The Human Scale Of Too Cold: How We Freeze (And How We Thaw)

Posted by on Jan 10, 2010 in The Everyday | 44 Comments

WinterNinja

What happens when you get too cold?

When we say “cold”, we usually mean one of two things. The first is the foot-stamping, hand-rubbing, nose-blowing kind that millions of us Brits are experiencing right now as we trudge through the slush, or curse when the snow billows in our opened car doors.

And then there’s the other kind.

You can be sure you’re at your optimum core temperature because you’re lucid and conscious. In fact, your ongoing survival is dependent on it, on hovering somewhere near 37°C every single day, for the rest of your life. Stray above or below more than a little, and you will start to die.

Luckily, you’re amazing. You’ve been fitted with an incredible piece of biotechnology, a kind of super-advanced thermostat called a hypothalamus. This almond-sized marvel, buried deep inside your brain, is why you’re alive today. Take a moment to say thanks. (I’ve just thanked mine).

Your hypothalamus performs a range of invaluable and breathtakingly elegant roles, but the one we’re giving thanks for is the maintenance of your good self as a homeotherm – an animal with a steady core temperature usually above that of its surrounding environment. Thanks to your thermoregulatory system (heroically led by the hypothalamus), you never need to worry too much about keeping just the right temperature – your body’s got it covered.

Usually.

It takes a lot to overwhelm your hypothalamus’s capacity to keep your core temperature stable. But once it’s achieved, the effects are rapidly catastrophic.

So let’s chill out a little and see what happens.

SandDunes

37°C (subzero-temperature air exposure)

There’s a dark little truth about your hypothalamus – it doesn’t care if you’re feeling cold on the surface. All that matters is what’s going on inside. So when the wind-chill starts savaging your exposed flesh, your capillaries squeeze the blood out of your skin, driving it inward where it can assist in maintaining your core temperature. Your paled, cracked, pinched extremities are being offered up for sacrifice – and unless you’re one of the lucky few who has a natural hunter’s response, it’s gonna start to hurt.

What’s the common response to a surface chill? Vigorous exercise of the flexing, stamping, wiggling kind, and a tendency to increase your pace of movement. This works a treat in the short term, burning up inner stores of energy and elevating your overall body temperature until you’re comfortable again.

The contrast is delicious, so you keep moving, keep burning up – until you start to sweat. Sweat cools (that’s its job) and before you know it, you’re clammy with freezing perspiration that drags your temperature lower and lower. Worse still, your skin is too cool to efficiently evaporate the sweat away, so it clings on, sucking the heat from your bones. (This is why moisture-wicking garments are quite literally lifesavers).

36°C

One degree down, and boy do you know it. Your muscles are tightening up (more formally, you’re experiencing pre-shivering muscle tone). It’s a forerunner of the muscle contractions that are shortly going to make you a clumsy invalid. Now’s the time to adjust tricky straps and tie shoelaces – another core temperature drop and you’ll be a juddering, uncoordinated mess.

Goosebumps

35°C

You’re a juddering, uncoordinated mess. As mild hypothermia sweeps through your body, your muscles leap to your defence with frenzied high-speed involuntary contractions, better known as shivering. Exercise generates heat – but with an unfortunate flip side. To spasm so violently, those muscles require an increased supply of blood – and so shivering can accelerate the rate of cooling at your core.

Plus, it’s horribly unpleasant. All your muscles have already tightened up, and now they’re shaking as well. This applies to all your muscles, even those around your eyes. Your basic senses are starting to go…

33°C

…but strangely, you don’t care. Your body is responding logically and sensibly by hoarding its resources and making itself slower and smaller in every way it can (this may save your life later on) – and the effect right now is to dull your thoughts, drugging you into apathy and then a stupor. Whatever. Yawn. A little sleep before you get back to fighting the cold is just what you need, surely?

31°C

Shivering hasn’t worked, so your body abandons it. (This helps you doze off). Your oxygen consumption has dropped significantly and your oxygen-starved brain is struggle to string a thought together – other than “I really need to pee“, thanks to all the inwardly-pushed body fluids flooding your kidneys.

30.5°C

If a loved one rescued you right now, you wouldn’t be able to recognise them.

30°C

Your heartrate is becoming arrhythmic, further restricting the amount of oxygen reaching the brain. Time for Harvey to make an appearance. In your stupified, thermal free-falling state, you’re hallucinating wildly. You probably think you’re being rescued. But then …

29.5°C

…you’re suddenly on fire. It’s a bleak irony that as you freeze to death, there comes a point where your skin feels like it’s alight, prompting you to struggle out of your clothes. This is called paradoxical undressing, and may happen because your ailing hypothalamus pops a fuse – or because it tries a last-ditch attempt at warming you, flinging all your capillaries open and giving you the mother of all full-bodied blushes. You’ll also feel the urge to crawl into a small space (terminal burrowing), a mechanism that often makes it harder for rescue parties to find severe hypothermia victims. This is not the finest hour of your survival instincts.

FrozenLight

28°C and below

You’re down – but not necessarily out. Your skin may be blue and cold, your pulse indetectable and your heart may be beating too slow to keep you alive under normal circumstances…but these are not normal circumstances. Remember that your entire body has slowed down as you cooled, including the most critical part of it, your brain. Your oxygen supply is way down – but so is the demand for it.

You’re not dead: you’re suspended between life and death. Or put another way, “you’re not dead until you’re warm and dead.”

Now the key to your survival is rescuers who know how to revive you. If they warm you too quickly, this delicate balance between supply and demand will be broken and you’re history.

In “rewarming shock,” the constricted capillaries reopen almost all at once, causing a sudden drop in blood pressure. The slightest movement can send a victim’s heart muscle into wild spasms of ventricular fibrillation. In 1980, 16 shipwrecked Danish fishermen were hauled to safety after an hour and a half in the frigid North Sea. They then walked across the deck of the rescue ship, stepped below for a hot drink, and dropped dead, all 16 of them.

- Peter Stark, Outside Magazine, 1997.

If you don’t fancy trusting your life to the specialist medical knowledge of the first bunch of people (probably strangers) to stumble across you…I don’t blame you. Ask yourself: what would your first instinct be if you found someone almost frozen to death? Warm them up as quickly as possible? Me too.

So keep yourself well-wrapped, plan journeys in advance, keep warm…and put your trust in the thermostat inside your head. After all, it hasn’t done a bad job this far.

References

Images: Paulo Brandão, alphadesigner, Melissa Maples, Mary Lane.

  • Pauline

    Great article Mike, your writing always sucks me right in but this time in particular I couldn’t look away. You had me hooked right to the end…..rather interesting I’d say. Thanks for the good read.

    • http://mikesowden.org/feveredmutterings Mikeachim

      Thanks, Pauline. The background reading had me hooked until the end (found at the links at the end of the article) so I’m glad I conveyed my enthusiasm!

  • http://www.judithgreenwood.com/thinkonit/ JudithinUmbria

    I agree, this is masterful, and now I am deeply depressed.

    • http://mikesowden.org/feveredmutterings Mikeachim

      Ta. :)

      And I recommend a hot milky drink. Even better, mulled wine. As long as it’s something piping hot. That’s important.

  • http://holeinthedonut.com Barbara Webel

    This post should have had a disclaimer at the beginning warning that it contains information of a graphic and unsettling nature! Absolutely fascinating.

    • http://mikesowden.org/feveredmutterings Mikeachim

      Unsettling indeed. We walk a scarily fine line between being too hot or too cold. However clever our innards are, it’s still a fine line. But inwardly, luckily, we’re *very* clever. I can’t help feeling inspired by that.

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  • http://ramblingfamilymanager.blogspot.com Kim, Rambling Family Manager

    We feel your pain here in “sunny” Florida. It’s a lot colder than it usually is and it’s lasted a lot longer so this is a particularly timely article. Brrrrrr!

    • http://mikesowden.org/feveredmutterings Mikeachim

      Yes, I’ve recently been reading news reports about Florida being hit with distinctly unFloridan weather. How much colder than usual is it?

  • http://atravelerslibrary.com Vera Marie Badertscher

    Oh, cheerful bit, that! (And what those other people said about your fine writing.)

    • http://mikesowden.org/feveredmutterings Mikeachim

      Thoroughly cheery, I agree. If you like a dab of ghoulish with your cheer.

      (And thank you).

  • Brid D

    Lovely writing. What happens when the temperature goes the other way?!

    • http://mikesowden.org/feveredmutterings Mikeachim

      Thank you!

      And I’m already ahead of you on that one…except I’m waiting for the summer to write it. ;)

  • Emily

    I guess my hypothalmus doesn’t have a clue what it’s supposed to do.. my body temperature’s been as low as 95.5 F (35 C) before when I haven’t been feeling the slightest bit cold or shivering, and even a raging infection won’t push it up to the ‘normal’ 98.6 F (37 C).

    Strangely, you’d think I could handle cold better than everyone else, but the reverse is true: I’m still comfy in temps over 100 F, and cold at anything below 70-75 F, even though I live in a place where people will wear shorts until 20 F (about -5 C).

    • http://mikesowden.org/feveredmutterings Mikeachim

      Thanks for commenting, Emily. You’re evidently one of the fascinating exceptions I read about in my background reading. :) At 35 degrees, the rest of us would be trembling like jello on a trampoline during an earthquake.

      I know that environment/climate can have an effect on standard core temperature (not much, but it’s there) and make some populations hardier to certain thermal conditions than others.

      So on that note – what corner of the world are you in?

  • http://MaleWeightLossNow.com Frank Dobner

    Hey Mike,

    Well written and very interesting. I had never heard the word “juddering” before. I assume that that is the English word for “shivering?” I really like these differences between English English and American English. For instance in the picture under 36 degrees C, the skin reaction there is referred to here in the States as “goose bumps.” What do you call it there.

    By the way, did you intend for the temperatures in this blog to in degrees F rather than C? I think 36 degrees C is pretty hot.

    Thanks and nice work
    Frank Dobner

    • http://mikesowden.org/feveredmutterings Mikeachim

      Thank you, Frank. :) Very kind words.

      Juddering (“To shake rapidly or spasmodically; vibrate conspicuously”, according to FreeDictionary.com) is a much more violent kind of shivering. Shivering is something you can fight – but the word “shivering” is inadequate to describe the state of shaking so hard that it almost robs you of your ability to think, and certainly of the ability to stand.

      (I’m speaking biographically here – I had something like that during a nasty bout of suspected food poisoning last month, and juddering was definitely the word).

      “Goose bumps”? As Anna says, yep, we know them as that, and also “goose pimples”. (Much less common is “goose flesh”).

      And yes, it seems hot, but it is indeed on the Celsius scale. We’re little ovens on legs.

  • Anna W

    @Frank Dobner.

    We use both “shivering” and “goosebumps” in the U.K. too, but we have many words for the same things, often regional differences.

    Fantastic writing Mike, captivating and with references – hurrah!

    Anna W

    • http://mikesowden.org/feveredmutterings Mikeachim

      Thanks, Anna. :)

      The references make for fascinating reading, and fill in the detail between my broad brushstrokes up there…

  • http://www.yshura.deviantart.com Yshura

    =O Great job Mike! This article gave me chills and made me involuntarily pull my blanket tighter around me. I love the detail and emotion you put into it… I can imagine it all so vividly! Scary D:

    • http://mikesowden.org/feveredmutterings Mikeachim

      Thank you. :) It was a lot of fun to write. And scary? Terrifying.

      But I’m more scared of cooking to death, so when I write that one (a sequel to this post), I’ll be a bit more…animated.

  • Andre

    Hi,

    I hail from Africa and now live in Geneva Switzerland so now I have experienced extremes on both sides of the temperature scale.

    Interesting is that people live in extreme conditions and survival rates are high, the body adapts very well.

    I am a bit confused by your temperature scales? C =Celsius? If so:

    0 degrees C = freezing temperature.

    37C = very hot and -37C = very cold ?

    In any case a great article and sent shivers up my spine! :-)

    • http://mikesowden.org/feveredmutterings Mikeachim

      Yep, Celsius indeed – which makes 37 degrees C piping hot. It’s astonishing that we can maintain such a temperature day in, day out – and all from food. We’re amazing machines.

      If only we could build machines that were as amazing as we are. :)

  • Caroline

    I bookmarked this for reference for my writing, in case I ever want to put any of my characters in such a situation…as could be very likely (evil cackle!). Have you done another one for heat?
    BTW, have you ever noticed, that in the height of summer when its (occassionally, in england) so damn hot you can’t bear it, you also can’t even conceive of the idea of putting on a wooly jumper and thick socks, and then when its bitter like it has been, you shudder at the thought of stripping off to your undies. You know that you do it, in the ‘other’ season, but out of season it becomes impossible to even contemplate. I wonder if this is a hypothalamus thing as well?

    • http://mikesowden.org/feveredmutterings Mikeachim

      Hi Caroline. Thanks for popping by.

      Nope, haven’t done one for heat, but planning to at the appropriate time of year (a heatwave would be ideal)!

      I’m sure the hypothalamus is inextricably intertwined with the rest of the brain and capable of stumulating all sorts of thoughts, including those of the visual imagination. And after all, the best way to get someone to do something is to show them, not tell them. So the very idea of putting on a jumper in summer might be enough to trigger the thermostat and break a sweat, and that reaction might make the thought even more horrible to contemplate…

      No, the brain is subtle. It pulls the strings. It’s like Gerry Anderson, inside our heads, and all we can do is dance and caper and do that unconvincing both-legs-off-the-ground walking thing.

      (Er, I may have lost control of that metaphor there. Bugger it).

  • anon

    It was good but u didn’t elaborate on the last part about how to save a life if you are not a medic.

    • http://mikesowden.org/feveredmutterings Mikeachim

      No, I didn’t – because I’m not a medic. :)

      I wouldn’t know where to start, and I gather it’s such a delicate procedure that the absolute best thing to do is leave it in the hands of a medic, or talk to one.

      It’s certainly something I plan to read into, but I know precious little right now and I’m not going to pretend I know more than I do.

      Thanks for reading, anon!

  • Nighteyes

    Thanks for writing this, it makes a good read, especially considering the weather recently.

    I actually find it very difficult to feel the cold, it doesn’t seem to affect me much (I’ve just been out most of the day in a t-shirt and jeans), but this certainly makes an interesting read either way.

    I eagerly await the “summer” part :)

    • http://mikesowden.org/feveredmutterings Mikeachim

      Thanks for stopping by, Nighteyes.

      I suspect I’m like you – I seem to feel the cold a lot less tham most folk, and occasionally get told off by people (hi Mum) for wearing “inappropriate clothing”. And I wonder…is there a biological reason for this? Is there something physiological that makes us less susceptible to cold, or is it all just a matter of psychology?

      Hmm.

  • http://www.glowingfaceman.com Glowing Face Man

    Wow– just reading this made me feel cold & nausea! You should publish some of these for other types of death.. what happens if you’re stranded in the Sahara for example..

    • http://mikesowden.org/feveredmutterings Mikeachim

      Dehydration?

      Already on it. ;)

  • Joe

    I live in Winnipeg MB Canada where the temperature is usually around -30, -40 ºC in January.
    Those in England (and anywhere else “cold”) I have to say I don’t feel your pain. -10 we are out in shorts (well sometimes) I find it silly looking at people all cold out there. I do understand however you’re not used to it (and it’s caused a lot of problems)

    On a lighter note… it was +6 today! a record high! :P the world has flipped it’s temperatures around.

    • http://mikesowden.org/feveredmutterings Mikeachim

      I do understand however you’re not used to it (and it’s caused a lot of problems)

      Yep, big problems. Human beings and human socities are tough and able to adapt to most situations on this planet (so far). But it’s the speed of adaptation that’s the issue in our case. When we get hit by anything approaching wintry Canadian weather, we’re in trouble. Hence, the local councils have been running out of grit for the roads. The Eurostar trains have been breaking down because they’re not designed for subzero temperatures. These are all surmountable problems if we have advance warning and can invest in some forward planning. But this time, nope.

      As for going out in shorts when it’s -10 degrees C? You’re a braver man than I. Have to say, though, that if I saw anyone wandering around without trousers in a subzero environment, I’d categorise him as a bit whimsical in the brainpan. ;)

  • http://www.Nancydbrown.com Nancy D. Brown

    Scary – facinating.

    • http://mikesowden.org/feveredmutterings Mikeachim

      Aye – and aye.

  • Slappy miliquentoast

    Oy !!! matey just give a call to fathead Al Gore the global warming bore
    maybe he can ship a little heat to you brits !!!!

  • http://www.hi5.com/friend/profile/displayJournalDetail.do?ownerId=487921294&journalId=106346414 Chip

    This is such a great post, thanks for the great info. and I am so excited to read more

    • http://mikesowden.org/feveredmutterings Mikeachim

      You’re very welcome!

  • JinxC

    I have to tell you the part that got me the most, was “If a loved one rescued you right now, you wouldn’t recognize them”

    To think of my boyfriend’s/dad’s/mom’s face, and be unable to recognize it?? Very frightening.

    Great read!

    • http://mikesowden.org/feveredmutterings Mikeachim

      Thank you! (Massively, massively belatedly).

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  • http://www.swedishdatingonline.com david miller

    I live in Helsinki, Finland so I know abbout the cold! Brrrr we went to minus 37c this winter and it was like being in an industrial freezer! i felt like one of the Birdseye peas jumping into the bag.

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