This article on hypothermia is part of the Science in Sci-fi, Fact in Fantasy blog series. Each week, we tackle one of the scientific or technological concepts pervasive in sci-fi (space travel, genetic engineering, artificial intelligence, etc.) with input from an expert. Please join the mailing list to be notified every time new content is posted.
The Expert: Rachel Berros
Rachel Berros is an emergency physician assistant who works closely with a virtual visit development team for her healthcare organization. During her spare time she writes speculative fiction that mixes the laws of science with magic, or just skirt the edge of possibility. You can check out her website, or follow her on Twitter for more information. She’d love to connect.
Hypothermia in Fiction: When It’s Hoth Outside
If you’re ever stuck on a frozen planet and are worried about hypothermia, climbing into a dead carcass could be a good idea, but only if it died recently. Though I suppose if the beast isn’t too frozen and you still have good control of your hands, you could skin it and use the pelt to stay warm. But really, who’s going to do that?
Possibly your character. So, let’s discuss the ins and outs of hypothermia and what your characters should look out for and do to survive.
First, I’d like to point out that it doesn’t have to be Hoth outside (frozen, windy, snow-covered, and Cold), to get hypothermia. If the conditions are ‘right’, a person could become hypothermic in temperatures in the 70s Fahrenheit. Hiking for hours, dampening the body and clothes with sweat, and burning calories leave a person primed for hypothermia.
What is Hypothermia?
The human body has many checks and balances, one being the ability to burn fuel to create heat by shivering. But if you’re the hiker listed above and get lost, wondering for hours after consuming all your day trip snacks, your body no longer has the fuel to make heat. Couple that with the convection effect of windchill on damp clothes and skin, and whatever little heat the body makes as a baseline is literally gone with the wind.
What does your hiker’s body do next? It gives up on shivering and prioritizes the internal organs by shunting all available heat their way. But what in the body carries that heat, you ask? The blood. One of those checks and balances I mentioned is the ability to constrict or dilate blood vessels as required. The smaller the tube, the less blood flow, and with less blood comes less heat. This also has the added bonus of reducing heat loss through radiation at the body’s surface.
What does this mean for you as our hiker? Well, it means first your extremities will get cold, then they progressively lose function. Muscles need blood to work and the body’s stealing it to preserve silly things like heart function. Consequently, you get clumsy. First fine motor skills go, like tying your shoes or manipulating a zipper. Then, if you’re out there long enough, gross motor skills follow. These include things like walking or making your hand reach your mouth.
Next, comes the Red Alert level where the body tries to take over your consciousness because obviously, you’re not making the best choices for its survival. (Please don’t be insulted) The blood now gets reduced in several areas of the brain as the body tries to get you to stop and take care of yourself. This leads to confusion and poor decision making and eventually could have you falling asleep. The body will continue to shut down more and more organs it deems ‘unnecessary’ until only the heart is kept active.
That final step is one reason some cultures hold wakes after people die. When people would ‘die’ (found unconscious without a palpable pulse) in cold ways before modern medicine, they couldn’t tell if the heart was still beating that tiny bit or not, so they’d leave the person on a table to warm and hopefully wake up. Today, a hypothermia patient isn’t declared dead until they’re warm and dead.
How to Fight Hypothermia
Okay, now you know the steps and process of getting hypothermia, so let’s discuss how to manage it.
If you’re only in the early stages of hypothermia, like the hiker above, and are found by search and rescue, they will first wrap you in a mylar or similar blanket to reflect what body heat you have and reduce the radiation and conduction loss. Then they should give you lukewarm hot chocolate. Too hot and you won’t be able to drink it, too cold and you miss an easy opportunity for more heat. They likely won’t fill the cup all the way either, but don’t be disappointed. Once you get some of that sugar in your system your body will aggressively utilize it. Translation: You’ll shiver like you’ve never shivered before and probably spill the rest of your hot chocolate, which would be a waste. Better to wait those first rigors out and drink that sugar later.
If you’re in one of those later stages from far lower temperatures, your body will need more help. Those same search and rescue heroes will crack a few chemical heat packs and place them in strategic locations around your body. Mostly, places large blood vessels get close to the surface, ie. The groin, armpit, and neck, and then wrap you in the heat-retaining blanket. In the hospital we use warmed IV fluids and electrically-heated blankets.
In the wild, your friends could start a fire to warm you—while drinking something sweet. Or if you’re bad enough, they could use warmed (not hot! No burns needed here!) rocks from around the fire in the same way as the chemical packs above and in a few hours, you should be good to go.
Before you go away from this page though, I want to point out a few more important things:
- When a person is in that final stage of hypothermia before death, they are extremely fragile. That heart is barely hanging on to normal function. Too much jostling or movement could throw the heart into a new and unstable rhythm that could kill them if not reversed. So, if you find someone cold, unconscious, and without a pulse in a setting that makes sense for hypothermia, call for help then do what you can to warm them without moving them until that help arrives.
- Cold is actually a brain preserver. Medicine uses it to help preserve brain function after critical illnesses like heart attacks. If your unconscious character does wake up, they might lose a few digits from frostbite (cold plus minimal to no blood flow leads to tissue death), but their brains should be back to normal.
- Yes, getting naked and into a sleeping bag with another living body would, in fact, help rewarm someone who falls in a frozen lake. So, by all means indulge that trope. However, getting the person some hot chocolate and a blanket in front of a fire would work just as well.
Thank you all for reading and stay safe out there!
(If you don’t have a Tauntaun to spare, remember to bring some extra snacks!)
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