Guest Post: Dealing With Hypothermia by Joe Alton, MD and Amy Alton ARNP

Joe and Amy are authors of The Survival Medicine Handbook: The Essential Guide For When Help Is Not On The Way and Alton’s Antibiotics And Infectious Disease: The Layman’s Guide To Available Antibiotics In Austere Settings. They also run which is an excellent source for austere medical knowledge.

The environment plays a large role in your success as medic in survival settings. If you don’t take weather conditions and other factors into account, you have made the environment your enemy, and it’s a formidable one. Different areas may pose special challenges. If you live in Miami, you might be treating a lot of people with heat stroke. If you live in Siberia, you’ll be treating a lot of people with cold-related exposure. In many places, you’ll be at risk for both, depending on the time of year.

Illness related to cold temperatures is known as ‘Hypothermia”. Normally, the body core ranges from 97.5 to 99.5 degrees Fahrenheit (36.5-37.5 degrees Celsius) when taken orally or rectally. Rectal temps tend to be slightly higher than oral, and oral temps slightly higher than skin readings, such as those taken in the armpit. Hypothermia begins when the body core drops below 95 degrees.

The body loses heat in various ways:

Evaporation – Perspiration (sweating) from physical exertion or other reasons releases heat from the body core.

Radiation – the body loses heat to the environment when the ambient (surrounding) temperature is below the core temperature. For example, you lose more heat if exposed to an outside temperature of 20 degrees F than if exposed to 80 degrees F.

Conduction – The body loses heat when its surface is in direct contact with cold temperatures, as in the case of someone falling from a boat into frigid water (think “Titanic”). Water, being denser than air, removes heat from the body much faster.

Convection – Heat loss where, for instance, a cooler object is in motion against the body core. The air next to the skin is heated and then removed, which requires the body to use energy to re-heat. Wind Chill is one example of air convection: If the ambient temperature is 32 degrees F but the wind chill factor is at 5 degrees F, you lose heat from your body as if it were actually 5 degrees F.

Identifying Hypothermia

The body, when it is exposed to cold, kicks into action to produce heat. It does this by muscle actions as the core cools. Muscles shiver to produce heat, and are a warning that you need to warm up. As hypothermia worsens, more symptoms will become apparent.

Aside from shivering, the most noticeable symptoms of hypothermia will be related to mental status. The person may appear confused, uncoordinated, and lethargic. The victim’s speech becomes slurred and they often will appear uninterested in helping themselves.

All this occurs due to the effect of cooling temperatures on the brain; the colder the body core gets, the slower the brain works. Other organs begin to shut down, and the victim loses consciousness. Any unconscious person you find exposed to cold weather is hypothermic until proven otherwise.

Cold-related tissue effects also includes local damage, such as frostbite. Frostbite affects areas like fingers, toes, nose, earlobes, and even lips. Sometimes called “Frostnip” or “Chilblains” in early stages, it begins as numbness, pins and needles sensations, and redness. Blistering may occur.

If not warmed, the skin turns progressively white and waxy, then blue, and, finally, black, a condition known as “gangrene”. Gangrenous tissue is dead and unsalvageable in survival settings, and may require debridement (the removal of dead tissue) or amputation.

Prevention of Hypothermia

An ounce of prevention is worth a pound of cure, and many cases of hypothermia can be prevented. To prevent hypothermia, you must anticipate the climate that you will be traveling through, including wind conditions and wet weather. Condition yourself physically to be fit for the challenge. Travel with a partner if at all possible, and have enough food and water available for the entire trip.

Remember the simple acronym C.O.L.D. This stands for: Cover, Overexertion, Layers, and Dry Cover. Dress appropriately for the weather. Protect your head by wearing a hat. This will prevent body heat from escaping from your head. Instead of using gloves to cover your hands, use mittens. Mittens are more helpful than gloves because they keep your fingers in contact with one another. This conserves heat.

Overexertion. Avoid activities that cause you to sweat a lot. Cold weather causes you to lose body heat quickly; wet, sweaty clothing accelerates the process. Rest when necessary and use rest periods to self-assess for cold-related changes. Pay special attention to the status of your elderly or juvenile group members. Diabetics are also at high risk.

Layers. Loose-fitting, lightweight clothing in layers allow a thin layer of warm air between and do the best job of insulating you against the cold. Use tightly woven, water-repellent material for wind protection. Wool or silk inner layers hold body heat better than cotton does. Some synthetic materials, like Gore-Tex, work well also. Especially cover the head, neck, hands and feet.

Dry. Keep as dry as you can. Get out of wet clothing as soon as possible. It’s very easy for snow to get into gloves and boots, so pay particular attention to your hands and feet.

Treating Hypothermia

Immediate measures must be taken to reverse the ill effects of hypothermia. Failure to act quickly may lead to organ failure and death. Important measures to take are:

Get the person out of the cold. Transport to a warm, dry location. If you’re unable to move the person out of the cold, shield them as much as possible. Be sure to place a barrier between them and the cold ground.

Monitor breathing. A person with severe hypothermia may be unconscious. Verify that the patient is breathing and check for a pulse. Begin CPR if necessary.

Take off wet clothing. If the person is wearing wet clothing, remove them gently. Cover them with layers of dry blankets, including the head, but leave the face clear.

Share body heat. To warm the person’s body, remove your clothing and lie next to the person, making skin-to-skin con- tact. Then cover both of your bodies with blankets. Some people may cringe at this notion, but it’s important to remember that you are trying to save a life. Gentle massage or rubbing may be helpful, but vigorous movements may be traumatic.

Give warm oral fluids. If the affected person is alert and able to swallow, provide a warm, nonalcoholic, non-caffeinated beverage to help warm the body. Alcohol does not warm you up; instead, it expands blood vessels and actually hastens the loss of heat from the body core.

Use warm, dry compresses. Use a first-aid warm compress or a makeshift compress of warm (not hot) water in a plastic bottle. Apply compresses to the neck, armpit, and groin. These areas will transport heat to the body core more effectively than placing warm compresses on the extremities, which sometimes worsens the condition.

Avoid applying direct heat. Don’t use hot water, a heating pad or a heating lamp directly on the person. The extreme heat can damage the skin, cause strain on the heart, or even lead to cardiac arrest.


The concern of anyone stranded in the cold, whether it’s in the wilderness, an urban environment, or a vehicle is to find the warmest shelter available. In the post-collapse city, many abandoned buildings will provide a refuge from the wind and, perhaps, fuel to build a fire. A vehicle can serve as its own shelter.

In the forest, a “tree well” shelter can be constructed out of the snow. A tree well is the sunken area around the trunk in very deep snow. This area is relatively easy to excavate and, if the tree has low-hanging branches, should provide some protection from falling snow. Look for natural barriers nearby that may serve as windbreaks, but beware of slopes where you may be exposed to drifting snow or avalanches.

The space you dig out should be small, as small shelters take less effort to keep warm than large ones. Pack your snow “walls” well, so that they can retain heat better and support a makeshift roof. Place evergreen boughs and debris on the floor to protect you from the cold ground. Then, add some on top to make a roof. Tarps or solar blankets may be used for this purpose, but winds might easily blow them off. Tie rocks to the corners as weights.

If you make a fire, be sure to have ventilation holes in your shelter. Entrances and ventilation holes should open at a 90 degree angle to the prevailing winds.

Let’s say you’re stuck in a stalled car on the road in a blizzard. Stay in the vehicle as, thanks to your body heat, the temperature in the vehicle is warmer than outside; in addition, you have protection from the wind. Leaving the vehicle might disorient you in driving snow.

If the motor runs, turn it on for only about 10 minutes each hour for heat. Although the heater helps, wet snow can block up your exhaust system and cause carbon monoxide gas to enter the passenger compartment. You’ll need fresh air, so crack a window on the opposite side from where the wind is coming. If you’re in a group, huddle together as best you can to create a warm pocket in the car.

Your muscles produce heat involuntarily by shivering, but you can rub your hands, put them in your armpits, or otherwise keep moving to achieve the same goal.

The Winter Survival Car Kit

There are a number of items that you should always have in your car, especially in cold weather. These are meant to keep you safe if the unthinkable happens and you’re stranded without hope of rescue. A full set of camping supplies would be useful to keep if you have space in your car, but there are some items that are especially important:

  • Wool blankets (for warmth; wool can stay warm even if wet)
  • Spare sets of dry clothes, especially socks, hats, and mittens.
  • Hand warmers or other instant heat packs (activated by shaking, they’ll last for hours)
  • Matches, lighters, and fire starters to manufacture heat Flashlights and candles (keep batteries in backwards until you need them to extend life).
  • Small multi-tool with blade, screwdrivers, pliers, etc.
  • Larger combination tool like a foldable Chinese Army shovel (acts as a shovel but also an axe, saw, etc.)
  • Sand or rock salt (to give traction where needed) Tow chain or rope
  • Flares
  • Starter cables (for jump starts)
  • Water and food (energy bars, MREs, dehydrated soups, candies) Baby wipes (for hygiene purposes)
  • A medical kit and medications
  • Tarp and duct tape (brightly colored ones will be more visible and aid rescue)
  • Metal cup or thermos (to melt snow, make soup, etc.) Noisemaker (whistle) to signal for help
  • Cell phone and charger, weather radio

It should be noted that some of the above materials, such as starter cables, are most helpful in normal times when rescue resources are available.

Winter can be harsh, but with some planning and supplies, it’ll be a bump in the road, but not the end of the road. Act quickly to help a victim of hypothermia, and you’ll save a life.


  1. Having been thru a military winter survival course (we were allowed to get hypothermia to experience it), you get to the point you no longer feel cold. You start to feel drowsy and actually feel good.
    Watch others for these symptoms, especially children, who have less body mass.

  2. A clean one-quart paint can with lid, a paint can opener, a roll of toilet paper (remove the cardboard core and toss that part away), a bottle of 91% alcohol, and a lighter.

    Squeeze the toilet paper tight and push into the clean paint can. Carefully pour alchohol over the TP until level is flush (your pun for today) with top of paper. Set can on the floor of your car away from flammable items.

    Light it and warm yourself. Make sure you previously capped the alchohol, remember you’ll be cold and jittery, so preplanning in your brain helps.

    When edge of TP starts turning color, put can lid over the it to smother the flame. Make sure flames are out, then refill with your alchohol container, seal with paint can lid or relight.

    I duct tape all components together as one unit gor packing away preps.

    I had my kids do this in their house by Spokane when power was off, and tested it myself. Try it. Total cost was less than 10 bucks. There are you tube vids on line.

    Best wishes and God Bless

  3. having had “mild” hypothermia twice in Alaska growing up I can tell you it’s awful. Initial symptoms of cold and shivering give way to feeling warm and sleepy and stupid, if you sleep, you die. Thawing out is the worst part when your skin is yellow and slightly lumpy, then it starts aching and throbbing, and you can actually feel your bones being cold and then you shiver and shudder as you warm up, but even in a hot bath it took hours. One of my high school teachers actually froze to death on the way home from a PTA meeting in winter, he’d had a few beers afterwards and decided to walk home about a mile, well he apparently got cold and tired and thought he would sit down by the side of the road and rest, and in a little town with no traffic at night, they found him there next morning..

  4. Thanks for this great article. It’s a good refresher! What type of containers do you use to keep water in your vehicle, considering that the water will likely freeze and thaw repeatedly, depending on the outside temperatures?

    1. Ma G, we live in the central USA where winter lows get down to about 0 degrees F. I did an experiment to test this. I filled 2 standard 16 oz water bottles from Walmart w/ a few drops of bleach. Then I put those 2 bottles in a zip-lock gal bag, to contain the mess it the bottles froze & split open. I kept them in the trunk of my SUV. Those bottles never did freeze. I concluded that those bottles could take more than I expected. Not sure where u live, but you could try the same experiment. One can also find 16 oz bottles that are hard-plastic (not the cheap kind that comes w/ water) that come with juice or ice tea in a convenience store. My guess is that the hard-plastic bottles can take more, but not sure.

      1. Actually, any somewhat soft (think, “stretchy”) plastic bottle is a good candidate for freezing. To test, fill with water, and put it in your freezer. Then after it is completely frozen, pull it out and let it thaw. If it can stand 2 or 3 cycles without leaking, you have a winner.

        On another note, keeping a few frozen water bottles in the freezer is a great way to keep ice ready for the cooler, for travel.

      2. Thanks for the input, Chris & cf. We moved over the summer from the SW US back to the North Central US after more than 30 years. Winter temps in our area can get down well below zero, and our vehicles will be parked outside. I think I’ll try starting with a plastic bicycle water bottle inside a ziploc back and see what happens. Although, if it were frozen and I needed the water, I couldn’t warm it over a fire. I guess that for anything more than just trips around town, we could just bring a couple gallon jugs from the house and keep them in the passenger compartment, then take them back inside when we return home.

    2. Heavy plastic sports drink bottles survive repeated freeze/thaw cycles, a tuna can made into a candle with 3-4 wicks can keep a car heated for a day or two and is safely and eadily stored. Don’t forget matches or lighter

      1. ThoDan, is Nalgene “stretchy” enough? Have you tried it? I have an empty nalgene bottle in my get home bag, not a filled one.

        In our former home state we were advised not to drink water that came from a plastic bottle that had sat in a vehicle when the temperature inside had risen to more than 100 degrees F because of possible off-gassing.

        So many variables to consider!

        1. I´ve never experienced them to stretch but the nalgene i use in my car was sometimes at least partially frozen and nothing happened to them.
          I like them for car use because i can use them one handed

  5. I like wool. But fleece is better. Fleece is hydrophobic and water can easily be squeezed out and what little is left will dry with body heat. Wool on the other hand once it is wet will stay wet unless placed in a dryer or exposed to warm sunlight for days. AND fleece will also still work to keep you warm after it has gotten wet.

    1. Fleece is good, but it does not meter perspiration like wool does, which means that the comfort range is much narrower. (Fleece is not good for protection from heat. Wool is.) So, layers must be added and removed more frequently. Also, fleece does not store heat chemically, as wool does, to be released when moisture is encountered. And around fire, fleece is much more vulnerable than wool. It melts with a spark, while wool singes over and insulates.

      Fleece is more washing-machine-friendly. However, if you get a front-loading washer with a “hand wash” cold-water cycle, wool can usually be machine-washed without shrinking.

      1. I disagree with all of your rebuttal except that fleece will indeed burn when you get too close to a fire.

        Fleece does a better job than wool at moving moisture away from the body. Wool is an excellent insulator and thus needs to have layers removed as your body over heats. But advantage fleece because it is lighter. Your chemical heat storage is fairy tale.

        There is a good reason that the military ECWCS is fleece and not wool.

  6. Wool can hold 30% of its weight in water and not feel wet. It does continue to retain heat even if wet, but depending on the fabric composition, will take longer to dry. I vaporized a Patagonia fleece jacket back once when I accidentally got too close to the iron fireplace front. Both products have advantages and disadvantages. I love my SmartWool clothing. You can wear it for several days in a row and it doesn’t hardly smell. Try that with synthetic socks. My fleece jackets are light, compressible, and not terrible expensive. I use both.

  7. Thanks Joe and Amy for a great article! I used your and Wranglestar’s advice to put together a winter survival box CHRISTmas present for my wife who will be traveling by car to the mountain west next week. I like it so much I plan to upgrade the kits I put together for our now adult children a few years ago.
    And I agree with Oz on use of both fleece and wool. At least it makes sense to a guy from the Deep South! 🙂

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