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(Accidental Hypothermia)

Pronounced: high-po-THER-mee-uh

En Español (Spanish Version)


Hypothermia is abnormally low body temperature. It is a dangerous condition caused when your body loses more heat than it can produce. It requires immediate medical attention.


Hypothermia is usually a result of exposure to very cold temperatures. It can also occur in less cold temperatures if there is a wind-chill, if your clothes are wet, or if you are in a position where you can’t move.

Risk Factors

A risk factor is something that increases your chance of getting a disease or condition. People who are at increased risk for hypothermia include:

  • Elderly people who don’t have enough heat, food, or clothing
  • Adults under the influence of alcohol or drugs
  • Mentally ill people
  • People who are outdoors for long periods of time (eg, hikers, hunters, and the homeless)
  • Babies sleeping in cold rooms

Risk is also increased by certain medications and illnesses that make it harder for your body to stay warm.


Symptoms of hypothermia usually happen gradually. Over time, mental and physical abilities are lessened. The main symptoms of hypothermia are:

  • Shivering—increases muscle activity as your body's way to keep you warm.
  • Confusion
  • Clumsiness
  • Memory loss
  • Slurred speech
  • Drowsiness
  • Irritability
  • Hallucinations
  • Slowed breathing
  • Cold, pale skin
  • The “umbles”—stumbles, mumbles, fumbles, and grumbles

The situation becomes very dangerous when shivering stops and confusion and drowsiness increase. Hypothermia is deadly because it causes the heartbeat to slow down, become irregular, and eventually stop.


Heart EKG

In hypothermia, the heartbeat slows dangerously. If left untreated the heart will stop altogether.

© 2008 Nucleus Medical Art, Inc.


Normal body temperature is 98.6˚F. Hypothermia is diagnosed when body temperature reaches 95˚F or lower. Only a special rectal thermometer that reads low temperatures can confirm that someone has hypothermia.

A victim should never be considered dead until attempts to warm him or her have been made.


It’s important to act quickly if you suspect that you or someone else has hypothermia:

  • Get to a warm, sheltered area.
  • Remove any wet clothing.
  • Use an electric blanket to warm the core of the body first—chest, neck, head, and groin.
  • If no electric blanket is available, use skin-to-skin contact under loose blankets or towels.
  • Give warm beverages to drink; do not give alcoholic beverages.
  • Get medical attention as soon as possible.

A person with severe hypothermia may be unconscious and appear to have no pulse. Medical attention is very important because, in some cases, people can be saved even though they appear dead.


Humans do not have a layer of hair or blubber to keep us warm like other mammals do. We are not built to be out in the cold for long periods of time. If you are planning to spend time outside, take the following precautions:

  • Be aware of the weather.
  • Wear the right clothing:
    • Hat, scarf, and mittens
    • Several layers of loose-fitting clothing
    • Water-resistant coat and shoes
    • Wind-resistant outer layer
  • Go inside when you are shivering or if you are wet.
  • Don’t drink alcohol.
  • Eat well-balanced meals and stay hydrated.

Also, take precautions with elderly people and babies. If rooms aren't kept warm enough, they can even be affected by hypothermia indoors.


CDC National Prevention Information Network

Hypothermia Prevention, Recognition, and Treatment

National Institutes of Health


Canadian Red Cross

Health Canada


Beers, MH, Fletcher AJ, Jones TV, et al. The Merck Manual of Medical Information . 2nd ed. Whitehouse Station, NJ: Merck Research Laboratories; 2003.

Hypothermia. Dynamed website. Available at http://dynamedical.com/dynamed.nsf?opendatabase . Accessed September 19, 2005.

Hypothermia. Mayo Clinic website. Available at http://www.mayoclinic.com/health/hypothermia/DS00333 . Accessed January 17, 2008.

Hypothermia: a cold weather hazard (AgePage series). National Institute on Aging, National Institutes of Health website. Available at: http://www.niapublications.org/engagepages/hypother.asp . Accessed September 19, 2005.

Hypothermia: a cold weather hazard (AgePage series). National Institute on Aging, National Institutes of Health website. Available at: http://www.niapublications.org/engagepages/hypother.asp . Accessed January 17, 2008.

Winter Weather FAQs. Centers for Disease Control and Prevention website. Available at: http://www.bt.cdc.gov/disasters/winter/faq.asp . Accessed January 17, 2008.

Last reviewed January 2008 by Rosalyn Carson-DeWitt, MD

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.

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