Stay with me?
December 28, 2007 1:15 PM   Subscribe

Is there any reason why people need to stay awake to avoid freezing? I've seen this over and over in movie and tv plots where one person tries to keep another awake.
posted by srboisvert to Health & Fitness (12 answers total) 1 user marked this as a favorite
It is tough to stay moving when you are sleeping. You can't call or look for help. Plus you can't provide any self-report. I am not a hypothermia expert but that might have something to do with it.
posted by Silvertree at 1:18 PM on December 28, 2007

It's not that one needs to stay awake necessarily to avoid freezing (though presumably being awake and as active as possible under the circumstances might generate additional heat and keep you further away from freezing), it's that the sleeping is a classic symptom/result of too much freezing. Ergo, if your buddy can verify that you're still awake, you haven't yet frozen.
posted by LoraxGuy at 1:27 PM on December 28, 2007

It's the other way around. Drowsiness is a sign of hypothermia.
posted by dhartung at 1:29 PM on December 28, 2007 [1 favorite]

Your metabolism also slows somewhat when sleeping.
posted by nathan_teske at 1:30 PM on December 28, 2007

In the movies and tv shows it is usually somebody who is stuck in some way, at the bottom of a crack in the ice or pinned under a rock, with somebody trying to keep them alive by repeatedly saying "Stay with me buddy".

Given that they are trapped self-reports of their condition are irrelevant and they are not going to be moving.

Is there any actual benefit to being awake?

I wonder because I know for some animals, some birds at least, hypothermic sleep is how they cope with cold.
posted by srboisvert at 1:32 PM on December 28, 2007

If you are in a situation were you might die from getting too cold (i.e. hypothermia) and you go to sleep, you may very well die in your sleep. If you stay awake, you'll have a chance to do something as you become more hypothermic (or at least it will be easier for the person with you to determine that you are becoming more hypothermic). Of course, the higher metabolic rate for awake versus asleep helps too. I'd imagine it is pretty tough to make sure that you maintain a body position that minimizes heat loss while asleep as well. I'm sure the psychological reason is important too: if you know you have a good chance of dying while asleep, you are going to do whatever you can to keep for falling asleep. Thus, if you let yourself fall asleep, you are giving up.

This isn't a movie trope: first aid manuals always tell you to keep the victim of hypothermia, shock, or pretty much any injury awake and talking if at all possible.
posted by ssg at 1:43 PM on December 28, 2007

Your metabolism slows considerably when you sleep, which means you produce less heat.
posted by Steven C. Den Beste at 2:42 PM on December 28, 2007

As you freeze, your body draws blood out of your extremities into your core. Your brainstem sort of says "can we live without this?" and then turns it off. The first things to go are the very non essentials, fingers and toes, then hands and feet, then arms and legs. Also, the body slows your metabolism and heartrate and respirations, to keep from moving the blood which will keep it from freezing. The more this happens, the more you become hypoxic (no oxygen) and the more tired you get. Also, by this time, you're far past freezing and your body is saying "Shit shit shit" to all the calories it burned trying to shake you warm. The longer it goes, your body starts shutting off non-essential organs---pancreas, gallbladder, stomach, intestines, etc. Last three things are, of course, lungs, heart, and brain--in that order.

Awake, you can respond to rescue calls or lights or sirens, and keep your non-reptilian brain alive and working. You fall asleep and it switches to reptilian brain, where its sole purpose is to stay alive--no thinking or feeling.

So, stay awake, stay alive. Of course, if you freeze, you can often be brought back if you haven't been frozen *too* long.
posted by TomMelee at 3:18 PM on December 28, 2007 [1 favorite]

It's been codified in culture: then find the text containng the word "freeze".
posted by andreap at 3:23 PM on December 28, 2007

I think you might be on to something, srboisvert. Probably you do generate somewhat more heat while you are awake, but you might also lose even more than that because you are breathing more rapidly, and you lose a lot of heat into your outgoing breath in cold conditions. Sleeping might be beneficial because it reduces the brain's demand for oxygen, and thereby allows you to slow down your breathing rate below the point at which brain damage would occur if you were awake, minimizing the critical quantity [(total heat lost)-(total heat produced)]/(unit of time), which would be directly proportional to the drop in your average temperature as you are slowly freezing to death, and so extending your survival time beyond what it would have been if you'd employed all available measures to stay awake as long as you could.

The fact that drowsiness is an early symptom of hypothermia raises by itself the strong possibility it is a defense against freezing to death rather than a mere indicator of progress toward that endpoint.
posted by jamjam at 5:26 PM on December 28, 2007

There's a piece written by Amundsen, the Norwegian who was the first (euro) to sail the northwest passage. He said a big problem was people striving to stay awake in the cold to the point where they were drowsy, made mistakes, and died. He wrote that he went and dozed knowing he would wake up and be refreshed to trek further. I can't remember the name of the essay.
posted by philfromhavelock at 8:16 PM on December 29, 2007

Here is the story of a Japanese man who apparently went into hibernation for 24 days after falling asleep in the cold:

A Japanese man has survived for 24 days in cold weather and without food and water by falling into a state of "hibernation", his doctor has said.

I found this at the time you posted this question, but didn't get around to putting it in this thread for some reason
posted by jamjam at 5:07 PM on December 4, 2008

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