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.

Heat Stroke

It’s hot outside, REALLY hot.  The air burns your lungs as you breathe and the sweat is dripping off your brow in a constant stream.  You run your fingers through your hair and it burns to the touch.  You feel parched even though you just guzzled a bottle of water and even though you’re walking slowly down the road, you’re heart is racing so fast that you can see your pulse in your eyes.  Suddenly, you realize that you’ve stopped sweating and you’re dizzy, you lean over and vomit the little bit of lunch you had onto the ground at your feet.

This is just the beginning of heat stroke and if it were to progress any further, you could very likely die.  Heat related illness is a very treatable illness, yet an average of around 300 people die from it every year.  In a post-apocalyptic environment, your chances of surviving heat stroke are lessened a great deal.  So the better you understand it, the better prepared you are to prevent and treat it.

Symptoms

Heat stroke, the most severe stage of heat illness, occurs when body core temperature exceeds 104 degrees Fahrenheit and your body’s normal heat regulation systems are no longer able to dissipate internal heat.  There are a number of symptoms to look for:

  • Rapid heartbeat even when not exerting
  • Light-headedness
  • Rapid or shallow breathing even when not exerting
  • Nausea
  • Lack of Sweat where sweating had occured before
  • Abnormal irritability or confusion
  • Headache
  • Fainting

If you happen to faint from heat exhaustion and you’re by yourself, you’re pretty much done for unless you get REALLY lucky.

Treatment

If you suspect that you are suffering from heat stroke, you need to immediatly cease any physical exertion and find a shady (prefereably cool) spot to sit.  Take off as much of your clothes as you can to promote evaporation on your skin and splash some water on your skin.  If you have a way of fanning yourself without exerting yourself, do it.  Sip (and I emphasize this) cool water.  If you drink too much too quickly or if the water is too cold, you’ll get stomach cramps and probably vomit.  Avoid anything with sugar or caffeine in it, these are diuretics and will cause you to dehydrate more.

You can take more drastic measures to cool yourself off.  If you are near a water source, jump in and soak in the water (preferably in the shade) until you cool off.  Avoid water that is too cold because this can cause vasoconstriction which will not allow for efficient heat transfer.  If you decide to soak in water, remember that your head dissipates heat much faster than the rest of your body, so stick your head under the water.

If you are sick enough that drinking water, no matter how slowly, causes you to feel sick to your stomach, it may be necessary to feed yourself water intravenously.  This is not difficult to do, but I will not go into it in this article.

Prevention

Urine Color Chart
Urine Color Chart

The most important thing you can do to prevent heat stroke is to drink fluids.  Stay hydrated!  Don’t gauge your hydration on thirst, especially in extreme heat.  By the time you’re thirsty, it’s already too late.  A better judge of hydration is the color of your urine.  On the included chart, you can see what color your urine should be and drink accordingly.  You should avoid drinking anything with a lot of sugar, caffeine, or alcohol as these will cause you to get dehydrated much faster.  You should be drinking 16-32 ounces of water an hour in extreme heat or when physically active.  Almost as important as hydration is salt intake.  If you drink too much water without replenishing salt and minerals this will lead to a condition called hyponatremia which can cause sudden heart failure and death.

When eating, avoid heavy meals and hot foods.  Particularly during the mid-day hours.  These types of foods tend to raise your core temperature and thus raise your risk of heat stroke.

Avoid being in the sun, especially during mid-day since this is when it will be hottest out.  If you have to be outside in the sun, limit your exposure time and level of exertion.  Take lots of breaks and be aware of how you feel.  You should try to wear lighweight clothing that is lighter in color, light colors reflect sunlight and the accompanying radiant heat and lightweight materials like cotton will draw sweat away from your skin and allow for quicker evaporation (and thus quicker cooling).

Avoid enclosed spaces (like a car) if at all possible.  Inside a building (assuming there is no air conditioning) should be okay, but just be wary of buildings that are warm inside.

Protect your head!  Wear a hat that will block sunlight from all sides.  There are hats out there that have vents in them.  Those vents allow for greater air flow, which will keep your head much cooler than a hat without them.

If at anytime you start to feel hot, take a break, dunk your head in some water, sit down and drink some water, etc.  Don’t feel like you ever need to power through it.

Further Reading