Dr Heather Massey on the joys, dangers, and discoveries of cold water swimming

Dr Heather Massey is an open water swimmer, a scientist, and a senior lecturer at the University of Portsmouth in the UK. As part of her job she researches the physiological effects of cold water, as well as the risks and potential benefits of cold water swimming. 

What happens to our body when we get into cold water? What’s the 'cold shock response' and what is 'afterdrop'? Who benefits from cold water, how, and why? How do people survive ‘ice swimming’, including in Antarctica? But most importantly, how can people get into cold water and return home safely? 

Heather’s advice includes:

• Have a plan for where you’re getting in and out of the water
• Don’t swim/dip/plunge alone
• ‘Claw hands’ (stiffness) or loss of coordination are signs that you need to get out asap
• Warm up quickly with snug clothes and a jacket, a hot drink, and wait a bit before you head home. Cold temperatures can cause a lack of coordination and concentration that may affect biking or driving.

Learn more about Heather’s research (and the Extreme Environments Laboratory) on the University of Portsmouth website

'Wild swimming scientist Heather Massey: "Hypothermia is not a pretty sight"'. Guardian article, June 2021

The Outdoor Swimming Society website

Water Safety NZ – 'Staying safe'

Photo of Heather by Terry Scott

Episode Transcript

(00:09):
Kyodo and Welcome to Swim Chats,a podcast about ocean swimming.
I'm Shona Riddell, a writer, former journalist and swimmer
from Wellington, Altero and New Zealand.
For each episode, I talk to a different guest from our swim
community. Remember, if you have any
questions, thoughts or suggestions, you can e-mail me
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(00:32):
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think would enjoy it, please tell them about Swim Chats.
Thanks for listening. Enjoy the water.
And here's today's episode with cold water researcher Doctor

(00:53):
Heather Massey. So Heather, first of all,
welcome to the Swim Chats podcast.
It's a real pleasure to to meet you and get to speak to you
today. Oh.
Thanks very much. Thanks for the invite.
So I'll just explain for you andfor listeners.

(01:13):
I first came across your research a few years ago when I
was doing my Master's degree, which was in science
communication. And I was doing a lot of writing
about the sea and learning aboutthe sea.
And it was also the time that I started getting in to the water
and learning how to swim properly and swimming past

(01:34):
summer, which is a, you know, felt like a big deal at the
time. And of course, I noticed things
that were happening to my body at the time, like what it feels
like to get into water that's a bit colder, and also what it
feels like to get out of water that's a bit colder.
And you're sort of learning all these things as you go.
And so reading your research papers, which I'll link to in

(01:56):
the show nights, really sort of helped me understand.
And they're written in a really accessible way, like not all
academic papers are. But yeah, I just, and you've, I
know you've become sort of a media spokesperson for the the
effects of cold water on the body.
Sorry, that's a really long monologue for me.

(02:18):
But yeah, it's just a real pleasure to get to talk to you.
I was just saying before we started recording, I've written
a lot of questions, so I'll try and prioritize them.
But I'll, I'll just explain. You're in the UK and it's
currently some of there. It's the middle of winter here
when we're recording this. So in the sea in in Wellington,

(02:39):
it's about 12, between 11 and 12°C.
We'll probably get a bit colder before the winter's out.
Just curious to know what's the temperature of the water where
you are right now? OK, so where we are, we're on
the South Coast of the UK in Portsmouth and the water
temperature varies depending on where you are.

(03:01):
So it can be between about 15 and about 20° depending on where
you are. Inland waters will be much
warmer, so some of the lakes that are are close by are up to
2223°C. So yes, it varies greatly.
And we've also just had some pretty intense flash storms and

(03:26):
that takes the water temperaturedown quite dramatically.
So you can take it down by two or three degrees just overnight.
Wow yeah, that's a lot and that can catch people out counter a
little bit, but we'll talk. Oh absolutely yeah, yeah.
So before we we talk about your research, let's talk about you
as a swimmer because I know you're an open water swimmer.

(03:47):
I was doing a bit of Googling. You competed in the World I
Swimming Championships, Is that that the right name in Germany
in 2017 and. Yeah, that's correct.
Yeah, Yeah. Amazing.
Yeah, that seems like a lifetimeago, but yeah, it nearly was.

(04:08):
Yeah. It's a very, very interesting
experience. I, I just crazy that I've done a
lot of outdoor swimming. I've I've swim all my life and
I've been lucky to be in locations where I could do that
and have access to water which was fairly safe to swim in.

(04:28):
And so I've got many years of adaptation and training before I
decided to go anywhere near colder winter temperature
waters. And yeah, it's actually, it was
a quite a well set up event. We had to fill in all medical
forms before we went. We had a medical the night
before we we were due to swim and then an acclimatization swim

(04:52):
just to check that we were OK with the the temperatures.
And it was a very interesting experience.
I did, I did compete. I did OK.
I'm never going to be the fastest swimmer of a value for
money swimmer, definitely. But I have noticed that I've got
and I still have a numb finger from, from from turning on the

(05:18):
the walls. So it's a it was a 25 meter pool
in effect that we swam in that was kept ice free by lots of
pumps overnight so that the water didn't freeze.
But the water was, I think it was nought .4 to 1°C.
So it's really quite bitterly cold and the air temperature -14

(05:39):
Oh my God. So yeah, absolutely.
So I still to this day, when it's chilly and when it's cold,
I still end up with a numb finger from from that
experience. So it's left a mark.
But it was a very interesting and experience if if people want
to do that, I did the 1K event. There's obviously shorter events

(06:00):
that people could try and but I just, yeah, caution that it's
something that you would build up to do and it's not something
you just decide to do straight away.
That is a really good point, yeah.
And especially because we're talking about cold water and the
the risks and the benefits. Absolutely, yeah.
And a couple of years after thatyou swam the English Channel,

(06:21):
which is also phenomenal. Congratulations.
That was about 33 kilometers. Is that correct?
Yeah. That's about, that's about
right. Yeah.
Well, I was slightly longer thanthat because of the tide.
It's very tidal, as you can imagine.
So because I took longer, I was sweat more with the tide.
But 33 kilometers, 33 kilometersas the crow flies.

(06:44):
Again, a very interesting swim. And yeah, lots of training, lots
of sacrifice, but it's somethingthat.
Yeah, You don't enjoy doing it because there's very little to
see or watch. But strangely enough, I remember
very little about it. I was so in the zone that you

(07:05):
get into that sort of mind mind state where you you just keep
going, you've got this. I was quite driven to achieve
this and I had sufficient support to to do it.
So yeah, I was. It's really interesting.
Wow, That's incredible. I have heard that from other
marathon swimmers that you can go into a sort of trance or

(07:28):
state while you're swimming. Couple of episodes ago, we spoke
to Philip Rush, who lives here in Wellington.
Yeah. And so he.
Yeah, he's the record holder forthe triple crossing.
Yeah. And he's talking to us about
that. Yeah.
I mean, that was overnight as well.
Yes, it my, most of my was overnight, but yeah, you, you,

(07:51):
you can start to get into sort of a very closed trance like and
there have been, there have beencases of where people of, of
swimmers of swimming to unconsciousness as well.
So it's something that that you do need adequate support for.
It's not something you could just go and do.
People have tried to do that, but you do need the right

(08:12):
pilots, the right support crew, the right training to be able to
do it. So to guard again against these
things, swimmers going doing these very long swims do need to
be looked after. They may think that they know
what they're doing, but they do need looking after.
Yeah, I think everybody needs a bit of looking after in the
water. So you're you research cold

(08:33):
water swimming. Did you become a researcher
because you had questions as a swimmer that you couldn't find
the answers to? Is that how your research
started? Yeah.
I suppose so. I've.
Yeah, as I said, I've been luckyto be an outdoor swimmer most of
my life. But although I've not really
called it that, I've just been, you know, just swim outdoors.

(08:54):
And I was. But yeah, sort of, I've managed
to mold a career around something that's quite a hobby
and sort of developed from there.
And yet I couldn't find the answers.
And so I thought, well, you know, let's go and speak to the
people that, that immerse peoplesafely and, and have have worked
very been been very lucky to work with Mike Tipton and at the

(09:17):
University of Portsmouth here inthe UK for a number of years
around water safety. And so that's where we come from
to start with is a, a position of if we can do something safe
and then what are the potential benefits of that?
And we, we know quite a lot about the, the harms that can
take place and that the, the unfortunate, the preventable

(09:39):
deaths that occur every year both here in New Zealand and in
the UK. But we know, we know a lot of
people have suggested that there's, they, they can have
benefit from taking part in outdoor swimming.
And so that's the next big thingis what, why, why are these
people experiencing benefit? And there's no science behind

(10:00):
that as such. There's lots of theory and lots
of and lots of people making claims that they have
experienced some positive benefit.
And it's not to belittle their claims, it's just the science
has not caught up with it. And so that's where I'm kind of
at is with this, where there's avacuum of no scientific

(10:20):
evidence. We get lots of people coming in
making wild claims. And So what we need to do now is
fill that vacuum with good rigorous science to stop the
wild claims being made. I, I, we, we regularly
experience and, and have contactfrom people that have, you know,

(10:42):
clearly experienced some beneficial effect from their
cold water swimming. What we need to do now is find
out why they experience that effect and who it helps, because
we do know that for some people,going into cold water would not
be something that's helpful at all.
And if we know why it helps, then there may be other things

(11:04):
that we can do that aren't cold water emotion, but use the same
magic ingredients for want of a better very non scientific
phrase. But use those mechanisms, magic
ingredients, and find activitiesthat people can do that that
would support their health as well.
What you're saying leads very nicely into my next question.

(11:25):
So one was about people who can't experience cold water
immersion or, you know, getting into a lake or the ocean.
Is a, is a cold shower beneficial?
Because I personally find them very uncomfortable.
But I I love getting into the sea.
It's for me, it's quite a different experience.
It definitely is a different experience and you're right,

(11:49):
natural locations aren't accessible to everybody and some
people do swear by having a coldshower.
Again, I I agree it's not for me, but that's possibly because
we're both very lucky to have outdoor spaces that are safe to
swim in regularly. It won't be.
In terms of the cold shock response, let's take it back to

(12:11):
the initial immersion in cold water.
So the cold shock response is that response where you take a
big inspiratory gasp and then breathe very quickly afterwards,
your heart rate increases and you'll get the superficial veins
of the superficial blood vesselsof the body will sort of
constrict. And so the blood flow is

(12:32):
restricted to the centre of the body.
That all happens very quickly assoon as you get into the cold
water, if you're getting into a body of cold water.
So just doing like maybe a head out dip in cold water, that
response is maximized at at water temperatures of 10 to
15°C. Now, if you have a cold shower

(12:53):
that's at fairly similar temperature, you won't have the
same level of increase in heart rate or increase in that
breathing response purely because the surface area of
which is immersed in the cold water is less.
So it's all about this surface area that's immersed, that's
important there. And so if you have a smaller

(13:14):
surface area exposed, your cold shock response will be smaller.
So I'm surmising and, and lots of this is going to be
supposition because we don't have the knowledge yet.
But what we do know is that those individuals that that see
or, or have reported benefit have been those that have dipped

(13:34):
or showered for short durations.Those that spend extended time
in the water and get very cold tend not to have that same
beneficial effect. And So what we're surmising is
that if you're having a short cold shower, then that may have
some beneficial effect. It might not be the same as if
you were able to get into cold water fully.

(13:58):
But again, this is still work that needs to be done properly.
Yeah, that makes sense. Thank you.
And is there a sort of a hard and fast definition for what is
cold water? Is that water that's below 15°C?
Or is or is cold water more of asubjective term?
It's definitely out for debate. So what we term thermal neutral

(14:21):
water is about 35°. So that's where you'd get into
water and you'd neither lose norgain heat.
You see, your body temperature would stay the same.
Now we maximize the cold shock response at 10 to 15°C.
Now lots of people say, oh, well, cold water therefore is
15. But actually we still get a cold

(14:42):
shock response at much higher water temperatures than that.
So we we don't say what temperature is cold, but we know
that people can experience a cold shock response in swimming
pool water. So that could be a heated
swimming pool. So that could be 20, seven,
2829°C. And in fact, we've got evidence

(15:04):
of that from our labs showing people do have a cold shock
response in that sort of temperature water.
Not everybody, but some people do.
So we don't have a strict definition of cold, although 15
is definitely cold. And we do know that
physiological responses occur athigher temperatures than 15°.

(15:24):
So I just acknowledge that 15 isis definitely cold, but we do
know that warmer, warmer water temperatures are also cold too.
Right. That makes sense.
And if I get into water, no matter what temperature it is,
but if I start saying that I'm cold or worrying that I'm cold,
does my body physically become colder?

(15:45):
Do you have you measured that interms of the just the, I guess
the I'm trying to think of the word, you know, the, the sort of
mental reaction we can have as well as physical.
That's a really interesting point.
I've, I've never really thought about that to be honest, but it

(16:05):
is interesting. And the only thing I can sort of
relate that to is when I've beendoing a number of, and this is
personal experience as opposed to science.
When I've been doing a number oftraining swings where maybe I've
got bored or I've not been able to stay in the zone and you
start to stop more frequently. And in stopping, what you do is

(16:27):
you aren't generating the same level of heat.
And so you do get colder. I can imagine that if you're in
that same mindset where you think, oh, I'm cold, you might
end up stopping more if you are doing the longer spin, for
instance. And so you will start to cool
more quickly because of that that process.
So that's the that's the only sort of thing I can think of.

(16:49):
But it's a very interesting question.
And we do think of it from a scientific point of view.
We do know that psychology does influence your experience or,
or, or the cold shock response itself.
So we've done a number of experiments where we've sort of
manipulated the sort of psychological variables.

(17:11):
So we've we've given some of oursports science, our PE students
some maths questions and then immerse them in cold water.
And we know that obviously mathsquestions for a sports science
or PE student is going to be quite anxiety inducing.
Or you can actually extend the cold shock response by by being

(17:32):
in a more anxious state. Equally, we know if we give
people psychological skills training about and explain what
the cold shock response is and the fact that if they're well
fit and healthy, it would just be an increase in heart rate and
breathing and they'll be fine thereafter, we can see that
there's a reduction in their cold shock response.

(17:54):
So it's definitely a psychological element to the
physiological experience of being in the cult.
Yeah, right. And just a more general question
that I was thinking because, youknow, you mentioned there's a,
there are sort of gaps and a need for rigorous science, you
know, to establish, you know, what's going on with our bodies

(18:14):
and, and the cold water. And I was thinking, you know,
people have been getting into the cold water for centuries,
but it feels like scientific research around it is a
relatively new thing. Is that correct?
The, the science at the moment is, is mainly around the area
of, of hazard and keeping peoplesafe.

(18:37):
And rightly that should be a good starting point.
But you're right. I mean, here in the UK, Dickens
was extolling the virtues of, ofcold therapies and cold water.
We've had, you know, a long history of, of outdoor bathing.
And then all of a sudden we wentinto swimming pools and they
were the end thing and everyone disappeared from going into

(18:58):
natural waterways. But you're right, it is an
understudied area. Possibly finance is the the
issue. And especially if it's something
around lifestyle around rather than any health benefits, it
tends to be less prioritized in terms of research.

(19:20):
So that there's a number of reasons why it's, it's not been
looked at before, but now specifically now that we are,
you know, we're more people are doing it than than have done it
before. We should be looking into these
things. And we've now got more people

(19:40):
expressing that they've receivedbenefits, but we've also got
more people on the influencer side trying to influence people.
And so we need to sort of counteract that with good hard,
rigorous science to make sure that that where there is
benefit, we know who can benefitfrom that rather than being
pushed on everybody in an inaccurate and imprecise way.

(20:07):
And we haven't talked about After Drop yet.
And a lot of people learn about After Drop the hard way, I
think, by experiencing it. Yeah.
You know, you get into the cold water, you spend a few minutes
in and you think, OK, I'm cold enough, I'm getting out.
And then you notice that after you get out, you continue to
feel even colder than you were in the water.

(20:29):
And that's after Drop. Is there, are there resources
that you sort of recommend people direct themselves to, to
learn more about after Drop and cold water immersion in general?
You know, so they don't necessarily have to learn about
it through experiencing it. That's a good question.

(20:51):
In terms of resource, there's, there's normally some good, the
the Outdoor Swimming Society, which is a a website have some
good resources about all experiences of cold water
emotion. And yeah, they have some good
resources there that that's worth having a look at.

(21:11):
They're they're some are writtenby the scientists, the medics,
some are written from an experiential point of view.
So definitely there's a lot out there on reputable websites.
Outdoor Sumo magazine, I've alsowritten about after drop as well
and continued cooling. But yeah, but what is after
drop? So when we go into cold water,

(21:33):
we know that we we're going to cool.
Physics will dictate that we aregoing to cool and we carry on
cooling at a fairly similar ratewhen we get out of the water.
That's the unexpected bit. But when you think about it,
it's really logical. What you're doing when you go
into cold water is you cool the skin initially.
That causes the cold shock response.

(21:54):
Then you start to cool the superficial nerves and muscles.
So that makes us all a little bit stiff and, and, and we can't
coordinate so well. And then we start to cool the
deep body and we've got all these cold tissues.
So when we get out of the water,they're not instantly becoming
rewarmed. It takes a while.

(22:16):
And while you're in the water, you might be shivering quite
heavily or swimming. So you're producing a lot of
energy, a lot of heat as a byproduct of, of your activity.
When you get out of the water, you're doing far less activity.
So your heat production will notbe the the same as it was when
you're in the water. You might still be shivering,
but it's not sufficient to immediately increase your body

(22:39):
temperature. You've got all of this cold
tissue that you've got to rewarm.
So in the meantime, while you'reshivering away, your muscles are
shivering away, Your tissues arestill cooling until you manage
to turn the corner. That can be anywhere between 30
minutes, 4560 minutes in extremecases, particularly I smile or I
swimming. And so yeah, the the the point

(23:03):
of exit from the water is is notthe end of your cooling journey.
I think that's really important to state and it could be some
time after. So there's a reason why we all
stay behind drink hot drinks, have a a nice snack and that is
to look after each other and monitor that after drop.
We're, we're currently doing some experiments looking at the

(23:26):
impact of continued cooling. So after drop in swimming and
looking at the effect of Dr. simulated driving performance.
We've, we did some experiments afew years ago for the
International Triathlon Union looking at the effect of the

(23:48):
water temperature for athlete welfare.
And we found that the number of triathletes that were, that did
their cold swim and then had problems with bike handling as
soon as they got off the bike was, oh, sorry, when they got on
the bike was quite extraordinary.
And so we, we also sort of wanted to think, well, well, why

(24:11):
might that be? And then start to apply it to
other sort of settings. And this is a classic where
people might go for a swim in cold water and then immediately
get in their car and drive somewhere.
It's the same idea as getting ona bike.
And so here in the UK, we don't keep statistics on why people

(24:32):
might have accidents or or problems in their car, other
than if they've taken drugs or alcohol.
So we don't know how many peopleare maybe having accidents or
problems on the roads because they've just come out of the
cold water. But so we want to try and sort
of make people aware that this could be a problem, if it is a

(24:53):
problem. And So what we're doing is we
have a driving simulator where we get people to do several
driving tests where they go around a series of cones and
then onto a motorway, a highway.And we, we can monitor all the
errors, crashes that they make or inaccuracies in their driving

(25:15):
and monitor that before they go and do this, their cold swim and
then after, and then sometime after about an hour after their
swim as well. So we're, we're just analyzing
those data now. So we, I go, I don't have a big
scoop to give to you. I'm sorry, but it's it.
I actually was one of the sort of sort of early trial, early

(25:37):
trials just to see if it worked.And it was quite interesting how
much my driving changed from immediately after I got out of
the cold water. I could barely coordinate and we
were using manual gearboxes as well.
So we had to change gear. How I my focus was very much on

(25:58):
my speed as opposed to being on what else was going on on the
road. And so it's just amazing how
much your focus changes just by being a little bit cold when
you've got out of the water. So just to bring it back to the
point is when you are going for a cold swim, if you do need to

(26:19):
leave straight away, get somebody else to drive you home,
but also get, you know, give it a little bit of time.
Let that deep body cooling carryon and hopefully get to the
bottom before of the cooling before you start to think about,
oh, OK, I am OK, I can drive. Because what we don't want to

(26:39):
happen is people just go, yeah, I've just had a swim, get
straight back in the car and they feel fine.
But 20-30 minutes later they're not really that sure how they've
got home. That's not a really, that's not
a strong place to be. That's your research is so
interesting, all the different experiments you're conducting.
And actually one of my questionswas going to be like, how do you

(27:00):
find people for your research? How do we find people?
People actually volunteer? We do?
Yeah, they do. Or yeah, they find me.
We do some pretty invasive stuff, to be fair.
Measuring deep body temperature.Well, there's no easy way of
doing that. You either have to swallow pills

(27:21):
or have to have probes down yourthroat which really
uncomfortable for swimming or you have to.
This is going to be a bit crude,but stick a thermometer up your
backside in order to accurately measure deep body temperature,
especially when you're going to cold water.
A lot of these skin worn sensorswill not provide you with

(27:41):
accurate deep body temperature and the ear thermometers won't
either because they rely on on algorithms and technology which
suggests a certain gradient between your skin and the deep
body, which doesn't apply when you're going to cold water.
So yes, some of the experiments that we do are quite invasive,
but they're all very applied. And that's, you know, some

(28:03):
people have come to us with experimental ideas that we then
sort of work on with them to, to, to, to try to bring to
fruition. So, yeah, it varies.
Some of the questions we, we think, well, that would be
interesting to do. And then we go and have a look
and see if we can get it done. Others are, are brought to us to
say, oh, do you want to try this?
This looks interesting. And so, yeah, we, we, it's a

(28:26):
mixture. And I, I know that a lot of your
research involves qualitative data, which is, you know, people
telling you things or you're observing people.
And a lot of your research involves the, the mental health
benefits of open water swimming as well as physical.

(28:49):
And so how do you measure mentalsort of the mental health
benefits when people tell you they feel happy or more alive
or? OK.
So yeah, particularly around mental health.
I do both qualitative and quantitative research.
In fact, I am mainly A quantitative researcher.

(29:10):
I have another good colleague, Hannah Denton, who is who is a
qualitative researcher. And so we work very closely
together on these, on these projects.
So in terms of the quantifying changes in severity of, of
depression or anxiety, there arevalidated scales which, which
are people fill in a question and then they have a certain

(29:34):
range of answers and they have anumber assigned to them.
So we can gain a quantitative assessment of, of somebody's
symptoms of depression or anxiety.
So that's kind of more the end Isit at is the quantitative side.
My colleague Hannah, who's an excellent qualitative research,

(29:54):
looks at the, the narrative, the, the, the, the, the dialogue
that people produce, the context.
And I think it's really important to do both together.
The reason being is that not everybody is a numbers person.
And who's to say that the validated scales, whilst they're
validated, they're not always, they're not always super

(30:17):
accurate and people vary from day-to-day in terms of what the
numbers that they would provide.So it provides a number for
those that require numbers. So lots of funding bodies, for
instance, like to have numbers in order to be able to quantify
change. And, and particularly within

(30:40):
this area, we want to know aboutsome of the mechanisms and some
of those magic ingredients as I explained before.
And you're not really going to get that from many of the
validated or quantitative scalesthat could be used.
You're going to get that from the narrative that people
provide the dialogue and the context.

(31:02):
And so it's really important to have both so that we can say,
well, we can see that there's been a change in this person and
they, they make their symptoms may have reduced and we can ask
them, well, what's happened. They're not then going to be
able to write hundreds of validated surveys to prove that
point because some of the surveys don't exist.

(31:23):
But we can gain some insight from their qualitative answers
about what's going on there, what their, what their
experiences are. And I think that's really the
key is having both. Right.
Yeah, that's really important. And as cold water, would you say
it's physically people talk about needing their cold water

(31:44):
fix like when they do it regularly, is it is it something
that is addictive or is it more just so enjoyable that people
want to keep doing it? That's a really good question.
I I don't know what the answer to that is, so I'll go with some
ideas of of what it could be. It's really challenging.

(32:09):
Going into cold water is an extreme activity like rock
climbing or parachute jumping orsomething like that.
So you get a massive hit of stress hormones that, that,
that, you know, that circulate. And so that could be one 'cause
I don't know. We, we, we, there have been

(32:30):
studies that have measured hormone responses to cold water
swimming and you do see spikes in them.
So it may be that people, once they've experienced it, they
like the hit and they want to carry on.
I do have to counter that by saying it's not for everybody.
And there are people that, that have found it, that they didn't
like it. And so we, we do have to watch

(32:51):
that. We're not evangelizing, being an
open water swimmer. There are definitely people that
have tried it and don't want to go back there.
So I'm mindful of that. Equally, we, we think that the
effects may not last too long. So it might be a few hours after

(33:12):
going into the cold water that, that, that, that those hormone
responses have settled back downagain.
And or the, the reset that they,they suggested that they've
experienced has now sort of wornaway.
So people think, well, I've had a reset from that swim or that
dip, I'll probably need to go and do it again.

(33:33):
And so yeah, there could be somereasons why it may be something
that people want to do regularlyand possibly find it addictive.
Equally, what we tend to see is people pushing the boundaries as
well. So they might start by dipping,
they might want to do some more challenges.
I fall into this bracket. So they'll do some more

(33:54):
challenging swims. They'll go longer, they'll go
colder, they'll go to more extreme, possibly some dangerous
places to up the challenge, to up the intensity, to up the goal
as well. So there's lots of there's been
an increase in the rise of swimming holidays as well,

(34:15):
experiencing different locations.
So it all feeds into the same sort of argument about people
find it interesting or pleasurable.
They want to try and incorporateit into into their their
routine, possibly into their holiday as well or or be more
defined by it. So it does build into that sort
of psyche quite well. Related to that, I remember in

(34:39):
the early days of the pandemic, a few articles coming out of the
UK that people were having ice baths in their backyards, like
filling Willy bins or barrels with ice water because they
must, being able to go to their local pole or or waterway.
Did those stories surprise you or was that more the exception

(35:01):
rather than the role? Do you think of what people?
It was definitely a phenomena here in the UK and it still is.
It's not one I would I would suggest is a good idea just
purely from the point of view ofsafety.
You know, we always dip or swimming groups so that there's

(35:22):
some help should then should youhave any, any problems or get
into difficulty. But yeah, it was, it was a well
trodden path here in the UK and it's 1:00.
We, we really tried to sort of say that, hey, maybe, you know,
just make sure there's somebody else in the house or, or
somebody else that can provide support if you need to, to go

(35:45):
and do that. But again, there's some other
things that go on in cold water that are very much people are
not aware of. So things that people aren't
aware of are the likes of, as you say, the after drop, but
also something called non freezing cold injuries, which is

(36:08):
which can be, we're not entirelysure, but we think it's a
neurological as well as sort of vascular problem.
So it affects both the nerves and and the the blood vessels of
the of the periphery particularly fingers, toes, any
extremity really. And it can be quite painful.

(36:29):
It causes swelling and could cancause long lasting numbness or
damage. Hence why my my middle finger is
still causing me some problems today.
And we know it has, it has similar, similar symptoms to or
similar pain levels to Reynos, but it's very much not, not

(36:52):
known about and it's only reallybeen studied in military
populations. So we just need to raise
awareness of some of these theseproblems and that actually if
you're doing something like thison your own, then there may be a
longer term consequences that unsafety implications that you
need to be aware of. Yeah.

(37:15):
And is there much of a difference between how men and
women experience the cold water according to your research, or
is it more an individual thing? Well.
When you say experience, I'm a physiologist, so I look at what
happens to the body when you go into cold water.
And so we have looked at this from the point of view of the
cold shock response and there are no physiological differences

(37:38):
between the the response that males and females have in terms
of the initial exposure to cold water.
But we do know that there are very distinct types of groups of
cold water swimmers or open water swimmers.
You have triathletes, which are mainly men, mainly wet suited,

(37:59):
and then the sort of more classic outdoor swimmer, which
may be a wild swimmer, which maybe a woman that's wearing a
swimming costume or bathing a bathing suit.
And so actually how people experience it, and hopefully I'm
not providing stereotypes here and I do want to break down
stereotypes, but people's experiences will be quite

(38:24):
different based on on the activity and the group that
they're in. And so, yeah, it's it's just
trying to find the right group for you that that's the
important thing we have. Part of the reason I ask is we
have a lot of dipping groups here in Wellington and I'm, I'm
in one of them. And a lot of the groups, not

(38:44):
all, but most are women who are sort of in their 40s, fifties
and 60s and, and beyond. And I know I think some of your
research has looked at the effect of cold water and women
going through menopause and how it can help with some of the the
symptoms. Yeah.
So we we've surveyed people thatwere already swimmers and asked

(39:07):
them. This is one of those questions
where somebody just wrote in andsaid, I've, you know, I've been
experiencing some quite nasty symptoms of menopause and I've
found cold water swimming has really helped with those
symptoms. So that's one of those questions
where you think, well, let's go.It helps to one person.

(39:28):
Let's, let's see what happens for other people.
So the research is really basic.It's only on people that already
swim. So that's an important thing to,
to say. And all we're trying to do is
gather opinion from that that group that are already swimming.
So what we're not saying is thatit could, could help people that
aren't doing it. What we're, we're saying is that

(39:49):
these are the experiences of people that already swim,
already dip in cold water. And people have said that
particularly for the the type ofdipping or swimming that they do
that they're they're symptoms of.
Depression or or or symptoms of anxiety related to menopause

(40:10):
were significantly reduced and that was sort of the main
headline finding from that survey type data.
Thank you. And you mentioned wet suits
before and I had a question about them.
I, I tend to wear a wet suit myself when I'm doing a longer
swim. And I notice in the colder
months that when I'm swimming with a wet suit, it's almost

(40:32):
like all the sort of the cold feeling is concentrated around
my head because it's sort of masked around the rest of my
body. And I don't know if you've done
any research around not wearing a wet suit versus wearing a wet
suit. And whether wearing one sort of
as a as a, I'm not sure what I'masking here, but whether it's
sort of inhibits the, the cold water effects and that your,

(40:57):
your body isn't receiving the, the messages that would receive
if you weren't wearing one, if that makes sense.
OK, so let I'll tell you what I have done around and hopefully
I'll, I'll answer some of your question by doing that
regardless of if you're going into cold water, wear whatever

(41:21):
you want to wear. When you go into cold water
wearing a wet suit, what you're doing that that wet suit to
work, you have to warm a layer of water against the surface of
the skin. So initially when you go into
the cold water, the wet suit hasto fill with cold water.
So you still receive the cold shock response.
It might not be quite as rapid because by the time the water is

(41:44):
filtered into the wet suit, it takes a bit of time to trickle
down your back, doesn't it? OK, so you, you, your cold shock
response might be a bit more staggered, but you're still
getting a cold shock response. Then when you're swimming
around, you're going to heat that water up that's trapped
against the wet suit and on yoursurface of your skin.

(42:04):
So you're not going to have the the same level of a reduction in
deep body temperature cooling that you would have from
swimming with without a wet suit.
Now we think that most of the, the, the potential for benefit
occurs around that cold shock response.
And so people wearing wet suits are still getting that cold

(42:26):
shock response. What you're not getting is
necessarily the, the level of, of hypothermia and therefore the
level of after drop that you would get if you were.
So you're getting some of the benefit of, of, of where you.
Well, wet suits are a benefit inlots of ways in terms of speed
in the water, extra buoyancy, sosafer, but also you're still

(42:48):
going to have that cold shock response initially and then
after drop will be less problematic as well.
So the wet suit is on the body. You've still got maybe your
hands uncovered and possibly your head uncovered as well.
And so this is where I think I may answer some of your

(43:10):
questions around this. So your, your head may be naked
if it's not got, you're not wearing a bonnet.
And so you're still going to experience quite significant
cooling of that body part in comparison to the rest of your
body. Same with your hands and feet as
well. They're they're they're
excellent means of cooling the body by having those exposed.

(43:33):
So I would if if you're going towear a wet suit, I'd also put
booties in and knits on as well.And if you can swim with a
bonnet as well to wear that. Getting into cold water can be
quite painful, especially if you're going into water
temperatures that are less than 8 or 10°.

(43:56):
It can be exceptionally painful.So wearing a wet suit won't
reduce that pain, but it might mean that it's it's manageable
for for your swim. So I hope I've kind of answered
your question, but I'm not sure they.
Have I I was going to say that'sa perfect answer to my very
inarticulate question. So thank you.

(44:17):
And related to related to that, going even colder, some people
become famous for swimming in extremely cold climates.
And I'm thinking here of Lynn Cox who swim in Antarctica and
Lois Pew, I think who also swim in Antarctica.
Are some people more built for swimming at that level, at that

(44:39):
those temperatures? Yes.
I think the short answer is yes.Particularly we're all going to
experience the cold shock response and, and Lynn and Lewis
Pew, Lynn cops and Lewis Pew aretwo people that have been in so
much cold water that they've reduced that cold shock response

(45:00):
to even to very, very cold water, but they will experience
it on some level. So once you've not that that
response, they're also, Lewis isquite a fast swimmer, but he's
also quite a tall man and quite well built.
So he has a certain mass about him that will mean that he's

(45:20):
able to retain more of his body heat.
He's also quite a quick swimmer as well.
So he generates a lot of heat and can store a lot of heat.
So he's going to be able to swimquite quickly to do the the swim
that he's doing in very cold water and then get out.
Lynn, like most, like some ladies that swim in in very cold

(45:42):
water, has some additional insulation that she's using to
best effect. So she's a good swimmer
generating heat, lots of body heat and she's able to retain
more of that heat within her body.
And so she's able to achieve theswims a little bit slower paced,
but she's able to get there because of the favourable body

(46:04):
composition that she has for that activity.
If you have a much more lean individual, so say take an elite
runner for instance, a long distance runner, they're
designed to lose heat. So they're very lean, very
muscular. And so a lot of the heat that
they generate will be put, if they put them in water, you

(46:25):
think that would leak straight out of their body and they'd
lose heat very, very quickly. So there's definitely a body
type and composition and physical activity level that is
required to be a good swimmer invery cold water.
Thank. You and we talked earlier about
the ice swimming championships that you took part in and in New

(46:47):
Zealand just over the last couple of years, we have our own
ice swimming championships that happen in and very cold
temperatures. So ice swimming for people who
don't know is below 5°C. And there's such a thing as the
ice mile where people, you know,complete the distance of a mile.

(47:08):
And there's now the extreme ice mile, which I believe is more
like 2 kilometers. Do you, I mean you must follow
some of these events with interest, do you, do you
envisage that people will continue to increase their
distances in in lower temperatures of water as they
continue to challenge themselves?

(47:29):
Is that sort of a passion you see developing with these?
I do, I do. And yeah, I do know of several
attempts to increase the the longest distance in in water
under 5°C as well. So there are people actively
training to beat that record at the moment.
I think, you know, all I'm goingto say about that is these

(47:53):
people have have a lot of training and a lot of support,
both in terms of the medical support they receive, but also a
lot of water safety support. And so this is not something
that people should just try and do stray it away.
They've dedicated many years of their lives to to becoming

(48:13):
better swimmers first and foremost, but also adapt their
body to being in much colder temperature waters.
And equally, there are a number of people that have done ice
smiles or extreme ice smiles that have had have had medical
problems as a consequence and sono longer swim in such cold

(48:35):
waters. So it's got to be something that
is you continually monitor your health around taking part in
these things and and it's going to be really important that you
maintain you you remain healthy if you're going to do these
attempts. It's not a good idea to to carry

(48:57):
on in such cold water temperatures if you're
experiencing health problems as a consequence.
And related to that, I was reading the your university
website where you talk about your, it's called the Extreme
Environments Laboratory where you researching not just cold
water, but also humidity and altitudes.

(49:20):
So conducting research. And also there are people there
who are working on training and endurance.
And there was a description about what what was called a
chamber immersion pool. I was wondering if you could
describe what a chamber immersion pool is?
Yeah. So we have a climatic chamber

(49:40):
that we can change the air temperature, we can alter the
humidity, we can remove the oxygen or part of, you know, to
simulate going to altitude. And within that climatic chamber
we also have an endless flume. So we can again, and we can
change the water temperature in that flume as well.

(50:01):
So we can simulate most of the terrestrial environments on
Earth in one climatic chamber. So we can do an item, we could
do cold water swim at every space camp for instance, or we
can do a cold water swim in in desert like conditions.

(50:22):
So we, we have that facility to be able to, to, to do, to run
controlled experiments using different environmental
stresses. What is the temperature range of
the pool? So we can, the temperature
there's a pool can vary from around 7:00 if we get it, it
takes a long time to do up to about 40°C, so quite a range on

(50:48):
the pool. The air temperatures we can take
from around around 10° up to 50°C with relative humidity from
from around 30% right up to 99 or 100% humidity.
So we can take, we have quite a range of different environments
that we can we can use. That's really exciting.

(51:12):
And I mentioned earlier that youknow, you've become sort of a go
to person. You've been in.
Well, I've, I've read sort of a few media articles that have
interviewed you about the the physiological effects of cold
water swimming. And I wondered if you had any
plans to to write your own book about it, about your research

(51:34):
and things you've learned. I've no plans to write a book
yet, but I'm still actively researching in the area.
We've got a clinical trial coming up that would be writing
up fairly soon. So my time at the moment is
spent actually actively researching and which I hope to

(51:54):
carry on doing. We, we've got some water safety
research coming up fairly soon around, around the importance
of, of what we call the float tolive message.
So my time is mainly spent doingthe active data collection and
research as opposed to writing up a book.
But I'm always happy to come on your podcast occasionally to to

(52:20):
talk about these things, but no plans as such to write a book
yet. Fair enough.
And with your research, it feelslike a lot of this research is
coming from you and and the UK and Portsmouth University.
Are there other universities around the world conducting
similar research, or is it really mostly where you are?

(52:40):
No, there's, there's several. So I've got colleagues at a
local university, well about 30 miles down the road in
Chichester. They're also doing some pretty
cool research in looking at water immersion and trying to
look at some of the questions that we've, we've not answered
yet. So they've picked up those.
So that's brilliant that they're, they're running with

(53:01):
that and some of their results will be coming out.
So John Kelly is, is one of the researchers there and he's, he's
doing a lot just with static immersion in cold water.
So that's, that's all up and coming.
But there's, there's, there's people that do bits and bobs.
It's really research is is really piece meal primarily

(53:23):
because of funding and research relies on funding for, you know,
for a whole host of reasons and researching something that that
could be classed as either a hobby or a lifestyle
intervention is very difficult to find funding for.
So that's possibly the reason behind the the the lack of

(53:44):
research. The main, the main research area
would be water safety, which obviously the people having
accidents or preventable deaths,that's where you're, that's,
that's where the, the funding right, you should go is to
prevent those deaths from happening rather than trying to
get more people in the water. We need to stop people having

(54:06):
problems. So yeah, we we do what we can
when we can with the the cold water swimming for benefit
research. Is the rate of people getting in
to the water in the UK is high as it was during the pandemic?
Because I know there was a quitea steep rise, you know, with

(54:27):
people unable, with pools closedor the places people usually
went for their exercise. There were more people just
getting into the the open water.Is that are you still seeing an
increase in that over the years?It's hard to say because what we
know that there's big explosion of outdoor swimmers or people

(54:48):
swimming outdoors during the pandemic, as you rightly say,
because of pool closures. And we have the what's called an
active live survey here in the UK where people's activity and
the type of activity and irregularity is sort of
monitored. The data lags massively behind
where we are. And so we, we, we do, we can

(55:09):
just about see that there's beena big increase during the
pandemic and mostly that those individuals that that started
or, or we have similar numbers now as we have we had in the
pandemic. So that hasn't really changed.
What has changed is the fact that we've had more swimmers

(55:30):
have accidents or water related deaths from entering the water.
And So what we're trying to do is an awareness campaign around
swimming in the right locations and the hazards of swimming.
So we know that lots of people join groups and go swimming, but
we also know that there's a lot of people that may swim

(55:52):
impulsively and that's possibly where they get into difficulties
as well. And is that difficulty often in
the the coldest seasons or is ityear round for for different
reasons? The we we do tend to see a big
spike in in water related deathsduring the summer holidays and
particularly big spike in deathsaround.

(56:14):
We have some bank holidays wherethe air temperature may have
spiked increased, but the water temperatures are still cold.
And as we sort of approach we'redrowning prevention day on the
26th of July, it we really need to just sort of highlight that
anyone can drown. But every, every death ship is

(56:36):
preventable around outdoor swimming.
So we really need to highlight the need for a safe outdoor
swimming. Yeah, 100% agree with you.
We have very high incidence of drowning in New Zealand, being
surrounded by water and particularly in summer, just
more people getting in the waterand often going alone or going

(57:00):
into water with strong currents and not just just not having the
awareness. Yeah.
I mean, yeah, I mean, just looking at water safety in New
Zealand's headlines, you know, 2024, you had 71 preventable
deaths in in New Zealand, and that's lower than the average,
but it's still too many. Yeah, exactly.

(57:22):
Well, Heather, we've been talking for almost an hour.
You've been so kind at answeringall of my random questions.
Thank you. What's the best way for people
listening to follow your research?
We have a a website at Portsmouth, so if you Google
Heather Massey, University of Portsmouth, my research is all

(57:43):
our researchers are put on on that page and people can follow
it there. That's the best way.
I don't tend to do much social media.
I'm really sorry. I'd rather be in the water than
on social media. So yeah, my mum tends to do that
for me. Totally get there.
Oh, your mum does that for you? I love that.

(58:04):
That's awesome. Well, you know, it's important
to have a support person. Definitely, yeah.
And do you swim year round yourself?
Yes, I do that. That swimming differs greatly
depending on the the conditions.So here now in the UK it's the
summer so we will do extended extended swims up to a couple of

(58:29):
hours and I've got a channel relay happening fairly soon with
some of my good friends that we swim with.
So that's we're. On what's called the Dover
Coaster now, so we're we're literally waiting for the call
to go down to Dover. So yeah, we're sorting that out.
But in the winter it will be maximum of a couple of minutes

(58:50):
as, as possibly you're experiencing right now.
And that would be very variable depending on the weather
conditions as well. So where we, where we're based,
it's very tidal, but it's also very windy.
And the combination of the two creates big waves and quite
hazardous undercurrents. So we we do have to be quite

(59:12):
careful about about going into the water in those in those
sorts of conditions. Yeah, good point.
Well, all the best with the relay.
That sounds. I'd quite like to do a relay as
well. It sort of takes the pressure
off. It was just more fun.
Yeah, it'd be more. Fun.
It's definitely more fun doing things like that with your
friends, yeah. Awesome.

(59:33):
Heather, thank you so much for your time today.
It's been a real pleasure talking to you.
I've learned a lot and I'm sure people listening will have
learned a lot too. And we'll link to Portsmouth
University in the show nights aswell as all your research.
The is that the Outdoor SwimmingSociety website that you
mentioned earlier? It's really, I know the website

(59:54):
you mean it has really good articles about getting into open
water swimming, but doing it safely and things forum ways to
prepare. Yeah.
So we'll include that. And I'm just just a just aware
it's a little bit UK centric, but equally they do Commission

(01:00:15):
articles. So maybe yourself, maybe
yourself or one of your listeners might want to put
something that's a bit more relevant for for yourselves up
there. But in general, if people
wanting to get advice on on going outdoor.
So it's a good place to start. Cool and finally, if you're ever
over on this side of the world, please do come for a swim.

(01:00:37):
There are a lot of people going to be happy to swim with you.
I've. Never been to New Zealand, I've
only ever made it as far as Australia, but my next.
Trip just a little bit further. Oh, no, yeah, just a long.
Time, yeah. Next.
Definitely next time. OK, cool.
Thank you, Heather. Thanks for your time and all the
best with the rest of your research which I'll be following

(01:00:59):
along with. Awesome.
Thank you very much. Take care.
Bye. Thanks for listening to this
episode of Swim Chats. Please remember to follow or
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