as it attempts to warm itself. It is one of the symptoms of hypothermia. Other symptoms include clumsiness or lack of coordination, slurred speech, confusion, poor decision making (i.e. removing clothes), drowsiness, apathy, loss of consciousness, weak pulse and shallow breathing. People with hypothermia often do not know what they are suffering from because of their confused state.
According to WebMD, treatment for hypothermia includes restoring warmth slowly. This is done by getting the person indoors and removing any wet clothing. If wet, dry the person off and warm their trunk first (warming extremities first can cause shock). Wrap the person in blankets or put dry clothes on them.
Do not immerse the person in warm water. Rapid warming can cause heart arrhythmia. If using hot water bottles or chemical hot packs, wrap them in cloth; don't apply them directly to the skin. Begin CPR, if necessary, while warming the person.
Give the person warm fluids if they are conscious, but not coffee or alcohol. Finally, keep them warm and seek medical treatment.