Hypothermia

If you are lucky enough to live in an area where temperatures never get severely cold, you probably don’t need to worry about hypothermia.  You also don’t know how to cope with it if it does happen.  Hypothermia is a condition in which your core temperature drops below the level necessary to maintain normal bodily functions.  An average adult’s core temperature should fall in between 94°F and 100°F.  Once you dip below that range you will start to experience hypothermia.  It may only be mild hypothermia, but mild hypothermia can quickly escalate to severe hypothermia.

It is key to remember that, no matter how drastic the situation may seem, there is no such thing as a “lost cause” with hypothermia victims.  As long as you take appropriate, moderate measures, the victim should recover.  A little girl in Sweden had a documented case of hypothermia in December 2010 in which her core temperature was close to 55°F and she survived!

Mild Hypothermia

Mild hypothermia is the most common form of hypothermia encountered, and luckily the least damaging.  Symptoms of mild hypothermia include:

  • shivering – Muscles near vital organs will involuntarily begin to spasm. This is a defense mechanism in order to insure that your organs stay warm.
  • hypertension and tachycardia – When you get cold, your body starts to pull blood away from your extremities and into your core to keep your vital organs warm.  This can caused increased blood pressure and heart rate.
  • tachypnea – Typically, you breathe at around 12-20 breaths per minute.  Breathing faster than that can be a sign of hypothermia.  This one is difficult to gauge since physical activity of any kind can increase your breathing cycle into that range.
  • vasoconstriction – When you start shivering and your muscles start to spasm, this can cause neighboring blood vessels to constrict, lower blood flow throughout the body.  This is also one of the ways in which your body keeps blood in your core and away from your extremities.
  • cold diuresis – As your body resrticts flow of blood to your core, other systems can get confused and think that you have an excess of liquid in your body.  This will signal the kidneys to start extracting some of that liquid from the bloodstream and remove it as urine.  This is why it is doubly important to stay hydrated in the cold.
  • mental confusion – If you or someone you are with starts to get confused, or act strangely, this is a sure sign of hypothermia.
  • hepatic dysfunction – Liver failure or dysfunction isn’t really a symptom so much as it is a result.  Even in the mild stage of hypothermia, serious damage can occur if not dealt with as soon as possible.
  • hyperglycemia – An increase in blood sugar is not uncommon, nor is it a problem if your blood sugar levels return to normal within a reasonable amount of time.  If left unchecked, it can lead to some nasty side effects including permanent blindness.

If you or someone you know is suffering for mild hypothermia, follow these steps to get them on the road to recovery.

  1. Reduce Heat Loss – Get them any additional layers of clothing you can get your hands on, swap out wet clothing for dry clothing, get them doing something physical, get them to shelter.  Passive rewarming is the best technique at this point.  Let them use their own body heat to get them back in working order.  Remember that overdoing it can be just as bad as not doing anything at all.
  2. Add Fuel & Fluids – It is essential to maintain hydration and energy consumption.
    1. Food Sources
      1. Carbohydrates are quickly converted to energy, making them ideal for someone with mild hypothermia.  They’ll give you a quick burst of energy that can increase body temperature.
      2. Proteins are more slowly converted, making them ideal as a preventative measure.
      3. Fats burn the slowest of all, but will give you the greatest energy conversion.  It takes a lot of water for your body to break fats down so it’s imperative that you keep yourself hydrated.
    2. Food Intake
      1. For someone suffering hypothermia, hot liquids are a great food source – you get the caloric intake plus an external heat source.
      2. Sugary snacks are a great way for someone in the throws of mild hypothermia to recover – they’ll get a fuel surge that should get them back to normal rather quickly.
      3. Trail mix is a wonderful (and tasty) combination of carbohydrates and fats that work well as a preventative measure against hypothermia and as a long term supplement to any sugars given to the victim.
    3. Things to Avoid
      1. Alcohol is a vasodilator, it will force open the constricted blood vessels in your extremities, which will in turn increase heat loss.
      2. Caffeine causes water loss increasing dehydration.
      3. Tobacco/nicotine – a vasoconstrictor, increases risk of frostbite
  3. Add Heat – You can do this be introducing an external heat source, such as fire or another body.  A classic survival technique for rewarming a hypothermic comrade is to climb into a sleeping bag or under a blanket together and share the normothermic persons body heat between the two people.  If you weren’t good friends before this experience, you will be afterwards!

Moderate Hypothermia

In the next stage of hypothermia, the extended duration of a low body temperature results in shivering becoming more violent. You will experience muscle miscoordination, where you have less control over your movements or they will be less accurate.  Movements will become slow and labored, accompanied by a stumbling pace and mild confusion. You will  become pale. Your lips, ears, or digits may have a blue tint to them.

To treat or prevent moderate hypothermia, follow the same steps as with mild hypothermia.

Severe Hypothermia

In the most devastating stage of hypothermia, you will begin to experience the following symptoms:

  • Difficulty in speaking,
  • sluggish thinking,
  • amnesia,
  • inability to use hands,
  • stumbling,
  • cellular metabolic processes shut down,
  • exposed skin becomes blue and puffy,
  • muscle coordination becomes very poor,
  • walking becomes almost impossible,
  • incoherent/irrational behavior,
  • pulse and respiration rates decrease significantly, but fast heart rates (ventricular tachycardia, atrial fibrillation) can occur,
  • major organs fail,
  • clinical death occurs (because of decreased cellular activity in stage 3 hypothermia, the body will actually take longer to undergo brain death).

A significant chunk of hypothermia deaths are associated with what is called “paradoxical undressing.”  As you become more brain-addled, you may start to undress, regardless of the temperature.  Experts theorize that this is either due to a malfunction in the hypothalamus, causing the brain to trick itself into being to warm, or because shivering muscles become exhausted and stop, allowing the blood vessels to dilate, allowing a surge of blood and glucose into the extremities, causing an actual increase in heat in the outer regions of the body.  Think about what happens when you come inside after being in the cold for a while: You stop shivering and suddenly everything is warm to the touch, or at least feels hotter than it should.

It is also not uncommon for people with severe hypothermia to resort to an action called “terminal burrowing” which is similar to what hibernating animals do.  When they get too cold, they make there way to their hibernation chamber and burrow in for the winter.  Humans aren’t equipped for hibernation, so when they “burrow in” (under a bed, behind a dresser, in a hole in the snow) they simply shut down and die.

Being that severe hypothermia is so… well… severe, you have to be incredibly cautious when trying to rewarm them.  Follow these guidelines and you may bring you comrade back in from the cold.

  1. Reduce Heat Loss – You want to wrap them up in as much insulation as possible.  Get them out of any wet clothes and into dry ones.  Wrap them in blankets, if you have an aluminum “space” blanket, wrap them in that first.  Stuff them in a sleeping bag or two. Wrap them in an outer layer of plastic to keep them protected from water and wind.  DO NOT put them in a sleeping bag with another person at this stage.  The drastic difference in temperature could actually burn them or cause other permanent damage.
  2. Add Fuel & Fluids – Do not give the victim any solids, their stomach has already shut down and won’t be able to digest any non-liquids.  Ideally, if you have some Jello, you should make a diluted form of that (use twice as much water as instructed).  This works so well because it contains sugar and protein, plus you can make it with warm water, just don’t make it too warm or you’ll risk burning them.
  3. Urination – In this state, the victim will most definitely be suffering from cold diurisis and will need to urinate often.  Whenever they feel the urge, let them.  Unwrap them from their cocoon, let them pee, then wrap them back up.  If urine is left in the bladder, your body wastes some of its heat energy keeping the contents of your bladder at body temperature.
  4. Add Heat – Apply mild heat too vital areas in order to transfer that heat to nearby arteries and into the blood stream.  Apply heat to the neck, armpits, groin, and palms of the hands.  These areas will transfer heat to the carotid, brachial, and femoral arteries, and the arterial arch respectively.
  5. Rescue Breathing can be used in severe cases to increase oxygen in the blood stream and to transfer heat.

Terminal burrowing – In the final stages of hypothermia, the brain stem produces a burrowing-like behavior. Similar to hibernation behavior in animals, individuals with severe hypothermia are often found in small, enclosed spaces, such as under the bed or behind wardrobes.

How to Stay Warm in the Cold

25% of the year (more or less) is going to be uncomfortably cold.  Most of us don’t realize just how cold it gets because we have car heaters and furnaces and so on.  If you live close enough to the equator that you don’t know what I’m talking about then you’re one of the lucky few that doesn’t need to read this article.  Congratulations!  You’re all set to survive “winter!”  For the rest of you there are a few things you can do to make winter survivable.

Know Your Limits.

I remember several occasions where I thought I was prepared for the cold weather only to find out how wrong I was.  That’s the first thing you need to do to survive the cold – Be Prepared and know you’re limits.  If it’s too cold out for you to go tromping around, don’t risk it.

If You Don’t Have To, Don’t Go Outside.

You’ve likely got some kind of shelter built (temporary or permanent) that protects you from the elements.  If you’re warm inside your shelter, don’t go out unless you need to.

Go South, Young Man!

Follow in the footsteps of your grandparents.  When winter starts  creeping in, start heading towards Florida.  The further South you get, the less inclement the weather will be.  If you get far enough, you won’t have to worry about staying warm.

Stay Dry

In my opinion, if you’re out in the elements, there is nothing more important than staying dry.  If you are soaking wet (from falling into a pond for instance), it is better to strip out of your wet clothes and rub off the excess moisture from your skin with snow than it is to stay in the wet, rapidly cooling clothes.  Your socks will get wet quickly and often, it is important to make sure your feet stay dry so change your socks when you can.

Layers

You should wear several layers of clothing.  Be constantly aware of your body temperature and adjust your clothing accordingly.  If you start getting a little warm, take off a layer.  If you start to get a little cool, put a layer on.  If you get to warm, you’ll start to sweat, the sweat will eventually cool off, making you cold and miserable (and possibly dead).

Avoid Cotton

Cotton is a great material in the summer time because it soaks up your sweat and allows it to evaporate rapidly, leading to a cooling effect of the skin.  This is the exact opposite of what we want in cold weather.  It is better to wear undergarments made of synthetic materials like polyester because these materials having a wicking effect that draws your sweat away from your skin, thus avoiding the cooling effect of cotton.

Keep your Hands and Feet Warm.

It is important to keep your extremities warm.  When cold, your body draws most of your blood into your core to keep your vital organs protected.  If your hands and feet get too cold, you’ll get frostbite and potentially lose fingers or toes.  Wear warm boots and socks, and wear warm mittens.  Gloves are okay, but mittens are better because your fingers stay warmer when they are all together.  There are mittens you can buy that the top half on the mitten flips off so you can use your fingers for particularly dexterous tasks.

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Keep your Head Warm.

Similar to the previous point, it is equally important to keep your head warm.  Your head accounts for 1/3 of your heat loss from less than 10% of the surface area of your body.  This means that if your head is warm, your whole body will feel warm (or at least warmer).  If your head is cold, it will precipitate limited blood flow to the extremities and heighten the risk of hypothermia/frost bite.

Keep Moving

When you exert yourself, you expend energy.  Particularly, energy in the form of heat.  Simply moving around will be enough for you to start to warm up.

Stay Hydrated

Being in the cold can sap your body of moisture just as quickly as being in the hot sun can, but it doesn’t feel like it.  Staying hydrated will stave off any ill effects of the cold.

Pee and Pee Often

You’re body spends a great deal of energy keeping your core temperature at around 98.6 degrees and that includes your bladder.  If your bladder is full, that’s even more energy being wasted on something that you’re going to get rid of anyway.

Breathe Through Your Nose

You have four pairs of sinus cavities that connect your nose to your trachea.  This isn’t a coincidence.  These cavities filter, humidify and warm the air as it enters your body.  If you breathe in cold air, by the time it gets to your lungs, it’s warm.  If you breathe through your mouth, you get a lungful of cold air which robs your core of warmth, expending more energy to keep you warm.