December 19, 2025 • 51 mins
In this episode, we speak with Matthew Walker. The British neuroscience professor is the author of “Why We Sleep: Unlocking the Power of Sleep and Dreams”, and he’s coming to Australia shortly to speak at Vivid Sydney in conjunction with the Sydney Writers' Festival. Walker has lately become the sleep expert of choice around the world for his deep research and clear thinking about one of life’s great mysteries – and necessities. This student of the sandman will be on stage in front of a packed audience at Sydney Town Hall on May 27, but for the moment, he joins Good Weekend senior writer Konrad Marshall for a chat about the incredible benefits of a good night's sleep.
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Episode Transcript
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S1 (00:14):
Hello, I'm Conrad Marshall, host of Good Weekend Talks. After
a short summer break, we'll be back in mid January
2026 with season seven of the podcast. We've got plenty
of exciting interviews booked in the calendar already, but during
this end of year break, we wanted to keep your
feed full by sharing a few of our most popular
episodes from 2025, including this chat with sleep expert Matthew Walker.
(00:38):
The British neuroscience professor is the author of Why We
Sleep Unlocking the Power of Sleep and Dreams, and he
came to Australia in 2025 for a speaking tour. You see,
Walker has basically become the sleep expert of choice around
the world for his deep research and clear thinking about
one of life's great mysteries and necessities. I was happy
(00:59):
to have this student of the Sandman all to myself
for a chat about dozing and snoozing siestas and slumber. Welcome, Matthew.
S2 (01:07):
It's a pleasure to be here. Thank you so much
for the kind introduction, and I'm so looking forward to
coming over and connecting with everyone there.
S1 (01:16):
I think audiences will be in for a treat. So
as I mentioned in the intro, you've become one of
the leading voices in sleep science around the world. Maybe
you could just take us into kind of briefly how
that happened. Like, were you getting bad sleep or great.
S2 (01:29):
Sleep.
S1 (01:29):
Or no sleep? Like, was there anything personal that led
you to explore this topic?
S2 (01:33):
I think most of us in the field are accidental
sleep scientists. You know, I don't think when you are
5 or 6 and the teacher's going around the room
and saying, you know, what would you like to be
when you grow up? No one's rocketing their hand up
and saying, I would desperately love to be a sleep scientist.
So we all fall into it by accident. And I did, too.
I was, um, I was back at medical school and
(01:54):
I was doing my PhD looking at brainwave patterns. And
this was in people with early stage dementia, and I
was trying to see what type of dementia they had
very early on, and I was failing miserably. Couldn't get
any good data for the first couple of years. And
then one weekend I was reading in the journals that
some of these dementias, they would have the sleep centers
(02:14):
attacked by the dementia and others, they would leave the
sleep centers untouched. So I thought, well, I'm measuring my
patients at the wrong time of day. I'm measuring them
whilst they're awake. I should be measuring them when they're asleep.
I started doing that. Got great results. And then I
started to ask, I wonder if the sleep problems are
not just a symptom of dementia. I wonder if it's
(02:36):
an underlying cause of dementia. And that was, gosh, almost
20 years ago now, and I just read everything I
could about sleep. I fell in love with this topic
called sleep. It is, I think, the most beguiling topic
in all of science. And I'm desperately biased, I know that.
And it's a love affair that has lasted me well
(02:57):
over two decades, and it will always be, uh, the
topic I study. So I am I'm a humble servant, uh,
of this thing called slumber. And, um, I thought back then,
20 years ago, you know, no one could answer a
very simple question. Why do we sleep? And the answer
back then was we sleep to cure sleepiness. Yes. Which
(03:21):
is the fatuous equivalent of saying, well, I eat to
cure hunger. No, you don't eat to cure hunger. You
eat for lots of physiological, biological reasons. But now, 20
years later, because of the work of all of my colleagues,
not not of my own. We've had to upend the question.
And instead, now we have to ask, is there any
major physiological system of your body, or is there any
(03:43):
operation of your mind that isn't wonderfully enhanced by sleep
when we get it, or demonstrably impaired when we don't
get enough? And the answer seems to be no so far?
S1 (03:52):
Well, I was going to ask about that link between
Alzheimer's and Sleep later on because I knew that it
had been an area. So what did you find? Was
there an underlying sort of causative factor rather than just
a correlation?
S2 (04:05):
Yeah. It's been we've been studying this now for probably
over 17 years now, and lots of other colleagues likewise.
And we now have we started off with correlation, um,
where we just knew that people across the lifespan who
were getting less than seven hours of sleep, especially less
than six hours of sleep, they were at a far
(04:26):
higher risk of developing Alzheimer's disease in later life. But
correlation is not causation. So then, um, we started to
do experimental studies where we could actually measure the amount
of toxic Alzheimer's proteins circulating either in the bloodstream or
in the cerebrospinal fluid. If we punctured that and took
(04:46):
a sample or even in the brain using special brain scans.
S1 (04:49):
Things like.
S2 (04:50):
Tau. And we would either like tau and amyloid protein.
Those are the two culprits. And if we deprive people
for a whole night of sleep, or even if we
selectively deprive them of just deep sleep the next day,
we could see an immediate build up in these Alzheimer's proteins,
in the bloodstream, in the spinal fluid, and in the
(05:11):
brain as well. So correlation went to causation. At that point,
causation begged a question which was mechanism. Why is it
when you don't get your sleep that Alzheimer's proteins build up?
And there's some great work. A pioneer in the field,
Maiken Nedergaard from the University of Rochester in the United States.
(05:31):
And what she discovered was three things. The first thing
that she discovered is that your brain has a cleansing system.
We didn't think it had it. Now, everyone has heard
of the cleansing system of the body. It's called the
lymphatic system. But she discovered that the brain has one.
It's called the glymphatic system. After the cells that make
it up called these glial cells.
S1 (05:52):
Okay.
S2 (05:52):
The second thing that she discovered was that this cleansing system,
the sewage system for the brain, isn't always switched on
in high flow volume across the 24 hour period. Right.
But instead, it's specifically during sleep and particularly during deep sleep,
where you get this power cleanse for the brain. Sort
of good night's sleep, clean as it were.
S1 (06:12):
Yes.
S2 (06:13):
The third thing that she discovered, which finally brought us
to mechanism, was that two of the pieces of metabolic
detritus that sleep was washing away every night beta amyloid
and tau protein, the two culprits of Alzheimer's disease. And
so we've gone from correlation to causation to mechanism. And
(06:34):
now things start to get very interesting. There's a recent
study by that same group just a few weeks ago,
demonstrating that one of the typical sleep medications that are
used by many people around the world, something called Ambien,
that drug, even though it it puts you to well,
let's just say that it's what we call a sedative. Hypnotic.
You're not necessarily naturally asleep. You're just sedated. That's what
(06:57):
these medications do. And so I'm not going to argue.
You're awake. You're not. But are you in natural sleep?
Maybe not. And what they demonstrated is that when they
were dosing animals with Ambien, yes, they slept longer. So
you would think that if the brain is sleeping longer,
it would have more time to cleanse the Alzheimer's proteins
and it would be even better. What they found was
(07:17):
that the Ambien decreased the amount of activity in the
brain centers that were meant to do the cleansing by
about 50%, and reduce the amount of amyloid and tau
protein removal by about 30%. So here was a case
where you're getting more sleep, but that more sleep, quote unquote,
(07:39):
doesn't seem to be functional. It's not transacting the natural
benefits of sleep. And it may potentially explain, although I
don't think so at this stage because it's not causal.
But it may explain why we see people who take those.
Typical sleeping pills are also at a higher risk of
getting Alzheimer's disease. Now, again, no good evidence that those
(08:02):
two things are correlational. It could simply be, for example,
people who are taking Ambien across their lifespan have had
bad sleep for most of their life, and it was
the bad sleep for most of their life, even before
they started taking the medication that was predicting their Alzheimer's disease.
You've always got to be so careful in not conflating
association with causation.
S1 (08:24):
Absolutely. All right. I'm going to come in hot with
my own personal questions about sleep, because when am I
going to get this chance otherwise? Um, so right now
I'm coming around to the conclusion that I probably have
sleep apnea. I have a lot of the symptoms, and
I'm going to get tested and and check this stuff out,
because I know it's something that I need to address.
And I know a lot of other people who feel
(08:45):
like they're in the same boat and they're like, oh, no,
I'm not gonna worry about it. You know, I think
they don't want to wear the the sleep mask. They
don't want to be hooked up to the CPAp machine
or whatever it is. Yeah. Um, what are they? What
what are they missing in? If they don't treat this
kind of thing to their detriment? Or. I guess the
broader question is here, what happens when you get routinely
(09:06):
bad sleep? Because there'll be a lot of people out
there that are getting really bad sleep.
S2 (09:11):
If you are snoring or you have a partner who snores,
or your partner is telling you that you snore, you
need to get tested. It will shorten not only your lifespan,
but what it will also shorten is your healthspan. That's
what most of us care about. We don't necessarily want
to live for decades and decades and decades longer. We
(09:32):
just want to live longer, free of disease and sickness.
That's your healthspan. Yes, sleep apnea will encourage a shorter life,
and that shorter lifespan will be filled with greater amount
of disease and sickness based on the evidence. So that's
the first thing. It is consequential to frame that for you.
(09:53):
What we the way that we measure sleep apnea is
by looking at how many obstructions or how many times,
let's say that you have these events where you stop
breathing and your oxygen saturation starts to drop. And very
mild sleep apnea is where you have, let's say, 5
to 15 of these events every hour that you're asleep.
(10:15):
So let's just call it ten events per hour. And
let's say that tonight you you sort of listen to
this odd, strange British guy and you say, I'm going
to have my eight hours of sleep. Okay. So for
80 times throughout the next night. Imagine if I were
to come into your bedroom and I were to throttle
you to the point where your oxygen saturation dropped, and
(10:38):
I were to do that repeatedly, ten times every hour
for eight hours. So 80 events like that. Do you
think your body would, and your brain would feel well
rested and restored and with life and biological health the
next day as a consequence? And of course, I'm being hyperbolic,
but the answer, of course, is no. And this is
very mild sleep apnea that we're talking about. Many people
(11:00):
out there, we estimate about 80% of people with sleep
apnea are undiagnosed, which is staggering.
S1 (11:07):
That is.
S2 (11:07):
So that's the first thing I would or the first
two things I would say it's consequential. And that is
exactly what's happening. And if you have if people are
listening and you just want to try this for Android
and Apple and I have no affiliation with them, there
is an app called Snore Lab, Snore Lab, and you
can download it and it's on your phone, and then
(11:30):
you just hit record and you place it by your bedside,
and it's going to record your breathing and your snoring
throughout the night. Okay. The next morning you open it up,
there's your eight hours and it will show you like
Richter shocks on a scale, the severity of your snoring,
and it ranks it from mild, moderate, significant and then epic.
S1 (11:49):
Oh man, I'm gonna do this. And I know it's
going to be confronting.
S2 (11:53):
And well, the more confronting part of this is you
can then go into any part of your night, you
can tap on any one of the Richter shocks, and
then you can listen to yourself gasping for breath.
S1 (12:04):
Mhm.
S2 (12:05):
And it really is I mean, just imagine if someone were,
you know, during the day in your office and they
were constraining your oxygen so that you were gasping all
the time. You know, you would never stay at that
job and you would actually file a claim. That's preposterous.
But that's what we're suffering with undiagnosed sleep apnea. So
to the the issue of the treatment, though, we used
(12:28):
to think of this kind of almost fighter pilot esque,
you know, Top Gun mask and big tube coming off,
you know. Right. Your significant other walks into the bedroom.
You've got I'm thinking, you know, I've never wanted you more.
It's not like that anymore. It's there are some great
companies and I think probably the best out there right
now in the business is called ResMed. And they have
a great presence there in Australia. And really now just
(12:50):
comes down to this little nasal pillow that just sits
just over your nose and it is connected to the airway.
And what happens is that in severe or moderate to
severe apnea, you will need a CPAp machine normally, and
it will just place gentle air up the airway. And
it acts like a splint, but it's actually a pressure
(13:11):
splint that will keep the airway open. So you breathe freely.
And many people will say, but I still don't sleep
very well with the mask on. I promise you that
even if you're sleeping not as well as you think
you were before, the quality of that sleep with the
airway splint activated is so much better that even if
(13:31):
it's shorter duration, the quality versus quantity is that much better,
it's well worth it. That said, though, there are great
advances in what we call these mandibular devices. And it
looks like a sports car.
S1 (13:44):
Top and.
S2 (13:45):
Bottom mouthguard. Yeah. And it's hinged at the back. And
it simply just moves the jaw. Just a few millimeters forward.
And everyone can do this test. You lie on your bed,
on your back, and you can try and make the
snoring noise. And every everyone can do it. Then just
grab your thumbs, put them under the jaw and move
your jaw forward, and then try and make the snoring
(14:06):
sound again. And it's immensely difficult. And just that slight
alteration in the anatomy of the jaw opens up the
airway and you can breathe. So many people may not
have to go for a CPAp machine if they're in
the mild category, they can do this. And then there's
other sort of you know, there are some dental and
(14:26):
surgical procedures. Some people will opt to actually have a
very small sort of stimulator implanted just under the skin
that will stimulate the airway open so they don't have
to use the the nasal pillow. So lots of different
treatment options out there for people. But start with snolab.
See if you're snoring. Do 5 or 6 nights sleep
(14:47):
are so idiosyncratic. 1 or 2 nights you're not going
to be representative. Get five nights, have a look at it,
and then really ask yourself, I think I need to
go and get tested and reach out to your doctor.
They will give you an at home test. You don't
even need to go to a sleep lab.
S1 (15:02):
I have a question for you about naps. I love
a good nap. Short and sweet. They kind of revive
me and I and I get up and I'm ready
to go. Go a little bit longer an hour or so,
and I am groggy as a result of it. It's
almost it's counterproductive. It has the opposite effect. I understand
that Thomas Edison was a massive napper, a very enthusiastic napper. Um,
(15:27):
and I feel like he had a novel method for
kind of hitting the sweet spot on a nap.
S2 (15:33):
Yeah, it's interesting that sort of sleep hangover effect, isn't it,
when you nap for a quote unquote too long? And
why is that? And I've got no idea. It was
just theoretical. But no, no, I do. I can explain it.
It's so. It's what we call sleep inertia. And here's
what happens if you want. I've got a friend over
(15:55):
here in the United States, a guy called Andrew Huberman.
He's always telling me protocols, everything. What's the protocol for? Everything. Okay,
what's the protocol for napping? I would say the optimal
nap is around 20 minutes. It's not the same. We've
done lots of studies that if you nap longer, you
continue to get more and more brain and body benefits.
But 20 minutes is the sweet spot because it's enough
(16:18):
to give you what most people want, which is a
restoration and refreshment of my alertness, my focus, my concentration,
my energy. But when you are going into sort of
that 20 minute territory, you haven't gone all the way
down into deep non-rapid eye movement sleep yet deep, dreamless sleep,
so that when you wake up, you kind of go
(16:38):
back up to operating temperature like a classic car engine
pretty quickly. But if you nap maybe 30 or 40 minutes,
you're now down into the deeper stages of sleep. And
then when you wrench yourself out of that, it's like
going from the basement to the penthouse and you get
stuck on the 13th floor. Now, if you wait for
an hour or so like a classic car engine, gradually
(16:59):
the oil temp will start to come up, and then
you'll be firing on all cylinders and you will feel
even better than when you did, you know, an hour
or so before. So you will get more benefits. You
just have to suffer the consequence of that initial dip.
But for most people, 20 minutes is the sweet spot.
Thomas Edison used naps. He was, um, a very, um,
(17:22):
sort of vociferous suggester of the the uselessness of sleep.
And he would say he would survive on 4 or
5 hours of sleep. There are lots of pictures of him.
And he was a habitual napper. I've got a great
picture of him on his inventors bench. A picture of
him in the garden. Looks like after a pretty good
garden party. He's out for the count. And he understood
(17:45):
the creative brilliance of sleep. And he used it ruthlessly
as a tool. Here's what he would do. He would
take two steel ball bearings, put them in his hand,
sit at his desk in his inventor's studio, have a
pad of paper and a pencil next to him, and
then he would take a metal saucepan and put it
underneath the armrest. And then he would gradually settle his
arm back down with his palm facing to the ceiling,
(18:07):
and he would relax back. And so he didn't go
too far into sleep. At some point, his muscle tone
would relax. They would release the steel ball bearings, they
would crash on the saucepan, wake him up, and then
he would write down all of the ideas that he
was getting from sleep. And he coined the phrase, it
was beautiful. He described it as the genius gap. This
(18:28):
gap between lucid waking consciousness and the depths of almost
nonconscious deep sleep. And in that transitional, that kind of
liminal state, you had all of these creative ideas. And
it's probably one of the reasons why no one's ever
told you that you really should stay awake on a problem.
And he recognized that.
S1 (18:47):
You mentioned just there that he he, um, described himself
as a as a very short sleeper, someone who didn't
need a lot to get by on. And, you know,
history is littered with, um, people, uh, who are like that.
I mean, Barack Obama likes to say that he can
exist on five. Martha Stewart only needs four hours a night.
I think Nikola Tesla was said to believe that he
(19:10):
could get by on 2 or 3 hours of sleep.
Is there any optimal optimal amount? I mean, is eight
hours what we should be striving for?
S2 (19:20):
It's a very interesting question, and there is definitely a range. And,
you know, and the people like, you know, Margaret Thatcher,
who was claimed to be the Iron Lady, claimed to
sleep 4 to 5 hours. Her compadre in the United States,
Ronald Reagan, an equal chess Peter about 4 to 5
hours of sleep a night, nothing more. Um, I don't
know if it's coincidental that both Thatcher and Reagan succumb
(19:41):
to the terrible disease of Alzheimer's, you know, towards the
end of their life. Um, but there is an absolute
range for most average adults. It's 7 to 9 hours
of sleep. Once you get less than seven hours of sleep,
we can start to measure impairments in your brain and
your body. And chronically sleeping less than seven hours is
(20:01):
associated with a number of disease risk predictors cardiovascular disease, diabetes,
immune and inflammation issues, certain forms of cancer, hormonal issues,
and then of course, issues around Alzheimer's disease and dementia.
So that said, though, it turns out that there are
(20:22):
a very small subset of the population that we now
call natural short sleepers, and they are genetically determined. We
know that there are at least two or maybe now
three genes that will allow you to get away with
as little as about. If you look at the data
six hours and 12 minutes, and these people can sleep
(20:45):
literally consistently six hours and 12 minutes or around there
and they show no impairment. We just can't measure any impairment.
And so it does seem to be that. Yeah. And
at that point, you know, probably there's lots of people listening, thinking, okay,
I think, I think I'm one of those genetic abnormal people.
And just to frame this in context, statistically, based on
(21:07):
the evidence, you're probably more likely to be struck by
lightning in your lifetime than you are to be a
natural short sleeper genetically.
S1 (21:15):
Right. Okay. We've spoken a little bit about the the
benefits of sleep in terms of your brain. Um, I've
been exercising a lot recently and have and have been
(21:36):
reading a whole lot about runners and athletes and sport
and sleep now seems to be one of the big
areas that they're trying to kind of unlock. It's like
they've focused on hydration, they've focused on fuel. They know
about strength this and stretching that. But it seems now
like sleep has become the the thing that they want
(21:58):
to use to. Yeah, unlock true high performance. Is that
something you've come across in your research.
S2 (22:03):
Yeah. So I've, I've worked with a number of sort
of professional teams around the world and several athletes and
several who are, uh, have been wonderfully vocal about how
much sleep that they get, because there is a terrible
stigma in society about getting sufficient sleep that you're lazy
or you're slothful, or if you've got, you know, enough
(22:24):
time to get seven hours of sleep, then you must
not be busy enough and busy is equated to importance.
And so there is this stepping stone chain of shame
that happens. And I think it's great that athletes have
been embracing it. You know, a couple that I'm familiar with, um,
you know, Federer is Roger Federer has been great in
(22:44):
terms of advocating that LeBron James equally so. Um, Usain
Bolt was was fantastic and would um, uh, one of
the times he'd literally, I think, been awake for about, um,
36 minutes before after a nap, um, and went out
and broke a world record. You know, so I think
there is.
S1 (23:02):
Right.
S2 (23:03):
But nevertheless, I used to say about 7 or 8
years ago that sleep was perhaps the greatest legal performance
enhancing drug that not enough athletes were abusing. But now
the game, I think, has moved on. And because you're
absolutely right, they've optimized, you know, almost all they can
from nutrition, from exercise physiology, from different regiments of mental health.
(23:28):
Sleep now has come onto the map as a professional edge,
and it doesn't take much. You know, if you look
at the difference between, let's say, first place and sixth place,
or a first round pick in the NBA versus a
seventh round pick, you know, the stats aren't that different.
Everyone is much more similar than they are different. So
every sort of edge counts. So we we work with
(23:52):
a lot of teams and but particularly individual athletes to
try to help them improve. And it's an especially difficult
challenge for two reasons. With athletes, the first is usually
before the game. Anxiety and stress is high. Yeah. And
anxiety and stress are probably they are probably the leading,
not the only, but the leading principle underlying cause of
(24:15):
insomnia in society. And I think we you know, and
I'm happy to speak about that. I think the second
component of that is just the travel that almost no
athlete that I've worked with simply performs locally. They all
perform nationally or globally, and they're always traveling. So you've
always got to try to augment a regiment that is
(24:37):
under the duress of jet lag. And so the challenge
is how do we get them to sleep to begin with?
5 or 6 years ago, the challenge was, how do
we convince them that they need to sleep? Now it's
the challenge. We accept that. How do we get it? Yeah.
S1 (24:52):
I imagine there's also you hear this a lot from
Australian rules football players. Anyway, they play a night game
and the adrenaline that's been coursing through their bodies for
2 or 3 hours while they play in front of
100,000 people under lights, is is wild. And then they're
not finished and warm down and kind of changed and
(25:14):
ready to go to bed until midnight. And it's still
kind of coursing through their body. I mean, how are
they expected to to get to sleep then?
S2 (25:22):
Yeah. And we see this in society a lot too.
Or a derivation of this. It's called the tired but
wired phenomenon. Now for them the wired is a chemical
physiological wired in the sense that they're just coursing with endorphins, dynorphins, adrenaline, cortisol.
Everything's racing through their veins. And it's completely antithetical to
the physiological state that is needed to to sleep. So
(25:46):
no wonder they can't. Even though they could tell you
I'm really tired. There's no way I'm going to be
able to sleep for the next two hours because they're
just so wired. And in society, we have that version
which again comes back to just stress and anxiety. You know,
we see people at the sleep center all the time saying,
I'm so tired. I am so desperately, desperately tired. But
(26:08):
I'm just so wired that the Rolodex of anxiety and
stress begins and I just cannot fall asleep. Or I
wake up and I just cannot get back to sleep.
S1 (26:19):
Just speaking about anxiety and stress and depression. Um, those
kinds of, um, mental health problems. Do you think sleep
is kind of overlooked by the medical community, either GPS
or psychologists or whoever it is, as, as a potential
kind of underlying cause, or at least a contributing factor
(26:39):
to those issues that people face?
S2 (26:41):
I think clinicians, um, are becoming more aware of the
fact of sleep's integral role that our sleep health is
intimately tied to our mental health. And I would say,
and this is probably the other largest area of research
that we do at my center is in mental health.
In the past 20 years of studying it, I've not
(27:03):
been able to discover a single psychiatric condition in which
sleep is normal. Um, and for me, that tells me
everything I need to know about the intimacy and the
strength of that connection. So I think psychiatry in the 80s.
90s and early 2000 would see the sleep problems in
(27:26):
mental illness as a concept, as a symptom, as a
consequence of the mental illness. Now, if you look at
the data, I think people are at least seeing it
as a two way street, and it really is a
two way street. We know that insufficient sleep can predispose
and even trigger mental health conditions. And we also know
that on the flip side, mental health conditions will themselves,
(27:49):
once they get started, instigate sleep disruption. So it is
a vicious cycle. And once those those things start sort
of working, it's almost like that tornado that just starts
to spin out of control.
S1 (28:02):
That flywheel.
S2 (28:03):
Yeah, exactly. Precisely. And in some ways it's a message
of hope, though, because sleep at least gives you a
sort of an entry point in to try to break
that cycle, that sometimes it's fiendishly difficult to try to
stabilize the mind with either therapy or medication. But if
(28:23):
you can try to stabilize sleep through its natural sort
of emotional first aid through its what I've described as
overnight therapy benefit. It can come in and it can
short circuit that constant negative spiral. And when you kind
of right the ship and you course correct sleep, you
often it's usually very uncommon that you don't at least
(28:47):
see some improvement in the mental health symptoms.
S1 (28:50):
When I was a teenager, I could sleep until 2:00,
3:00 in the afternoon on a on a Saturday or
a Sunday. Now, granted, I was sitting up late watching movies,
and so that sort of only makes sense, but I
always felt like I was actually just clawing back some
of the sleep that I missed during the week from
(29:11):
getting up early to go to school. Um, school does
kind of start early for kids all around the world.
And I feel like you have some pretty specific views
on this on how early, um, we get kids up
and out the door and into the classroom.
S2 (29:28):
Yeah, I think this consistent and you can see it
across almost all first world nations. The there's this incessant
model of marching school start times back and back and
back earlier and earlier and earlier. And as we go
through those adolescent teen years, something biologically interesting happens on
(29:50):
natural rhythms. Start getting forced forward in time. So when
before when we were, say, you know, ten years old,
you know, you could get into bed and you could
fall asleep nine, ten, you know, maybe earlier, but now
once you're 15 years old, you now can't go to
sleep or get sleepy until, let's say, midnight. And it's
(30:13):
not because you're trying to be rebellious. There is actual biology.
There's physiological machinery that shifts during that adolescent phase to
push teenagers to a later to bedtime and later wake
up time. It's not their fault, is point number one.
The second point is that you're absolutely right. They have
(30:37):
been lumbered with this incessant chronic sleep debt by forcing
them to wake up so early. And if you look
at these, um, models throughout the world where they've decided
to kind of push back against this mentality and delay
school start times, what you typically see when school start
times are delayed are academic grades increase truancy rates, decrease
(31:01):
attendance rates as a consequence, increase psychiatric and psychological referrals decrease.
And then something also interesting happened. The lifespan of these
individuals increased on average. And you think, well, wow, hang
on a second. I don't understand how you could measure
or track that. Well, the leading cause of death in
(31:22):
adolescent teens from 16 to 18 is actually not suicide.
That's second. It's road traffic accidents. And here, sleep matters enormously.
There's a great study from, um. It was Teton County
in Wyoming in the United States. They shifted their school
start times from 735 in the morning to 855 in
(31:43):
the morning. And what they found was that not only
were those kids getting an extra one hour of reported
sleep the next following year, road traffic accidents dropped by 70%,
so car crashes dropped seven zero in that age 16
to 18 range. Now, to put that in context, you know,
the advent of ABS technology, anti-lock brake systems in cars
(32:06):
that dropped accident rates from 20 to 25%. But here
is a physiological thing which is called giving your teenagers
enough sleep that will drop accident rates by up to 70%. So,
you know, I don't mean to trivialize it. Getting children
to school at a certain time is not easy. Parents
(32:28):
have got to get to work themselves. Bus unions and
school buses, they've all got to sort of try to find.
So it's not a it's not an easy thing I
understand that. I also think, however, that we've been able
to put people on the moon. So I think we
can solve this because if you look at the data,
when sleep is abundant, minds flourish. And when it is not,
(32:52):
they don't. And I fear that we are we are
doing a disservice to our children in the most sort
of incredibly spectacular manner with this incessant model of early
school start times. So I've been trying to lobby it
throughout the throughout the United States and go state by
state in terms of legislative law, and we're starting to
(33:14):
make it happen. But it's very, very difficult.
S1 (33:16):
I'm one of those people who does not remember my dreams,
at least unless I wake up and go, remember that dream,
remember it, focus on it. Um, and I've got to say,
I also can't think of anything more boring than hearing
about someone else's dreams. I hate it when someone says
you won't believe what I dreamed last night. It was
so bizarre. Imagine if you're walking.
S2 (33:38):
Through the world as a sleep scientist. That's all people
want to tell you about. Either that or how to
fix my sleep. But. But keep going. Yeah.
S1 (33:47):
So I was going to ask, though, what did you
dream about last night? And and what, uh, what purpose
do dreams serve? I mean, dreams were referenced in the,
in the subtitle of your book, so they're not a
small part of what you, um, what you study and consider.
S2 (34:03):
Yeah. Dreams are fascinating. They, you know, we used to
think of dreams as just epiphenomenal that they are just
the byproduct of the stage of sleep from which they
arise from which is principally rapid eye movement sleep. And
the analogy would be coming back to Thomas Edison, let's say,
you know, think about a light bulb. The reason that
you've constructed the apparatus of a light bulb is to
(34:23):
create this thing called light. But when you create light
in that way, you also produce something called heat. Heat
was never the design, purpose or brief of the light bulb.
It's just epiphenomenal. What happens when you create light in
that way? And so too, we believe dreams were the
heat of the REM sleep light bulb, right? But now
(34:46):
I think we've got substantive evidence that dreams serve at
least two unique functions above and beyond the stage of
sleep from which they come, which is rapid eye movement.
The first is that dreaming is almost like a form
of informational alchemy. It's that during dreaming we start to collide.
All of the recent things that we've learned with all
(35:08):
of the back catalog of information that we've got stored
up in our brain, and as a consequence, we wake
up with a revised mind wide web of associations that
is capable of divining solutions to previously impenetrable problems.
S1 (35:24):
Okay, so it's sort of this, this period in which
we knit together the the past and the present.
S2 (35:29):
Yeah, yeah. You know, it's it's almost like group therapy
for memories. You know, everyone gets a name badge, and
you all go into this room of REM sleep at
night and REM sleep. What's interesting, though, relative to wakefulness
during wake, we build the obvious first kind of order connections.
The logical ones. Dream sleep is like the Google search
(35:49):
algorithm gone wrong that you input, you know, into this
sort of, you know, um, you know, vivid Sydney. And
all of a sudden you get something that is about
a field hockey game in Utah in the United States.
And you think, hang on a second. But if you look,
there's a very strange, non-obvious association that seems to happen.
And dream sleep has this kind of almost biased algorithm
(36:13):
to seeking out the very distant, non-obvious associations. Because when
you start to fuse things together that shouldn't normally go together,
but when they do, they offer marked advances in evolutionary fitness.
It sounds like the basis of biological creativity, and that's
one of the functions of dream sleep. The second function
(36:34):
of dream sleep is radically different. It is a form of,
as I sort of said before overnight therapy, that it's
during dream sleep and the special chemical cocktail that happens
during dream sleep, that the brain is able to strip
away the emotion from our memory experiences the day before.
So a better analogy would be, um, dreaming. It's almost
(36:58):
like a nocturnal soothing balm. Okay, that dreaming sort of
comes along and it just takes the sharp edges off
those painful, difficult experiences so that you come back the
next day and they're not as painful anymore. So you
went to bed with an emotional memory, and you wake
up the next day with a memory of an emotional event,
(37:20):
but it's no longer emotional itself. Dreaming comes along and
it almost divorces the emotion from the memory. It strips
the bitter emotional rind from the informational orange, as it were.
And that's why it provides this sort of, um, mental help, uh,
therapy overnight.
S1 (37:37):
So what about what about, um, the opposite then? So
if I, I have to sleep in, like, boxer shorts.
Probably too much information for you there, but I can't
sleep in heavy layers. I need a sheet rather than
a big doona, whereas my my wife is sort of
cuddled under a bunch of different layers. But the long
(37:57):
point I was getting to is if if I am
wearing too much, if I'm too warm, I can guarantee
I'm going to have a nightmare. So I just wanted
to ask, what's the purpose of nightmares then? Or why
do we have nightmares given, you know, the value of
dreams that you were just talking about?
S2 (38:14):
And it is interesting, you know, to your first point,
sleep is immensely temperature sensitive. And we know that there
is this unique kind of three part stanza to good
temperature sleep, which is that you have to warm up
to begin with at your surface to draw all of
the blood out of the core. So you have to
warm up to cool down. So you bring the blood
(38:35):
to the surface by warming it, and then you radiate
the heat out from the core that's trapped there like
a snake charmer. And then your core body temperature plummets.
So you have to warm up to cool down, to
fall asleep. And then you have to stay cool to
stay asleep. And then you have to warm up to
wake up. And I'm absolutely like you, you know, I,
I have to sleep now I sleep hot. And I'm
(38:57):
usually there in kind of like a kind of like
I'm like you, you know, my wife, it looks like it's,
you know, it's Somewhere. Polar vortex. You know, because. And
you know, I don't know, I may have lost it
during the night. It's somewhere down the rabbit hole of covers.
It's this monstrosity. So. So with rescue parties, most mornings
it works out. But to your point, what's also interesting
(39:18):
is that we don't just need to warm up to
wake up. We need to warm up to go into
dream sleep.
S1 (39:25):
Right?
S2 (39:26):
But if you get too hot, your dream sleep starts
to get fragmented. So normally dream sleep or REM sleep
has what we call a thermo neutral sweet spot. Which
means that if you get the ambient around you in
underneath that blanket and it's just a small little layer,
if you get that ambient temperature close to your core
(39:49):
body temperature, then you are going to be riding nicely
high on this thing called REM sleep. But if you
get too warm, your REM sleep starts to become fragmented
and you wake up more. And it could be that
waking up more, that fragmented nature of the REM sleep
makes that dream sleep committed more to memory, which can
(40:09):
also lead to frustration or sort of embedding some of the,
you know, the negative parts of the dream or the
fearful parts. And that can lead you to think I'm
having more nightmares as a consequence. Nightmares, per se, aren't
necessarily problematic. Many people will have nightmares. It just seems
to be part and parcel of natural sleep. However, if
(40:30):
the nightmares are causing you daytime distress or nighttime distress
where you actually are starting to fear the notion of
going to bed because you don't want a nightmare, then
seek out a specialist. We now have some great treatments
for nightmares. One of the treatments that people can just
Google and find someone locally, um, who will provide this
(40:54):
service is called image rehearsal therapy or I r t.
S1 (41:01):
Okay.
S2 (41:01):
And you worked with a therapist, and you start recalling
the dream during the therapy session. But what you do
is you take the traumatic part of the memory of
the dream, and you change it. It's like going into
a word document of a nightmare and saying, you know,
towards the end it got really scary and I don't
like that. So I'm just going to rehearse. I'm just
going to kind of cross it out, and I'm going
(41:22):
to go in there and do some suggested edits, some
tract changes. And if you do that time and time again,
the memory circuit actually gets rewritten. So you're going to
rewrite your own nightmare autobiographical history. And if you keep
doing that day after day and then sleep to strengthen
that newly updated memory, over time the nightmare frequency decreases.
S1 (41:47):
Fantastic. I can't believe we've eaten up so much time.
I've got so many other questions I could ask you
about sleep. I wanted to talk about the the kind
of growing commercial field of sleep, wellness and what's next
on the horizon in sleep research and whatnot. But I
feel like I've made listeners wait long enough for the
thing that they probably want from this and that, the
(42:10):
thing that people probably want from you every time they
run into you. It's the it's got to be the
top tips for for good sleep, right? What what can
people do to ensure that they get better sleep and
enjoy all these benefits that you've been talking about today?
S2 (42:25):
Yeah, I would say the the first set is probably
the really boring stuff that everyone's heard, which is sleep hygiene.
You know, we think about dental hygiene. Well, there's sleep
hygiene and that's things like, you know, making sure that
you are trying to stay away from too much caffeine
in the afternoon, certainly in the evening, trying to limit
your alcohol use. You know, alcohol, people will say, if
(42:48):
I have a cup of nightcaps in the evening, I
fall asleep. Great. Alcohol is in a class of drugs
that we call the sedatives. And sedation is not sleep.
So you're just mistaking the former for the latter in
that regard. The other thing I would say is alcohol
will also fragment your sleep. So even if you fall asleep,
you will wake up many times throughout the night. But
you don't commit the wakening, the wake ups to memory.
(43:10):
So you wake up the next day and now you're
kind of reaching for 3 or 4 cups of coffee
because you don't feel restored and refreshed. And now what
happens is that you get overactivated on stimulants during the day,
and you have to take on board more alcohol in
the evening to try to bring you back down. So
it's basically a kind of a go pill and a
stop pill. It's this sort of this, this real sort of, um,
(43:34):
unfortunate cycle and dependency that starts to develop, um, some
of the sleep hygiene, keep it cool. Bedroom temperature probably
around about, sort of about sort of 17 to 18 degrees. Um,
sounds cold for most people, but you need to sort
of keep it around there. Wear socks, you know, put
(43:54):
a hot water bottle at the end of the bed.
That's fine too. But the ambient has to be cold. Mhm. Um,
as for the kind of unconventional tips, the first thing
I would probably tell people is do this experiment for
the next seven days. And if it doesn't work, just
say that guy is full of absolute nonsense. Set an
(44:14):
alarm for one hour before you expect to go to
bed when that alarm goes off. Shut down almost all
of the lights in your house. You will be stunned
by how sleepy and soporific that will make you feel.
And it does a number of things. Firstly, we're a dark,
deprived society in this modern era, and we need darkness
at night to trigger the release of a hormone called
(44:35):
melatonin to help structure our sleep. The second thing is
that it stops you being so mentally active when it's
dark around you, it's hard to get activated and agitated.
It also starts to reduce down. The likelihood doesn't stop it,
but the likelihood that you then want to jump onto
your laptop or on your phone because you're looking at
(44:56):
the screen with the dark ambient around you, it's almost
a little bit too much. The second tip, I would say,
is the devices that we use are we used to
think were a problem for sleep because of the blue light.
And there was some good studies suggesting that now really
based on a fantastic, um, sleep scientist, uh, from Australia,
(45:20):
Michael Gradisar single handedly has really just converted the field.
He's demonstrated it's not really the blue light, it's that
these devices are attention capture devices, and they are designed
to fleece you of your attention economy, and they do
it ruthlessly well. And so it's because these devices are
(45:43):
so activating that you could be very sleepy. And if
you took them away and it was just pitch black,
you'd say, gosh, actually I'm surprised. I'm actually quite sleepy.
But they hit the mute button on your sleepiness and
they keep and they cause what's called sleep procrastination. So
I would say in the last hour before bed lights
go out. It will bring you back down physiologically and psychologically.
(46:06):
Try to limit the use of those devices not because
of the blue light, but because they are activating. And
then the following rule of thumb if you absolutely have
to take your phone into your bedroom, and I know
I understand that the following rule is this you can
only use your phone in the bedroom standing up. And
(46:27):
then at that point after about 7 or 8 minutes,
you then you think, ah, I'm just I'm just going
to have a bit of a sit down. Sorry. At
that point phone goes away. The other thing I would
say that probably the biggest issue that people face with sleep,
either falling asleep or staying asleep is anxiety. Stress. It's
the Rolodex of anxiety because in the modern era, we're
(46:51):
constantly on reception, and very rarely do we do reflection,
and the only time we now do reflection in society
is when we turn the light out and our head
hits the pillow. And that's the worst time to be
doing reflection.
S1 (47:03):
Right.
S2 (47:03):
And so at that point, if you can't fall asleep
and that stress has started to happen in the mind
at that point, you start to ruminate. When you ruminate,
you catastrophize. And when you catastrophize, you're dead in the
water for the next two hours. Because everything, at least
to me, feels twice as bad in the dark of
night as it does in the light of day. So
(47:26):
your job at 3 a.m. in the morning is the following.
Get your mind off itself. How do you do that?
At least five different ways. First meditation. It's well proven
to help people. It may not be your thing. So
what else do you have for me? The next thing
that you can do is just do what's called a
body scan. Start at the top of the head. Just
(47:47):
start to feel the tension in your body. Is your
forehead too tense? Start to relax it. Feel the tension
in your neck. Start to relax and just move throughout
the body. If you don't like the sound of that
do box breathing, you can inhale in for five seconds,
hold it for five seconds, and then exhale for 7
or 8 seconds. And there's lots of different versions of
that you can do. Another thing that you can do
(48:09):
is take yourself on a mental walk.
S1 (48:12):
Okay.
S2 (48:13):
So this is a great study also by an Australian researcher.
But um, here at UC Berkeley in the United States,
Alison Harvey, she firstly and this is the fifth point,
do not count sheep. What she found was that counting
sheep makes it even worse because you're thinking about not sleeping.
What she found as an alternative was go on a
hyper vivid mental walk. And what I mean by this is,
(48:36):
let's say I'm going to take my dog out on
a walk that I know very well. So I open
the drawer. Which leash am I going to take? I'll
take the the blue one, not the red one. Clip
the dog in with my right hand, open the door
with my left hand. Start to move out and walk
down the left. Then the car comes around the corner
too quick. It's in kind of 4K, hyper vivid detail
that you need to do the mental walk. What is
(48:58):
common about all of those things I've just described is
that they all get your mind off itself. They are
all distracting your mind. Sleep at 3 a.m. in the
morning is like trying to remember someone's name. The harder
you try, the further you push it away. And as
soon as you stop trying, that's when it comes back.
(49:19):
So when you do these types of techniques, usually what
typically happens is that the next thing you remember is
your alarm going off in the morning. Why? Because you've
got your mind off itself. If none of those things work,
the final thing I would tell you is the following.
Don't panic. Don't worry about everything that we've discussed about
Alzheimer's disease and cardiovascular disease. Don't worry about that. Everyone
(49:43):
has a bad night of sleep. It's not going to
do you any major disservice for the most part. Instead,
just accept the following. Tonight is not my night, and
that's okay. I'm not going to stress about it. Instead,
here's what I'm going to do. I am just going
to take this opportunity to rest. Wouldn't it be lovely
if someone came into your office at midday and said,
(50:03):
actually just come through to the next room, we've got
a bed set up for you. I don't want you
to sleep. I just want you to have a rest.
Just sit there and just have a rest for the
next hour. How about that? You think that sounds rather
lovely to me? Well, just rest and keep your eyes open.
You have to stay awake and keep your eyes open
and just rest. And all of a sudden, what you'll
(50:25):
find is that your eyes start to become a little
bit heavy. But you've got to keep them awake. And
you've just got to rest. And then once again, usually
the next thing that happens is you're getting woken up
by your alarm.
S1 (50:37):
Fantastic. Ah, look, now, I can't wait to get to
sleep at night. It's, you know, early in the morning here. Um,
thank you so much for your time, Matthew. I really
appreciate it. I'm sure our listeners have gotten a lot
out of it. Have a great day.
S2 (50:50):
Okay. Take care. Good luck with the sleep apnea.
S1 (50:52):
Thank you. That was sleep professor Matthew Walker in conversation
with Conrad Marshall for good weekend talks. If you enjoyed
this episode, please remember to subscribe, rate, and comment wherever
you get your podcasts and keep tuning in for more
compelling conversations. Season seven starts on January 17th. Good Weekend
(51:13):
Talks is brought to you by the Sydney Morning Herald
and The Age. Proud newsrooms powered by subscriptions to support
independent journalism. Search, subscribe Sydney Morning Herald or The Age?
Good Weekend Talks is produced by Konrad Marshall and edited
by Tim Mummery, with technical assistance from Kai Wong, Cormac
Lally and Josh towers. Our executive producer is Tammy Mills.
(51:35):
Tom McKendrick is head of audio and Melissa Stevens is
the editor of Good Weekend.
Hello, I'm Conrad Marshall, host of Good Weekend Talks. After
a short summer break, we'll be back in mid January
2026 with season seven of the podcast. We've got plenty
of exciting interviews booked in the calendar already, but during
this end of year break, we wanted to keep your
feed full by sharing a few of our most popular
episodes from 2025, including this chat with sleep expert Matthew Walker.
(00:38):
The British neuroscience professor is the author of Why We
Sleep Unlocking the Power of Sleep and Dreams, and he
came to Australia in 2025 for a speaking tour. You see,
Walker has basically become the sleep expert of choice around
the world for his deep research and clear thinking about
one of life's great mysteries and necessities. I was happy
(00:59):
to have this student of the Sandman all to myself
for a chat about dozing and snoozing siestas and slumber. Welcome, Matthew.
S2 (01:07):
It's a pleasure to be here. Thank you so much
for the kind introduction, and I'm so looking forward to
coming over and connecting with everyone there.
S1 (01:16):
I think audiences will be in for a treat. So
as I mentioned in the intro, you've become one of
the leading voices in sleep science around the world. Maybe
you could just take us into kind of briefly how
that happened. Like, were you getting bad sleep or great.
S2 (01:29):
Sleep.
S1 (01:29):
Or no sleep? Like, was there anything personal that led
you to explore this topic?
S2 (01:33):
I think most of us in the field are accidental
sleep scientists. You know, I don't think when you are
5 or 6 and the teacher's going around the room
and saying, you know, what would you like to be
when you grow up? No one's rocketing their hand up
and saying, I would desperately love to be a sleep scientist.
So we all fall into it by accident. And I did, too.
I was, um, I was back at medical school and
(01:54):
I was doing my PhD looking at brainwave patterns. And
this was in people with early stage dementia, and I
was trying to see what type of dementia they had
very early on, and I was failing miserably. Couldn't get
any good data for the first couple of years. And
then one weekend I was reading in the journals that
some of these dementias, they would have the sleep centers
(02:14):
attacked by the dementia and others, they would leave the
sleep centers untouched. So I thought, well, I'm measuring my
patients at the wrong time of day. I'm measuring them
whilst they're awake. I should be measuring them when they're asleep.
I started doing that. Got great results. And then I
started to ask, I wonder if the sleep problems are
not just a symptom of dementia. I wonder if it's
(02:36):
an underlying cause of dementia. And that was, gosh, almost
20 years ago now, and I just read everything I
could about sleep. I fell in love with this topic
called sleep. It is, I think, the most beguiling topic
in all of science. And I'm desperately biased, I know that.
And it's a love affair that has lasted me well
(02:57):
over two decades, and it will always be, uh, the
topic I study. So I am I'm a humble servant, uh,
of this thing called slumber. And, um, I thought back then,
20 years ago, you know, no one could answer a
very simple question. Why do we sleep? And the answer
back then was we sleep to cure sleepiness. Yes. Which
(03:21):
is the fatuous equivalent of saying, well, I eat to
cure hunger. No, you don't eat to cure hunger. You
eat for lots of physiological, biological reasons. But now, 20
years later, because of the work of all of my colleagues,
not not of my own. We've had to upend the question.
And instead, now we have to ask, is there any
major physiological system of your body, or is there any
(03:43):
operation of your mind that isn't wonderfully enhanced by sleep
when we get it, or demonstrably impaired when we don't
get enough? And the answer seems to be no so far?
S1 (03:52):
Well, I was going to ask about that link between
Alzheimer's and Sleep later on because I knew that it
had been an area. So what did you find? Was
there an underlying sort of causative factor rather than just
a correlation?
S2 (04:05):
Yeah. It's been we've been studying this now for probably
over 17 years now, and lots of other colleagues likewise.
And we now have we started off with correlation, um,
where we just knew that people across the lifespan who
were getting less than seven hours of sleep, especially less
than six hours of sleep, they were at a far
(04:26):
higher risk of developing Alzheimer's disease in later life. But
correlation is not causation. So then, um, we started to
do experimental studies where we could actually measure the amount
of toxic Alzheimer's proteins circulating either in the bloodstream or
in the cerebrospinal fluid. If we punctured that and took
(04:46):
a sample or even in the brain using special brain scans.
S1 (04:49):
Things like.
S2 (04:50):
Tau. And we would either like tau and amyloid protein.
Those are the two culprits. And if we deprive people
for a whole night of sleep, or even if we
selectively deprive them of just deep sleep the next day,
we could see an immediate build up in these Alzheimer's proteins,
in the bloodstream, in the spinal fluid, and in the
(05:11):
brain as well. So correlation went to causation. At that point,
causation begged a question which was mechanism. Why is it
when you don't get your sleep that Alzheimer's proteins build up?
And there's some great work. A pioneer in the field,
Maiken Nedergaard from the University of Rochester in the United States.
(05:31):
And what she discovered was three things. The first thing
that she discovered is that your brain has a cleansing system.
We didn't think it had it. Now, everyone has heard
of the cleansing system of the body. It's called the
lymphatic system. But she discovered that the brain has one.
It's called the glymphatic system. After the cells that make
it up called these glial cells.
S1 (05:52):
Okay.
S2 (05:52):
The second thing that she discovered was that this cleansing system,
the sewage system for the brain, isn't always switched on
in high flow volume across the 24 hour period. Right.
But instead, it's specifically during sleep and particularly during deep sleep,
where you get this power cleanse for the brain. Sort
of good night's sleep, clean as it were.
S1 (06:12):
Yes.
S2 (06:13):
The third thing that she discovered, which finally brought us
to mechanism, was that two of the pieces of metabolic
detritus that sleep was washing away every night beta amyloid
and tau protein, the two culprits of Alzheimer's disease. And
so we've gone from correlation to causation to mechanism. And
(06:34):
now things start to get very interesting. There's a recent
study by that same group just a few weeks ago,
demonstrating that one of the typical sleep medications that are
used by many people around the world, something called Ambien,
that drug, even though it it puts you to well,
let's just say that it's what we call a sedative. Hypnotic.
You're not necessarily naturally asleep. You're just sedated. That's what
(06:57):
these medications do. And so I'm not going to argue.
You're awake. You're not. But are you in natural sleep?
Maybe not. And what they demonstrated is that when they
were dosing animals with Ambien, yes, they slept longer. So
you would think that if the brain is sleeping longer,
it would have more time to cleanse the Alzheimer's proteins
and it would be even better. What they found was
(07:17):
that the Ambien decreased the amount of activity in the
brain centers that were meant to do the cleansing by
about 50%, and reduce the amount of amyloid and tau
protein removal by about 30%. So here was a case
where you're getting more sleep, but that more sleep, quote unquote,
(07:39):
doesn't seem to be functional. It's not transacting the natural
benefits of sleep. And it may potentially explain, although I
don't think so at this stage because it's not causal.
But it may explain why we see people who take those.
Typical sleeping pills are also at a higher risk of
getting Alzheimer's disease. Now, again, no good evidence that those
(08:02):
two things are correlational. It could simply be, for example,
people who are taking Ambien across their lifespan have had
bad sleep for most of their life, and it was
the bad sleep for most of their life, even before
they started taking the medication that was predicting their Alzheimer's disease.
You've always got to be so careful in not conflating
association with causation.
S1 (08:24):
Absolutely. All right. I'm going to come in hot with
my own personal questions about sleep, because when am I
going to get this chance otherwise? Um, so right now
I'm coming around to the conclusion that I probably have
sleep apnea. I have a lot of the symptoms, and
I'm going to get tested and and check this stuff out,
because I know it's something that I need to address.
And I know a lot of other people who feel
(08:45):
like they're in the same boat and they're like, oh, no,
I'm not gonna worry about it. You know, I think
they don't want to wear the the sleep mask. They
don't want to be hooked up to the CPAp machine
or whatever it is. Yeah. Um, what are they? What
what are they missing in? If they don't treat this
kind of thing to their detriment? Or. I guess the
broader question is here, what happens when you get routinely
(09:06):
bad sleep? Because there'll be a lot of people out
there that are getting really bad sleep.
S2 (09:11):
If you are snoring or you have a partner who snores,
or your partner is telling you that you snore, you
need to get tested. It will shorten not only your lifespan,
but what it will also shorten is your healthspan. That's
what most of us care about. We don't necessarily want
to live for decades and decades and decades longer. We
(09:32):
just want to live longer, free of disease and sickness.
That's your healthspan. Yes, sleep apnea will encourage a shorter life,
and that shorter lifespan will be filled with greater amount
of disease and sickness based on the evidence. So that's
the first thing. It is consequential to frame that for you.
(09:53):
What we the way that we measure sleep apnea is
by looking at how many obstructions or how many times,
let's say that you have these events where you stop
breathing and your oxygen saturation starts to drop. And very
mild sleep apnea is where you have, let's say, 5
to 15 of these events every hour that you're asleep.
(10:15):
So let's just call it ten events per hour. And
let's say that tonight you you sort of listen to
this odd, strange British guy and you say, I'm going
to have my eight hours of sleep. Okay. So for
80 times throughout the next night. Imagine if I were
to come into your bedroom and I were to throttle
you to the point where your oxygen saturation dropped, and
(10:38):
I were to do that repeatedly, ten times every hour
for eight hours. So 80 events like that. Do you
think your body would, and your brain would feel well
rested and restored and with life and biological health the
next day as a consequence? And of course, I'm being hyperbolic,
but the answer, of course, is no. And this is
very mild sleep apnea that we're talking about. Many people
(11:00):
out there, we estimate about 80% of people with sleep
apnea are undiagnosed, which is staggering.
S1 (11:07):
That is.
S2 (11:07):
So that's the first thing I would or the first
two things I would say it's consequential. And that is
exactly what's happening. And if you have if people are
listening and you just want to try this for Android
and Apple and I have no affiliation with them, there
is an app called Snore Lab, Snore Lab, and you
can download it and it's on your phone, and then
(11:30):
you just hit record and you place it by your bedside,
and it's going to record your breathing and your snoring
throughout the night. Okay. The next morning you open it up,
there's your eight hours and it will show you like
Richter shocks on a scale, the severity of your snoring,
and it ranks it from mild, moderate, significant and then epic.
S1 (11:49):
Oh man, I'm gonna do this. And I know it's
going to be confronting.
S2 (11:53):
And well, the more confronting part of this is you
can then go into any part of your night, you
can tap on any one of the Richter shocks, and
then you can listen to yourself gasping for breath.
S1 (12:04):
Mhm.
S2 (12:05):
And it really is I mean, just imagine if someone were,
you know, during the day in your office and they
were constraining your oxygen so that you were gasping all
the time. You know, you would never stay at that
job and you would actually file a claim. That's preposterous.
But that's what we're suffering with undiagnosed sleep apnea. So
to the the issue of the treatment, though, we used
(12:28):
to think of this kind of almost fighter pilot esque,
you know, Top Gun mask and big tube coming off,
you know. Right. Your significant other walks into the bedroom.
You've got I'm thinking, you know, I've never wanted you more.
It's not like that anymore. It's there are some great
companies and I think probably the best out there right
now in the business is called ResMed. And they have
a great presence there in Australia. And really now just
(12:50):
comes down to this little nasal pillow that just sits
just over your nose and it is connected to the airway.
And what happens is that in severe or moderate to
severe apnea, you will need a CPAp machine normally, and
it will just place gentle air up the airway. And
it acts like a splint, but it's actually a pressure
(13:11):
splint that will keep the airway open. So you breathe freely.
And many people will say, but I still don't sleep
very well with the mask on. I promise you that
even if you're sleeping not as well as you think
you were before, the quality of that sleep with the
airway splint activated is so much better that even if
(13:31):
it's shorter duration, the quality versus quantity is that much better,
it's well worth it. That said, though, there are great
advances in what we call these mandibular devices. And it
looks like a sports car.
S1 (13:44):
Top and.
S2 (13:45):
Bottom mouthguard. Yeah. And it's hinged at the back. And
it simply just moves the jaw. Just a few millimeters forward.
And everyone can do this test. You lie on your bed,
on your back, and you can try and make the
snoring noise. And every everyone can do it. Then just
grab your thumbs, put them under the jaw and move
your jaw forward, and then try and make the snoring
(14:06):
sound again. And it's immensely difficult. And just that slight
alteration in the anatomy of the jaw opens up the
airway and you can breathe. So many people may not
have to go for a CPAp machine if they're in
the mild category, they can do this. And then there's
other sort of you know, there are some dental and
(14:26):
surgical procedures. Some people will opt to actually have a
very small sort of stimulator implanted just under the skin
that will stimulate the airway open so they don't have
to use the the nasal pillow. So lots of different
treatment options out there for people. But start with snolab.
See if you're snoring. Do 5 or 6 nights sleep
(14:47):
are so idiosyncratic. 1 or 2 nights you're not going
to be representative. Get five nights, have a look at it,
and then really ask yourself, I think I need to
go and get tested and reach out to your doctor.
They will give you an at home test. You don't
even need to go to a sleep lab.
S1 (15:02):
I have a question for you about naps. I love
a good nap. Short and sweet. They kind of revive
me and I and I get up and I'm ready
to go. Go a little bit longer an hour or so,
and I am groggy as a result of it. It's
almost it's counterproductive. It has the opposite effect. I understand
that Thomas Edison was a massive napper, a very enthusiastic napper. Um,
(15:27):
and I feel like he had a novel method for
kind of hitting the sweet spot on a nap.
S2 (15:33):
Yeah, it's interesting that sort of sleep hangover effect, isn't it,
when you nap for a quote unquote too long? And
why is that? And I've got no idea. It was
just theoretical. But no, no, I do. I can explain it.
It's so. It's what we call sleep inertia. And here's
what happens if you want. I've got a friend over
(15:55):
here in the United States, a guy called Andrew Huberman.
He's always telling me protocols, everything. What's the protocol for? Everything. Okay,
what's the protocol for napping? I would say the optimal
nap is around 20 minutes. It's not the same. We've
done lots of studies that if you nap longer, you
continue to get more and more brain and body benefits.
But 20 minutes is the sweet spot because it's enough
(16:18):
to give you what most people want, which is a
restoration and refreshment of my alertness, my focus, my concentration,
my energy. But when you are going into sort of
that 20 minute territory, you haven't gone all the way
down into deep non-rapid eye movement sleep yet deep, dreamless sleep,
so that when you wake up, you kind of go
(16:38):
back up to operating temperature like a classic car engine
pretty quickly. But if you nap maybe 30 or 40 minutes,
you're now down into the deeper stages of sleep. And
then when you wrench yourself out of that, it's like
going from the basement to the penthouse and you get
stuck on the 13th floor. Now, if you wait for
an hour or so like a classic car engine, gradually
(16:59):
the oil temp will start to come up, and then
you'll be firing on all cylinders and you will feel
even better than when you did, you know, an hour
or so before. So you will get more benefits. You
just have to suffer the consequence of that initial dip.
But for most people, 20 minutes is the sweet spot.
Thomas Edison used naps. He was, um, a very, um,
(17:22):
sort of vociferous suggester of the the uselessness of sleep.
And he would say he would survive on 4 or
5 hours of sleep. There are lots of pictures of him.
And he was a habitual napper. I've got a great
picture of him on his inventors bench. A picture of
him in the garden. Looks like after a pretty good
garden party. He's out for the count. And he understood
(17:45):
the creative brilliance of sleep. And he used it ruthlessly
as a tool. Here's what he would do. He would
take two steel ball bearings, put them in his hand,
sit at his desk in his inventor's studio, have a
pad of paper and a pencil next to him, and
then he would take a metal saucepan and put it
underneath the armrest. And then he would gradually settle his
arm back down with his palm facing to the ceiling,
(18:07):
and he would relax back. And so he didn't go
too far into sleep. At some point, his muscle tone
would relax. They would release the steel ball bearings, they
would crash on the saucepan, wake him up, and then
he would write down all of the ideas that he
was getting from sleep. And he coined the phrase, it
was beautiful. He described it as the genius gap. This
(18:28):
gap between lucid waking consciousness and the depths of almost
nonconscious deep sleep. And in that transitional, that kind of
liminal state, you had all of these creative ideas. And
it's probably one of the reasons why no one's ever
told you that you really should stay awake on a problem.
And he recognized that.
S1 (18:47):
You mentioned just there that he he, um, described himself
as a as a very short sleeper, someone who didn't
need a lot to get by on. And, you know,
history is littered with, um, people, uh, who are like that.
I mean, Barack Obama likes to say that he can
exist on five. Martha Stewart only needs four hours a night.
I think Nikola Tesla was said to believe that he
(19:10):
could get by on 2 or 3 hours of sleep.
Is there any optimal optimal amount? I mean, is eight
hours what we should be striving for?
S2 (19:20):
It's a very interesting question, and there is definitely a range. And,
you know, and the people like, you know, Margaret Thatcher,
who was claimed to be the Iron Lady, claimed to
sleep 4 to 5 hours. Her compadre in the United States,
Ronald Reagan, an equal chess Peter about 4 to 5
hours of sleep a night, nothing more. Um, I don't
know if it's coincidental that both Thatcher and Reagan succumb
(19:41):
to the terrible disease of Alzheimer's, you know, towards the
end of their life. Um, but there is an absolute
range for most average adults. It's 7 to 9 hours
of sleep. Once you get less than seven hours of sleep,
we can start to measure impairments in your brain and
your body. And chronically sleeping less than seven hours is
(20:01):
associated with a number of disease risk predictors cardiovascular disease, diabetes,
immune and inflammation issues, certain forms of cancer, hormonal issues,
and then of course, issues around Alzheimer's disease and dementia.
So that said, though, it turns out that there are
(20:22):
a very small subset of the population that we now
call natural short sleepers, and they are genetically determined. We
know that there are at least two or maybe now
three genes that will allow you to get away with
as little as about. If you look at the data
six hours and 12 minutes, and these people can sleep
(20:45):
literally consistently six hours and 12 minutes or around there
and they show no impairment. We just can't measure any impairment.
And so it does seem to be that. Yeah. And
at that point, you know, probably there's lots of people listening, thinking, okay,
I think, I think I'm one of those genetic abnormal people.
And just to frame this in context, statistically, based on
(21:07):
the evidence, you're probably more likely to be struck by
lightning in your lifetime than you are to be a
natural short sleeper genetically.
S1 (21:15):
Right. Okay. We've spoken a little bit about the the
benefits of sleep in terms of your brain. Um, I've
been exercising a lot recently and have and have been
(21:36):
reading a whole lot about runners and athletes and sport
and sleep now seems to be one of the big
areas that they're trying to kind of unlock. It's like
they've focused on hydration, they've focused on fuel. They know
about strength this and stretching that. But it seems now
like sleep has become the the thing that they want
(21:58):
to use to. Yeah, unlock true high performance. Is that
something you've come across in your research.
S2 (22:03):
Yeah. So I've, I've worked with a number of sort
of professional teams around the world and several athletes and
several who are, uh, have been wonderfully vocal about how
much sleep that they get, because there is a terrible
stigma in society about getting sufficient sleep that you're lazy
or you're slothful, or if you've got, you know, enough
(22:24):
time to get seven hours of sleep, then you must
not be busy enough and busy is equated to importance.
And so there is this stepping stone chain of shame
that happens. And I think it's great that athletes have
been embracing it. You know, a couple that I'm familiar with, um,
you know, Federer is Roger Federer has been great in
(22:44):
terms of advocating that LeBron James equally so. Um, Usain
Bolt was was fantastic and would um, uh, one of
the times he'd literally, I think, been awake for about, um,
36 minutes before after a nap, um, and went out
and broke a world record. You know, so I think
there is.
S1 (23:02):
Right.
S2 (23:03):
But nevertheless, I used to say about 7 or 8
years ago that sleep was perhaps the greatest legal performance
enhancing drug that not enough athletes were abusing. But now
the game, I think, has moved on. And because you're
absolutely right, they've optimized, you know, almost all they can
from nutrition, from exercise physiology, from different regiments of mental health.
(23:28):
Sleep now has come onto the map as a professional edge,
and it doesn't take much. You know, if you look
at the difference between, let's say, first place and sixth place,
or a first round pick in the NBA versus a
seventh round pick, you know, the stats aren't that different.
Everyone is much more similar than they are different. So
every sort of edge counts. So we we work with
(23:52):
a lot of teams and but particularly individual athletes to
try to help them improve. And it's an especially difficult
challenge for two reasons. With athletes, the first is usually
before the game. Anxiety and stress is high. Yeah. And
anxiety and stress are probably they are probably the leading,
not the only, but the leading principle underlying cause of
(24:15):
insomnia in society. And I think we you know, and
I'm happy to speak about that. I think the second
component of that is just the travel that almost no
athlete that I've worked with simply performs locally. They all
perform nationally or globally, and they're always traveling. So you've
always got to try to augment a regiment that is
(24:37):
under the duress of jet lag. And so the challenge
is how do we get them to sleep to begin with?
5 or 6 years ago, the challenge was, how do
we convince them that they need to sleep? Now it's
the challenge. We accept that. How do we get it? Yeah.
S1 (24:52):
I imagine there's also you hear this a lot from
Australian rules football players. Anyway, they play a night game
and the adrenaline that's been coursing through their bodies for
2 or 3 hours while they play in front of
100,000 people under lights, is is wild. And then they're
not finished and warm down and kind of changed and
(25:14):
ready to go to bed until midnight. And it's still
kind of coursing through their body. I mean, how are
they expected to to get to sleep then?
S2 (25:22):
Yeah. And we see this in society a lot too.
Or a derivation of this. It's called the tired but
wired phenomenon. Now for them the wired is a chemical
physiological wired in the sense that they're just coursing with endorphins, dynorphins, adrenaline, cortisol.
Everything's racing through their veins. And it's completely antithetical to
the physiological state that is needed to to sleep. So
(25:46):
no wonder they can't. Even though they could tell you
I'm really tired. There's no way I'm going to be
able to sleep for the next two hours because they're
just so wired. And in society, we have that version
which again comes back to just stress and anxiety. You know,
we see people at the sleep center all the time saying,
I'm so tired. I am so desperately, desperately tired. But
(26:08):
I'm just so wired that the Rolodex of anxiety and
stress begins and I just cannot fall asleep. Or I
wake up and I just cannot get back to sleep.
S1 (26:19):
Just speaking about anxiety and stress and depression. Um, those
kinds of, um, mental health problems. Do you think sleep
is kind of overlooked by the medical community, either GPS
or psychologists or whoever it is, as, as a potential
kind of underlying cause, or at least a contributing factor
(26:39):
to those issues that people face?
S2 (26:41):
I think clinicians, um, are becoming more aware of the
fact of sleep's integral role that our sleep health is
intimately tied to our mental health. And I would say,
and this is probably the other largest area of research
that we do at my center is in mental health.
In the past 20 years of studying it, I've not
(27:03):
been able to discover a single psychiatric condition in which
sleep is normal. Um, and for me, that tells me
everything I need to know about the intimacy and the
strength of that connection. So I think psychiatry in the 80s.
90s and early 2000 would see the sleep problems in
(27:26):
mental illness as a concept, as a symptom, as a
consequence of the mental illness. Now, if you look at
the data, I think people are at least seeing it
as a two way street, and it really is a
two way street. We know that insufficient sleep can predispose
and even trigger mental health conditions. And we also know
that on the flip side, mental health conditions will themselves,
(27:49):
once they get started, instigate sleep disruption. So it is
a vicious cycle. And once those those things start sort
of working, it's almost like that tornado that just starts
to spin out of control.
S1 (28:02):
That flywheel.
S2 (28:03):
Yeah, exactly. Precisely. And in some ways it's a message
of hope, though, because sleep at least gives you a
sort of an entry point in to try to break
that cycle, that sometimes it's fiendishly difficult to try to
stabilize the mind with either therapy or medication. But if
(28:23):
you can try to stabilize sleep through its natural sort
of emotional first aid through its what I've described as
overnight therapy benefit. It can come in and it can
short circuit that constant negative spiral. And when you kind
of right the ship and you course correct sleep, you
often it's usually very uncommon that you don't at least
(28:47):
see some improvement in the mental health symptoms.
S1 (28:50):
When I was a teenager, I could sleep until 2:00,
3:00 in the afternoon on a on a Saturday or
a Sunday. Now, granted, I was sitting up late watching movies,
and so that sort of only makes sense, but I
always felt like I was actually just clawing back some
of the sleep that I missed during the week from
(29:11):
getting up early to go to school. Um, school does
kind of start early for kids all around the world.
And I feel like you have some pretty specific views
on this on how early, um, we get kids up
and out the door and into the classroom.
S2 (29:28):
Yeah, I think this consistent and you can see it
across almost all first world nations. The there's this incessant
model of marching school start times back and back and
back earlier and earlier and earlier. And as we go
through those adolescent teen years, something biologically interesting happens on
(29:50):
natural rhythms. Start getting forced forward in time. So when
before when we were, say, you know, ten years old,
you know, you could get into bed and you could
fall asleep nine, ten, you know, maybe earlier, but now
once you're 15 years old, you now can't go to
sleep or get sleepy until, let's say, midnight. And it's
(30:13):
not because you're trying to be rebellious. There is actual biology.
There's physiological machinery that shifts during that adolescent phase to
push teenagers to a later to bedtime and later wake
up time. It's not their fault, is point number one.
The second point is that you're absolutely right. They have
(30:37):
been lumbered with this incessant chronic sleep debt by forcing
them to wake up so early. And if you look
at these, um, models throughout the world where they've decided
to kind of push back against this mentality and delay
school start times, what you typically see when school start
times are delayed are academic grades increase truancy rates, decrease
(31:01):
attendance rates as a consequence, increase psychiatric and psychological referrals decrease.
And then something also interesting happened. The lifespan of these
individuals increased on average. And you think, well, wow, hang
on a second. I don't understand how you could measure
or track that. Well, the leading cause of death in
(31:22):
adolescent teens from 16 to 18 is actually not suicide.
That's second. It's road traffic accidents. And here, sleep matters enormously.
There's a great study from, um. It was Teton County
in Wyoming in the United States. They shifted their school
start times from 735 in the morning to 855 in
(31:43):
the morning. And what they found was that not only
were those kids getting an extra one hour of reported
sleep the next following year, road traffic accidents dropped by 70%,
so car crashes dropped seven zero in that age 16
to 18 range. Now, to put that in context, you know,
the advent of ABS technology, anti-lock brake systems in cars
(32:06):
that dropped accident rates from 20 to 25%. But here
is a physiological thing which is called giving your teenagers
enough sleep that will drop accident rates by up to 70%. So,
you know, I don't mean to trivialize it. Getting children
to school at a certain time is not easy. Parents
(32:28):
have got to get to work themselves. Bus unions and
school buses, they've all got to sort of try to find.
So it's not a it's not an easy thing I
understand that. I also think, however, that we've been able
to put people on the moon. So I think we
can solve this because if you look at the data,
when sleep is abundant, minds flourish. And when it is not,
(32:52):
they don't. And I fear that we are we are
doing a disservice to our children in the most sort
of incredibly spectacular manner with this incessant model of early
school start times. So I've been trying to lobby it
throughout the throughout the United States and go state by
state in terms of legislative law, and we're starting to
(33:14):
make it happen. But it's very, very difficult.
S1 (33:16):
I'm one of those people who does not remember my dreams,
at least unless I wake up and go, remember that dream,
remember it, focus on it. Um, and I've got to say,
I also can't think of anything more boring than hearing
about someone else's dreams. I hate it when someone says
you won't believe what I dreamed last night. It was
so bizarre. Imagine if you're walking.
S2 (33:38):
Through the world as a sleep scientist. That's all people
want to tell you about. Either that or how to
fix my sleep. But. But keep going. Yeah.
S1 (33:47):
So I was going to ask, though, what did you
dream about last night? And and what, uh, what purpose
do dreams serve? I mean, dreams were referenced in the,
in the subtitle of your book, so they're not a
small part of what you, um, what you study and consider.
S2 (34:03):
Yeah. Dreams are fascinating. They, you know, we used to
think of dreams as just epiphenomenal that they are just
the byproduct of the stage of sleep from which they
arise from which is principally rapid eye movement sleep. And
the analogy would be coming back to Thomas Edison, let's say,
you know, think about a light bulb. The reason that
you've constructed the apparatus of a light bulb is to
(34:23):
create this thing called light. But when you create light
in that way, you also produce something called heat. Heat
was never the design, purpose or brief of the light bulb.
It's just epiphenomenal. What happens when you create light in
that way? And so too, we believe dreams were the
heat of the REM sleep light bulb, right? But now
(34:46):
I think we've got substantive evidence that dreams serve at
least two unique functions above and beyond the stage of
sleep from which they come, which is rapid eye movement.
The first is that dreaming is almost like a form
of informational alchemy. It's that during dreaming we start to collide.
All of the recent things that we've learned with all
(35:08):
of the back catalog of information that we've got stored
up in our brain, and as a consequence, we wake
up with a revised mind wide web of associations that
is capable of divining solutions to previously impenetrable problems.
S1 (35:24):
Okay, so it's sort of this, this period in which
we knit together the the past and the present.
S2 (35:29):
Yeah, yeah. You know, it's it's almost like group therapy
for memories. You know, everyone gets a name badge, and
you all go into this room of REM sleep at
night and REM sleep. What's interesting, though, relative to wakefulness
during wake, we build the obvious first kind of order connections.
The logical ones. Dream sleep is like the Google search
(35:49):
algorithm gone wrong that you input, you know, into this
sort of, you know, um, you know, vivid Sydney. And
all of a sudden you get something that is about
a field hockey game in Utah in the United States.
And you think, hang on a second. But if you look,
there's a very strange, non-obvious association that seems to happen.
And dream sleep has this kind of almost biased algorithm
(36:13):
to seeking out the very distant, non-obvious associations. Because when
you start to fuse things together that shouldn't normally go together,
but when they do, they offer marked advances in evolutionary fitness.
It sounds like the basis of biological creativity, and that's
one of the functions of dream sleep. The second function
(36:34):
of dream sleep is radically different. It is a form of,
as I sort of said before overnight therapy, that it's
during dream sleep and the special chemical cocktail that happens
during dream sleep, that the brain is able to strip
away the emotion from our memory experiences the day before.
So a better analogy would be, um, dreaming. It's almost
(36:58):
like a nocturnal soothing balm. Okay, that dreaming sort of
comes along and it just takes the sharp edges off
those painful, difficult experiences so that you come back the
next day and they're not as painful anymore. So you
went to bed with an emotional memory, and you wake
up the next day with a memory of an emotional event,
(37:20):
but it's no longer emotional itself. Dreaming comes along and
it almost divorces the emotion from the memory. It strips
the bitter emotional rind from the informational orange, as it were.
And that's why it provides this sort of, um, mental help, uh,
therapy overnight.
S1 (37:37):
So what about what about, um, the opposite then? So
if I, I have to sleep in, like, boxer shorts.
Probably too much information for you there, but I can't
sleep in heavy layers. I need a sheet rather than
a big doona, whereas my my wife is sort of
cuddled under a bunch of different layers. But the long
(37:57):
point I was getting to is if if I am
wearing too much, if I'm too warm, I can guarantee
I'm going to have a nightmare. So I just wanted
to ask, what's the purpose of nightmares then? Or why
do we have nightmares given, you know, the value of
dreams that you were just talking about?
S2 (38:14):
And it is interesting, you know, to your first point,
sleep is immensely temperature sensitive. And we know that there
is this unique kind of three part stanza to good
temperature sleep, which is that you have to warm up
to begin with at your surface to draw all of
the blood out of the core. So you have to
warm up to cool down. So you bring the blood
(38:35):
to the surface by warming it, and then you radiate
the heat out from the core that's trapped there like
a snake charmer. And then your core body temperature plummets.
So you have to warm up to cool down, to
fall asleep. And then you have to stay cool to
stay asleep. And then you have to warm up to
wake up. And I'm absolutely like you, you know, I,
I have to sleep now I sleep hot. And I'm
(38:57):
usually there in kind of like a kind of like
I'm like you, you know, my wife, it looks like it's,
you know, it's Somewhere. Polar vortex. You know, because. And
you know, I don't know, I may have lost it
during the night. It's somewhere down the rabbit hole of covers.
It's this monstrosity. So. So with rescue parties, most mornings
it works out. But to your point, what's also interesting
(39:18):
is that we don't just need to warm up to
wake up. We need to warm up to go into
dream sleep.
S1 (39:25):
Right?
S2 (39:26):
But if you get too hot, your dream sleep starts
to get fragmented. So normally dream sleep or REM sleep
has what we call a thermo neutral sweet spot. Which
means that if you get the ambient around you in
underneath that blanket and it's just a small little layer,
if you get that ambient temperature close to your core
(39:49):
body temperature, then you are going to be riding nicely
high on this thing called REM sleep. But if you
get too warm, your REM sleep starts to become fragmented
and you wake up more. And it could be that
waking up more, that fragmented nature of the REM sleep
makes that dream sleep committed more to memory, which can
(40:09):
also lead to frustration or sort of embedding some of the,
you know, the negative parts of the dream or the
fearful parts. And that can lead you to think I'm
having more nightmares as a consequence. Nightmares, per se, aren't
necessarily problematic. Many people will have nightmares. It just seems
to be part and parcel of natural sleep. However, if
(40:30):
the nightmares are causing you daytime distress or nighttime distress
where you actually are starting to fear the notion of
going to bed because you don't want a nightmare, then
seek out a specialist. We now have some great treatments
for nightmares. One of the treatments that people can just
Google and find someone locally, um, who will provide this
(40:54):
service is called image rehearsal therapy or I r t.
S1 (41:01):
Okay.
S2 (41:01):
And you worked with a therapist, and you start recalling
the dream during the therapy session. But what you do
is you take the traumatic part of the memory of
the dream, and you change it. It's like going into
a word document of a nightmare and saying, you know,
towards the end it got really scary and I don't
like that. So I'm just going to rehearse. I'm just
going to kind of cross it out, and I'm going
(41:22):
to go in there and do some suggested edits, some
tract changes. And if you do that time and time again,
the memory circuit actually gets rewritten. So you're going to
rewrite your own nightmare autobiographical history. And if you keep
doing that day after day and then sleep to strengthen
that newly updated memory, over time the nightmare frequency decreases.
S1 (41:47):
Fantastic. I can't believe we've eaten up so much time.
I've got so many other questions I could ask you
about sleep. I wanted to talk about the the kind
of growing commercial field of sleep, wellness and what's next
on the horizon in sleep research and whatnot. But I
feel like I've made listeners wait long enough for the
thing that they probably want from this and that, the
(42:10):
thing that people probably want from you every time they
run into you. It's the it's got to be the
top tips for for good sleep, right? What what can
people do to ensure that they get better sleep and
enjoy all these benefits that you've been talking about today?
S2 (42:25):
Yeah, I would say the the first set is probably
the really boring stuff that everyone's heard, which is sleep hygiene.
You know, we think about dental hygiene. Well, there's sleep
hygiene and that's things like, you know, making sure that
you are trying to stay away from too much caffeine
in the afternoon, certainly in the evening, trying to limit
your alcohol use. You know, alcohol, people will say, if
(42:48):
I have a cup of nightcaps in the evening, I
fall asleep. Great. Alcohol is in a class of drugs
that we call the sedatives. And sedation is not sleep.
So you're just mistaking the former for the latter in
that regard. The other thing I would say is alcohol
will also fragment your sleep. So even if you fall asleep,
you will wake up many times throughout the night. But
you don't commit the wakening, the wake ups to memory.
(43:10):
So you wake up the next day and now you're
kind of reaching for 3 or 4 cups of coffee
because you don't feel restored and refreshed. And now what
happens is that you get overactivated on stimulants during the day,
and you have to take on board more alcohol in
the evening to try to bring you back down. So
it's basically a kind of a go pill and a
stop pill. It's this sort of this, this real sort of, um,
(43:34):
unfortunate cycle and dependency that starts to develop, um, some
of the sleep hygiene, keep it cool. Bedroom temperature probably
around about, sort of about sort of 17 to 18 degrees. Um,
sounds cold for most people, but you need to sort
of keep it around there. Wear socks, you know, put
(43:54):
a hot water bottle at the end of the bed.
That's fine too. But the ambient has to be cold. Mhm. Um,
as for the kind of unconventional tips, the first thing
I would probably tell people is do this experiment for
the next seven days. And if it doesn't work, just
say that guy is full of absolute nonsense. Set an
(44:14):
alarm for one hour before you expect to go to
bed when that alarm goes off. Shut down almost all
of the lights in your house. You will be stunned
by how sleepy and soporific that will make you feel.
And it does a number of things. Firstly, we're a dark,
deprived society in this modern era, and we need darkness
at night to trigger the release of a hormone called
(44:35):
melatonin to help structure our sleep. The second thing is
that it stops you being so mentally active when it's
dark around you, it's hard to get activated and agitated.
It also starts to reduce down. The likelihood doesn't stop it,
but the likelihood that you then want to jump onto
your laptop or on your phone because you're looking at
(44:56):
the screen with the dark ambient around you, it's almost
a little bit too much. The second tip, I would say,
is the devices that we use are we used to
think were a problem for sleep because of the blue light.
And there was some good studies suggesting that now really
based on a fantastic, um, sleep scientist, uh, from Australia,
(45:20):
Michael Gradisar single handedly has really just converted the field.
He's demonstrated it's not really the blue light, it's that
these devices are attention capture devices, and they are designed
to fleece you of your attention economy, and they do
it ruthlessly well. And so it's because these devices are
(45:43):
so activating that you could be very sleepy. And if
you took them away and it was just pitch black,
you'd say, gosh, actually I'm surprised. I'm actually quite sleepy.
But they hit the mute button on your sleepiness and
they keep and they cause what's called sleep procrastination. So
I would say in the last hour before bed lights
go out. It will bring you back down physiologically and psychologically.
(46:06):
Try to limit the use of those devices not because
of the blue light, but because they are activating. And
then the following rule of thumb if you absolutely have
to take your phone into your bedroom, and I know
I understand that the following rule is this you can
only use your phone in the bedroom standing up. And
(46:27):
then at that point after about 7 or 8 minutes,
you then you think, ah, I'm just I'm just going
to have a bit of a sit down. Sorry. At
that point phone goes away. The other thing I would
say that probably the biggest issue that people face with sleep,
either falling asleep or staying asleep is anxiety. Stress. It's
the Rolodex of anxiety because in the modern era, we're
(46:51):
constantly on reception, and very rarely do we do reflection,
and the only time we now do reflection in society
is when we turn the light out and our head
hits the pillow. And that's the worst time to be
doing reflection.
S1 (47:03):
Right.
S2 (47:03):
And so at that point, if you can't fall asleep
and that stress has started to happen in the mind
at that point, you start to ruminate. When you ruminate,
you catastrophize. And when you catastrophize, you're dead in the
water for the next two hours. Because everything, at least
to me, feels twice as bad in the dark of
night as it does in the light of day. So
(47:26):
your job at 3 a.m. in the morning is the following.
Get your mind off itself. How do you do that?
At least five different ways. First meditation. It's well proven
to help people. It may not be your thing. So
what else do you have for me? The next thing
that you can do is just do what's called a
body scan. Start at the top of the head. Just
(47:47):
start to feel the tension in your body. Is your
forehead too tense? Start to relax it. Feel the tension
in your neck. Start to relax and just move throughout
the body. If you don't like the sound of that
do box breathing, you can inhale in for five seconds,
hold it for five seconds, and then exhale for 7
or 8 seconds. And there's lots of different versions of
that you can do. Another thing that you can do
(48:09):
is take yourself on a mental walk.
S1 (48:12):
Okay.
S2 (48:13):
So this is a great study also by an Australian researcher.
But um, here at UC Berkeley in the United States,
Alison Harvey, she firstly and this is the fifth point,
do not count sheep. What she found was that counting
sheep makes it even worse because you're thinking about not sleeping.
What she found as an alternative was go on a
hyper vivid mental walk. And what I mean by this is,
(48:36):
let's say I'm going to take my dog out on
a walk that I know very well. So I open
the drawer. Which leash am I going to take? I'll
take the the blue one, not the red one. Clip
the dog in with my right hand, open the door
with my left hand. Start to move out and walk
down the left. Then the car comes around the corner
too quick. It's in kind of 4K, hyper vivid detail
that you need to do the mental walk. What is
(48:58):
common about all of those things I've just described is
that they all get your mind off itself. They are
all distracting your mind. Sleep at 3 a.m. in the
morning is like trying to remember someone's name. The harder
you try, the further you push it away. And as
soon as you stop trying, that's when it comes back.
(49:19):
So when you do these types of techniques, usually what
typically happens is that the next thing you remember is
your alarm going off in the morning. Why? Because you've
got your mind off itself. If none of those things work,
the final thing I would tell you is the following.
Don't panic. Don't worry about everything that we've discussed about
Alzheimer's disease and cardiovascular disease. Don't worry about that. Everyone
(49:43):
has a bad night of sleep. It's not going to
do you any major disservice for the most part. Instead,
just accept the following. Tonight is not my night, and
that's okay. I'm not going to stress about it. Instead,
here's what I'm going to do. I am just going
to take this opportunity to rest. Wouldn't it be lovely
if someone came into your office at midday and said,
(50:03):
actually just come through to the next room, we've got
a bed set up for you. I don't want you
to sleep. I just want you to have a rest.
Just sit there and just have a rest for the
next hour. How about that? You think that sounds rather
lovely to me? Well, just rest and keep your eyes open.
You have to stay awake and keep your eyes open
and just rest. And all of a sudden, what you'll
(50:25):
find is that your eyes start to become a little
bit heavy. But you've got to keep them awake. And
you've just got to rest. And then once again, usually
the next thing that happens is you're getting woken up
by your alarm.
S1 (50:37):
Fantastic. Ah, look, now, I can't wait to get to
sleep at night. It's, you know, early in the morning here. Um,
thank you so much for your time, Matthew. I really
appreciate it. I'm sure our listeners have gotten a lot
out of it. Have a great day.
S2 (50:50):
Okay. Take care. Good luck with the sleep apnea.
S1 (50:52):
Thank you. That was sleep professor Matthew Walker in conversation
with Conrad Marshall for good weekend talks. If you enjoyed
this episode, please remember to subscribe, rate, and comment wherever
you get your podcasts and keep tuning in for more
compelling conversations. Season seven starts on January 17th. Good Weekend
(51:13):
Talks is brought to you by the Sydney Morning Herald
and The Age. Proud newsrooms powered by subscriptions to support
independent journalism. Search, subscribe Sydney Morning Herald or The Age?
Good Weekend Talks is produced by Konrad Marshall and edited
by Tim Mummery, with technical assistance from Kai Wong, Cormac
Lally and Josh towers. Our executive producer is Tammy Mills.
(51:35):
Tom McKendrick is head of audio and Melissa Stevens is
the editor of Good Weekend.
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