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

MikeachimThe Everyday50 Comments


What happens when you’re getting too cold?

PSA: This post is about how to freeze to death. If that sounds a bit too morbid and creepifying, try this post instead – it’ll keep you busy until Doomsday.

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.


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.


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).


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.



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…


…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?


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.


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


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 …


…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.


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.

Images: Paulo Brandão, alphadesigner, Victor Velez, 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.

    • 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!

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

    • Ta. :)

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

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

    • 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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  • 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!

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

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

    • 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?!

    • 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).

    • 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?

  • 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

    • Thank you, Frank. :) Very kind words.

      Juddering (“To shake rapidly or spasmodically; vibrate conspicuously”, according to 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

    • Thanks, Anna. :)

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

  • =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:

    • 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


    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! :-)

    • 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?

    • 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.

    • 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 :)

    • 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?


  • 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..

  • 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.

    • 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. ;)

  • Scary – facinating.

  • 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 !!!!

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

  • 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!

    • Thank you! (Massively, massively belatedly).

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  • 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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  • april

    Great post, I really enjoyed it. It’s very interesting. Just out of curiosity, does your body usually have to be 35 degrees before you start shivering? I start shivering and my teeth start chattering on a Autumn day in Sydney. God knows what would would happen if I lived in Britain and experienced an actual winter. I think it might be a low-blood pressure thing? I would say my body’s just not built for the cold, but in the heat I get fatigue and nauseous and am prone to fainting if I stand in the heat for more then 10 min.
    So apparently room temperature’s the way to go.

  • yemil

    I would like to know why I can withstand extremely cold temperatures during the winter months in the Colorado Rockies without ever wearing a hat or gloves in temperatures just as low as they can ever get. I can downhill ski in freezing temperatures or cross country ski in a tank top in the middle of winter when it is snowing and still be comfortably warm, still minus the hat and gloves and even with bare arms and shoulders.I used to think it was the strenuous activity that I was doing that helped but I once had a job welcoming skiers off ski lifts first thing in the morning as a resort helper. Standing still for two hours worked just as well to keep me warm. At a point when most people would be extremely uncomfortable in such conditions I feel just fine dressed the way I am, in fact I prefer it to actually wearing a hat or gloves.
    People think I am crazy but the craziest part is that I have never suffered from frostbite either.
    I enjoy the experience of being a little bit different but I am as mystified as anyone else as to why my body adjusts so well to the cold. It has always been this way since I was a child. When I spent all my time outdoors as a kid even in the worst weather conditions without being properly attired my mother would say “no sense…no feeling “….

    • Awesome. Perhaps you’re a modern-day Wim Hof! Does your family have a history of living in cold climates – ie. is there a hereditary clue there? I have met a few people like you – the last being in Scotland (see the beginning of this). Have you ever had a doctor check out your ability to react to the cold? The results might be fascinating.

    • It could be that you have an unusually effective layer of brown fat: There are folk around the world who, through genetic quirks, are exceptionally good at regulating body temperature – see how the human body adapts to extremes with peoples living near the equator or the far north.or south. Something interesting to investigate there! Take a DNA test – you may find a little Inuit in your ancestry..

  • You’re not going to freeze in 28°C weather. That’s 82°F. If you’re shivering at 32°C (86°F) you might want to talk to your doctor. Maybe the author meant to use F instead of C?

    • That’s not 28 C outside of the body. That’s 28 C human body core temperature. :) The temperature deep inside your body, past all your amazing ways of keeping warm. Totally different things.

      There are folks in Canada right now who are experiencing temperatures as low as minus 40 C – but they’re all wrapped up, to keep their core temperature in the right margins. But if your core temperature drops below 28 C, you’re almost certainly dead – unless the people who warm you back up really, *really* know what they’re doing.