September 2, 2025 • 57 mins
For all our wondrous adaptations as a species - our big brains, our capacity for language, our opposable thumbs - we humans are not well-equipped to deal with the cold. Take us out of our insulated dwellings, take away our winter clothes, and things can get dicey fast. From frostbite to hypothermia, the cold can settle into our bones, leading us down a path where injury or death are possible outcomes. In this episode, we explore that path: how our meager cold-survival adaptations are vastly outshone by other animal species, the long and grim history of hypothermia in war, and what exactly is happening inside your body when your temperature drops. Tune in to this unexpectedly strange grab-bag of an episode.
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Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
Speaker 1 (00:00):
The cold was so intense. One constantly found men who,
overcome by the cold, had been forced to drop out
and had fallen to the ground, too weak or too
numb to stand. Ought one to help them along, which
practically meant carrying them. They begged one to let them alone.
There were bivouacs all along the road, ought one to
(00:22):
take them to a campfire. Once these poor wretches fell asleep,
they were dead. If they resisted the craving for sleep,
another passerby would help them along a little farther, thus
prolonging their agony for a short while, but not saving them.
For in this condition, the drowsiness engendered by cold is
irresistibly strong. Sleep comes inevitably, and to sleep is to die.
(00:48):
I tried in vain to save a number of these unfortunates.
The only words they uttered were to beg me for
the love of God, to go away and let them sleep.
To hear them, would have thought sleep was their salvation. Unhappily,
it was a poor wretch's last wish. But at least
he ceased to suffer without pain or agony. Gratitude and
(01:12):
even a smile was imprinted on his discolored lips. What
I have related about the effects of extreme cold and
of this kind of death by freezing is based on
what I saw happen to thousands of individuals. The road
was covered with their corpses.
Speaker 2 (02:14):
What Aaron is that from?
Speaker 1 (02:19):
That is from Napoleon's close advisor Armand de Callancourt about
the retreat from Moscow. And I'll talk a little bit
more about it, but it is it is horrific. Yeah,
the words can't adequately describe. Yeah. Hi, I'm Aaron Welsh.
Speaker 2 (02:40):
And I'm Erin on Updyke.
Speaker 1 (02:42):
And this is this podcast will kill You.
Speaker 2 (02:44):
Today's very uplifting episode. It's going to be about hypothermia.
Speaker 1 (02:50):
It is about hypothermia. And it's one of two parts
because as we kind of were talking about hypothermia and
the effects of cold, and we thought, well, it's it's
unfair to paint cold in just one light. It's this
bad thing and hypothermia. So this is a two parter.
Part one is cold is bad and part two is
(03:13):
cold can be Good? Right?
Speaker 2 (03:15):
Are those our titles? Because I love it. Part one
hypothermia cold is bad. Part two Cold is not always bad?
Speaker 1 (03:24):
Yeah, Yeah, there's nuance even to cold. How about that?
I am excited. There's I feel like this is a
topic that we have not really I mean, I guess
we've done fever, but it's like so related to infection,
whereas this is just like what happens when your body
(03:45):
is stretched beyond its physiological lembits. I know.
Speaker 2 (03:47):
And it's interesting because especially like, well at least you
live somewhere where you probably are people are seeing hypothermia
more than like where I live. I'm like, how come
we didn't choose heat stress as our first temperature because.
Speaker 1 (04:02):
It is July. We're recording this quite early. It is July.
Like the heat. The heat is so strong. I am
in a long sleeve wool sweater with skiers on it.
You've got some deer also wool. Are they elk?
Speaker 2 (04:17):
Not sure they're sweaty? You're sweat they are.
Speaker 1 (04:21):
They're sweaty. Yeah, we are sweaty sweaters. But it also
was reading about hypothermia now and about the cold was
kind of like, oh, yeah, there is another temperature besides
besides heat ninety one degrees. Yeah.
Speaker 2 (04:39):
Yeah, Well we'll get into all of it, but first,
it's quarantine time.
Speaker 1 (04:45):
What are we drinking this week? The uncommon cold? I
mean hypothermia is I'm sure you'll have stats later. It's not.
Speaker 2 (04:54):
Yeah, I don't many stats honestly, but it's not that.
It just very much depends on where you live.
Speaker 1 (04:59):
But right right, yeah, it's not that's more uncommon than
the common cold. Yeah, okay, definitely, And we thought, in
light of the fact that cold can be bad and good,
we're going to do a cold blended drink, but that
also has heated elements into it. Spicy. Yeah, so it's
like have an arrow margarita.
Speaker 2 (05:20):
Yeah, blended blended, which is not my favorite kind of margarita.
So if you don't want that, don't do that.
Speaker 1 (05:26):
Yeah, you do whatever you want.
Speaker 2 (05:27):
Listen. We'll post the full recipe on our website, this podcast,
amplay dot com, and all of our social media channels.
To make sure you're following us there, please.
Speaker 1 (05:35):
Do please do. On our website This podcast will Kill
You dot com, you can find all sorts of things.
You can find transcripts. You can find sources for each
and every one of our episodes. Links to bookshop dot org,
affiliate account, links to our Goodreads list, links to music
by Bloodmobile, links to a contact us form, links to
a submit your first hand account form, Patreon merch things.
(06:00):
Check it out.
Speaker 2 (06:01):
This podcast will kill you dot com rate, review, and
subscribe on your favorite podcast, which might be iHeart podcasts.
Did you know we're there? We're also on Apple of
the podcast. We're also on the Spotify and now on YouTube.
Speaker 1 (06:14):
You I can't bring myself to say that, but yes
we are.
Speaker 2 (06:18):
I can't not say it that way. Go to the.
Speaker 1 (06:22):
Exactly right YouTube channel and you can subscribe so you
never miss an episode.
Speaker 2 (06:27):
Okay, moving on, Erin, tell me about the history of hypothermia.
What I mean, listen, I'm assuming we've always frozen.
Speaker 1 (06:37):
Yeah, that's true, but we'll get into a little bit
more of that good right after this break. Humans have
(07:10):
existed thrived, even on the farthest reaches of the Earth,
for tens of thousands of years.
Speaker 2 (07:16):
True.
Speaker 1 (07:17):
The earliest evidence of humans in the European Arctic, for example,
dates back forty thousand years.
Speaker 2 (07:23):
Wow. Yeah, that's a long time.
Speaker 1 (07:25):
There were It is a long time. There were mammoth
tusks with human made cuts, sliced wolf bones, stone artifacts,
and other animal bones with like clear human you know,
manipulation or whatever found above the Arctic Circle.
Speaker 2 (07:40):
Pretty cool.
Speaker 1 (07:40):
That means that, like only a few thousand years after
humans reached Europe, they just kept right on heading north.
Speaker 2 (07:46):
Okay, why just looking for something new? I guess by amos.
Speaker 1 (07:53):
But I feel like if you have spent a winter
in or close to the Arctic, it might be like
which you have it's cut I have. Yeah, it's a
natural question to ask. Even if you absolutely love the
winter and you long for the days to get shorter
so that you can break out your favorite pomp pom
wool hat and cozy sweaters, or even if you get
(08:14):
to see the southern or northern lights in the winter
and you love to snowshoe or ski, you have to
admit that the polar regions are not an easy place
to live, and they don't let you forget it. Grabbing
the wrong jacket before you step outside, losing a glove,
a window that's lost its insulating ability. These things don't
(08:37):
go unnoticed, at least not for very long. Whether immediately
or eventually, the cold makes itself known. It insinuates itself
into the nooks and crannies of your jacket, of your body,
the tips of noses, toes, fingers, and it settles into
your bones until you feel like you'll never be warm again.
Speaker 2 (08:58):
That is the exact way that I would describe living
in Illinois.
Speaker 1 (09:04):
Will I ever be warm against any like?
Speaker 2 (09:08):
So many memories of that feeling of like your bones
being so cold, which I know they're not really, but
your bones being so cold that you don't it is
impossible to remember warmth.
Speaker 1 (09:21):
Yeah, right now, it's impossible for me to remember cold,
even though I'm talking about it. I'm so so witty.
I'll have to try to remember this moment come February exactly. Yeah.
But I think that many of us lower latitude dwellers
have kind of a sense of awe, at least I
do for those living in the Antarctic and Arctic regions
(09:43):
of the world, because even with the warmest of jackets
and the most insulated of shelters, polar life exists on
a knife edge, where even the tiniest thing can tip
the scales, turning a minor mistake or a minor accident
into a fatal outcome. I cruised the Wikipedia page for
(10:04):
hypothermia related deaths, which is quite morbid, I know, and
the one thing that really stuck out to me was
just how easily it can happen. I went through and
I like read different people's stories and it was just
like and then on one wrong step, yeah, and that
was it. That was it. And how powerless you are
(10:26):
when the cold really sets in. And yet many species
call these polar regions their home, not just humans. Why
would an animal live in a place that is so brutal,
so unforgiving, although not all the time, as we'll see,
there are all sorts of reasons. Maybe it's more available, habitat,
(10:47):
less competition for resources, escape from predators, escape from parasites,
a combination, or something else entirely, But for this episode,
the why isn't as interesting to me as the how,
Like how can species live at the ends of the earth,
not just like eking out a meager existence, but flourishing
despite the deadly cold. Humans have innovated incredible clothing, shelter, transportation,
(11:13):
and tools to help protect from freezing temperatures, and animals
have evolved a vast array of strategies anatomical, physiological behavioral
to resist hypothermia and other harmful consequences of cold, like frostbite.
Would you like to learn about some of these thrilled?
(11:35):
Thrilled to learn about these one way is just to
avoid it. Just migrate the heck out of it. Birds.
Birds love this, they're big fans of the migration.
Speaker 2 (11:46):
Yeah.
Speaker 1 (11:47):
And some bats and you know, other things, but way
big for birds. Yeah. And then there's torpor, which includes
hibernation and dormancy. Basically, an animal just turns down the
dials on body temperature, activity and metabolism to get through
the winter. Bears, ground squirrels, bats, some frogs. And then
(12:07):
there's cold resistance, so like you keep operating mostly as
normal during the cold months, but you just bump up
your your own systems, your defense against Yeah, and that
would be something like arctic foxes, polar bears and so on.
And these strategies they're not mutually exclusive. You can have
a little bit of this and a little bit of that.
(12:28):
And there's also a great variation within some of these,
So like hibernating black bears only drop their body temperature
by a few degrees celsius, while some mammals, small mammals
drop temperatures twenty to thirty degrees celcish body temperatures. What
oh it gets it gets better. Wood frogs, Oh, do
you know about wood? Yes, I know about wood. Frogs.
(12:49):
Who does it? But no, lots of people don't. I
had I had to refresh my memory because the stats
are I was like, this can't be. I was like,
I need to fact check this right multiple places.
Speaker 2 (12:59):
I love this real.
Speaker 1 (13:00):
They're the Hall of Famers for dormancy. They survive freezing
temperatures below minus twenty celsius for months on end, like
seven months, seven merely freezing, Yeah, nearly freezing solid. Fifty
to sixty five percent of their body water is frozen. Wow,
just frozen. Yeah. These are frogs that live above the
(13:23):
Arctic circle. What what Like? I just can't get over it.
And then you've got the fish that avoid freezing in
Antarctic waters by using anti freeze proteins that let them
keep swimming around. Other animals like polar bears, ptarmigan wolves
and hares make simple burrows in the snow to help
(13:44):
with insulation.
Speaker 2 (13:45):
Question, which is, yeah, what's a ptarmagan?
Speaker 1 (13:48):
It's a bird? Okay, thank you. Yeah, they're really cute. Yes,
or sometimes they'll employ bagel formation, which is not the
technical term, but I love those. Okay. It's like where
you make yourself into a tiny ball, like a little
ball to trap heat like the doggies do you Yeah, okay, exactly,
you just tuck your little nose and you're in bagel formation.
(14:11):
Bagel formation. And then other animals that live in colonies,
like walruses and penguins, they'll huddle together for warmth, especially
baby emperor penguins.
Speaker 2 (14:23):
Yes, they're very cute.
Speaker 1 (14:26):
They're very cute. Thick fur and blubber help to reduce
heat loss, as do changes in the circulatory system or
even the type of hemoglobin that an animal has, So
like pretty cool, yeah, because of and then there's like
circulatory changes, so because there are these specialized changes in
blood flow in pawpads of Arctic wolves and foxes that
(14:48):
allows them to stand on the ground that has a
temperature of minus fifty celsius but their feet don't freeze
or become damaged. What I don't know. And then nasal cavities.
I didn't realize that, like the shape of a nasal
cavity could be so important, but it is.
Speaker 2 (15:05):
I feel like I remember learning this at some point.
Speaker 1 (15:07):
Tell me about it, Aaron, Okay, okay, So reindeer have
nasal cavities that warm the air before it enters the
body and it sort of like warms it and then
there's like water condensation, right, But then instead of losing
that heat and water to the environment, they also somehow
cool the air before it leaves, and so you're basically
(15:30):
conserving heat and water because of the way that they're
nasal cavities. Oh that's fascinating. Yeah. Babies of Arctic animals
are born well equipped with extra warm fur or feathers
or brown adipose tissue that keeps them super warm, and
mom will also often provision them with super fatty milk.
(15:53):
One of my go to fun facts to share at
a cocktail party is that some whale milk is so fatty,
like thirty to sixty percent fat, that it has the
consistency of toothpastete. That's one of my favorite things too. Yeah,
just I love it.
Speaker 2 (16:09):
Baby whales lap it up toothpaste in the ocean.
Speaker 1 (16:12):
I mean, I think it also must help with like
not just just diluting into the environment. Yeah, so they
can kind of like yeah, get it. Yeah, But for comparison,
human breast milk is like four percent fat compared to
thirty to sixty for some whales.
Speaker 2 (16:29):
Like imagine the lipped cream you could make oh my, I.
Speaker 1 (16:32):
Mean it's already whipped, right, it's like solid, Like, what
do you do, It's like butter, It's just butter. Yeah,
it's actually just butter. Okay, So one last fun fact
before I get to humans. One of the major challenges
with living in polar regions is food availability. It's not
always reliable, and in those times of scarcity, you're not
(16:52):
only expending energy trying to find food, you're also using
more energy staying warm. And some Arctic species deal with
this by cashing food. So like one arctic fox hoard
had one hundred and thirty six seabirds and then yeah.
Speaker 2 (17:07):
It was just like little He's like, listen, they're frozen.
They're going to keep don't worry about it. Yeah, I
feel through the wind chest freezer.
Speaker 1 (17:14):
This is my cost code. Yeah. And an ermine was
found to have hidden over one hundred and fifty lemmings
as white.
Speaker 2 (17:26):
You know, I still like, I know that a lemming
is an animal, but I have no idea what they
look like. I cannot picture a lemming.
Speaker 1 (17:32):
Little rodenty things. I only do you.
Speaker 2 (17:35):
Remember that game the lemmings going over a cliff?
Speaker 1 (17:39):
You don't remember this game? No, there was it was
on what hard on what device?
Speaker 2 (17:44):
Computer computer? It was a computer game where there's I
think they were they were called lemmings, but they were
like little people looking things and they just were going.
Speaker 1 (17:53):
Over a cliff. If you, oh, no, I'm going to
need to look this up. I feel great. I feel wow. Yeah.
Is it like Ski Free era? You remember that game
with the Yes?
Speaker 2 (18:04):
Okay, I don't know if it was same era. I
have no idea.
Speaker 1 (18:07):
Okay, sorry, we'll have to We'll have to find it.
Speaker 2 (18:12):
That's what I think of when I think of vings,
and that's why I can't like picture that there's an
animal called letting.
Speaker 1 (18:16):
Just pictured tiny humans just okay, I don't think they
look like miniature humans with little like gnome hats on. No,
I don't believe that they have constructed nome hats irl okay, okay.
So another besides casing food and lemmings uh not with
(18:40):
no mats, another approach is storing extreme amounts of fat,
so seal pups undergo something called catastrophic molting, which sounds
a lot scarier than it actually is. They just lose
all their fur at once, and then they have to
wait a while to grow back a new layer, and
so during that time they can't go in the water
for food because they'll get hypothermia, so they don't eat. Oh,
(19:03):
they can go fifty two days without food or water.
Speaker 2 (19:07):
Wow, and that Wow, it's a really long time.
Speaker 1 (19:11):
It's a really long time. And so my point with
all of this, besides being able to share with everyone
the whale milk toothpaste fun fact, so that you have
something to share at like, you know, the next round
table ice breaker type thing.
Speaker 2 (19:25):
And the wood frogs icebreaker, but wood.
Speaker 1 (19:28):
Frogs, my god, icebreaker would also have been a good quarantine.
Speaker 2 (19:31):
Wow.
Speaker 1 (19:31):
Anyway, Yeah, that animals have evolved. My whole point is
that animals have evolved an incredible array of ways to
deal with the cold, and unfortunately humans lag behind in
this respect. And so under the right set of circumstances,
our body struggles to warm itself, our temperature drops and
(19:53):
we slip into hypothermia, which is something that we've been
doing for as long as we've been human. So even
though I just spent a good deal of time in
the polar regions with polar animals, you can get hypothermia
anywhere on Earth. Some of the earliest references to hypothermia
come from ancient Greece, which is certainly not arctic. Hippocrates,
(20:14):
of course, noted the benefits of cold, but also the
dangers quote cold is bad for the bones, teeth, nerves, brain,
and the spinal cord. In four point fifty BCE, the
Greek historian Herodotus wrote about soldiers dying in a sea expedition.
Quote some were seized by these sea monsters and so perished,
(20:35):
while others were dashed against the rocks, and some of
them did not know how to swim, and perished for
that cause, others again by reason of cold end quote seamusters.
War has always been a bad spot for hypothermia. In fact,
most historical records of hypothermia come from various wars throughout history.
(20:55):
In two eighteen BCE, Hannibal's army of twelve thousand cavalry,
ninety thousand infantry, and forty elephants was cut down to
nineteen thousand men and some uncertain number of elephants during
their march over the Alps, with many of them dying
of cold. During the American Revolutionary War, countless soldiers suffered
(21:18):
frostbite and hypothermia, especially during the winter of seventeen seventy
seven seventeen seventy eight, when nearly a fifth of the
eleven thousand men who retreated into Valley Forge did not
have shoes or boots at all. Oh, I just imagine
that in the winter. No, I can't imagine that. And
then there's Napoleon's army, this retreat from Moscow in eighteen twelve.
(21:41):
So he this is like where this is infamous, and
we've talked about this in several other times of the podcast.
Napoleon and his army started out in June with nearly
half a million soldiers. By the time they had gotten
to Moscow in late fall, numbers had dwindled pretty substantially
by at least one hundred thousand. But when they arrived,
(22:05):
they found a burned out, abandoned city, no opportunity to restock,
to refuel, no food, nothing. The Russian forces had adopted
this like scorched earth tactic, and that would prove to
be Napoleon's downfall. So he waited around a bit just
trying to figure out what do I do here? Do
we stay?
Speaker 2 (22:23):
Do we go?
Speaker 1 (22:24):
And then was like, you know what, we should just
get back to France. So a retreat to France. That
was the move. The army started back in October, still
dressed in their summer uniforms, and they pushed through the
snow and ice and frozen rivers in November through December
and even into January. Count Philippe Paul de Segur, a
(22:45):
brigadier an aid to Napoleon, wrote, quote, Russian winter in
this new guy's attacked them on all sides. It cut
through their thin uniforms and worn shoes. Their wet clothing
froze on them, and this icy shroud molded them their
bodies and stiffen their limbs. The sharp wind made them
gasp for breath and froze the moisture from their mouths
(23:07):
and nostrils into icicles on their beards end. Quote. By
the time they got back to France, all that remained
of Napoleon's five hundred thousand troops was ten thousand. Oh
my gosh. Yeah, some died in battle, others from their
injuries or infections. If you remember back to our Typhus episode,
(23:28):
that was a major, major killer, but many succumbed to
the cold. A frost bitten and constantly water logged foot
turned gangrenous with the infections spreading to the rest of
the body. A raid on a liquor store allegedly killed
eight hundred soldiers who imbibed a bit too much and
fell asleep in the snow. At the time, it was
(23:49):
thought that alcohol was warming and helped stave off the
negative effects of the cold, although I'm not sure they
were drinking it as medicine. And by the way, it
is not warming. It is not what you should use
to treat someone suffering from hypodermy.
Speaker 2 (24:03):
Alcohol actually can can There's actually thought that not just
the risk of you know, drowsiness or falling asleep or
you know, making decisions about what clothes you might wear
that are impaired because of the effects of alcohol, there's
actually thought that the alcohol, the effects of alcohol itself
also contribute to hypothermia.
Speaker 1 (24:21):
Yeah, so more heat loss exactly, yeah, yeah, yeah yeah.
And then there was also just poor nutrition and grueling
conditions that took many others just after they drifted off
to sleep. One of Napoleon's surgeons wrote quote, the first
hours of sleep offered deceptive delight, precursor to the grave
that yawned for them. Far from finding safety in the
(24:43):
sweets of sleep, they were seized and benumbed by cold,
and never saw daylight. More along the road, in the
neighboring ditches of fields were perceived human carcasses, heaped up
and lying at random in fives, then fifteens, and twenties
of as had perished during the night end quote. No
(25:04):
one was spared, not even the surgeons, who wrote how
their brains had become so dulled by the cold that
they could barely recognize one another. So many dyed or
suffered permanent injuries from the cold on this retreat, not
just because of poor quality clothing and shoes or insufficient food,
but also because no one really knew how to treat
(25:25):
hypothermia or frostbite. Those words didn't even exist yet, a
practical thermometer that could be used clinically was still decades away. Instead,
the effects of cold were kind of grouped together under
the term asphyxia, partial asphyxia usually referring to frostbite, and
(25:45):
general asphyxia referring to hypothermia. Interesting, these were diagnosed from
like subjective observation, so it was thought that like basically
there was congealing in your body, fluids were congealing and
blood in start at the at the extremity, right at
your flick fingertips and nose, and then yeah, and then
as it grew your whole if you're so, that was
(26:07):
like frostbite, so you're like, okay, there's no it's all congealed.
And then then hypothermia it was like your whole body.
It's not that far off. Yeah, yeah, I say, yeah
and so. But because of this, treatment usually took the
form of slowly rewarming to get everything to re liquefy,
and you were supposed to start in reverse. So you
(26:28):
start with snow, rubbing snow on your you know, frostbitten fingers,
and then yeah, and then cold water and then cool water,
then tepid water. You get the really okay, interesting go
slow yeah. Earlier physicians had learned their lesson the hard
way not to use extreme heat, and revival efforts were
occasionally successful during Napoleon's retreat, but they often weren't even
(26:52):
attempted if someone looked dead, and it wasn't widely known
at the time how many of the signs of hypothermia,
signs that mimicked death could be reversed. One of the surgeons,
later learning of this, wrote quote how many resurrections might
have been made on the retreat from Moscow, probably lots,
(27:13):
and as later, medical advancements in the late nineteenth but
especially the first half of the twentieth century revealed hypothermia
did not always carry with it a death sentence, and
doctors could more readily measure temperature thresholds beyond which recovery
was unlikely. And as the term hypothermia came into more
usage in the first decades of the twentieth century and
(27:36):
it became a distinct clinical entity, focused interest in prevention
and treatment of the condition increased, especially during World War Two.
So I don't know when exactly I tried to find
when exactly the phrase you're not dead until you're warm
and dead you originated. Yeah, but it was likely in
the last few decades of the twentieth century, showing the
(27:58):
huge amount of progress made understanding hypothermia and reversing it.
And so before I turn it over to you, Aaron,
to tell us what exactly is happening when our body
temperature dropped to dangerous levels and what we do about it,
I want to end with one of the most amazing
hypothermia revival stories that shows just how far we've come. Oh,
(28:18):
I love it. Like Napoleon's surgeon's minds would have been
absolutely blown by learning of this story. Okay. In nineteen
ninety nine, a twenty nine year old Swedish woman named
Anna moved to a small town in northern Norway in
the Arctic Circle to complete her medical residency or above
the Arctic Circle, and part of the reason that she
(28:39):
chose this location was because she was an avid and
very experienced backcountry skier. In May, she and a couple
friends who also had medical training, went out skiing for
the day. At six twenty pm, Anna or Anna maybe
lost her balance and fell headfirst into a waterfall gully,
where she became wedged in the ice and water. Her
(29:01):
friends couldn't get her out. They tried to pull her out,
and they couldn't get to her, and so they called
for help, and unfortunately help was slow to arrive. The
only rescue helicopter available was on its way to transport
a sick child, which was in the other direction from Anna.
At seven pm, she stopped moving those forty minutes in
(29:22):
the ice. At seven point forty a ground rescue team
arrived and extracted her from the ice. She was clinically dead.
The helicopter arrived around eight pm and she was loaded
onto it for transport to Tromso Hospital, which is about
an hour's flight away, and with the adage you're not
dead until you're warm and dead in mind, resuscitation efforts
(29:44):
were started in transit and continued along with rewarming at
the hospital. When she got there, doctors found that she
was not breathing, She had no pulse, her pupils were
widely dilated and unresponsive to light. Her EEG was flatline.
Nurses and doctors continued their chest compressions in ventilation as
they prepped to put her on a heart lung machine.
(30:06):
At nine fifty two pm, so this is three and
a half hours after she went into the ice, her temperature,
her body temperature was measured at thirteen point seven degrees
celsius or fifty six point six degrees fahrenheit. Wow. At
that point, yeah, she'd been three hours without a heartbeat.
(30:27):
But then at I guess I kind of spoiled it
at the beginning by saying revival story, but I mean,
you know where this is going. But then at ten
fifteen pm something on the monitor a heart beat, then another,
then a steady rhythm. She woke up ten days later
and spent another couple of weeks in the intensive carry unit,
(30:48):
and initially she showed signs of paralysis below the neck
and struggled with various organ dysfunctions, but over time she
made an almost complete recovery. After five months she was
like basically back to normal, back to skiing. It's an
amazing story that shows what both the human body and
(31:09):
modern medicine are capable of. And that being said, every
year many people, especially those who are unhoused or struggle
to keep their homes warm in the winter who can't
afford to do so, die of hypothermia. And most of
these deaths are they represent a failure not of modern
medicine but of our society in providing a safety net
(31:31):
to prevent death in this way, because like stories like
Annas show us, it is possible, and it can sometimes
be reversed. But in a lot of these cases it
should never have happened in the first place. Yeah, but
now Erin, I'll turn it over to you to tell
me more about how we deal with hypothermia today. I
(31:54):
would love to.
Speaker 2 (32:25):
You mentioned at the top erin the last time that
we talked about human body temperature was in relation to fevers,
and we learned in that episode, and maybe everyone forgotten.
That's fine, I'm gonna tell you again. But we learned
that a fever is what happens when our temperature set
point gets moved. Right. Our brain, specifically our hypothalamus controls
(32:51):
our temperature set point, and so a fever is what
happens when our hypothalamis is like, we need to get hotter, right,
But most of the time, outside of a fever, we
as humans seek to exist at about thirty seven degrees
celsius ninety six or so fahrenheit, right, And that is
(33:13):
that particular temperature is what our body is constantly maintaining.
And because we are endotherms like all mammals, we maintain
this temperature by physiologic mechanisms within our own body.
Speaker 1 (33:30):
Right.
Speaker 2 (33:30):
We don't rely on the sun or our environment to
warm us or cool us, right I. And all of this, like,
all of these processes are basically coordinated in our brain
by our hypothalmis because this is controlling our temperature set point.
So hypothermia is like the easiest way to look at
it is just that this is what happens when we
(33:52):
can no longer do that, when all of the mechanisms
that we have to keep our bodies warm and at
the right temperature fail us. And that happens mostly when
the environment is either just way too cold or it's
just a little cold but for way too long for
(34:15):
us to generate enough heat via our metabolism and all
the things going on inside of our bodies, okay, and
the external trappings that we use of course as humans,
so we can pretty well maintain our body at a
constant temperature without our bodies having to work very hard
to do it, even if we were totally naked. If
(34:36):
we exist between like twenty five and thirty celsius, which
is like seventy seven to eighty six fahrenheit, that's our
like thermoneutral zone. Once you get above this or below this,
our bodies are going to have to work harder to
maintain our temperature. Now, that's seventy seven fahrenheit twenty five celsius.
That's not cold, no, it's quite warm, it's quite warm.
(35:00):
But below around that temperature means that our body is
having to do something to generate heat. Right if you were,
if you were totally naked like, but we're off if
you were totally naked those onto So that's that's behavioral adaptations.
So what I want to talk about is less about
the behavioral adaptations because those are obviously important, But I'm
(35:22):
really going to focus on our bodies. How do we
typically deal with temperature stressors? What are we doing inside
of our body to generate heat when we're exposed to cold,
so that then we can understand what happens once those
start to fail us. And then next week we're going
to talk about kind of building off of that story
that you told Aarin and what we know about what
(35:45):
cold does to our bodies once it kicks in, and
the ways that people have thought to maybe use this
to their advantage to treat various conditions.
Speaker 1 (35:55):
Harness one of nature's elements.
Speaker 2 (35:57):
Ooh good, that's a good one. Okay, So two big
body compartments to think about when we think about temperature management.
We have our core body, which is our brain and
our internal organs, and then we have all the rest
of it, or our peripheral body that's our skin, our
subcutaneous tissue, our fat, our limbs. It's not the important stuff,
(36:21):
right when you think about your body existing.
Speaker 1 (36:24):
Yeah, I mean, you can lose a pinky, but if
your heart freezes, you're done the devastation.
Speaker 2 (36:31):
Yeah, exactly, and so and our body knows this, and
our hypothalamis knows this, and so because our hypothalamis knows this,
our body regulates our temperature by regulating heat loss and
essentially kind of sacrificing the things that are less important
as well as finding ways to keep heat in the
(36:54):
core of our bodies. Okay, to keep our internal organs warm.
So one of the the first things that our body
does in order to keep our core warm is vaso
constriction of peripheral veins and arteries in our skin. And
what that does is it keeps our blood, which is
warm in our deeper circulation.
Speaker 1 (37:17):
This is going to.
Speaker 2 (37:18):
Reduce the amount of heat loss from all of our
surface area of our skin, right. It's also going to
reduce the temperature of our skin and our extremities, which
can lead to frostbite.
Speaker 1 (37:31):
Yes.
Speaker 2 (37:32):
Ah, So I quick detour before we talk about hypothermia
itself to talk about frostbite, which you can kind of
think of as like extreme localized hypothermia. So frostbite is
when you get tissue injury that's due really to freezing itself,
and so frostbite you do tend to have to be
(37:52):
in pretty cold conditions rather than the more mild conditions
where you could still get hypothermia but without frostbite.
Speaker 1 (38:00):
Like water versus snow, I mean, yes and no.
Speaker 2 (38:05):
Snow is like, if you're in a snowy environment, it's
very likely that the air temperature and the wind chill
and the snow itself is below freezing. So in some
cases you might be even more likely to get frost
bite in those scenarios. In water, you could still get
like freezing if the water was cold enough, But it's
(38:27):
very easy to get totally hypothermic in the water because
you lose heat so much more rapidly in water because
it's a really good conductor of heat just deals right
away from us.
Speaker 1 (38:36):
So like snow, you would get frost bite first and
then hypothermia.
Speaker 2 (38:41):
Potentially, yeah, potentially, whereas.
Speaker 1 (38:43):
Water you're gonna get hypothermia first.
Speaker 2 (38:46):
Yeah.
Speaker 1 (38:46):
Yeah, Yeah, that's a good way to think about it.
Love it.
Speaker 2 (38:49):
I was confused and thought you meant the opposite, but
that totally makes your sense there, So yes, and the
degree of damage really varies. Right, you have degrees of frostbite.
The first degree you might just have kind of redness
of the area. It might progress to kind of a white,
almost waxy skin or blister formation. And then of course
(39:12):
the most severe, which is considered grade four, is black
or necrotic tissue, where your entire tissue just dies.
Speaker 1 (39:20):
Yeah, and all of this is.
Speaker 2 (39:22):
Going to depend on how long you're exposed and to
what degree of temperature you're exposed to, right, And the
damage that you get is due to this vaso constriction itself. Right,
It's also due to the effects of that cold on
our blood because our blood. You mentioned this in the
like what people thought happened to your blood way back,
(39:43):
when they're not wrong. Our blood actually becomes thicker and
kind of sludgy when it gets that cold. And then
you can also get blood clots in some of your
small vessels, which might lead to more damage due to
lack of blood flow there. And because of the actually
freezing itself, the extracellular water freezes and that ice crystal
(40:05):
formation can cause direct tissue damage. Right, So it's very multifactorial.
And in terms of treatment for frostbite, the treatment is
to rewarm that area to try and increase blood flow
to that area, But as likely happened during Napoleon's army,
if there is a risk that things will refreeze, you
(40:28):
cannot start to rewarm because freezing and then warming and
then refreezing actually causes significantly more damage.
Speaker 1 (40:37):
So is there a point, like, because you talked about
the stages where there's red and then there's white, and
then there's black tissue, Yeah, like necrotic, I guess is
there a point at which the point of no return?
I'm guessing is when there's necrotic tissue, there is there nerve.
Can you regain nerve sensation when it's when the tissue
(41:00):
becomes like whitened or it depends? It totally depends.
Speaker 2 (41:04):
Yeah, so you can obviously, like if it progresses all
the way to the tissue completely dying, that's when you
might lose limbs, or lose fingers or lose the tips
of noses, right where even after rewarming, that tissue will
not come back to life. Prior to that though, even
if the tissue itself can be saved, there can absolutely
be permanent nerve damage and things like that. It just
(41:25):
it totally depends on the specific scenario. So that's frostpine done. Well,
let's keep talking about cold, Okay. All we've said so
far is that we start with vasoconstriction in our peripheral
tissues and in our blood vessels. Sometimes that's not enough
(41:46):
to maintain heat. So the next thing that our body
does is to increase the production of heat inside of
our bodies. Yeah, and there's two main ways that we
do that. One is shivering, so our skeletal muscle activity
involuntarily starts to shiver and you have these repeated contractions
and that increases metabolism, and so that increases heat production.
(42:11):
But the downside of that is that it utilizes a
lot of energy, right, Yeah, it's costly, it's costly. It's
a very costly thing to do, but it can generate
a lot of heat, so that can help to keep
our bodies warm in some scenarios. There's another mechanism that
we use, which is brown fat, brown outapost tissue. You
mentioned this, and brown fat is so fascinating to me
(42:33):
because it generates only heat. So metabolism in all of
the other tissues of our body just generates heat as
like a byproduct. It doesn't it doesn't mean to, but
it happens too. But brown fat doesn't generate any energy.
It only generates heat.
Speaker 1 (42:50):
It's like, that's the point. That's the point, and it
is the point.
Speaker 2 (42:53):
And newborns have quite a lot of it, they do,
and as adults we have significantly less m hm. And
so you have it, but just a little bit, so
we can't use it all that much. Yeah, but sometimes
we might be exposed to cold that continues, and our
shivering and our brown fat and all of this increase
in metabolism simply can't keep up. So what happens to
(43:18):
the body if we cannot keep up? The first thing
is that we see what's called a cold diarysis, which
basically means that because all of our blood has been
shunted into our core, it's flowing very quickly through our organs,
including our kidneys, and so our kidneys are furiously filtering
all of this blood and we start to see an
(43:40):
increase in urine production.
Speaker 1 (43:43):
I feel like I came across that somewhere, and I
don't know where if it was like, yeah, I read
the Shackleton's Expedition.
Speaker 2 (43:53):
Book for this one of my husband's favorite books.
Speaker 1 (43:55):
It's great. I mean it's like it's unbelievable. And the pictures,
the fact that there are pictures is wild, yeah to me.
But anyway, I don't remember if that's where somebody was
talking about peeing a lot, or if it was because
they're like freezing at night and no one wanted to
go outside until it was like who didn't want to
play the one or who didn't want to play the
game where it was like the last person who fills
the pot has to empty it, so you just hold it.
Speaker 2 (44:16):
Anyway, Well, yes, you do start to have a cold
diuresis this is not a good sign.
Speaker 1 (44:24):
It means that things are not going well.
Speaker 2 (44:26):
And on top of that, not only is it just
not a good sign, but what it means is that
you can end up getting dehydrated right because you're losing
all of this fluid through your urine. You could end
up with acid base disturbances, you can end up with
electrolyte issues, and eventually our body really cannot keep up
with all of this loss, and our core body temperature
(44:47):
will start to decrease. And as our core body temperature decreases,
our energy expenditure also starts to decrease, and pretty dramatically actually,
h I think for every one degree celsius decrease in
core body temperature, our energy expenditure decreases by like thirteen percent.
(45:09):
So there's no more shivering a lot of times. A
lot of times shivering will stop. Yeah, because things are
just sort of slowing down, and all of our cellular
functions start to slow down, and this eventually results in
our central nervous system slowing down so much that we
lose consciousness. Usually that doesn't happen until our central like
(45:29):
our core body temperature drops to around thirty degrees celsius.
Should have looked up what that is in fahrenheit, but
I didn't. It's cold, Yeah, it's cold. But what is
usually lethal is not the effects on our central nervous system,
but actually the effects on our heart. Because first you
can get those acid base like and electrolyte disturbances from
(45:50):
all of this diarysis that can affect the contractility of
your heart and it can lead to arrhythmias. Okay, And
as our heart beat is slowing down and all of
this metabolism is slowing down in our heart, the time
between beats can prolong, so we get what's called breta cardia.
Your heart beat is slowing down, and then the time
(46:12):
that it takes for the electric signals to actually be
conducted through the heart also gets affected, so you end
up with a rhythmias. There's a bunch of different types
that you can get, but most often it's ventricular fibrillation,
which is your heart just kind of quivering instead of contracting,
and then eventually it stops completely. And that is how
(46:35):
death usually happens with hypothermia.
Speaker 1 (46:39):
It's so it's I this makes me really look forward
to next week because I'm trying to figure out is
this Are there are clear costs costs, yes, and so
there must be enough of a benefit or is there
enough of benefit? But that's a question I guess.
Speaker 2 (46:55):
For next week.
Speaker 1 (46:56):
Next week, Yes, okay, I feel like I have some questions.
So what about are you going to talk about like
rewarming and how okay? Okay, so yeah, so you know,
I guess the rate at which hypothermia occurs is dependent
upon the individual, upon the environmental conditions, on clothing, upon
(47:16):
too much to even go into, right, So are their thresholds?
Are there established thresholds for like the risk or something?
Speaker 2 (47:27):
No I knew you were going to ask, and no,
it's it's what's really I think it's one of the
things that's very interesting about hypothermia. Right, there's not like
a textbook that's like, below this temperature you are at
risk of hypothermia because it depends, like you said, on
so many different things. We do know that extremes of
age are more susceptible to hypothermia. So newborn babies and
(47:49):
small babies and infants in general have a much greater
surface area to volume ratio, So even though they have
that great brown fat and everything, they just lose a
lot more heat, and so they're at higher risk of
core temperature drops and hypothermia people who are elderly, So
as you get older, you have less efficient, we think,
(48:10):
thermoregulatory mechanisms. We also often see changes in like body
mass composition during aging, and so that makes it so
that you're less able to regulate your temperature. If you
think about like your grandparents are cold all the time, right,
they're just not as able to maintain their heat.
Speaker 1 (48:27):
You mentioned being.
Speaker 2 (48:28):
Unhoused, right, not having access to the behavioral mechanisms that
we as humans rely on to maintain our temperature, like
adequate clothing and shelter, fires or other forms of heat
to keep us warm. And then also substance use like
alcohol and other central nervous system medications like opioids or
(48:49):
any any kind of thing that's affecting your central nervous
system and depressing your central nervous system function is going
to put you at higher risk of hypothermia hugely. So, Yeah,
but there's not like you can certainly see we see
hypothermia here in San Diego, even in the winter, and
it doesn't get very cold here, right, Yeah, In terms
(49:10):
of how we treat it, it really depends on how
severe it is, and then like the specifics of the
person and the scenario themselves. But across the board, it's rewarming, rights,
it is rewarming that person's body back to a normal temperature.
But whether that means just insulating them against any more
heat loss, like if they're just mildly hypothermic, or if
(49:33):
you need to actively rewarm somebody, and that might mean externally,
like putting them in warm water or using we have
in the hospital these things called bear huggers. Yeh, I'm
pretty sure that's a brand name, Okay, But it's like
these forced air it's like these blanket, paper, blankeant things
that you put over someone. We use them in surgery
a lot too, but also in hypothermia, and they just
(49:56):
force hot air, so then you're like insulated with this
blanket of hot air that's moving over you. They're quite cute,
uh huh. And then heated blankets. These are all like
external ways that you could warm a person's body if
they're mildly hypothermic. Okay, and then there's internal rewarming, which
is of course much more invasive, and there's obsceeded on
(50:20):
er I'm sure you have many times. There's a lot
of different ways that you can do it. You can
do it with just like heated ivy fluids, so like
just in you know, a peripheral line. You can do
it via body like U body cavity levage, so like
any of your body cavities. You can flush warm fluid
through those body cavities and then drain it out, I know.
(50:42):
And then you also could use essentially like an ECMO
machine that's extra extra corporeal rewarming machine that just takes
your blood from your body, runs it through a machine,
warms it up and oxygenates it, and then returns it
back to your.
Speaker 1 (50:56):
Body pretty darn cordn incredible. Yeah, and that's that is it? Arin. Okay,
So I have a question about something that you I
don't know, I don't think you mentioned it, but like
the your your ability to make decisions kind of gets
(51:20):
all funky too. So that's one of the things. There's
this what is it called where you disrobe, like you
start to take off your clothes.
Speaker 2 (51:27):
Yeah, paradoxical dysrobing, I think, or something they call it
what it is. Yeah, yeah, I mean I don't We
don't really have a great understanding of why and how
that happens, but it is something that you can see,
and we think that it's just due to Even though
you might not lose consciousness until your body gets quite cold,
like a core temperature of around thirty, the effects on
your brain and your central nervous system can be pretty substantial,
(51:50):
even at relatively mild hypothermia, which means that yeah, people
might not be like and we don't really know, like
no one's thankfully today doing human experiments to figure out
like what are you thinking about when your body is
getting to be that cold? And so we don't have
great data on like why do these types of things
(52:10):
but it can certainly complicate. I read a couple of
like forensic examiner type papers where they were, like, hypothermia
deaths if you're like investigating them as like a forensic
medical person, can be really complicated because sometimes it is
just hypothermia, but it can look like there's a lot
of foul play involved, or it can look like really
complicated scenarios and then it's ultimately determined that it's all
(52:33):
just due to hypothermia. But so it is. It's really fascinating. Yeah, okay, okay,
And what I think is also so fascinating about hypothermia
are the kinds of stories, like you told Aaron, of
people actually being able to recover. Yeah, especially when you
(52:53):
contrast it to heat stress, right, like hyperthermia, the way
that extreme heat induces damage to our proteins, to our
cell structures itself, that has a pretty poor prognosis if
your body temperature gets way too hot.
Speaker 1 (53:11):
Yeah, you're looking at like a degree of a few
degrees versus like tens of degrees that people have come
back from exactly.
Speaker 2 (53:18):
And it's in part because hypothermia overall is reducing our
cellular functioning and our energy demands, which means that we
need less oxygen and our cells can therefore survive in
absence of oxygen, and that is why people have thought
(53:42):
to use this in medicine as a therapeutic device. And
that is what we're going to talk about next week.
Speaker 1 (53:51):
Loved that Cliffhanger transition. Loved it. Thank You's great, Thank
you so much. It was great. I'm really looking forward
to that because I want to know. I feel like
I have made some assumptions about therapeutic hypothermia, so I'm
ready to have those corrected. I can't wait. I'm excited
if it need be.
Speaker 2 (54:09):
Yeah, maybe they're all correct.
Speaker 1 (54:10):
I don't know who. I don't know much, but I'll
know more next week. And if you want to know
more this week.
Speaker 2 (54:19):
Right now, so many sources, Okay.
Speaker 1 (54:22):
Let me pull mine up. So for both of these episodes,
I read a book that gave me a lot of
different ideas called Out Cold by Phil Jakol. It's a
chilling descent into the macabre, controversial, life saving history of
hypothermia book from twenty twenty one. And then if you
want to read more, I absolutely loved this review paper
(54:43):
about it's called Adaptations to Polar Life in Mammals and Birds.
I love it by Blicks from twenty sixteen. And it's
just like such a fun, fascinating, just like a paper
that talks a.
Speaker 2 (54:55):
Lot fun all the ways.
Speaker 1 (54:56):
I love it. Yes, then there's for more of the history,
especially the Napoleon stuff. There's a paper by Lankfort from
twenty sixteen titled Dull Brains and Frozen Feet, a historical
essay on cold And finally, I want to just put
a plug in for a short story by Jack London
called to Build a Fire and it's available. Just search it.
(55:18):
You can find a PDF. It's by the public domain.
And it is I mean, it's a story of hypothermia.
Is it is chilling and good and yeah, I clearly
should have thought of more better adjectives before telling people
to read it, but it is really it's it's I
think it does a really good job of kind of
(55:39):
taking you through how what hypothermia might feel like and
sort of the one fault like one false step, one
one miss misstep, one one bad move.
Speaker 2 (55:53):
Aaron, I don't have like really fun recommendation like that, Aaron.
I have you know a page called body temperature and
it's regulation by kot and Farmery from Antesesion Intensive Care Medicine.
I've Got Hypothermia by Turk in Forensic Science, Medicine Pathology.
That one was kind of interesting. Accidental Hypothermia from the
(56:14):
New England Journal Medicine nineteen ninety four. We got a
few other papers. Okay, there is an update from twenty
twenty two on the accidental hypothermia one.
Speaker 1 (56:22):
So listen.
Speaker 2 (56:22):
You can find all of the sources from this episode
and every single one that we've ever done on our
website this podcast willkin you dot com.
Speaker 1 (56:29):
You can. You can thank you to Bloodmobile for providing
the music for this episode and all of our episodes.
Speaker 2 (56:36):
Thank you to Leanna and Tom and Brent and Pete
and Jessica and Mike and everyone else. I think there's
more people. I'm probably forgetting to say thank you too,
but thank you also.
Speaker 1 (56:47):
Everyone at exactly right and every one of our listeners
are watchers. Anyone who participates in this podcast in some way,
we really appreciate it, and especially to our patrons, your
support means it means the world to us. It really
does so much. Thank you. Well, until next time, wash
your hands you kill the animals.
Speaker 2 (57:12):
M
The cold was so intense. One constantly found men who,
overcome by the cold, had been forced to drop out
and had fallen to the ground, too weak or too
numb to stand. Ought one to help them along, which
practically meant carrying them. They begged one to let them alone.
There were bivouacs all along the road, ought one to
(00:22):
take them to a campfire. Once these poor wretches fell asleep,
they were dead. If they resisted the craving for sleep,
another passerby would help them along a little farther, thus
prolonging their agony for a short while, but not saving them.
For in this condition, the drowsiness engendered by cold is
irresistibly strong. Sleep comes inevitably, and to sleep is to die.
(00:48):
I tried in vain to save a number of these unfortunates.
The only words they uttered were to beg me for
the love of God, to go away and let them sleep.
To hear them, would have thought sleep was their salvation. Unhappily,
it was a poor wretch's last wish. But at least
he ceased to suffer without pain or agony. Gratitude and
(01:12):
even a smile was imprinted on his discolored lips. What
I have related about the effects of extreme cold and
of this kind of death by freezing is based on
what I saw happen to thousands of individuals. The road
was covered with their corpses.
Speaker 2 (02:14):
What Aaron is that from?
Speaker 1 (02:19):
That is from Napoleon's close advisor Armand de Callancourt about
the retreat from Moscow. And I'll talk a little bit
more about it, but it is it is horrific. Yeah,
the words can't adequately describe. Yeah. Hi, I'm Aaron Welsh.
Speaker 2 (02:40):
And I'm Erin on Updyke.
Speaker 1 (02:42):
And this is this podcast will kill You.
Speaker 2 (02:44):
Today's very uplifting episode. It's going to be about hypothermia.
Speaker 1 (02:50):
It is about hypothermia. And it's one of two parts
because as we kind of were talking about hypothermia and
the effects of cold, and we thought, well, it's it's
unfair to paint cold in just one light. It's this
bad thing and hypothermia. So this is a two parter.
Part one is cold is bad and part two is
(03:13):
cold can be Good? Right?
Speaker 2 (03:15):
Are those our titles? Because I love it. Part one
hypothermia cold is bad. Part two Cold is not always bad?
Speaker 1 (03:24):
Yeah, Yeah, there's nuance even to cold. How about that?
I am excited. There's I feel like this is a
topic that we have not really I mean, I guess
we've done fever, but it's like so related to infection,
whereas this is just like what happens when your body
(03:45):
is stretched beyond its physiological lembits. I know.
Speaker 2 (03:47):
And it's interesting because especially like, well at least you
live somewhere where you probably are people are seeing hypothermia
more than like where I live. I'm like, how come
we didn't choose heat stress as our first temperature because.
Speaker 1 (04:02):
It is July. We're recording this quite early. It is July.
Like the heat. The heat is so strong. I am
in a long sleeve wool sweater with skiers on it.
You've got some deer also wool. Are they elk?
Speaker 2 (04:17):
Not sure they're sweaty? You're sweat they are.
Speaker 1 (04:21):
They're sweaty. Yeah, we are sweaty sweaters. But it also
was reading about hypothermia now and about the cold was
kind of like, oh, yeah, there is another temperature besides
besides heat ninety one degrees. Yeah.
Speaker 2 (04:39):
Yeah, Well we'll get into all of it, but first,
it's quarantine time.
Speaker 1 (04:45):
What are we drinking this week? The uncommon cold? I
mean hypothermia is I'm sure you'll have stats later. It's not.
Speaker 2 (04:54):
Yeah, I don't many stats honestly, but it's not that.
It just very much depends on where you live.
Speaker 1 (04:59):
But right right, yeah, it's not that's more uncommon than
the common cold. Yeah, okay, definitely, And we thought, in
light of the fact that cold can be bad and good,
we're going to do a cold blended drink, but that
also has heated elements into it. Spicy. Yeah, so it's
like have an arrow margarita.
Speaker 2 (05:20):
Yeah, blended blended, which is not my favorite kind of margarita.
So if you don't want that, don't do that.
Speaker 1 (05:26):
Yeah, you do whatever you want.
Speaker 2 (05:27):
Listen. We'll post the full recipe on our website, this podcast,
amplay dot com, and all of our social media channels.
To make sure you're following us there, please.
Speaker 1 (05:35):
Do please do. On our website This podcast will Kill
You dot com, you can find all sorts of things.
You can find transcripts. You can find sources for each
and every one of our episodes. Links to bookshop dot org,
affiliate account, links to our Goodreads list, links to music
by Bloodmobile, links to a contact us form, links to
a submit your first hand account form, Patreon merch things.
(06:00):
Check it out.
Speaker 2 (06:01):
This podcast will kill you dot com rate, review, and
subscribe on your favorite podcast, which might be iHeart podcasts.
Did you know we're there? We're also on Apple of
the podcast. We're also on the Spotify and now on YouTube.
Speaker 1 (06:14):
You I can't bring myself to say that, but yes
we are.
Speaker 2 (06:18):
I can't not say it that way. Go to the.
Speaker 1 (06:22):
Exactly right YouTube channel and you can subscribe so you
never miss an episode.
Speaker 2 (06:27):
Okay, moving on, Erin, tell me about the history of hypothermia.
What I mean, listen, I'm assuming we've always frozen.
Speaker 1 (06:37):
Yeah, that's true, but we'll get into a little bit
more of that good right after this break. Humans have
(07:10):
existed thrived, even on the farthest reaches of the Earth,
for tens of thousands of years.
Speaker 2 (07:16):
True.
Speaker 1 (07:17):
The earliest evidence of humans in the European Arctic, for example,
dates back forty thousand years.
Speaker 2 (07:23):
Wow. Yeah, that's a long time.
Speaker 1 (07:25):
There were It is a long time. There were mammoth
tusks with human made cuts, sliced wolf bones, stone artifacts,
and other animal bones with like clear human you know,
manipulation or whatever found above the Arctic Circle.
Speaker 2 (07:40):
Pretty cool.
Speaker 1 (07:40):
That means that, like only a few thousand years after
humans reached Europe, they just kept right on heading north.
Speaker 2 (07:46):
Okay, why just looking for something new? I guess by amos.
Speaker 1 (07:53):
But I feel like if you have spent a winter
in or close to the Arctic, it might be like
which you have it's cut I have. Yeah, it's a
natural question to ask. Even if you absolutely love the
winter and you long for the days to get shorter
so that you can break out your favorite pomp pom
wool hat and cozy sweaters, or even if you get
(08:14):
to see the southern or northern lights in the winter
and you love to snowshoe or ski, you have to
admit that the polar regions are not an easy place
to live, and they don't let you forget it. Grabbing
the wrong jacket before you step outside, losing a glove,
a window that's lost its insulating ability. These things don't
(08:37):
go unnoticed, at least not for very long. Whether immediately
or eventually, the cold makes itself known. It insinuates itself
into the nooks and crannies of your jacket, of your body,
the tips of noses, toes, fingers, and it settles into
your bones until you feel like you'll never be warm again.
Speaker 2 (08:58):
That is the exact way that I would describe living
in Illinois.
Speaker 1 (09:04):
Will I ever be warm against any like?
Speaker 2 (09:08):
So many memories of that feeling of like your bones
being so cold, which I know they're not really, but
your bones being so cold that you don't it is
impossible to remember warmth.
Speaker 1 (09:21):
Yeah, right now, it's impossible for me to remember cold,
even though I'm talking about it. I'm so so witty.
I'll have to try to remember this moment come February exactly. Yeah.
But I think that many of us lower latitude dwellers
have kind of a sense of awe, at least I
do for those living in the Antarctic and Arctic regions
(09:43):
of the world, because even with the warmest of jackets
and the most insulated of shelters, polar life exists on
a knife edge, where even the tiniest thing can tip
the scales, turning a minor mistake or a minor accident
into a fatal outcome. I cruised the Wikipedia page for
(10:04):
hypothermia related deaths, which is quite morbid, I know, and
the one thing that really stuck out to me was
just how easily it can happen. I went through and
I like read different people's stories and it was just
like and then on one wrong step, yeah, and that
was it. That was it. And how powerless you are
(10:26):
when the cold really sets in. And yet many species
call these polar regions their home, not just humans. Why
would an animal live in a place that is so brutal,
so unforgiving, although not all the time, as we'll see,
there are all sorts of reasons. Maybe it's more available, habitat,
(10:47):
less competition for resources, escape from predators, escape from parasites,
a combination, or something else entirely, But for this episode,
the why isn't as interesting to me as the how,
Like how can species live at the ends of the earth,
not just like eking out a meager existence, but flourishing
despite the deadly cold. Humans have innovated incredible clothing, shelter, transportation,
(11:13):
and tools to help protect from freezing temperatures, and animals
have evolved a vast array of strategies anatomical, physiological behavioral
to resist hypothermia and other harmful consequences of cold, like frostbite.
Would you like to learn about some of these thrilled?
(11:35):
Thrilled to learn about these one way is just to
avoid it. Just migrate the heck out of it. Birds.
Birds love this, they're big fans of the migration.
Speaker 2 (11:46):
Yeah.
Speaker 1 (11:47):
And some bats and you know, other things, but way
big for birds. Yeah. And then there's torpor, which includes
hibernation and dormancy. Basically, an animal just turns down the
dials on body temperature, activity and metabolism to get through
the winter. Bears, ground squirrels, bats, some frogs. And then
(12:07):
there's cold resistance, so like you keep operating mostly as
normal during the cold months, but you just bump up
your your own systems, your defense against Yeah, and that
would be something like arctic foxes, polar bears and so on.
And these strategies they're not mutually exclusive. You can have
a little bit of this and a little bit of that.
(12:28):
And there's also a great variation within some of these,
So like hibernating black bears only drop their body temperature
by a few degrees celsius, while some mammals, small mammals
drop temperatures twenty to thirty degrees celcish body temperatures. What
oh it gets it gets better. Wood frogs, Oh, do
you know about wood? Yes, I know about wood. Frogs.
(12:49):
Who does it? But no, lots of people don't. I
had I had to refresh my memory because the stats
are I was like, this can't be. I was like,
I need to fact check this right multiple places.
Speaker 2 (12:59):
I love this real.
Speaker 1 (13:00):
They're the Hall of Famers for dormancy. They survive freezing
temperatures below minus twenty celsius for months on end, like
seven months, seven merely freezing, Yeah, nearly freezing solid. Fifty
to sixty five percent of their body water is frozen. Wow,
just frozen. Yeah. These are frogs that live above the
(13:23):
Arctic circle. What what Like? I just can't get over it.
And then you've got the fish that avoid freezing in
Antarctic waters by using anti freeze proteins that let them
keep swimming around. Other animals like polar bears, ptarmigan wolves
and hares make simple burrows in the snow to help
(13:44):
with insulation.
Speaker 2 (13:45):
Question, which is, yeah, what's a ptarmagan?
Speaker 1 (13:48):
It's a bird? Okay, thank you. Yeah, they're really cute. Yes,
or sometimes they'll employ bagel formation, which is not the
technical term, but I love those. Okay. It's like where
you make yourself into a tiny ball, like a little
ball to trap heat like the doggies do you Yeah, okay, exactly,
you just tuck your little nose and you're in bagel formation.
(14:11):
Bagel formation. And then other animals that live in colonies,
like walruses and penguins, they'll huddle together for warmth, especially
baby emperor penguins.
Speaker 2 (14:23):
Yes, they're very cute.
Speaker 1 (14:26):
They're very cute. Thick fur and blubber help to reduce
heat loss, as do changes in the circulatory system or
even the type of hemoglobin that an animal has, So
like pretty cool, yeah, because of and then there's like
circulatory changes, so because there are these specialized changes in
blood flow in pawpads of Arctic wolves and foxes that
(14:48):
allows them to stand on the ground that has a
temperature of minus fifty celsius but their feet don't freeze
or become damaged. What I don't know. And then nasal cavities.
I didn't realize that, like the shape of a nasal
cavity could be so important, but it is.
Speaker 2 (15:05):
I feel like I remember learning this at some point.
Speaker 1 (15:07):
Tell me about it, Aaron, Okay, okay, So reindeer have
nasal cavities that warm the air before it enters the
body and it sort of like warms it and then
there's like water condensation, right, But then instead of losing
that heat and water to the environment, they also somehow
cool the air before it leaves, and so you're basically
(15:30):
conserving heat and water because of the way that they're
nasal cavities. Oh that's fascinating. Yeah. Babies of Arctic animals
are born well equipped with extra warm fur or feathers
or brown adipose tissue that keeps them super warm, and
mom will also often provision them with super fatty milk.
(15:53):
One of my go to fun facts to share at
a cocktail party is that some whale milk is so fatty,
like thirty to sixty percent fat, that it has the
consistency of toothpastete. That's one of my favorite things too. Yeah,
just I love it.
Speaker 2 (16:09):
Baby whales lap it up toothpaste in the ocean.
Speaker 1 (16:12):
I mean, I think it also must help with like
not just just diluting into the environment. Yeah, so they
can kind of like yeah, get it. Yeah, But for comparison,
human breast milk is like four percent fat compared to
thirty to sixty for some whales.
Speaker 2 (16:29):
Like imagine the lipped cream you could make oh my, I.
Speaker 1 (16:32):
Mean it's already whipped, right, it's like solid, Like, what
do you do, It's like butter, It's just butter. Yeah,
it's actually just butter. Okay, So one last fun fact
before I get to humans. One of the major challenges
with living in polar regions is food availability. It's not
always reliable, and in those times of scarcity, you're not
(16:52):
only expending energy trying to find food, you're also using
more energy staying warm. And some Arctic species deal with
this by cashing food. So like one arctic fox hoard
had one hundred and thirty six seabirds and then yeah.
Speaker 2 (17:07):
It was just like little He's like, listen, they're frozen.
They're going to keep don't worry about it. Yeah, I
feel through the wind chest freezer.
Speaker 1 (17:14):
This is my cost code. Yeah. And an ermine was
found to have hidden over one hundred and fifty lemmings
as white.
Speaker 2 (17:26):
You know, I still like, I know that a lemming
is an animal, but I have no idea what they
look like. I cannot picture a lemming.
Speaker 1 (17:32):
Little rodenty things. I only do you.
Speaker 2 (17:35):
Remember that game the lemmings going over a cliff?
Speaker 1 (17:39):
You don't remember this game? No, there was it was
on what hard on what device?
Speaker 2 (17:44):
Computer computer? It was a computer game where there's I
think they were they were called lemmings, but they were
like little people looking things and they just were going.
Speaker 1 (17:53):
Over a cliff. If you, oh, no, I'm going to
need to look this up. I feel great. I feel wow. Yeah.
Is it like Ski Free era? You remember that game
with the Yes?
Speaker 2 (18:04):
Okay, I don't know if it was same era. I
have no idea.
Speaker 1 (18:07):
Okay, sorry, we'll have to We'll have to find it.
Speaker 2 (18:12):
That's what I think of when I think of vings,
and that's why I can't like picture that there's an
animal called letting.
Speaker 1 (18:16):
Just pictured tiny humans just okay, I don't think they
look like miniature humans with little like gnome hats on. No,
I don't believe that they have constructed nome hats irl okay, okay.
So another besides casing food and lemmings uh not with
(18:40):
no mats, another approach is storing extreme amounts of fat,
so seal pups undergo something called catastrophic molting, which sounds
a lot scarier than it actually is. They just lose
all their fur at once, and then they have to
wait a while to grow back a new layer, and
so during that time they can't go in the water
for food because they'll get hypothermia, so they don't eat. Oh,
(19:03):
they can go fifty two days without food or water.
Speaker 2 (19:07):
Wow, and that Wow, it's a really long time.
Speaker 1 (19:11):
It's a really long time. And so my point with
all of this, besides being able to share with everyone
the whale milk toothpaste fun fact, so that you have
something to share at like, you know, the next round
table ice breaker type thing.
Speaker 2 (19:25):
And the wood frogs icebreaker, but wood.
Speaker 1 (19:28):
Frogs, my god, icebreaker would also have been a good quarantine.
Speaker 2 (19:31):
Wow.
Speaker 1 (19:31):
Anyway, Yeah, that animals have evolved. My whole point is
that animals have evolved an incredible array of ways to
deal with the cold, and unfortunately humans lag behind in
this respect. And so under the right set of circumstances,
our body struggles to warm itself, our temperature drops and
(19:53):
we slip into hypothermia, which is something that we've been
doing for as long as we've been human. So even
though I just spent a good deal of time in
the polar regions with polar animals, you can get hypothermia
anywhere on Earth. Some of the earliest references to hypothermia
come from ancient Greece, which is certainly not arctic. Hippocrates,
(20:14):
of course, noted the benefits of cold, but also the
dangers quote cold is bad for the bones, teeth, nerves, brain,
and the spinal cord. In four point fifty BCE, the
Greek historian Herodotus wrote about soldiers dying in a sea expedition.
Quote some were seized by these sea monsters and so perished,
(20:35):
while others were dashed against the rocks, and some of
them did not know how to swim, and perished for
that cause, others again by reason of cold end quote seamusters.
War has always been a bad spot for hypothermia. In fact,
most historical records of hypothermia come from various wars throughout history.
(20:55):
In two eighteen BCE, Hannibal's army of twelve thousand cavalry,
ninety thousand infantry, and forty elephants was cut down to
nineteen thousand men and some uncertain number of elephants during
their march over the Alps, with many of them dying
of cold. During the American Revolutionary War, countless soldiers suffered
(21:18):
frostbite and hypothermia, especially during the winter of seventeen seventy
seven seventeen seventy eight, when nearly a fifth of the
eleven thousand men who retreated into Valley Forge did not
have shoes or boots at all. Oh, I just imagine
that in the winter. No, I can't imagine that. And
then there's Napoleon's army, this retreat from Moscow in eighteen twelve.
(21:41):
So he this is like where this is infamous, and
we've talked about this in several other times of the podcast.
Napoleon and his army started out in June with nearly
half a million soldiers. By the time they had gotten
to Moscow in late fall, numbers had dwindled pretty substantially
by at least one hundred thousand. But when they arrived,
(22:05):
they found a burned out, abandoned city, no opportunity to restock,
to refuel, no food, nothing. The Russian forces had adopted
this like scorched earth tactic, and that would prove to
be Napoleon's downfall. So he waited around a bit just
trying to figure out what do I do here? Do
we stay?
Speaker 2 (22:23):
Do we go?
Speaker 1 (22:24):
And then was like, you know what, we should just
get back to France. So a retreat to France. That
was the move. The army started back in October, still
dressed in their summer uniforms, and they pushed through the
snow and ice and frozen rivers in November through December
and even into January. Count Philippe Paul de Segur, a
(22:45):
brigadier an aid to Napoleon, wrote, quote, Russian winter in
this new guy's attacked them on all sides. It cut
through their thin uniforms and worn shoes. Their wet clothing
froze on them, and this icy shroud molded them their
bodies and stiffen their limbs. The sharp wind made them
gasp for breath and froze the moisture from their mouths
(23:07):
and nostrils into icicles on their beards end. Quote. By
the time they got back to France, all that remained
of Napoleon's five hundred thousand troops was ten thousand. Oh
my gosh. Yeah, some died in battle, others from their
injuries or infections. If you remember back to our Typhus episode,
(23:28):
that was a major, major killer, but many succumbed to
the cold. A frost bitten and constantly water logged foot
turned gangrenous with the infections spreading to the rest of
the body. A raid on a liquor store allegedly killed
eight hundred soldiers who imbibed a bit too much and
fell asleep in the snow. At the time, it was
(23:49):
thought that alcohol was warming and helped stave off the
negative effects of the cold, although I'm not sure they
were drinking it as medicine. And by the way, it
is not warming. It is not what you should use
to treat someone suffering from hypodermy.
Speaker 2 (24:03):
Alcohol actually can can There's actually thought that not just
the risk of you know, drowsiness or falling asleep or
you know, making decisions about what clothes you might wear
that are impaired because of the effects of alcohol, there's
actually thought that the alcohol, the effects of alcohol itself
also contribute to hypothermia.
Speaker 1 (24:21):
Yeah, so more heat loss exactly, yeah, yeah, yeah yeah.
And then there was also just poor nutrition and grueling
conditions that took many others just after they drifted off
to sleep. One of Napoleon's surgeons wrote quote, the first
hours of sleep offered deceptive delight, precursor to the grave
that yawned for them. Far from finding safety in the
(24:43):
sweets of sleep, they were seized and benumbed by cold,
and never saw daylight. More along the road, in the
neighboring ditches of fields were perceived human carcasses, heaped up
and lying at random in fives, then fifteens, and twenties
of as had perished during the night end quote. No
(25:04):
one was spared, not even the surgeons, who wrote how
their brains had become so dulled by the cold that
they could barely recognize one another. So many dyed or
suffered permanent injuries from the cold on this retreat, not
just because of poor quality clothing and shoes or insufficient food,
but also because no one really knew how to treat
(25:25):
hypothermia or frostbite. Those words didn't even exist yet, a
practical thermometer that could be used clinically was still decades away. Instead,
the effects of cold were kind of grouped together under
the term asphyxia, partial asphyxia usually referring to frostbite, and
(25:45):
general asphyxia referring to hypothermia. Interesting, these were diagnosed from
like subjective observation, so it was thought that like basically
there was congealing in your body, fluids were congealing and
blood in start at the at the extremity, right at
your flick fingertips and nose, and then yeah, and then
as it grew your whole if you're so, that was
(26:07):
like frostbite, so you're like, okay, there's no it's all congealed.
And then then hypothermia it was like your whole body.
It's not that far off. Yeah, yeah, I say, yeah
and so. But because of this, treatment usually took the
form of slowly rewarming to get everything to re liquefy,
and you were supposed to start in reverse. So you
(26:28):
start with snow, rubbing snow on your you know, frostbitten fingers,
and then yeah, and then cold water and then cool water,
then tepid water. You get the really okay, interesting go
slow yeah. Earlier physicians had learned their lesson the hard
way not to use extreme heat, and revival efforts were
occasionally successful during Napoleon's retreat, but they often weren't even
(26:52):
attempted if someone looked dead, and it wasn't widely known
at the time how many of the signs of hypothermia,
signs that mimicked death could be reversed. One of the surgeons,
later learning of this, wrote quote how many resurrections might
have been made on the retreat from Moscow, probably lots,
(27:13):
and as later, medical advancements in the late nineteenth but
especially the first half of the twentieth century revealed hypothermia
did not always carry with it a death sentence, and
doctors could more readily measure temperature thresholds beyond which recovery
was unlikely. And as the term hypothermia came into more
usage in the first decades of the twentieth century and
(27:36):
it became a distinct clinical entity, focused interest in prevention
and treatment of the condition increased, especially during World War Two.
So I don't know when exactly I tried to find
when exactly the phrase you're not dead until you're warm
and dead you originated. Yeah, but it was likely in
the last few decades of the twentieth century, showing the
(27:58):
huge amount of progress made understanding hypothermia and reversing it.
And so before I turn it over to you, Aaron,
to tell us what exactly is happening when our body
temperature dropped to dangerous levels and what we do about it,
I want to end with one of the most amazing
hypothermia revival stories that shows just how far we've come. Oh,
(28:18):
I love it. Like Napoleon's surgeon's minds would have been
absolutely blown by learning of this story. Okay. In nineteen
ninety nine, a twenty nine year old Swedish woman named
Anna moved to a small town in northern Norway in
the Arctic Circle to complete her medical residency or above
the Arctic Circle, and part of the reason that she
(28:39):
chose this location was because she was an avid and
very experienced backcountry skier. In May, she and a couple
friends who also had medical training, went out skiing for
the day. At six twenty pm, Anna or Anna maybe
lost her balance and fell headfirst into a waterfall gully,
where she became wedged in the ice and water. Her
(29:01):
friends couldn't get her out. They tried to pull her out,
and they couldn't get to her, and so they called
for help, and unfortunately help was slow to arrive. The
only rescue helicopter available was on its way to transport
a sick child, which was in the other direction from Anna.
At seven pm, she stopped moving those forty minutes in
(29:22):
the ice. At seven point forty a ground rescue team
arrived and extracted her from the ice. She was clinically dead.
The helicopter arrived around eight pm and she was loaded
onto it for transport to Tromso Hospital, which is about
an hour's flight away, and with the adage you're not
dead until you're warm and dead in mind, resuscitation efforts
(29:44):
were started in transit and continued along with rewarming at
the hospital. When she got there, doctors found that she
was not breathing, She had no pulse, her pupils were
widely dilated and unresponsive to light. Her EEG was flatline.
Nurses and doctors continued their chest compressions in ventilation as
they prepped to put her on a heart lung machine.
(30:06):
At nine fifty two pm, so this is three and
a half hours after she went into the ice, her temperature,
her body temperature was measured at thirteen point seven degrees
celsius or fifty six point six degrees fahrenheit. Wow. At
that point, yeah, she'd been three hours without a heartbeat.
(30:27):
But then at I guess I kind of spoiled it
at the beginning by saying revival story, but I mean,
you know where this is going. But then at ten
fifteen pm something on the monitor a heart beat, then another,
then a steady rhythm. She woke up ten days later
and spent another couple of weeks in the intensive carry unit,
(30:48):
and initially she showed signs of paralysis below the neck
and struggled with various organ dysfunctions, but over time she
made an almost complete recovery. After five months she was
like basically back to normal, back to skiing. It's an
amazing story that shows what both the human body and
(31:09):
modern medicine are capable of. And that being said, every
year many people, especially those who are unhoused or struggle
to keep their homes warm in the winter who can't
afford to do so, die of hypothermia. And most of
these deaths are they represent a failure not of modern
medicine but of our society in providing a safety net
(31:31):
to prevent death in this way, because like stories like
Annas show us, it is possible, and it can sometimes
be reversed. But in a lot of these cases it
should never have happened in the first place. Yeah, but
now Erin, I'll turn it over to you to tell
me more about how we deal with hypothermia today. I
(31:54):
would love to.
Speaker 2 (32:25):
You mentioned at the top erin the last time that
we talked about human body temperature was in relation to fevers,
and we learned in that episode, and maybe everyone forgotten.
That's fine, I'm gonna tell you again. But we learned
that a fever is what happens when our temperature set
point gets moved. Right. Our brain, specifically our hypothalamus controls
(32:51):
our temperature set point, and so a fever is what
happens when our hypothalamis is like, we need to get hotter, right,
But most of the time, outside of a fever, we
as humans seek to exist at about thirty seven degrees
celsius ninety six or so fahrenheit, right, And that is
(33:13):
that particular temperature is what our body is constantly maintaining.
And because we are endotherms like all mammals, we maintain
this temperature by physiologic mechanisms within our own body.
Speaker 1 (33:30):
Right.
Speaker 2 (33:30):
We don't rely on the sun or our environment to
warm us or cool us, right I. And all of this, like,
all of these processes are basically coordinated in our brain
by our hypothalmis because this is controlling our temperature set point.
So hypothermia is like the easiest way to look at
it is just that this is what happens when we
(33:52):
can no longer do that, when all of the mechanisms
that we have to keep our bodies warm and at
the right temperature fail us. And that happens mostly when
the environment is either just way too cold or it's
just a little cold but for way too long for
(34:15):
us to generate enough heat via our metabolism and all
the things going on inside of our bodies, okay, and
the external trappings that we use of course as humans,
so we can pretty well maintain our body at a
constant temperature without our bodies having to work very hard
to do it, even if we were totally naked. If
(34:36):
we exist between like twenty five and thirty celsius, which
is like seventy seven to eighty six fahrenheit, that's our
like thermoneutral zone. Once you get above this or below this,
our bodies are going to have to work harder to
maintain our temperature. Now, that's seventy seven fahrenheit twenty five celsius.
That's not cold, no, it's quite warm, it's quite warm.
(35:00):
But below around that temperature means that our body is
having to do something to generate heat. Right if you were,
if you were totally naked like, but we're off if
you were totally naked those onto So that's that's behavioral adaptations.
So what I want to talk about is less about
the behavioral adaptations because those are obviously important, But I'm
(35:22):
really going to focus on our bodies. How do we
typically deal with temperature stressors? What are we doing inside
of our body to generate heat when we're exposed to cold,
so that then we can understand what happens once those
start to fail us. And then next week we're going
to talk about kind of building off of that story
that you told Aarin and what we know about what
(35:45):
cold does to our bodies once it kicks in, and
the ways that people have thought to maybe use this
to their advantage to treat various conditions.
Speaker 1 (35:55):
Harness one of nature's elements.
Speaker 2 (35:57):
Ooh good, that's a good one. Okay, So two big
body compartments to think about when we think about temperature management.
We have our core body, which is our brain and
our internal organs, and then we have all the rest
of it, or our peripheral body that's our skin, our
subcutaneous tissue, our fat, our limbs. It's not the important stuff,
(36:21):
right when you think about your body existing.
Speaker 1 (36:24):
Yeah, I mean, you can lose a pinky, but if
your heart freezes, you're done the devastation.
Speaker 2 (36:31):
Yeah, exactly, and so and our body knows this, and
our hypothalamis knows this, and so because our hypothalamis knows this,
our body regulates our temperature by regulating heat loss and
essentially kind of sacrificing the things that are less important
as well as finding ways to keep heat in the
(36:54):
core of our bodies. Okay, to keep our internal organs warm.
So one of the the first things that our body
does in order to keep our core warm is vaso
constriction of peripheral veins and arteries in our skin. And
what that does is it keeps our blood, which is
warm in our deeper circulation.
Speaker 1 (37:17):
This is going to.
Speaker 2 (37:18):
Reduce the amount of heat loss from all of our
surface area of our skin, right. It's also going to
reduce the temperature of our skin and our extremities, which
can lead to frostbite.
Speaker 1 (37:31):
Yes.
Speaker 2 (37:32):
Ah, So I quick detour before we talk about hypothermia
itself to talk about frostbite, which you can kind of
think of as like extreme localized hypothermia. So frostbite is
when you get tissue injury that's due really to freezing itself,
and so frostbite you do tend to have to be
(37:52):
in pretty cold conditions rather than the more mild conditions
where you could still get hypothermia but without frostbite.
Speaker 1 (38:00):
Like water versus snow, I mean, yes and no.
Speaker 2 (38:05):
Snow is like, if you're in a snowy environment, it's
very likely that the air temperature and the wind chill
and the snow itself is below freezing. So in some
cases you might be even more likely to get frost
bite in those scenarios. In water, you could still get
like freezing if the water was cold enough, But it's
(38:27):
very easy to get totally hypothermic in the water because
you lose heat so much more rapidly in water because
it's a really good conductor of heat just deals right
away from us.
Speaker 1 (38:36):
So like snow, you would get frost bite first and
then hypothermia.
Speaker 2 (38:41):
Potentially, yeah, potentially, whereas.
Speaker 1 (38:43):
Water you're gonna get hypothermia first.
Speaker 2 (38:46):
Yeah.
Speaker 1 (38:46):
Yeah, Yeah, that's a good way to think about it.
Love it.
Speaker 2 (38:49):
I was confused and thought you meant the opposite, but
that totally makes your sense there, So yes, and the
degree of damage really varies. Right, you have degrees of frostbite.
The first degree you might just have kind of redness
of the area. It might progress to kind of a white,
almost waxy skin or blister formation. And then of course
(39:12):
the most severe, which is considered grade four, is black
or necrotic tissue, where your entire tissue just dies.
Speaker 1 (39:20):
Yeah, and all of this is.
Speaker 2 (39:22):
Going to depend on how long you're exposed and to
what degree of temperature you're exposed to, right, And the
damage that you get is due to this vaso constriction itself. Right,
It's also due to the effects of that cold on
our blood because our blood. You mentioned this in the
like what people thought happened to your blood way back,
(39:43):
when they're not wrong. Our blood actually becomes thicker and
kind of sludgy when it gets that cold. And then
you can also get blood clots in some of your
small vessels, which might lead to more damage due to
lack of blood flow there. And because of the actually
freezing itself, the extracellular water freezes and that ice crystal
(40:05):
formation can cause direct tissue damage. Right, So it's very multifactorial.
And in terms of treatment for frostbite, the treatment is
to rewarm that area to try and increase blood flow
to that area, But as likely happened during Napoleon's army,
if there is a risk that things will refreeze, you
(40:28):
cannot start to rewarm because freezing and then warming and
then refreezing actually causes significantly more damage.
Speaker 1 (40:37):
So is there a point, like, because you talked about
the stages where there's red and then there's white, and
then there's black tissue, Yeah, like necrotic, I guess is
there a point at which the point of no return?
I'm guessing is when there's necrotic tissue, there is there nerve.
Can you regain nerve sensation when it's when the tissue
(41:00):
becomes like whitened or it depends? It totally depends.
Speaker 2 (41:04):
Yeah, so you can obviously, like if it progresses all
the way to the tissue completely dying, that's when you
might lose limbs, or lose fingers or lose the tips
of noses, right where even after rewarming, that tissue will
not come back to life. Prior to that though, even
if the tissue itself can be saved, there can absolutely
be permanent nerve damage and things like that. It just
(41:25):
it totally depends on the specific scenario. So that's frostpine done. Well,
let's keep talking about cold, Okay. All we've said so
far is that we start with vasoconstriction in our peripheral
tissues and in our blood vessels. Sometimes that's not enough
(41:46):
to maintain heat. So the next thing that our body
does is to increase the production of heat inside of
our bodies. Yeah, and there's two main ways that we
do that. One is shivering, so our skeletal muscle activity
involuntarily starts to shiver and you have these repeated contractions
and that increases metabolism, and so that increases heat production.
(42:11):
But the downside of that is that it utilizes a
lot of energy, right, Yeah, it's costly, it's costly. It's
a very costly thing to do, but it can generate
a lot of heat, so that can help to keep
our bodies warm in some scenarios. There's another mechanism that
we use, which is brown fat, brown outapost tissue. You
mentioned this, and brown fat is so fascinating to me
(42:33):
because it generates only heat. So metabolism in all of
the other tissues of our body just generates heat as
like a byproduct. It doesn't it doesn't mean to, but
it happens too. But brown fat doesn't generate any energy.
It only generates heat.
Speaker 1 (42:50):
It's like, that's the point. That's the point, and it
is the point.
Speaker 2 (42:53):
And newborns have quite a lot of it, they do,
and as adults we have significantly less m hm. And
so you have it, but just a little bit, so
we can't use it all that much. Yeah, but sometimes
we might be exposed to cold that continues, and our
shivering and our brown fat and all of this increase
in metabolism simply can't keep up. So what happens to
(43:18):
the body if we cannot keep up? The first thing
is that we see what's called a cold diarysis, which
basically means that because all of our blood has been
shunted into our core, it's flowing very quickly through our organs,
including our kidneys, and so our kidneys are furiously filtering
all of this blood and we start to see an
(43:40):
increase in urine production.
Speaker 1 (43:43):
I feel like I came across that somewhere, and I
don't know where if it was like, yeah, I read
the Shackleton's Expedition.
Speaker 2 (43:53):
Book for this one of my husband's favorite books.
Speaker 1 (43:55):
It's great. I mean it's like it's unbelievable. And the pictures,
the fact that there are pictures is wild, yeah to me.
But anyway, I don't remember if that's where somebody was
talking about peeing a lot, or if it was because
they're like freezing at night and no one wanted to
go outside until it was like who didn't want to
play the one or who didn't want to play the
game where it was like the last person who fills
the pot has to empty it, so you just hold it.
Speaker 2 (44:16):
Anyway, Well, yes, you do start to have a cold
diuresis this is not a good sign.
Speaker 1 (44:24):
It means that things are not going well.
Speaker 2 (44:26):
And on top of that, not only is it just
not a good sign, but what it means is that
you can end up getting dehydrated right because you're losing
all of this fluid through your urine. You could end
up with acid base disturbances, you can end up with
electrolyte issues, and eventually our body really cannot keep up
with all of this loss, and our core body temperature
(44:47):
will start to decrease. And as our core body temperature decreases,
our energy expenditure also starts to decrease, and pretty dramatically actually,
h I think for every one degree celsius decrease in
core body temperature, our energy expenditure decreases by like thirteen percent.
(45:09):
So there's no more shivering a lot of times. A
lot of times shivering will stop. Yeah, because things are
just sort of slowing down, and all of our cellular
functions start to slow down, and this eventually results in
our central nervous system slowing down so much that we
lose consciousness. Usually that doesn't happen until our central like
(45:29):
our core body temperature drops to around thirty degrees celsius.
Should have looked up what that is in fahrenheit, but
I didn't. It's cold, Yeah, it's cold. But what is
usually lethal is not the effects on our central nervous system,
but actually the effects on our heart. Because first you
can get those acid base like and electrolyte disturbances from
(45:50):
all of this diarysis that can affect the contractility of
your heart and it can lead to arrhythmias. Okay, And
as our heart beat is slowing down and all of
this metabolism is slowing down in our heart, the time
between beats can prolong, so we get what's called breta cardia.
Your heart beat is slowing down, and then the time
(46:12):
that it takes for the electric signals to actually be
conducted through the heart also gets affected, so you end
up with a rhythmias. There's a bunch of different types
that you can get, but most often it's ventricular fibrillation,
which is your heart just kind of quivering instead of contracting,
and then eventually it stops completely. And that is how
(46:35):
death usually happens with hypothermia.
Speaker 1 (46:39):
It's so it's I this makes me really look forward
to next week because I'm trying to figure out is
this Are there are clear costs costs, yes, and so
there must be enough of a benefit or is there
enough of benefit? But that's a question I guess.
Speaker 2 (46:55):
For next week.
Speaker 1 (46:56):
Next week, Yes, okay, I feel like I have some questions.
So what about are you going to talk about like
rewarming and how okay? Okay, so yeah, so you know,
I guess the rate at which hypothermia occurs is dependent
upon the individual, upon the environmental conditions, on clothing, upon
(47:16):
too much to even go into, right, So are their thresholds?
Are there established thresholds for like the risk or something?
Speaker 2 (47:27):
No I knew you were going to ask, and no,
it's it's what's really I think it's one of the
things that's very interesting about hypothermia. Right, there's not like
a textbook that's like, below this temperature you are at
risk of hypothermia because it depends, like you said, on
so many different things. We do know that extremes of
age are more susceptible to hypothermia. So newborn babies and
(47:49):
small babies and infants in general have a much greater
surface area to volume ratio, So even though they have
that great brown fat and everything, they just lose a
lot more heat, and so they're at higher risk of
core temperature drops and hypothermia people who are elderly, So
as you get older, you have less efficient, we think,
(48:10):
thermoregulatory mechanisms. We also often see changes in like body
mass composition during aging, and so that makes it so
that you're less able to regulate your temperature. If you
think about like your grandparents are cold all the time, right,
they're just not as able to maintain their heat.
Speaker 1 (48:27):
You mentioned being.
Speaker 2 (48:28):
Unhoused, right, not having access to the behavioral mechanisms that
we as humans rely on to maintain our temperature, like
adequate clothing and shelter, fires or other forms of heat
to keep us warm. And then also substance use like
alcohol and other central nervous system medications like opioids or
(48:49):
any any kind of thing that's affecting your central nervous
system and depressing your central nervous system function is going
to put you at higher risk of hypothermia hugely. So, Yeah,
but there's not like you can certainly see we see
hypothermia here in San Diego, even in the winter, and
it doesn't get very cold here, right, Yeah, In terms
(49:10):
of how we treat it, it really depends on how
severe it is, and then like the specifics of the
person and the scenario themselves. But across the board, it's rewarming, rights,
it is rewarming that person's body back to a normal temperature.
But whether that means just insulating them against any more
heat loss, like if they're just mildly hypothermic, or if
(49:33):
you need to actively rewarm somebody, and that might mean externally,
like putting them in warm water or using we have
in the hospital these things called bear huggers. Yeh, I'm
pretty sure that's a brand name, Okay, But it's like
these forced air it's like these blanket, paper, blankeant things
that you put over someone. We use them in surgery
a lot too, but also in hypothermia, and they just
(49:56):
force hot air, so then you're like insulated with this
blanket of hot air that's moving over you. They're quite cute,
uh huh. And then heated blankets. These are all like
external ways that you could warm a person's body if
they're mildly hypothermic. Okay, and then there's internal rewarming, which
is of course much more invasive, and there's obsceeded on
(50:20):
er I'm sure you have many times. There's a lot
of different ways that you can do it. You can
do it with just like heated ivy fluids, so like
just in you know, a peripheral line. You can do
it via body like U body cavity levage, so like
any of your body cavities. You can flush warm fluid
through those body cavities and then drain it out, I know.
(50:42):
And then you also could use essentially like an ECMO
machine that's extra extra corporeal rewarming machine that just takes
your blood from your body, runs it through a machine,
warms it up and oxygenates it, and then returns it
back to your.
Speaker 1 (50:56):
Body pretty darn cordn incredible. Yeah, and that's that is it? Arin. Okay,
So I have a question about something that you I
don't know, I don't think you mentioned it, but like
the your your ability to make decisions kind of gets
(51:20):
all funky too. So that's one of the things. There's
this what is it called where you disrobe, like you
start to take off your clothes.
Speaker 2 (51:27):
Yeah, paradoxical dysrobing, I think, or something they call it
what it is. Yeah, yeah, I mean I don't We
don't really have a great understanding of why and how
that happens, but it is something that you can see,
and we think that it's just due to Even though
you might not lose consciousness until your body gets quite cold,
like a core temperature of around thirty, the effects on
your brain and your central nervous system can be pretty substantial,
(51:50):
even at relatively mild hypothermia, which means that yeah, people
might not be like and we don't really know, like
no one's thankfully today doing human experiments to figure out
like what are you thinking about when your body is
getting to be that cold? And so we don't have
great data on like why do these types of things
(52:10):
but it can certainly complicate. I read a couple of
like forensic examiner type papers where they were, like, hypothermia
deaths if you're like investigating them as like a forensic
medical person, can be really complicated because sometimes it is
just hypothermia, but it can look like there's a lot
of foul play involved, or it can look like really
complicated scenarios and then it's ultimately determined that it's all
(52:33):
just due to hypothermia. But so it is. It's really fascinating. Yeah, okay, okay,
And what I think is also so fascinating about hypothermia
are the kinds of stories, like you told Aaron, of
people actually being able to recover. Yeah, especially when you
(52:53):
contrast it to heat stress, right, like hyperthermia, the way
that extreme heat induces damage to our proteins, to our
cell structures itself, that has a pretty poor prognosis if
your body temperature gets way too hot.
Speaker 1 (53:11):
Yeah, you're looking at like a degree of a few
degrees versus like tens of degrees that people have come
back from exactly.
Speaker 2 (53:18):
And it's in part because hypothermia overall is reducing our
cellular functioning and our energy demands, which means that we
need less oxygen and our cells can therefore survive in
absence of oxygen, and that is why people have thought
(53:42):
to use this in medicine as a therapeutic device. And
that is what we're going to talk about next week.
Speaker 1 (53:51):
Loved that Cliffhanger transition. Loved it. Thank You's great, Thank
you so much. It was great. I'm really looking forward
to that because I want to know. I feel like
I have made some assumptions about therapeutic hypothermia, so I'm
ready to have those corrected. I can't wait. I'm excited
if it need be.
Speaker 2 (54:09):
Yeah, maybe they're all correct.
Speaker 1 (54:10):
I don't know who. I don't know much, but I'll
know more next week. And if you want to know
more this week.
Speaker 2 (54:19):
Right now, so many sources, Okay.
Speaker 1 (54:22):
Let me pull mine up. So for both of these episodes,
I read a book that gave me a lot of
different ideas called Out Cold by Phil Jakol. It's a
chilling descent into the macabre, controversial, life saving history of
hypothermia book from twenty twenty one. And then if you
want to read more, I absolutely loved this review paper
(54:43):
about it's called Adaptations to Polar Life in Mammals and Birds.
I love it by Blicks from twenty sixteen. And it's
just like such a fun, fascinating, just like a paper
that talks a.
Speaker 2 (54:55):
Lot fun all the ways.
Speaker 1 (54:56):
I love it. Yes, then there's for more of the history,
especially the Napoleon stuff. There's a paper by Lankfort from
twenty sixteen titled Dull Brains and Frozen Feet, a historical
essay on cold And finally, I want to just put
a plug in for a short story by Jack London
called to Build a Fire and it's available. Just search it.
(55:18):
You can find a PDF. It's by the public domain.
And it is I mean, it's a story of hypothermia.
Is it is chilling and good and yeah, I clearly
should have thought of more better adjectives before telling people
to read it, but it is really it's it's I
think it does a really good job of kind of
(55:39):
taking you through how what hypothermia might feel like and
sort of the one fault like one false step, one
one miss misstep, one one bad move.
Speaker 2 (55:53):
Aaron, I don't have like really fun recommendation like that, Aaron.
I have you know a page called body temperature and
it's regulation by kot and Farmery from Antesesion Intensive Care Medicine.
I've Got Hypothermia by Turk in Forensic Science, Medicine Pathology.
That one was kind of interesting. Accidental Hypothermia from the
(56:14):
New England Journal Medicine nineteen ninety four. We got a
few other papers. Okay, there is an update from twenty
twenty two on the accidental hypothermia one.
Speaker 1 (56:22):
So listen.
Speaker 2 (56:22):
You can find all of the sources from this episode
and every single one that we've ever done on our
website this podcast willkin you dot com.
Speaker 1 (56:29):
You can. You can thank you to Bloodmobile for providing
the music for this episode and all of our episodes.
Speaker 2 (56:36):
Thank you to Leanna and Tom and Brent and Pete
and Jessica and Mike and everyone else. I think there's
more people. I'm probably forgetting to say thank you too,
but thank you also.
Speaker 1 (56:47):
Everyone at exactly right and every one of our listeners
are watchers. Anyone who participates in this podcast in some way,
we really appreciate it, and especially to our patrons, your
support means it means the world to us. It really
does so much. Thank you. Well, until next time, wash
your hands you kill the animals.
Speaker 2 (57:12):
M
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