Oh my god, Yeah, that's cold. Okay, this is this is
this is a podcast where I must let I swear, isn't it? Okay?
So this is welcome to another episode of Modern Outdoor Survival. My name
is Richard. And because I am in my very early forties and I spent
too long listening to Joe Rogan podcasts and stuff like that, I have a
homemade cold plunged tank in the bottom of the garden and this is this is
a two and a half thousand liter water stock drinking water tank thing, and
it's not well. I think this was once a hot tub made a's a
diy thing by our friend crab boat Stew and now it's it's it's this and
they use it for reducing inflammation and meant to be repair and cold water stuff
and things I'm not gonna try and remember now. But this is this is
not an episode about cold water immersion. This is an episode about wet cold
versus dry cold. And it's not actually that cold in here. According to
the little floating thermometer thing, this water is what as I say, that
says here, it says it's an eight degrees centigrade celsius whatever, which I
think is about forty six in freedom fahrenheit units, but it's not actually that
cold, and the air temperature is even warmer. That's about ten degrees or
I think it's about is that fifty? I don't know. I can't do
the maths. So this isn't even full immersion. This is just the bottom
half of me. This is full immersion. So the reason people use cold
water rather than just going into a cold area, well, it's cheaper and
easier to do at home. But water will suck the heat away from your
body much quicker than air. And if I do things like this to move
arms, then it will feel colder because if you sit perfectly still, you
build a little area of not warm but not as cold water right next to
your skin. But if you move your arms, if you move your body,
you are constantly moving into colder water around you, and it makes you
feel colder. And there's all sorts of things the body's meant to be doing.
Now, with regards to all sorts of things, this is not what
the podcast is about. The podcast is about the difference between between wet and
cold and dry and cold. So because it's going to sound well, let's
just face it's going to sound inappropriate if I keep talking like this throughout the
whole episode. I'm going to finish my cold water immersion thing here, and
then we're going to cut to us sat at the table in the garden once
I've got out of here and I've put some clothes on, so three two
one, So now I'm fully clothed again and I'm sat here with a coffee
in the field, sitting in the sun. It's a bird in the hedgerow
behind me, is you can possibly hear? This is a lovely spring day.
It's mid April here in the UK. It's been a late spring this
year. It's been really wet and windy winter, so it hasn't been that
cold. It's just been wet and there's we haven't had many days where there
hasn't been wind, and that's that's really a factor in what I'm about to
talk about with this episode. This episode is something that I've had on my
list for a while that i wanted to cover because it's an important topic and
it's something that requires a bit of a bit of subtlety and a bit of
subtlety in your understanding of it. It also partners really well with our next
episode. So our next episode is already recorded. That is a story told
by friends of ours about a trip that went wrong in the United States.
Nobody died, no long lasting injuries, but it is a really interesting story
and there are lots of learning points from that. So that's covered in the
next episode, but this one is a good partner to it. So I'm
going to be talking about dry cold versus wet cold, or another way of
saying that is the subtle factors that affect how you feel temperature and how temperature
affects you in the outdoors. Because as humans were quite good at regulating our
body temperature with it across a wide range of temperatures. We have indigenous humans
in the far Arctic, and we have indigenous humans on the equator and in
the hottest places on Earth. So people have managed to adapt to a wide
bread of temperatures. But those environments are not equal to each other in any
way. Different humidities, different weather patterns, different amounts of daylight, sunlights,
angle of the sun, all of these things come into it when we're
doing stuff in the outdoors. Wherever you are, when you're listening to this,
there are certain factors that will really affect how you feel cold, how
temperature affects you. One of them is moisture, whether that is humidity in
the air, moisture on your skin, how wet your clothing is, whether
you're lying on wet ground versus dryer ground. All of that comes down to
moisture and how that interacts with your body. The other aspect is a moving
element, whether it's wind moving across your body or your body moving through air,
or whether it's water moving across your body and moving water versus still water.
So I'm going to cover the moisture water aspect first, but before that,
I just want to quickly go through a refresher about what cold weather injuries
are or cold injuries. See, you tend to have two really that people
talk about and that are the most obvious. One is hypothermia. So hypothermia
is defined as a core temperature core being not your fingers, your not your
face, not your forehead temperature, but right there in the middle of your
torso a core temperature of below thirty five degrees celsius. Average normal temperature for
people for humans is about thirty seven degrees celsius. If that drops two degrees
then you have slipped into the start of mild hypothermia, and the three states
of medically defined hypothermia. There's mild hypothermia, which is anything below thirty five
to about thirty two degrees celsius. You have moderate, which is thirty two
down to twenty eight three cell, and then anything below twenty eight is the
core temperature is severe hypothermia, and that brings in all sorts of other risks
as well. So you may have heard these stories about people who've survived very
very cold temperatures and they've been rushed to hospital and they've appeared to be dead,
but upon medical intervention and other things, they have actually sort of come
back to life, or it seems like they've come back to life. You
may have heard a phrase that you're not dead until you're warm and dead.
If you've done any kind of outdoor first aid, any outdoor medical training,
you probably have come across that. And that's from that world. It's from
that phenomenon of if somebody is actually very very cold and the cold was the
thing that put them into that state, they might appear to be dead.
We won't know for sure until we've tried to rewarm them. So severe hypothermia
can look like death or can just lead to death, depending on the outcome.
So that's hypothermia. So a core temperature dropping below thirty five degrees of
celsius. There's a bee attacking me currently, so that might be on the
microphone. Nature is a guest on this podcast, Will you go away?
Thank you? Just feeling cold, feeling a bit chilly isn't hypothermia. Your
skin being cold to the touch isn't hypothermia. Just saying oh, I need
to rewarm is not hypothermia. Hypothermia is a medical designation, is a medical
limit of you have a core temperature of below thirty five degrees celsius, but
you can feel cold and uncomfortable before that point. The second type of cold
injury frostbite, frost nip, skin freezing, or skin starting to drop below
a temperature where it can self regulate. That is not hypothermia. That is
a separate injury. You can have a completely frozen hand. You can have
a hand that you've been dipped in liquid nitrogen or you've wrapped it in eye
so it's now completely frozen solid to the core, and still have a core
temperature in the center of your body above thirty five and you have not got
hypothermia. So these are two separate injuries hypothermia, core temperature dropping below thirty
five degrees, frost bite, frost nip, those kind of things that is,
think about skin freezing or starting to freeze. In this episode, we're
going to talk about hypothermia more. All the things we're going to talk about
will have an impact on frost nip, frost bite. And you do need
to be able to manage the temperature of your extremities through clothing, through the
way you're using it, through pre planning, through careful use of these things.
And the cold of the temperature is and the more wind and wet stuff
there is around, you really need to be aware of that. But separate
the mount as to being two different injuries hypothermia and freezing skin freezing or starting
to freeze. So when your skin is wet, it could lose heat at
a rate four times faster than if it were dry. How your skin gets
wet, how wet it is, the ambient temperature, what's happening with airflow
and stuff like that will all have an impact on that. But just know
that wet skin will lose heat more quickly the environment you're losing heat into matters.
So if you search for something called wet bulb temperature, this is something
you might see lots of articles coming up now about climate change and how the
wet bulb temperature is actually more important and the thing that we need to keep
an eye on more more than the actual dry temperature. So wet bulb there's
got nothing to do with light bulbs. It is imagine classic thermometer glass tube
thermometer that somebody has taken a wet piece of fabric and wrapped it around the
bottom of the thermometer that reads the temperature that expands and pushes the fluid up
or down. That is a wet bulb. So it is to do with
the humidity of the air, it is to do with the ambient temperature,
and it is to do with the dew point. So this is a thing
for meteorology and weather and those kind of observations. You're not going to be
sat there on the side of a mountain calculating this, but know that there
is actually scientific observation around humidity and air temperature and the point at which water
will start to form and dewe points and so on. So you don't have
to understand any of that, but know that yet to know that this being
wet versus dry is significant because and it will have an effect on the way
human observe and feel temperature around them. So if you were to stand out
somewhere in completely completely naked but with dry skin, in low temperatures, with
no air movement, you could stand there for longer and not feel the effects
of cold compared to being wet. If you had wet skin, if somebody
came along and soaked you with a hose, poured a bucket of water over
your head, you would feel the cold, but up to a four times
factor than if you were just completely dry in zero air. Those kind of
things don't tend to happen, though, I mean, unless you're in the
habit of diving under waterfalls, when you're out walking in the mountains, or
somebody follows you around with a watering can, you're probably not going to suddenly
get wet unless it rains, or you'll hit by spray of some kind from
something else, or you get sweaty. And when you start to think about
things in those terms, you think is actually quite a lot of the natural
environment that will make you wet, will put you in that state of having
wet skin versus dry skin. So you need to be aware first of all
of when your skin is starting to get wet. The thing that causes that
you can mitigate to a degree. You cannot stand under the waterfall, you
cannot go out when it's rainy. You can only go out on dry weather,
and you can make sure that you don't sweat. But I've been doing
this for quite a long time now, and if I didn't go out when
it was raining, then I'd never go out in the UK. That would
preclude any kind of water sports canoeing, paddling, stand up paddle boarding,
swimming, surfing, or any of the other stuff I like to do.
And my genetics just won't allow me to go out without sweating. Minus twenty
degrees celsius is about my happy temperature for not really sweating, and even then
for moving around and not sweat, not sweating anything more than that, if
I'm moving around, I'm generating sweat somewhere on my body. Of all those
things, the sweat is the thing that I really have to pay attention to.
So if I am somewhere where the air temperature around me is quite low.
I have to be really conscious of how sweaty I get, how much
sweat is building up in my base layer, in my mid layer, on
the area next to my skin that is difficult for me to get rid of.
I can moderate that to a degree by moving slower. But if I
if I'm moving so slowly I can't actually get anywhere, then I'm not really
doing the job I need to do in that place. If I'm walking from
somewhere to somewhere else, or I'm walking up hill, or I'm snowshoeing,
or the few times I've been skiing, or anything like that, where I
need to move, then I need to move at a certain rate in order
to make progress. And if you're carrying a rucksack, if you're walking uphill,
if you're doing something slightly harder, then you will be sweating more or
more likely too sweat. So I need to find a way to manage the
level of moisture on my body. It is harder in high humidity air,
so the amount of the moisture level in the air. It is harder in
high humidity for sweat to evaporate away. So if it is high humidity and
my body is sweaty and my base layer is sweaty, then it is going
to stay sweaty in lower humidity, really dry air. If I sweat,
that moisture is going to disappear quite quickly, so I won't stay wet for
very long. This is why, in the other end of the scale,
when you're talking about hyper thermia and being too hot, high humidity conditions and
high temperatures are more dangerous than high temperatures and low humidity because it is harder
to cool down. In humid conditions. You'll be sweating, but your body
will just create a warm air of water around you and you won't. It
won't disappear, and you won't and you'll just keep building up heat and building
up heat. Your sweat in colder conditions is not an advantage. It is
something that will make your life harder. It is more likely to send you
into a state of hypothermia because your body will then stay wet and you will
lose heat up to four times faster. So managing the moisture on your next
to your body is really important. I can't emphasize that enough. You can
just think, oh, well, I'm getting sweaty. It's a good workout,
or you know, look at this, or I'll just get sweaty.
But I don't mind being wet and sweaty. And I don't mind even if
your body is quite clean anyway, and you showered recently, then the sweat
probably won't smell. You might think, oh, yeah, I can deal
with it. But the moisture next to your body is the problem, no
matter how it was formed. Sweat is a thing that means you could form
moisture next to your body through exercise at a wide range of temperatures. At
lower temperatures, that is going to start to become an issue. So in
cold temperatures you make sure you don't build up a sweat, or even in
mild temperatures like we have now, if I was to stand around in the
shadow in the valley at the bottom of the mountain waiting for my mates to
get there, then i might be wearing my base layer. I'm a midlayer,
and then a jacket on top of that, and then I'm still wearing
that when I set off up the trail, up the track and start walking
uphill, and I'll quickly build up sweat and start building up heat and then
start to sweat and I will have to stop and then take those layers off
to get rid of that heat and stop me sweating. That's why when we
take people out into the mountains, and when we take clients out on trips
or we advise clients, we always advise a layering system. So then you
can have a layer that you just wear next to your skin that will absorb
some of that moisture and pull it away from your body a little bit.
But you can just wear that, or you can wear another layer on top
of that, or a layer on top of that, or a layer on
top of that, up to four layers. But those four layers means that
you mean that you can take off one layer, two layers, three layers
and still not be standing there topless or bottomless. If it's that half on
the side of a mountain, you can still have some degree of protection on
your body, but you will be able to regulate your temperature so you won't
sweat as much. The type of fabric those layers are made from is how
you'll handle the sweat that you do generate anyway, So if you're walking uphill
with a rucksack and you're starting to sweat, you strip down to just your
base layer. If possible, you start off taking off one layer, then
maybe a second layer. And for me most cases, I'm stripping right down
to my base layer, just to the layer against my skin. I will
still be sweating there, but because that base layer is made from a fabric
that isn't cotton, so it's a polyester or more likely these days, a
marino wall type fabric, it will pull the moisture away from my body and
then try and get rid of it quite quickly. It won't saturate and hold
on to a lot of it. It will only hold out so much and
then try and push it out away from my body. That will then evaporate
out into the air. It will move out to other places. But the
fabric type that I've chosen will hopefully mean that that sweat layer doesn't stay next
to my body for too long. We've got other episodes that really cover that
and layering and how to manage that body. You're sweat next to your body,
but wet clothing, wet layers next to your skin will mean you lose
heat more quickly. Do what you can to reduce that sweat from building up.
If you have got wet clothing. If you have got a completely saturated
wet base layer from walking up hill slightly humid weather, it's not actually that
cold, but it's cold enough, and you're working hard walking up hill with
a heavy rucksackle or your mountain biking in right in the bottom gear in granny
gear, grinding up the hill, trying to get up this trail, you
are probably going to build a level of sweat. Anyway, Your next thing
is that when you stop, you are now stood there in wet clothing and
your body is losing heat. If you stand there long enough and stay wet,
you will drop into hypothermia. Your core temperature will drop, your body
won't be able to regulate with that amount of moisture on your skin. You
will drop into hypothermia. Eventually, you'll probably get bored and move on before
or you reach that point. But if you have other factors like poor diet,
or you're not feeling particularly well that day, or other factors like wind
and air movement on you, which will talk about in a moment, you
will develop hypothermia more quickly when you stop with a wet bas layer with wet
clothing against your skin. So when you do stop. That's when you want
to stop. Get a layer out of your bag, put it on top,
just for the moment you're stopping there, because then you've still got a
wet layer against your skin, but you've added insulation on top of that to
reduce that heat loss a little bit. Not one hundred percent, and you
won't be able to do it one hundred percent, but you have reduced the
effects of that moisture against your skin. So when you're walking uphill with a
slightly sweaty base layer and you stop and you put a layer on to keep
warm, what you're doing there is you're mitigating the effects of the wet base
layer as much as anything else. That's why it doesn't really matter whether you're
putting a nice puffy down jacket on or just a waterproof hard sholler. One
will feel nicer than the other. But really what you're doing is stopping the
moisture, pulling the heat away from your body as quick as it can,
because it's only pulling it out as far as that next layer. If you
then had to stand in that place and stay there for as long as possible,
So say you for some reason you had to walk up this hill for
two hours and then stay in that spot for the next two days. You
would want to try and get dry as quick as you can and remove that
moisture from your body. And on the odd times, I've done that with
different jobs and different bits of work. Back years and years ago, when
we used to do mountain safety cover for big races and things like that,
and we used to or either employ people to do that or do it myself.
You'd be stationed out on the side of a mountain for six hours watching
runners come passed, or mountain bikers or whatever the race was. I would
take a separate basse layer for that, and I'd walk up hill quickly with
a lot of gear, and then stop and then change the bass layer out
to a nice dry one because i can walk down in the dry one.
But I've now taken away that moisture from my body. I've dried my skin
up by putting a dry bass layer on, and I can stand there for
a longer and be happier with dry skin rather than wet skin. I'm not
saying that you just carry fifteen bass layers with you for every mountain trip,
but you do consider the effects of that moisture on your skin. Monitor how
quickly your base layer is drying. If it's getting sweaty, how quickly is
it drying up. If you stay wet for longer, you will cool down
more quickly. And this is where the problem with hypothermia comes in, because
you can get cold and get to a stage of hypothermia or mild hypothermia without
realizing it. You can look at your body and go, well, I'm
still sweating. I can't be cold. But actually you're entering the early stages
of hypothermia, and you've started to lose some cognitive ability, some strength,
some flexibility, some ability to control your limbs. You've lost some dexterity in
your fingers, you've lost the ability to carefully place your foot on the edge
of a rock and something like that. I've seen that before with clients in
the mountains, where they've started to enter the early stages of hypothermia, but
they haven't noticed because they still feel a little bit too hot because they're really
sweaty. So's at these subtle edges that's where the difference comes in. So
be aware of the moisture on your body from sweat. The next thing is
rain and stuff like that. That's why we always say you should carry some
way of keeping your body dry. Hard shell waterproof layers I think generally are
better, or some kind of waterproof system like paramo or something that pulls moisture
away from your body and stop and if it's working properly, doesn't let rain
through. Your aim is to try and keep your body as dry as possible.
And that's the main takeaway from this part of it is keep your body
as dry as possible. If it does get wet, pay attention to how
wet it's got, how quickly it's drying out, and what it's doing to
you in that environment, and know that when your body is wet, it
is losing heat more quickly than if it was dry. There are little micro
factors to this as well, like if you're sat on wet ground, if
you're sat on a wet rock, you're going to be losing heat more quickly
than if you're sat on a dry rock. If you're touching wet surfaces,
you're going to lose heat more quickly than if you're touching dry surfaces. All
of these things will make a difference. So try and keep your body dry
and try and manage that moisture. If you can't manage a moisture, if
you're doing something like swimming, if you're doing something like water sports where you're
going to be getting wet, you need to be aware of that risk there
and manage it differently. So if you're swimming, and in the notes are
going to link out to the Outdoor Swimming Society, they've got some great notes
on cold water swimming and the effects of your body of cold water and some
real myth busting and stuff like that. Your body's reaction to cold water is
something you really need to pay attention to, and it's something you can acclimatize
to. And that's the part of what I'm doing with a cold water tank.
And there's some other benefits to it as well. But you can acclimatize
to it, but it's not something that you can just jump into. Cold
water needs management. The temperature doesn't have to be that low for it to
be classified as cold water. Five degrees celsius, So what's up forty one
two degrees fahrenheit. That's a cold day, but it is if it was
the air temperature. But it's something that you can deal with quite happily.
Five degrees water temperature in a river or a lake or something like that,
that is going to give you ten to twenty minutes, depending on your body
before you start to really lose coordination, lose strength, lose literally power in
your muscles, you can't move as much, you lose dexterity. You will
get to the point after about ten to fifteen minutes in five degree water one
forty two fahrenheit degree water that you can't pull yourself out of it. You
can't pull yourself back onto a dock or onto a boat. You can extend
your body's ability to deal with those lower tens through training, and there are
all sorts of training programs for it. Some people are just naturally better at
it than others. The difference between a slightly cool day on the shore and
you're in a survival situation the moment you enter the water, it can be
the same temperature. So if you're doing stuff around water, be prepared to
manage that risk of the water. So if you're swimming, if you're getting
in the water, if you're in a wet suit or something like that,
that's going to add some insulation or a dry suit even or an immersion suit.
That's really going to add some insulation, but it's going to bring its
own factors loss of mobility, loss of flexibility, extra weight, extra bulk,
whatever. But if you're getting in the water, you manage it through
training. You manage it through awareness of that temperature, and through just how
long you're spending in there and what you're going to do when you get back
on shore to rewarm. Be aware of being in that water, be aware
of your management strategies for it. The really dangerous areas I think are when
you're near the water, where you might go into the water. And this
does and this is relevant to the next episode, if you might end up
in the water, you should have a strategy for getting into that water.
You might think, well, it's not frozen, it's fresh water, it's
not frozen, so it's got to be above freezing, and I can deal
with temperatures above freezing. No. I mean, like, I was in
that cold water tank there for a few minutes or eight degrees and it was
starting to get unpleasant. And I noticed because I actually had to spend longer
in there while we sorted out some stuff for the recording of the podcast.
So I spent sight long longer in there than I normally would have done.
I lost some of the flexibility in my legs, in my feet, my
toes, so I was stumbling slightly as we got out in temperatures that would
I was happily working in in a T shirt yesterday when it was the air
temperature on land. So if you're working near water, either on a shore
or on rocks above it or something like that, or more likely in a
boat, in a vessel of some type, be prepared to enter that water
and what you're going to do afterwards, because if you enter the water and
the water temperature is even anything below twenty degrees eighteen degrees, it could quickly
and send you into a situation where hypothermia is not just a real risk,
it is happening to you. Your core temperature can drop very very quickly.
You can lose dexterity in your fingers, you can lose the ability to think,
you can lose or at least to problem solve. You can lose strengthen
your muscles. There's all sorts of things. We are breathing. We've got
the mammalian dive reflex, and you know we can go into that, but
just think that if you enter that cold water and it does not have to
be that cold, you are then in a survival situation. If you enter
it unexpectedly, you're happily going along doing a thing, and now you're in
the water, then in many ways that's worse because you haven't even got the
ability to mentally prepare for it. But if you're going somewhere where the water
is going to be cold or cool and there is a reasonable chance you could
end up in there, you should have a management strategy for that before you
get there. So that strategy could be clothing, it could be spare clothing,
it could be what is attached to your person. There are all sorts
of things around canoe journeys, and we're going to talk about this in the
next episode and given away a little bit what that's about, but how you
plan for that, but be prepared to enter that cold water and for you
then to be in a survival situation where you need to sort yourself out afterwards.
And if you're on your own, you're going to be already in a
position where it's harder to sort yourself out, harder to fix that situation because
you are cold. So generally for if somebody has entered cold water and they've
become wet, and they have entered cold moving water, particularly, then you
get them out onto the shore. You don't then keep them in their wet
clothing and add stuff on top. You get them out of the wet clothing
and get them dry as soon as possible. If you're staying there in the
wet clothing, you are going to still be losing heat, and you can
be pulling heat away from your body and crucially away from your core, and
send you into that state of hypothermia quicker if you are wet. So get
them out of the water, get them out of the wind, and we'll
talk about that. I keep teasing this, but we'll talk about that shortly.
But get them out of the wet clothing and into dry clothing quickly.
The moisture is the real factor here that you need to be aware of.
It's not just temperature. It's not okay, we'll make them warm and wet
rather than cold and wet. Okay, how about you make them warm and
dry. I keep emphasizing this. The rate at which the moisture pulls the
heat away from your body so much higher than dry clothing. Dry dry surfaces,
So manage that moisture, manage that water, manage that wetness as much
as the temperature. If you've only got one set of clothing with you and
that's all wet now, then you have a problem. The whole point of
this podcast when we first started it a few years ago, was to counter
some of the stupid stuff we see online, some of the stupid stuff you
hear from other places, some of the stuff that's more about reinforcing a tough
man image or some other weird skewed thing about making things as uncomfortable for yourself
as possible, and instead push it back to what we know that works,
which is making good decisions and doing good planning, make choosing good equipment,
doing the right things at the right time, and some of those things you
had to have done weeks ago. And you can't just wait for a bad
situation to happen and then pull out your magical piece of equipment that's going to
fix it all. If you entered that water without any way of getting warm
and dry soon after, it doesn't matter that you've got yourself out of the
river or out of the lake and drag yourself onto the shore you're lying there
on a wet beach, in wet clothing, still losing heat, be losing
heat, maybe a little bit less quickly than you were when you were in
the water, but you're still losing heat. Getting dry is really crucial here,
and that leads us on to the second part, which is a bit
I keep teasing wind. Any kind of moving air is going to be pulling
the little bit of heat that you've lost away from your body through the sweat,
which will make it pull away more quickly. But even in dry air,
on dry skin, rather, it will pull that heat away from your
body much more quickly. Because imagine you're standing there. You're standing there naked
in cool air, and your body is losing heat. It's losing heat from
what the surface you're touching, it's losing heat from the breath coming out of
your mouth, it's losing heat through radiation. But it is losing heat just
by warming up the area of air around your body. So think about little
invisible suit you're wearing of heat being pulled out, warming up a little zone
of air and next to your body. If you then were to grab that
little zone of heat and pull it away from you, lost that heat and
you can't get it back. That's what wind does. It pulls this little
zone of warmth you have around you and pushes it off over there where it's
of no use to you. So it's like being sucked away from you like
smoke. Insulating clothing helps reduce this by keeping the little warm area of heat
next to your body under that clothing, under that insulation. But if you
take it off, the air can then pull it away, or even on
a day without wind, if you're moving through it, you're leaving that heat
behind. So if you're mountain biking, or you're cycling or on a motorbike
or whatever, you're leaving even on a day without wind, you're leaving the
heat behind you. And you've probably experienced this when you go downhill and you
go down, you go or you go faster, you feel cooler because I
think there was a nice breeze now moving. No, what's happening is all
of the heat that you're losing from your body. As soon as it leaves
your body, it's gone. It's off there behind you somewhere. You're leaving
little zone of heat behind you. Slightly weird thing to think about, but
is kind it's an important concept to get that. If there's movement of air
around your body, whether it's through wind or whether you're creating it. Because
you're moving through still air, you're leaving the heat behind or the heat's being
pulled away from you. So even though you might you might be losing heat
at a set rate because you've got dry skin or wet skin or all that
stuff we've talked about, the fact that the air is pulling it away means
that that will be happening more quickly. So you may have heard the term
wind chill, and there are all sorts of wind chill calculators you can find
online, and I think we'll link out to a couple, but they're all
a bit weird because it still doesn't adequately reflect the temperature you'll feel in that
environment. So one windshield calculator we use says that if the ambient temperature or
the air temperature around you is minus eighteen celsius and the zero wind, that's
about thirty minutes in that temperature before you start to really develop any kind of
cold weather injury and for an average person, and really start to feel that
the effects of that cold in a meaningful way. But if you add a
fifteen mile an hour wind to that minus eighteen temperature, or it's about twenty
four kilometers an hour, it's going to feel like you were stood in minus
twenty eight celsius. Still there. That's all in dry conditions. If you
were wet in either of those conditions, so wet skin, minus eighteen celsius,
no air movement, you're in a bad state. You're not going to
be lasting very long at all. If there was a fifteen mile an hour
wind and it's minus eighteen and you're wet, I don't fancy your chances.
You've got to sort this situation out pretty quickly or you're going to die.
So all of that stuff I said about wet clothing being wet, wet through
sweat, wet through rain, wet through immersion into water, If you factor
in air movement on top of that, it starts to become a real issue.
And that's why it's still an issue even though we're not in the depths
of winter now and here in the UK we didn't really have the depths of
the winter. Barely went blow freezing, but it was wet most days,
and it was windy most days, and I've had quite a few days this
winter where I've been working out in the fields, working in the woodlands,
doing the other work we do, where I felt I'm on the edge of
mild hypothermia here because I'm wet and the wind is pulling the heat away from
me. So I've had to choose my clothing to reflect that, and I've
been having to balance out. Okay, i need a windproof layer of some
kind to stop that heat being pulled away from me by the wind. But
if I'm working in a windproof layer, I'm going to get sweaty, so
I'll have wet clothing. So I've had to bring two or three different layers
out with me on different days to achieve different things. Managing body temperature in
wet conditions and in windy conditions, I think is much much harder than managing
body temperature in sub zero Arctic dry conditions. Scottish winter. Scottish wet winter
is a harder environmental I've found to deal with than high Himalayan mounting cold dry
air, because that moisture is a real factor, the wind is a real
factor, and together that is a hyperthermia factory. And I worry more about
hyperthermia. Don't do about frostbite, frost nip, those kind of things,
because the hypothermia creeps up upon you on days when you don't even think about
it because you're wet and it's slightly windy. So the wind is an easy
one to talk about. And the faster the wind, the more quickly it's
going to pull the heat away from you, and the more the colder you
will feel. Water is another factor with this. You've got the water on
your skin pulling the heat away four times faster. But and if you do
cold the cold plunge thing, or you used to go swimming in cold water,
you'll know what this feels like. If you stay completely still in still
water in cold water, you can eventually feel like you're starting to acclimatize to
it, because what you're doing is building up a little bubble of warm urh
not warm warmer water right next to your skin. You're still losing heat into
that zone, and you will develop hyperthermia eventually. If you stand there but
you've got this little warm area right next to your skin and it doesn't feel
quite as bad, and then swirl your arms around and move around, you
will immediately feel much much colder, because what you're doing is the equivalent of
that wind pulling the heat away from your body. You're moving into colder water
all the time, and your body hasn't got a chance to heat up a
little layer next to it. It's just moving it around all the time.
So that's why moving water will always feel colder than completely still water, or
if you're moving through the water. So if you stand, if you float
completely still, it's submerged in water, the water doesn't move, you don't
move, you will feel warmer than if you start swimming through it. You
might build up some heat inside and your core through the exercise of swimming,
and that will have its own effect, But immediately you will feel colder because
you've started moving through the water, or if the water starts moving around,
or if you're in a river, that heat is being pulled away from you
straight away. So the movement of that little warm zone next to your body
from either wind or water in the outdoors is going to be another factor.
So these are the two things. If your body gets wet, it will
lose heat much more quickly if your body is an environment where the heat is
being pulled away from you. But by either airflow or water flow, you
will lose heat a lot more quickly. If you are wet and an environment
where there is airflow around you, you are going to lose heat very quickly.
If you are in cold water and it is moving or you're moving through
it, you will lose heat very quickly. So you've got to be aware
of those two things, moisture movement, and that's why it's taken a whole
episode to go through this, and it's a really subtle thing to get your
head around because how you deal with it, how you manage it, is
going to be very dependent on what you're doing, what the temperature is,
what you're going to be doing next, what equipment you have with you,
how you're using that equipment. Way more than we can go into with this,
this is part of good outdoor skills, which you've got to go out
and make mistakes and make soft mistakes, makes lots of little mistakes and get
cold and uncomfortable in a way that you can recover from and that where you
can do safely and learn what happens. We could talk about, as I've
talked about a lot in this episode, walking up hill with a rucksack,
but I could do a whole episode on managing your body for moisture and air
temperature and moving air when mountain biking versus road cycling. Do another one for
swimming, do another one for canoeing. All of these things, all of
these activities in these different environments. You've got to manage yourself else. But
take that away colder temperatures hypothermia. Think about the moisture on your body and
how that is held there, and what's happening with that moisture, how it
got there, what you're doing to keep it out, what you're doing to
get rid of it, what you're doing to prevent it happening again, what
you're doing to stop the effects of that moisture by changing into other layers.
And then the movement of things around your body, air or water, those
two factors. If you can manage those and think about those, that is
going to be your best chance at preventing hypothermia. But remember, hypothermia is
different to frostbite, it's different to frost nip. It is a completely separate
designation hypothermia. Drop core temperature drops blow thirty five and then you have mild,
moderate, and severe. That is the takeaway. It's moisture management,
wet management, water management, whatever you want to call it, and movement
management. What's that window to you? How much in the wind are you?
What are you doing to reduce the effects of it? How prepared are
you for it? Or moving water versus still water. I don't think I
can break it down any more than that without giving hyper specific examples. So
now we're going to move on to talking about things in the after show.
So thank you for listening, and keep an ear out for that next episode
because it really ties into this one and it comes up with some really practical
examples of what happens when this doesn't go quite as well as you hoped.
Thank you for listening to this episode of Modern Outdoor Survival from Original Outdoors.
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three principles of Modern outdoor Survival and they are Number one, make good decisions
at the right times. Number two, prioritize training over shiny new equipment.
Number three remember Instagram is not your training provider. Five