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Hypothermia 101

Hypothermia suit testing on Lake Superior.

Hypothermia suit testing on Lake Superior.

"You're not dead unless you're warm and dead," said Larry Wittmers, a hypothermia expert and associate professor at the University of Minnesota Duluth's school of medicine. Severely hypothermic people can appear dead, but doctors don’t give up on them and rescuers shouldn’t either. With the knowledge and technology available, hypothermia is treatable and preventable.

Hypothermia occurs when a person's core temperature falls below 95°F. A person can become hypothermic in any season and environment. Cold water is especially effective at stealing heat. Cold water conducts heat away from a body up to 25 times faster than cold air.

Combating Hypothermia with Body-to-Body Contact? Think Twice

Medical professionals are amassing data that indicate sharing body heat with a hypothermic person is unproductive. "My concern with this is that you will end up with two cold people," said Wittmers. Researchers have found that the warmer person will lose heat while blunting the colder person’s shivering response. Shivering is the body's natural way of warming itself. The person offering up their body heat may not be doing any physical good for a hypothermic victim since they are giving about as much heat as they are taking away by restricting the victim’s shivering response. And, they are making themselves cold. With this old-school treatment technique, you may just end up with two hypothermia victims.


When a hypothermia victim is found, the following actions should be taken:

  • Move them to a warmer environment, if possible

  • Remove wet clothing

  • Cover them with warm clothing and blankets, especially the head and neck

  • Give them something warm and non-alcoholic to drink, if they are awake and able

  • Seek medical help

When dealing with a severely hypothermic victim, it is important to move them with the utmost care. Too much excess stimulation could restrict their blood vessels, which may impair heat transfer to the core and blunt their shivering response.

If a severely hypothermic victim is found without pulse or respiration, do not assume they are beyond help; actions should still be taken to warm them as much as possible with the above techniques. CPR is a controversial issue for treatment, with the same concern about restriction of the blood vessels. Some experts recommend that CPR be administered on the way to the hospital, along with oxygen and warming. However, Wittmers points out that it is important to continue the CPR and warming once it is started.


Dress right! To protect yourself from becoming hypothermic, appropriate clothing is essential. Wearing cotton in chilly weather or when you get wet or sweaty is risky since the fabric retains water, and water quickly conducts heat away from the body. Evaporation also moves heat away from the body more quickly. Synthetic and wool fabrics provide superior insulation and dry more quickly.

Just say "NO" to drugs and alcohol! Alcohol or drug intoxication often contribute to hypothermia. Alcohol increases blood flow to the body's extremities, thereby increasing heat loss. Alcohol may cause the victim to feel warm, but it actually allows heat to rapidly exit the body. "Alcohol inspires you to do dumb things," said Wittmers.

Wear a life jacket! Life jackets are designed to keep the wearer's head above the water, so you will not drown even if you are unconscious. Wittmers explains that it usually takes several hours to die from hypothermia, but if you drown first there isn't much that can be done.

Surviving a Plunge in Cold Water

If you should fall into the water, do your best to keep calm and control your breathing while attempting to get out of the water. If you were in a boat that has capsized, try to flip it upright. If it cannot be made right, climb on top of it.

If separated from your boat and flotation devices, try to stay as still as possible and avoid panicking. Physical exercise such as swimming causes the body to lose heat at a much faster rate than remaining still in the water. Blood is pumped to the extremities and is quickly cooled. Few people can swim a mile in 50-degree water. Air trapped in clothing can provide some buoyancy as long as you remain still in the water.

The major body heat loss areas are the head, neck, armpits, chest and groin. If you are with others, huddle together facing each other to retain body heat.

Learn More

Minnesota Sea Grant has updated its popular Web page on hypothermia and added a quirky video, Stayin’ Alive. In it, a brave man jumps into Lake Superior during the January 2009 Special Olympics Polar Plunge and endures the consequences of starring in a public service message about hypothermia. To learn more about hypothermia and to watch the video, see: www.seagrant.umn.edu/coastal_communities/hypothermia.

By Kendra Richards
December 2009

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This page last modified on March 01, 2018     © 1996 – 2019 Regents of the University of Minnesota     The University of Minnesota is an equal opportunity educator and employer.
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