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Acute Hypothermia

Medically reviewed by Last updated on Aug 31, 2022.

What is acute hypothermia?

Hypothermia is a condition that develops when body temperature drops below 95˚F (35˚C). Acute means the condition starts suddenly, gets worse quickly, and lasts a short time. Hypothermia may develop if your body loses too much heat or cannot keep a constant temperature. Hypothermia is classified according to temperature. Mild is 90-95˚F (32.2-35˚C). Moderate is 82.4-89.9˚F (28-32.1˚C). Severe is below 82.4˚F (28˚C).

What increases my risk of hypothermia?

  • Exposure to cold: Your temperature can drop quickly if you are not dressed warmly in cold weather. A fall into cold water can also lower your temperature quickly.
  • Age: You may have more trouble keeping a constant body temperature as you get older. Your metabolism may slow as you age. You may not be able to feel the cold as well as younger people do.
  • Injury: A severe burn can make you lose large amounts of heat. Spinal cord injuries can prevent you from shivering.
  • Medical conditions: Hypothyroidism, Lupus, or heart failure can affect your ability to regulate your body temperature.
  • Alcohol use: Alcohol makes your blood vessels dilate (get bigger), which can cause you to lose body heat. Alcohol can also make it harder for you to feel that you are cold.
  • Lack of movement: Hypothermia can occur during bedrest or other times when you move less, because your body creates less heat. This is more likely to occur if you cannot regulate your body temperature.

What are the signs and symptoms of hypothermia?

  • Mild: Symptoms include shivering, fast breathing, and a fast heartbeat. You may feel sleepy, clumsy, and confused. A cold sweat may begin. The skin on your hands and feet may start to become pale or blue.
  • Moderate: Shivering stops and your breathing slows. Your heart slows and may start to beat out of rhythm. Your skin may look swollen, blue, or gray. Your reflexes become slower. Muscles may become tight and hard to move. You may lose consciousness.
  • Severe: Movement, breathing, and heartbeat slow and begin to stop.

How is hypothermia diagnosed?

Your healthcare provider will take your temperature and check your pulse and blood pressure. He or she will examine you for signs of hypothermia and ask about your symptoms. He or she will look for signs of frostbite (damaged tissue). Frostbite usually happens on the fingers, toes, ears, or nose. Tell him about any long-term exposure to cold, and any medicines you take. He or she will want to know if you drank alcohol right before symptoms began. You may need the following tests to check for complications of acute hypothermia:

  • Blood and urine tests: These tests will check for infection. Your electrolyte (body salt) levels, liver and kidney function, and heart enzyme levels will also be tested.
  • Blood gases: These tests are also called arterial blood gases (ABGs). Blood is taken from an artery to measure oxygen, acids, and carbon dioxide levels in your blood.
  • ECG: This is done to check the rate and rhythm of your heartbeat.
  • X-rays: X-rays of your neck, chest, and abdomen can show if you have any injuries. A chest x-ray can show if you have pneumonia (lung infection) or pulmonary edema (fluid in the lungs).

How is hypothermia treated?

You may need to have frostbite treated. Ask for more information about treatment for frostbite. You may also be given medicines to treat health conditions that caused your hypothermia or to prevent complications. You will receive treatment based on the severity of your hypothermia:

  • Mild: Wet clothes will be removed, and your skin will be dried. Your torso must be covered to prevent more heat loss. Healthcare providers will use blankets, a hat, heat packs, or aluminum foil to help trap body heat. You may need other treatments to prevent your condition from worsening.
  • Moderate: Healthcare providers may use a device to circulate warm air around your body. You may be given heated IV fluids into a vein.
  • Severe: Healthcare providers may use an IV to flush warm liquids into your stomach, intestines, or bladder. Tubes may be placed to keep your airway open while you receive warm, moist oxygen. You may need to have your blood cycled through a warming machine and returned to your body.

What are the risks of hypothermia?

  • Hypothermia affects all of your body functions. Blood flow to your muscles and tissues decreases. This can damage your blood vessels and lead to muscle and tissue death. You may develop pneumonia or pulmonary edema. Heart, liver, and kidney functions may slow or stop. You may lose fingers, toes, or other parts if frostbite damage is severe.
  • Damage to your bladder and kidneys may not return to normal. Hypothermia changes the way your blood clots. You may bleed more or develop blood clots, which can cause organ failure, a stroke, or a heart attack. Hypothermia can be life-threatening, especially if you have other health problems.

How can I prevent hypothermia?

  • Dress in layers. Wear gloves, a warm hat, and thick socks in cold weather. Wear socks and a warm cap when you sleep. Keep an emergency bag with a dry, insulating blanket in your car in case you get lost or injured.
  • Do not drink alcohol when you are outside in cold weather.
  • Try to keep your home heated above 64.4˚F (18˚C). A hot drink at bedtime, hot water bottle, or electric blanket can help keep you warm while you sleep.
  • Get up and move at least once an hour.
  • Ask family, friends, or neighbors to check on you in cold weather. Ask your healthcare provider about services that can help if you need shelter, warm clothing or food, or heating assistance.

Where can I get support and more information?

  • American Red Cross National Headquarters
    2025 E Street NW
    Washington , DC 20006
    Phone: 1- 202 - 303-4498
    Web Address:

When should I contact my healthcare provider?

Contact your healthcare provider if:

  • You are shivering, breathing fast, or your heart is beating faster than usual.
  • You feel clumsy or confused.
  • Your hands and feet become pale.
  • You have questions or concerns about your condition or care.

When should I seek immediate care?

Seek care immediately if:

  • You are breathing more slowly than usual, or your heartbeat is slow and out of rhythm.
  • Your skin becomes swollen and blue or gray.
  • Your muscles feel tight and are hard to move.

Care Agreement

You have the right to help plan your care. Learn about your health condition and how it may be treated. Discuss treatment options with your healthcare providers to decide what care you want to receive. You always have the right to refuse treatment. The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

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