The normal body temperature is between 35.6˚C and 37.5˚C (96.08˚F and 99.5˚F). Hypothermia is a health condition in which the internal body temperature drops below 35˚C or 95˚F. It is a medical emergency which requires a prompt and appropriate treatment so that the person can recover with little or no consequences.

The body parts which have poor blood circulation are more susceptible to injury with hypothermia. These include hands, nose and ears and heart.

Hypothermia mainly occurs due to the overwhelming cold environment which cannot be regulated by the body’s thermal defense system. The body generates less heat and loses more heat in such environments.

The other hypothermia causes are:

  • Not dressing appropriately for cold weather
  • Not drying properly after getting wet in rain

Risk factors for hypothermia include:

  • Young children and elderly patients, as they cannot regulate their body temperature efficiently
  • Alcohol or drug addicts
  • Certain mental illnesses such as Alzheimer's disease
  • Some medicines such as sedatives
  • Some medical conditions such as diabetes, hypothyroidism, malnutrition, spinal cord injuries, burns and Parkinson's disease

The hypothermia symptoms vary based on the degree of lowering of your body temperature.

Symptoms of mild hypothermia (32-35˚C):

  • constant shivering
  • cold or pale skin
  • low energy and tiredness
  • hyperventilation (fast breathing)

Symptoms of moderate hypothermia (28-32˚C):

  • drowsiness
  • slurred speech
  • confusion
  • loss of reasoning, thinking and judgment (removing clothes despite being very cold)
  • difficulty moving around
  • loss of co-ordination
  • hypoventilation (slow, shallow breathing)

There is no shivering in such people indicating a deteriorated condition which needs immediate medical help.

Symptoms of severe hypothermia (below 28˚C):

  • dilated pupils
  • a weak, irregular pulse, or no pulse
  • coma that can result in death
  • shallow or no breathing

A person who has a severe hypothermia appears to be dead, but immediate medical intervention can sometimes be helpful for such patients.

Babies with hypothermia may look healthy, but have a cold skin, are unusually quiet and refuse to feed.

The diagnosis is based on the patient's history and physical examination. Some patients may show abnormalities with the ECG (electrocardiogram) due to the development of bradycardia (slow heart rate). Blood tests may be performed to understand the severity of hypothermia.

If an older person shows the symptoms of confusion, speech difficulty and lack of coordination, a rectal thermometer is used to measure the low temperatures.

Hypothermia can make the affected person more vulnerable to other cold-related conditions such as:

  • Frostbite – Freezing of body tissues
  • Gangrene – Decay and death of tissue due to an interrupted blood flow

If you find that someone is having the hypothermia symptoms, the first step you should take is to check for breathing and pulse and start cardiac resuscitation. Following this, rewarming should be done.

Before arriving at the hospital for treatment of hypothermia, external rewarming can be performed. Warm packs of water bottles or chemical packs (around 41˚C) can be placed on the armpits, groin or abdomen of the patient. Palm and soul should not be rubbed to generate heat. This is because it can lead to stress in the heart and the lungs. You may provide warm, non-alcoholic beverages.

In severe cases, hypothermia treatment should be started immediately to prevent heart arrhythmias. Bretylium is used to treat arrhythmias in hypothermia patients. The patient is kept in a warm environment. The wet clothing, if present is replaced with dry blankets or towels. After this, additional treatment with intravenous saline (heated about 45 ˚C or 113 ˚F). Instilling warm fluid into the patient's bladder is also recommended in severe cases.

Less drastic methods are employed for patients with mild to moderate hypothermia without other injuries or problems.