|(Photo credit: Wikipedia)|
Now, I love to wear cotton clothes, I'm not trying to upset the cotton industry with this article, but the idea is that cotton absorbs water and holds moisture, losing any insulating properties and lowering the core temperature. This is a lesson I've learned the hard way. You can read about that in my articles about Writers' Police Academy and playing the victim in an airplane crash.
If you want to make your victim cold fast, dress her in cotton and then have her run for her life, sweating, getting her clothes nice and humid despite the chilly night. There! You've written a crisis. Dress her in synthetics (especially fleece) or wool, and she has a better chance.
There are three basic stages of hypothermia:
- Increased urine production
- Sympathetic nervous system activated:
- increased heart rate and blood pressure (You have a character with a heart condition? This could be bad.)
- blood glucose goes up (Does your character have Type 1 or Type 2 diabetes? When their blood runs out of glucose, they will drop into hypoglycemia)
- Shivering becomes more violent
- Coordination becomes a problem - movements are slow and difficult to execute. Stumbling will probably occur
- Mild confusion
- Character becomes pale
- Lips, ears, fingers and toes become blue (Blood stays in the core)
- Now the heart rate, respiration rate, and blood pressure all drop.
- Difficulty speaking
- Difficulty getting thoughts together
- Unable to use hands
- Poor muscle coordination/walking is nearly impossible
- Skin is blue and puffy
- Irrational behavior including terminal burrowing and paradoxical undressing (I'll explain these below)
- Major organs fail
Also, imagine how much they know about being in the elements and what they need to do to save themselves. For example: Sitting on a rock or lying directly on the ground are things that should be avoided as they, like wet cotton, wicks the heat away from a body. Are your characters up and doing calisthenics? Are they working madly to build a fire to dry their clothes? Are they staying really well hydrated? Did your character have a nip of brandy to take the chill off? (some research suggests that about 70% of hypothermia includes an element of alcohol.) Your character's choices and background are the difference between life and death. (Article on snowbound survival in a car)
We've talked a little about prevention here are some more subtle points to put into your book:
They've found your heroine! Whoop! Now what?
Search and Rescue are trained to look for two signs that there is a hypothermic patient even before we've found someone: clothing and burrowing.
Crazily enough, in our trek from caveman to modern man, we have developed a tendency--between moderate to severe levels of hypothermia--to become disoriented and even combative (though that energy might just raise the body temps) in this state people tend to take off their clothes. I know! Crazy, right? But 20-50% of hypothermic deaths includes this paradoxical undressing. Researchers believe that the human system miscues and the body actually thinks it's overheating instead of freezing to death.
Sometimes it's hard to find folks who are freezing to death because in the first stages of hypothermia a person will get into small spaces. In a house, (such a homeless character who is squatting in an abandoned building) this might mean in a closet or behind a piece of furniture. Out in nature, however, this might mean getting under piles of leaves - which makes sense in that leaves are insulating; only we can't find them to rescue them.
Water is a problem - as in water lowers the body temperature much quicker than the air could. In 50 F water, your character would have about an hour. If it was a 50 F day, and they were dry, they'd have a much longer rescue window.
In freezing water (think Titanic), people will die in around fifteen minutes. Though here's a truism cold and dead is not the same as warm and dead. We actually use hypothermia in some operating procedures and then the patient's body temperature is slowly raised. There was a incident in Sweden where a girl was given CPR for hours and she was brought back. So if your character is without vitals signs, have rescue do their thing. It might just work. Or not. You know your plot line.
Usually, unless there are signs of unsurvivable trauma, death is not called until the body is warmed to near normal temps. A body under an avalanche for more than a half hour with snow in their mouth is dead even if cold. But other than that you can effect heroic efforts for your characters and they have a chance, albeit a small chance, but a chance of surviving.
|Note: The difference between fever and hyperthermia is the underlying mechanism. Different sources have different cut-offs for fever, hyperthermia and hyperpyrexia.|
Here's a handy temperature chart:
- Synthetic and wool work as insulation even wet (fleece is great)
- Clothing should be loose fitting and in layers, tight clothes limit circulation. So your heroines jeggings are gonna be a problem.
- Plan for coldest possible day at that time of year and take off/put on layers as needed.
- Building shelters is a good idea.
- Rocks and earth as well as metal pulls heat away so mrph - don't use those unless you want your character in big trouble, then by all means - go for it!
- Shelters should be small so they retain the body heat. (But mark them so they can be found by rescue otherwise your character risks a burrowing death)
- A reflective blanket and an emergency candle are a good light-weight/easy-to-carry survival tool. (More about this in Hug a Tree article)
If the rescuers do this wrong, it could injure or kill her.
- If unresponsive. Start ABCs airways, breath, circulation this may means CPR and artificial breathing AS you rewarm/get them out of the cold conditions.
- Move the characters as little and as gently as possible.
- Don't put them in a warm bath, massage the legs and arms, or give a heating pad. These might get the blood to the skin and drop the blood pressure and could kill them. Eep! This is called Rewarming shock.
- Get the wet clothes off. Give them insulating dry clothes/blankets. Move them to a warm environment. Heat reflective emergency blankets are great. You can put warmth under the armpits or at the groin - maybe one of those chemical pocket warmers, for example.
- A nice warm sweet drink - tea, for example. No, not a nip from the ... too late, no brandy won't do the job. Opposite. Alcohol is a no no. And of course they should be alert and able to swallow the arm beverage.
Here's hoping your heroine warms up and lives to finish the plot and maybe even get her happily ever after.