Trusted medical advice from the
American Academy of Family Physicians.


What is hypothermia?

Hypothermia is a medical condition. It occurs when you are exposed to bitter cold for a long time. Normal body temperature is 98.6°F. You have hypothermia if your body temperature drops below 95°F. Hypothermia also can occur in temperatures that are not bitterly cold, like those above 40°F. This is usually due to a person being wet, sweaty, or trapped in cold water. It is dangerous and can be life threatening. Most people don’t know they have it until it’s too late. If left untreated, hypothermia can cause a heart attack, liver damage, kidney failure, or death.

Hypothermia is different from frostbite. You can have frostbite by itself or with hypothermia. It depends on the type. Frostbite is an injury you get when a part of your body freezes. Common locations of frostbite are your nose, ears, fingers, and toes. With frostbite, your body parts can be numb, stiff, and/or white or grayish-yellow. The effects can be long-term for severe injuries. It may require amputation.

However, hypothermia is more serious and requires urgent medical care.

Symptoms of hypothermia

Symptoms are difficult to spot in babies and older people. Warning signs include:

  • Shivering, fumbling hands, and/or decreased movement
  • Unclear speech
  • Sudden exhaustion or low energy
  • Sudden confusion (unable to think clearly)
  • Cold, red, and/or raw skin (skin may turn blue in later stage)
  • Decreased breathing or heart rate

What causes hypothermia?

Hypothermia is caused by a drop in your body temperature. When your temperature drops, your body uses stored energy to stay warm. Hypothermia begins when the stored energy is used up. Your body can no longer produce heat. There are a few types of this condition with varying causes.

Acute hypothermia

This occurs when your body temperature drops suddenly. This can happen if you fall into cold water. It also can happen if you are wet and in the cold. Hikers, hunters, and people who are without housing are at risk. People who are stranded outside in the cold for too long are at risk.

Chronic hypothermia

This occurs when your body temperature drops over a period of time. Elderly people and babies have a harder time controlling their body temperature. They are at risk of getting hypothermia over time. People of low incomes who don’t have access to heat or proper clothing are at risk.

Exhaustion hypothermia

This occurs when your body temperature drops because it is too tired to produce heat. People who are sick, have certain health conditions, or have substance use disorders are at risk.

Perioperative hypothermia

This occurs when your body temperature drops after surgery in a hospital. It can be hard to maintain heat after receiving anesthesia.

How is hypothermia diagnosed?

If you suspect a person has hypothermia, take their temperature. A reading of less than 95°F means they could have hypothermia. You should get medical care immediately. A doctor will perform a physical exam. He or she will want to know the person’s lifestyle to determine what may have caused or contributed to the hypothermia. Additional tests include:

  • Temperature test: The doctor or nurse will test the ear or rectum (bottom). This provides the most accurate reading.
  • Electrocardiography (EKG): This test uses electric waves to look at your heartbeat. This will determine if it’s normal or not.
  • Chest X-ray: This test uses radiation to look your chest and surrounding organs. Your doctor is looking for disease or injuries.
  • Blood test: This test checks for substances in your blood.
  • Computed tomography scan (CT scan): This test uses X-rays to check for internal injuries or other health problems.
  • Magnetic Resonance Imaging (MRI): This test uses radio waves to check for other injuries, such as tissue damage.

Can hypothermia be prevented or avoided?

You can prevent or avoid most cases of hypothermia. To reduce your risk:

  • Prepare for cold weather. Warm clothing and hats retain heat. Wear layers to prepare for changing conditions.
  • Proper winter clothing includes:
    • Mittens (not gloves)
    • Raincoat and windbreaker
    • Two pairs of socks (not cotton)
    • Scarf and hat (that covers the ears)
  • If you get wet, change your clothes immediately. Look for a warm, indoor area.
  • Keep extra items in your car when traveling. This includes clothes, food, water, and blankets. If you get stranded in your car, call or signal for help right away. Stay in your car. Run the car heater for 10 minutes per hour to conserve gas. Make sure your car’s exhaust pipe is not blocked by snow. This can cause carbon monoxide poisoning.
  • Do not eat snow or drink alcohol. This lowers your body temperatures.
  • In cold temperatures, stay active to produce body heat and store energy.
  • Keep your heat at home above 68°F. Close the vents and doors in rooms you don’t use. This retains heat and saves money.
  • Care for babies. Check in on elderly people. Make sure they are warm, dry, clothed, and fed.

Hypothermia treatment

See a doctor immediately if you suspect you or someone else has hypothermia. Additionally:

  • Move the person into a warm place as soon as possible.
  • Give the person warm clothing. If their current clothes are wet, remove them.
  • Cover the person with blankets or towels. Use an electric blanket or heating pad, if possible. Make sure they do not get too hot, though.
  • Skin-to-skin contact with another person helps increase body temperature.
  • Have the person drink warm liquids. Water, tea, or coffee are best. Do not drink alcohol. Do not give drinks to someone who is unconscious.

If the person is not breathing, begin CPR right away. Stay with the person until help arrives.

A hospital may provide other treatment. One example is infusing warm fluids into the body or providing oxygen. Another example is to flow the person’s blood through an external device to warm it up.

Living with hypothermia

Hypothermia can be cured with little to no lasting effects. Severe hypothermia may require ongoing treatment. Medical conditions that caused the hypothermia will need to be treated.

Questions to ask your doctor

  • How long can you safely stay outdoors if you are dressed appropriately?
  • How can I tell the difference between hypothermia and frostbite?
  • Do you feel numb when you have hypothermia?
  • How long can you have untreated hypothermia before you die?
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