0:00

Good morning, Erinds.

0:01

Good morning everyone, and thank you for the invitation

0:03

to come and share a story that I

0:06

went through my career. In

0:08

twenty twelve, I was an intern back

0:10

in Dublin in a large teaching hospital. I

0:13

was six months after finishing my intern

0:15

year, aged twenty three,

0:17

and I was working in a busy surgical unit.

0:20

It was January and I

0:23

was woken up about six am

0:25

to go and start my journey

0:27

to work. As I've gone to work,

0:30

I've where in mind.

0:31

It's a Thursday.

0:31

I've already undertaken about thirty six hours

0:34

of work within this

0:36

work week from Monday, and I'm about to go

0:38

and start on another Thursday. I

0:41

feel I'm relatively well rested, but

0:44

I know that I'm not feeling particularly

0:46

good going in to start a very

0:48

large shift, which I'm going to elaborate on a little

0:50

bit now. At six point

0:52

thirty, I arrive into work and I

0:55

undertake results checking. We look at all

0:57

the results of our patients from the day before,

1:00

recent blood tests, recent scan results,

1:02

and ultimately to prepare for the ward round when

1:05

our surgeons and the consultants and

1:07

the senior doctors will start undertaking

1:09

looking at every patient on their list. At

1:12

seven o'clock, we start sharp and we finish

1:15

about eight o'clock. And at eight o'clock those senior

1:17

surgeons will head off to surgery, and us as

1:19

the junior doctors, will then undertake.

1:20

The tasks of the day.

1:22

We'll look at organizing consultations,

1:25

We'll be writing letters, discharging patients,

1:27

admitting new ones, and then deal with

1:29

problems as they occur on the wards. It's

1:33

fast paced. It's a busy

1:35

unit, but it's something.

1:36

That I thrive.

1:37

I enjoy the

1:40

challenges as they present. I really

1:42

am passionate about the work and I'm very happy

1:45

to work in such a busy environment. Even though

1:47

you might only be getting twenty minutes for a

1:49

quick lunch break, you feel very valued,

1:51

You feel wanted and

1:54

a key cog in that machine of the hospital.

1:57

But there's very much a drive. You have to have

1:59

the work done and it has to be done correctly.

2:01

It's got to be done with precision, because

2:03

at the end of the day, patient care depends on it.

2:07

As the day continues, we

2:09

tick over to about quarter to six in

2:11

the evening, and then the surgeons are starting

2:13

to come out of theater and then we start doing a further

2:16

round through the hospital again of all the patients

2:18

that have been under the lists, of

2:21

the surgeons whom have operated, and those who are still

2:23

waiting after their operations. These

2:26

rounds then can finish about quarter past seven.

2:28

So bear in minds I've been in the hospital since six point

2:30

thirty and it's now quarter past seven at night, and

2:33

then start the next part of my shift. And

2:35

back in twenty twelve, we were routinely

2:38

rostered to do twenty four hours, So I

2:40

will then move from my day job to

2:42

then providing night cover in the tertiary

2:44

hospital, of which there are only four

2:46

interns. All of us have only

2:48

done six months prior,

2:51

and we're all fresh out of college, maybe

2:53

twenty three, twenty four to twenty five. We

2:57

each cover in the region about one hundred and eighty patients,

3:00

each with one senior doctor to call upon for assistance

3:03

as we go.

3:04

Through the night.

3:05

Now, usually you would get a scattering of sleep

3:07

here or there of a few hours,

3:10

maybe hold each other's pages. This

3:13

particular night in question, that

3:15

was not going to be one of those cases. We

3:18

were dealing with six patients across the hospital

3:20

and in my particular area that I was looking after I

3:23

know offhand I was dealing with the patient who was having

3:25

an acute stroke on the middle of the ward,

3:28

as well as a patient who was bleeding post operatively

3:30

on the ward and trying to get them back to theater for

3:32

emergency surgery. Jobs

3:35

kept creeping up as we went through the

3:37

night, and they did not stop. But

3:39

then we were getting to six point thirty in the

3:41

morning, and I was then starting to get

3:44

set for the next ward round, which my.

3:45

Team were getting prepared for.

3:48

And it's at that point that I've been notified that

3:50

we have a sick doctor on and

3:52

I'm going to be required to stay, and my

3:54

boss has asked me to stay and

3:57

conduct surgery with them. Now,

4:00

I'm not a surgeon, and I'm working under

4:02

complete supervision of very senior surgeons at

4:04

the time. I'm not putting any patient within

4:07

risk because I'm simply holding a retractor.

4:09

I'm not doing anything that's going to be compromising

4:12

them. It is simply to be able to hold

4:15

something in theater and provide that extra

4:17

bit of support so the surgeon and their

4:19

assistant can do their work under

4:21

full supervision. At that time, I

4:24

finished and wrapped up about eleven thirty in

4:27

the morning and I'm excused, at which point

4:29

I've probably been awake for about twenty

4:31

nine hours and scatterings of sleep

4:34

here or there. I make

4:36

the decision to drive home, and

4:39

nobody forced me to make this decision. I

4:41

took that completely on myself. And

4:43

as I'm driving down the Grand Canal in Dublin,

4:46

I fall asleep at the wheel and I

4:48

wake up with a jolt and I've put my car

4:50

into the back of a large Dublin bus.

4:53

I get out of the car, look

4:56

at the smashed windscreen, completely obliterated

4:59

bonnet, and smoke coming up the engine. I'm shaking.

5:01

I'm uninjured, but really

5:04

fraught with anxiety

5:07

and just fear of what's happened. I

5:11

call my dad, who's been a fantastic

5:13

wealth of wealth

5:16

of advice and support for me over the years, who helps

5:18

me to navigate the situation in

5:20

relation to getting insurance, calling

5:22

retrieval authorities, etc. To get the cars

5:25

off the road. He slowly

5:27

makes his way to come and see me on the Grand Canal

5:29

dock, and as traffic starts to move on,

5:31

we get the daggered looks of

5:33

the frustrated drivers whose days have

5:36

been interrupted by my accident.

5:40

But my dad has been a wealth of advice

5:42

over the years, says to me is that this has been a very valuable

5:45

learning curve for you, and

5:47

you've gone through it without anybody

5:49

being injured. And for me, that was what was

5:52

really interesting, was because now as I reflect

5:54

back on that, my life could have taken a very different

5:56

turn. Not only was

5:58

I uninjured, but I did not injure

6:01

anybody else. And it's something

6:03

that it really does strike

6:06

fear in me that I didn't

6:08

only put myself in a position of danger, but I put

6:10

others in danger and it only

6:12

cost me the price of my car, not the cost

6:14

of someone's life or my own life, and

6:16

leaving a family potentially

6:19

having an injured family member or even

6:21

my own family where they would have to have

6:23

dealt with my debt because of the decision I made.

6:25

But in reality, I was far too fatigued

6:28

to make that decision correctly.

6:30

And as I said, no one forced me to do this. This was something

6:32

that I did on my own bat and

6:35

it's something I reflect on every day as

6:37

I go to work, whether I'm making sure that

6:39

I am not in a position where I can

6:41

make an error like.

6:42

That again, that

7:29

is just a terrifying and very

7:31

relatable story.

7:32

And I'm glad that you were okay.

7:34

I'm glad everything turned out okay, and

7:36

just thank you very much for sharing the story

7:38

with us.

7:39

Yeah, thank you. We're so glad, like you

7:41

said that the accident wasn't worse than it was, and

7:43

we really appreciate you sharing it with everybody here

7:45

today. I think it's something that unfortunately

7:47

a lot of us can probably relate to. So

7:50

thank you so much, thank.

7:51

You for having me. Thank you. Hi.

7:58

I'm Aaron Welsh and I'm a'm

8:00

an update and.

8:01

This is this podcast will kill You

8:03

and we are coming to you live

8:06

with our very first recorded live

8:08

episode from Perth, Australia, The

8:10

Lovely Perth. We're here at the

8:12

twenty twenty four AIOH Annual

8:15

Scientific Conference and Exhibition and

8:17

we are just thrilled to be here.

8:19

We really are.

8:19

Thank you all so much for having us.

8:22

A huge thank you to Zach and Kelly

8:24

and David and everybody who helped organize

8:27

this conference. We are truly honored

8:29

to be up here today speaking with you all.

8:30

Really and in light of the fact

8:32

that we are at the annual meeting of the

8:35

Australian Institute of Occupational

8:37

Hygienists, and we just flew across one

8:39

million time zones to get here, not an exaggeration.

8:42

We decided to focus on a topic

8:45

that is of central importance to pretty

8:47

much every industry, and that is

8:49

fatigue, specifically fatigue

8:51

caused by disruption in our circadian rhythms

8:54

in the context of shift work.

8:56

And because that alone is

8:59

such a huge topic that there's no

9:01

way that we could fit it all into a ninety minute plenary,

9:03

We're not going to make you sit here for one hundred hours.

9:06

Don't worry, We're going to take

9:08

you through just a few parts of that. So

9:10

first I'm going to focus on what do we mean

9:13

by fatigue, how do we define that,

9:15

and what does that actually mean, how our

9:17

circadian rhythms actually work,

9:19

and how disruption in circadian rhythms

9:22

can lead to symptoms like fatigue, excessive

9:24

daytime sleepiness, and so many other chronic

9:26

health conditions.

9:27

And then I'll get into how our

9:29

understanding of circadian rhythms has evolved

9:32

over time, the changes that

9:34

led to shift work becoming as

9:36

widespread as it is today, and how

9:38

we came to recognize those negative effects

9:41

of shift work. And then we're going to

9:43

bring on a subject matter expert, doctor

9:45

Ian Dunkin, who will share some of the current

9:47

exciting research that's going on on circadian

9:50

rhythms and how to combat the negative

9:52

effects of things like shift work and

9:54

jet lag.

9:55

Yes, but first, no

9:58

episode of our podcast this pla I Guess

10:00

We'll kill you would be complete without a beverage

10:03

that we call a quarantinie or

10:05

in our case of place berta, because we don't have any

10:07

alcoholic spirits in it.

10:09

But we are drinking one today. Today

10:13

we're drinking TikTok. You don't

10:15

stop get it because it's

10:18

like a clock. Yes, it'll

10:20

be funny. We explain jokes so

10:22

that they're not funny anymore. But

10:26

in TikTok, you don't stop.

10:27

There.

10:27

It's a delicious beverage consisting of

10:29

one ingredient, which is Australian

10:32

ginger beer.

10:33

So thank you.

10:33

It's delicious and also

10:36

easily modified. You can add whatever spirit

10:38

you would like or just leave.

10:39

It with a little bit of lime in there. Delicious.

10:42

Sorry, we should have really had the foresight to make

10:44

a drink for everyone, like under your seats you can

10:46

find oh, my gosh, very

10:49

Oprah.

10:49

Cheers to

10:52

you all.

10:53

Okay, now, drinks

10:55

are drunk, shall we

10:57

We'll get into the biology

10:59

of are circadian with us?

11:01

I can't wait. Yeah, tell me all about it.

11:02

It's going to be fun. So

11:16

we decided to do this talk today on fatigue

11:19

because it's kind of this universal

11:21

experience that also happens

11:23

to be an occupational hazard in so

11:25

many different industries.

11:27

Everyone has at.

11:28

Some point been fatigued

11:31

experienced fatigue. But when we

11:33

talk about this idea, what do

11:35

we actually mean, Like, how do we define fatigue?

11:37

Right?

11:38

It's super easy to define, right, Right,

11:40

there's not a definition.

11:42

There is not a single definition of fatigue,

11:44

but there are a lot of different definitions.

11:47

Most of them use a lot of synonyms, things

11:50

like tiredness or exhaustion.

11:53

Most of the definitions include something like

11:55

the decreased ability to function at

11:57

your normal capacity or something of

12:00

decreased capacity for mental or physical

12:02

work.

12:03

Okay, So overall we're.

12:04

Looking at fatigue as this generalized

12:07

lack of energy that overall has

12:09

some kind of impairment on your ability

12:11

to function, be that your physical function or

12:14

your cognitive function.

12:15

All right, makes sense?

12:16

Okay, And following but in that definition, what's

12:18

important about it is that we then have to intentionally

12:20

separate fatigue from sleepiness.

12:23

Right, right, And how does one do that?

12:25

How does one do that by defining

12:28

sleepiness?

12:29

Okay, more definitions, more definitions.

12:31

So we can do this by defining sleepiness

12:34

as directly related to the physiologic

12:36

phenomenon that is the act of falling

12:38

asleep, okay, because that means that

12:40

it's something that we can measure, okay,

12:43

at least to a better degree than we can fatigue,

12:45

which is so nebulous. Right, And

12:47

we do this. We can measure sleepiness with a couple

12:49

of different tests. There's one called the

12:52

multiple sleep latency test, which

12:55

is I'm going to put you in a dark room and you're going to lay down

12:57

and fall asleep. How long does it take you?

12:59

Wow? Not stressful at all, right.

13:02

And then there's also the maintenance of wakefulness

13:04

test, which is how long can you stay awake

13:07

if we sit to you in a dark room and ask

13:09

you to not sleep.

13:11

We have to be sitting just sitting with your

13:13

thoughts in a dark room. No, I don't like

13:15

that idea.

13:17

Now, sleepiness itself like

13:19

falling asleep, It's not a bad thing.

13:21

Inherently, we have to sleep.

13:23

It is required of all humans,

13:25

and as humans are diurnal species, we have

13:27

evolved to sleep.

13:28

At night when it is dark and be

13:31

awake when it is light.

13:32

So being sleepy at night time itself

13:35

is not a bad thing, but if

13:37

that sleepiness is happening when we shouldn't

13:39

be asleep, then it can lead to what's

13:41

called excessive daytime sleepiness, or

13:43

this inability to stay awake during

13:45

hours when you should be awake, and

13:48

that can be bad or, as we heard in

13:50

our first hand account, even downright dangerous.

13:53

Both excessive sleepiness and

13:55

fatigue, though they are different,

13:57

and these definitions are important, also

14:00

kind of two halves of a story,

14:03

and they both contribute to the kinds

14:05

of accidents and workplace events like we heard

14:07

about in our first hand account. And while

14:09

circadian rhythm disruptions themselves

14:12

are by no means the only things that

14:14

can cause excessive daytime sleepiness

14:16

or fatigue, these are two

14:18

of the most immediate consequences that

14:20

we see from circadian dysfunction.

14:23

So having a basic understanding of what

14:25

our circadian rhythms are and how they work

14:27

can go a really long way to understanding

14:30

what happens if they get pushed out

14:32

of sync, which then can

14:35

lead us to better anticipate the hazards

14:37

that might be inherent to some professions,

14:40

or recognize these symptoms when they start

14:42

to crop up during certain phases of life.

14:44

Hello newborns, Gotta love them.

14:48

And then evaluating and understanding

14:50

these consequences of this type of circadian

14:52

disruption can help us to actually implement

14:54

strategies in the future to help

14:56

mitigate some of these.

14:58

Hopefully we'll get there. Yeah, can

15:00

it be done?

15:00

Can it? So?

15:02

Then, first we have to start with what really is

15:04

circadian rhythm? And I think most

15:06

people probably have a sense of what

15:08

this.

15:08

Means in their mind right.

15:10

It comes from the Latin circa means about

15:13

and ds or DM means.

15:14

Day stole my line, Yeah, thank you,

15:17

I try so.

15:19

When we talk about a circadian rhythm, we're

15:21

talking about cycles that are happening in our

15:23

bodies on an about

15:25

twenty four hour timeframe. And

15:27

Aaron, I know later you're going to talk about why

15:30

we have these rhythms. Yeah, like from

15:32

an evolutionary perspective, yep, what

15:34

are they.

15:34

Doing for us? It's they're important? Are they?

15:36

Let's find out yeah.

15:38

But I'm going to focus first on how

15:40

they actually work. And everyone

15:43

is probably most familiar with a circadian rhythm

15:45

in the context of sleep and

15:47

our sleep wake cycle, because

15:49

our sleep wake cycle is one of the most classic

15:52

examples of our circadian rhythm in action. So

15:55

we can see a few different things

15:57

that oscillate in our sleep wake cycles.

16:00

One of them is something like melotone

16:02

in secretion. So our melotonin peaks

16:05

in the couple of hours before we go to sleep,

16:07

and then we'll go to sleep, our corticol

16:10

levels will peak in the morning right about

16:12

the time that we tend to wake up. We

16:14

also see oscillations in our body temperature,

16:17

with the lowest body temperature happening

16:19

in the wee hours of the night while you're still asleep.

16:22

I just want to ask why for each one

16:24

of these.

16:25

I don't have great answers, but I can

16:27

tell you that what these like the why

16:29

is that these processes together are

16:32

what are driving our drive

16:34

for wakefulness okay, and our

16:37

pressure for sleep okay. So

16:39

these three things, they're not the only things that are involved

16:41

in what's literally keeping us awake during the

16:43

day and telling our bodies we need to go to

16:46

sleep at night.

16:46

But these are three of the big.

16:48

Drivers of that drive for wakefulness

16:50

that happens during the day and that pressure

16:52

for sleep that happens through like.

16:54

Towards the night. But what's the deal with temperature?

16:57

Oh?

16:57

I don't know? And also what is.

16:58

That so use the body? But are changes

17:01

by how many degrees?

17:02

I knew you were going to ask that, and I meant to like look it up

17:04

again to try and get in. I don't know.

17:08

I don't know that it's twenty it's just the fool

17:10

Yes, like a proportions

17:13

of a degree.

17:14

Yeah, yeah, yeah, Okay, we're little changes.

17:16

But it's enough that it's sort of in that

17:18

period when we're close to waking up.

17:21

That drop in temperature is what helps our bodies

17:23

stay asleep essentially, right, it's

17:25

colder, stay asleep, et cetera.

17:27

Rkay, Okay, explain why didn't

17:30

sleep well when I have that power?

17:32

Yeah, we're going off track. So,

17:34

as humans, because we're diurnal, we see

17:36

these particular cycles again

17:38

on this twenty four hour clock where sleep

17:41

is happening at dark and a week time is happening

17:43

during the light. So this is what we

17:45

all think of when we think of circadian rhythm. But

17:48

it is not just this

17:51

our circadian rhythm, like literally

17:53

every single function and process

17:55

in our bodies from the cellular

17:58

level, like the genes that are controlling

18:00

which cells are going to divide, when the

18:02

genes that are controlling DNA repair, does

18:04

it happen in what cells? And when things

18:07

like our immune system, our metabolism,

18:10

our hunger cues, our bowel

18:12

movements, our libidos,

18:14

every function in our body is controlled

18:16

to one degree or another by circadian

18:19

processes.

18:20

It's like the ultimate but weight. There's more. It's

18:22

not just sleepwake, it's everything.

18:25

Everything, and these all

18:27

are our circadian rhythms. It's not

18:30

just sleep, but sleep is a big part

18:32

of our circadian rhythm. And

18:34

these circadian rhythms are mechoganized internally

18:37

in our bodies by what's called an intrinsic

18:40

circadian clock. But not

18:42

just one clock. We have multiple

18:44

clocks. We have a main

18:47

clock in the part of our brain that's called the super

18:49

chismatic nucleus.

18:51

I'm really glad that you pronounced

18:53

this because I just wrote SCN over and

18:55

over again.

18:56

I don't even know if I talk about SCN. But no,

18:58

now I.

18:59

Know how to pronounce the SCN or the super

19:01

chismatic nucleus, and this region

19:03

in our brain functions as like a master regulator

19:06

of our internal clock. But all of our peripheral

19:08

cells and tissues, they all have clocks of

19:10

their own, and together all

19:13

these clocks drive our many many

19:15

circadian rhythms, in large

19:17

part by the build up and then the breakdown

19:20

of specific proteins whose

19:23

literal job it is to

19:26

be made build up and

19:28

then break down on a

19:30

twenty four hour cycle to keep these clocks

19:33

all in sync with each other.

19:34

Okay, does that make sense?

19:35

Yeah, it's like pretty basic, right,

19:38

super simple.

19:39

I'm sure it took no time at all to figure that out.

19:41

No, no, no, So that's how

19:43

these circadian clocks are working on like a cellular

19:46

level. And I said that these are

19:48

intrinsic, and we know that these

19:50

are intrinsic because these

19:52

cycles will persist on

19:54

an.

19:54

About twenty four hour basis.

19:56

In humans, it's a little long. We

19:59

tend to run about twenty four hours and ten

20:01

minutes.

20:02

I got eleven in here.

20:03

Eleven minutes, eleven minutes, nine to eleven

20:06

is what the literature says.

20:08

We can have a rate anywhere from nine to eleven

20:10

minutes and twenty four hours.

20:12

And twenty four hours and eleven minutes nine

20:14

to eleven and our clocks keep doing

20:16

this even if we put someone in a dark

20:19

room with absolutely no external environmental

20:21

clue cues like in absence

20:23

of the environment, our clocks still run.

20:26

However, these

20:28

environmental cues are in fact an

20:30

essential part of our circadian rhythm because

20:33

a lot like clocks, old

20:35

tiny clocks, not new fangled watches

20:37

which work by magic.

20:39

Is how my magic I watch works.

20:41

Okay, old tiny clocks

20:44

mechanical ones you used to have to wind

20:46

in order for them to keep correct time.

20:49

Our circadian clocks also have to

20:51

be wound in order to keep

20:53

them on as close to a twenty four

20:55

hour cycle as possible, and this

20:57

happens through a process called entrainment.

21:00

And the environmental cues that we use for

21:03

entrainment in our circadian clocks

21:05

are called zight gabers. Which

21:08

is my attempt at German, and

21:10

that is German for timegiver.

21:12

How'd she do?

21:13

Did anyone speak German?

21:14

And not?

21:15

Great?

21:15

I can tell I tried

21:17

really hard.

21:20

Zight gabers.

21:21

In humans, it is light, predominantly

21:24

light from the sun that acts as

21:26

our number one zyp giver or

21:28

time giver, and the sun

21:31

light from the sun is detected by these specialized

21:33

cells in the back of our eyeballs that

21:36

project directly to that SCN,

21:39

the super chismatic nucleus, and

21:41

that part of our brain again is this pacemaker

21:44

that coordinates the cycles in

21:46

all of the rest of our body. And

21:49

they do this, they coordinate the timing of like

21:52

so many different processes, right

21:54

through direct and indirect pathways

21:56

to keep us on this twenty

21:59

four hour cycle in sync

22:01

with the sun or the light around us.

22:04

Now, light is by no means our only

22:06

zight gaper. Food can be a powerful

22:09

one, especially for other mammals other than

22:11

humans.

22:12

We also can.

22:12

See, exercise, social activity, other

22:14

things can serve as zitkeepers, but light

22:17

is by far the primary one

22:20

that our particular clocks use, which

22:22

means that although these rhythms are generated

22:25

internally, they do require

22:27

entrainment, mostly via light in

22:30

order for so many of our biological

22:32

processes to match our environment.

22:36

So when our environment changes, like

22:38

when we travel across exactly nine

22:41

time zones I counted between California

22:43

and Western Australia to come to a conference ten

22:45

for me, suffice

22:47

to say, our internal clock no longer

22:49

matches our external environment.

22:51

I'm feeling okay, though I will say thank

22:53

you caffeine.

22:54

Yeah, that's a big part of it, right, And

22:56

we all know this particular phenomenon very well.

22:59

This is jetlag. And with jet

23:01

lag, because of this discrepancy between

23:03

your external environment, the timing

23:05

of light exposure, and where your internal

23:08

circadian clock was set before you left,

23:10

you end up feeling pretty terrible.

23:13

Right, not

23:15

myself, not today right now, we feel great,

23:18

but you can end up feeling pretty terrible.

23:20

You might have symptoms like a really hard time

23:23

falling asleep when it's time to fall asleep,

23:26

or maybe you simply cannot keep your eyes

23:28

open for like an afternoon meeting when you get

23:30

to where you're going. And because

23:32

again, this malagested timing is

23:34

affecting every body

23:37

system that we have, not just sleep,

23:40

it's not just being fatigued or

23:42

being excessively sleepy, you might also

23:44

have gi upset, mood changes,

23:46

brain fog, and so much

23:48

more. Now, in addition

23:50

to regular old jet lag,

23:53

there's also a phenomenon called social jet

23:55

lag.

23:57

We'll separate it all.

23:58

Right, and social jetla is basically

24:00

this idea that we all as

24:03

like a society at large, not us

24:05

in this room here. We have all decided

24:07

that our day starts at like eight am,

24:09

right, or whatever we

24:12

can say for it, and that is

24:14

where the day is supposed to start for everyone across the

24:16

board.

24:17

But a lot of us.

24:18

Maybe end up relying on like our alarm

24:20

clocks to wake us up on the weekdays

24:22

to be able to get ready for work on time.

24:24

A lot of us, I mean of us who doesn't

24:27

that would be amazing?

24:29

Yeah, And then when that happens,

24:31

many of us might perhaps on

24:33

weekends, when our schedule permits

24:35

it, sleep in later, go to bed later,

24:38

stay up later. So we have this

24:40

shift in what our schedule looks like between

24:43

weekdays and weekends. And

24:45

it turns out that different people might

24:47

feel differently. Some of you might be like, oh, yeah, I do that,

24:49

and others are like, noth dude, six am, I'm.

24:52

Ready to go.

24:53

That's because we all have different chronotypes,

24:56

and a chronotype is like different natural

24:58

tendencies to either sleep early or

25:00

sleep late, like early bird, night owl. It's a

25:02

real thing. Which are I'm an early bird.

25:04

You're an early bird? Like so what is the

25:07

threshold? Like? What a fun question?

25:09

I don't know. I don't know.

25:11

I don't know if there's like a specific thing.

25:13

And can you be neither or can you be like a light early?

25:16

You can be neither, you can be whatever you want to be.

25:18

Okay, are you an early bird? I think about

25:21

mild early bird.

25:22

Mild early bird?

25:23

Ye like and not too early? Yeah bird?

25:25

Yeah, I don't want the first word.

25:28

One would be fuels.

25:29

Are still left at the book and want them all

25:32

gone.

25:34

I love that I'm an early very

25:36

early No, No, probably not.

25:39

Maybe I wish I was. It's

25:41

too much.

25:42

But for people, especially who veer more night

25:44

owl, then they might

25:47

have an especially hard time waking

25:49

up for that eight am start every day.

25:51

Right.

25:51

This is especially true for teenagers. And

25:53

that's not just a stereotype teenagers.

25:55

Actually we see shifts in their intrinsic circadian

25:58

clocks during the teen years, and like.

25:59

Most teenagers at least in the US,

26:02

start their days at like.

26:03

Before seven, right, which is do

26:05

we do it? It was miserable.

26:06

It wasn't my idea.

26:09

And so this system of forcing these

26:11

early wakings on some days and then

26:13

maybe seeing a shift in what your patterns

26:15

are like on the weekends, it can end up causing

26:17

chronic sleep deprivation. And so that's what

26:20

we see in this phenomenon of social jet

26:22

lag, and that's something that a lot of us have probably

26:24

experienced to one degree or another. But

26:27

we also then have even more severe

26:29

or persistent disruptions in our circadian

26:31

cycle that can result from a more

26:33

chronic forced mismatch

26:35

between our environmental cues and our

26:37

intrinsic clocks. And this is what

26:39

we can see in shift work. So

26:42

across the globe, it's estimated that

26:44

anywhere between ten and thirty percent

26:46

of all adults in industrialized countries.

26:49

Which is a lot.

26:50

That's a lot, work in shift work.

26:52

And often if you work in shift

26:54

work, then you might end up working

26:57

outside of a traditional eight to five of

26:59

like a regular old job, and that might

27:01

mean you're working night shifts. And night shifts, of course,

27:03

are going to require a complete flip

27:05

of your circadian.

27:06

Cycle where you have to adapt to working.

27:08

Entirely during the dark hours and being

27:10

asleep during the light hours.

27:13

Right, But it might

27:15

not just be night shift. It can also mean rotating

27:17

shifts.

27:18

It can mean late afternoon shifts that bleed

27:20

into night time, or it can

27:23

mean early early morning shifts that require

27:25

you to start your day before the dawn.

27:27

My mom was an afternoon night shift

27:29

work, or an afternoon worker as a nurse.

27:31

But she loved it because she would just lay out at the pool

27:33

until three pm. She said,

27:36

she was like, I loved it, and then I would go home. And maybe

27:38

she is she a night owl, not

27:40

anymore.

27:43

Because that would track.

27:46

But so all of any of

27:48

these scenarios can serve to end

27:51

up disrupting our circadian clock because they're

27:53

disrupting the typical timing of our

27:55

light dark exposure. In a lot

27:57

of cases, it might be exposing our eyes and

27:59

thus our brains to light

28:01

essentially twenty four hours a day. And

28:04

while sometimes people can adjust

28:07

the timing of when they're asleep and when they're awake,

28:09

like maybe they sleep just fine during the day, they

28:11

like sleeping in late and then laying out in the sun

28:14

or whatever, what we do see

28:16

is that the vast majority of shift

28:18

workers do not show a complete

28:21

shift in all of their circadian

28:23

rhythms, meaning things like

28:25

their melatonin secretion, as an

28:27

example, will still happen at night

28:30

time, and in some cases can

28:32

be up to twelve hours out of phase

28:34

from when they're actually sleeping. Wow

28:36

right.

28:37

Yeah.

28:37

There was one paper I read that estimated that only

28:39

about twenty five percent of people who work

28:42

night shift long term actually show

28:44

evidence of having a lot of these circadian

28:46

rhythms actually being shifted in

28:49

line with their real life. Wow

28:51

right, it's a pretty low percentage, okay.

28:54

And this is like continuous night shift work, not

28:56

like rotating shift work or like two

28:58

weeks on two week two exactly.

28:59

This was a people who are like night shift for the long term.

29:01

Yeah yeah, And so this can

29:04

unsurprisingly result in what's called shift

29:06

work disorder, which

29:08

is a disorder that can be characterized by things

29:10

like insomnia, which is difficulty

29:12

falling asleep or staying asleep, or

29:14

it might be excessive sleepiness like

29:16

falling asleep when you shouldn't be at work or

29:19

micronapping. But it can also

29:21

lead to increased irritability, it can

29:23

lead to mood changes like depression or anxiety,

29:26

and it overall can lead to this mental

29:28

fog that can lead to increases in

29:30

mistakes because of all of this fatigue and

29:32

sleepiness. So some studies suggest

29:35

that working during the night alone

29:38

increases the risk of workplace accidents

29:40

by forty to one hundred percent.

29:42

WHOA, which is huge.

29:43

It's a huge range also, but it's also

29:46

huge, like very significant. And

29:49

shift work disorder alone is not

29:51

that uncommon. Some papers estimate

29:53

up to twenty seven percent of shift workers

29:55

meet the formal definition of shift

29:57

work shift work disorder.

30:00

But on a practical.

30:01

Level, everyone who has work shift work has probably

30:03

experienced, to one degree or another, this

30:05

negative effects of this circadian disruption. Yeah,

30:08

but again, it's not just fatigue and sleepiness

30:11

at work or outside of work, because

30:13

especially what we see with time

30:15

spent working night shifts

30:17

having really significant impacts

30:19

on long term health. Shift

30:22

workers are at about a twenty to

30:25

thirty five percent increased risk of

30:27

breast cancer, prostate cancer,

30:29

colorectal cancers, but also

30:32

type two diabetes, coronary artery

30:34

disease, and depression and many

30:36

other chronic health conditions as well.

30:38

Eric, But like, what is the mechanism

30:40

for that? Like why, Yeah, what do we know about

30:42

that?

30:43

We don't know everything, which

30:46

is a classic line,

30:48

and I will say that there has in the literature

30:50

been some pushback as to like how

30:53

causal is this relationship because

30:55

a lot of these disorders also have a lot

30:57

of other lifestyle factors that influence them

31:00

as well, and so sometimes you might see

31:02

difference in lifestyle between people who work

31:04

shift work or night shift work specifically

31:06

compared to day shift workers and things like that.

31:09

But the evidence, especially

31:12

for cancers in animal studies,

31:14

is so significant that circadian

31:18

rhythm destruction in animal studies leads

31:20

to cancer formation, tumor growth. And

31:23

it is such overwhelming evidence that the International

31:26

Agency for Research on Cancer named

31:29

night shift work a probable carcinogen

31:31

all the way back in.

31:32

Two thousand and seven. Wow, this is like a new

31:34

information.

31:35

But then if we dig even deeper on like what is

31:37

the mechanisms, we know

31:39

that our circadian rhythms are affecting

31:42

so much of our overall

31:45

body functions, and what we see

31:47

is that disynchrony of our

31:49

sleep wake cycles and our

31:51

endogenous circadian rhythms ends

31:54

up leading to things like increases in blood pressure,

31:56

reduced insulin sensitivity, elevated

31:59

lipid concentration, and so all of these

32:01

might put us at risk for things like diabetes, hypertension.

32:04

Cardiovascular disease.

32:05

There's also some evidence between like timing

32:08

of and amount of melatonin secretion

32:11

and the effects on uncogenesis

32:13

or cancer formation.

32:14

That's interesting exactly.

32:16

So at like a basic level, what it's

32:18

thought to be is that all of these increases

32:21

in risk are a result of the fact that so

32:23

many of us working night shifts. Our

32:25

endogenous circadian rhythms do not

32:28

adapt to this forced pattern

32:30

of being a weak.

32:31

At night and being asleep during the day.

32:33

So it's a mismatch between our internal

32:35

cycles and the environment.

32:37

So that's the best answer I've got. I mean, I

32:39

think that's a pretty good awer.

32:41

Parts it is, yeah, and probably

32:43

a lot of specific mechanisms that go into each of

32:45

the different disorders and things like

32:47

that, But on the whole, I

32:50

think I've convinced you all that

32:52

it's abundantly clear that our circadian

32:54

rhythms are very, very integral, not

32:57

just in our sleeping and our weakness and our alertness

32:59

or fatigue, but also in so

33:01

much of our health. So circadian

33:04

rhythms are an important thing to consider in the context

33:07

of a lot of our stages of life, a lot

33:09

of our professions.

33:10

So I have a question for you erin uh huh,

33:13

ask go ahead.

33:14

If this thing, these things,

33:16

these circadian rhythms that seem

33:19

today to be it's so easy for us

33:21

to disrupt them, to get get messed up. You

33:23

just hop on a plane, just change.

33:24

Your clocks back, just go into a grocery store

33:27

at night.

33:27

Right.

33:28

If it's so easy for them to get disrupted,

33:30

and when they get disrupted, they can cause

33:32

so much trouble, why

33:34

do we have them? What

33:36

do they do for us as humans or

33:39

creatures like you?

33:40

And when?

33:41

How did we know all of this? Tell me everything?

33:43

Okay, I'll tell you as much as I can tell you, maybe

33:46

not everything. Wherever

34:05

you are, whether you're here in this

34:07

room in Perth, Australia at this conference,

34:10

or you're tuning in from across the

34:12

world. I want you to imagine yourself

34:15

as a dot on the globe, as a

34:17

pin on the map I've.

34:18

Marked Perth here.

34:21

Now, let's rewind time, let's

34:24

say two hundred million years or so,

34:27

keeping that pin in its original coordinates,

34:29

and I want you to picture a time lapse

34:32

of the continents shifting, colliding,

34:35

separating, oceans, expanding

34:37

and shrinking, mountains forming

34:39

and crumbling.

34:41

What is your pin witnessing in

34:43

all of this?

34:44

Has it mostly been a drift in a vast

34:47

ocean, or has it been at the

34:49

center of continental action, witness

34:51

to collisions and separations, or

34:54

maybe your pin has seen it all.

34:58

As our time lapse comes to an end

35:00

eventually and the continents

35:02

have settled into the familiar positions,

35:05

let's take a minute to marvel at the incredible

35:08

dynamic changes that our planet has

35:10

seen over those two hundred million years,

35:12

which is just a fraction of the Earth's four

35:14

and a half billion year existence. Grasslands

35:18

turned to deserts, rainforests

35:20

turned to freshwater lakes, and

35:22

temperature rainfall and atmospheric

35:24

composition shifting tremendously

35:27

over these millennia. Life

35:29

on Earth has had to deal with

35:31

a lot of change, even

35:33

just over those two hundred million years. But

35:36

throughout those transformations, there

35:38

has remained one near constant.

35:41

The sun always rises and the sun

35:44

always sets.

35:45

I love that so profound.

35:48

And while the time between sunrise and sunset

35:51

varies across latitudes and seasons,

35:53

the existence of a day has always

35:56

been a feature of life on Earth. So

35:58

let's go back to your pain the map the

36:00

two hundred million years ago, the day

36:02

you'd experience outside of like having to

36:05

fight and hide from dinosaurs,

36:07

is nearly identical to the one that you'll

36:09

experience today, just about

36:11

an hour shorter thanks to the Earth's

36:13

s gradual slow down. In a world

36:16

filled with so much uncertainty,

36:19

it can be reassuring to have that one

36:21

constant. And this sentiment

36:23

is shared across much of life on Earth.

36:26

Most organisms have evolved to

36:28

anticipate these daily changes. Plants,

36:31

animals, fungi, algae,

36:34

even cyanobacteria all possess

36:36

internal clocks that control the timing

36:39

of biological, physiological,

36:41

and behavioral responses.

36:42

We love that we see it, even in bacteria,

36:45

likely fascinating.

36:47

It's so cool. I also love that someone looked for that.

36:49

Right They're like, we've got to find it here.

36:52

It's not just us, It's not just us,

36:54

it's everyone. Or is it?

36:57

Is it that I don't know.

37:02

Rhetorical question.

37:03

But these behavioral responses,

37:06

or these biological responses, things like sleep,

37:09

like the release of certain hormones, or like

37:11

feeding that occurs at certain times of day

37:13

or night, and we call these rhythms

37:15

that are these responses that repeat

37:18

over a roughly twenty four hour period, of course,

37:20

are circadian rhythms. The ubiquity

37:23

of these rhythms across all

37:25

or almost all of life. I guess I don't

37:27

know what's going on in like the worms that live in

37:29

the deep sea events.

37:31

Whether they have they always mess things up.

37:33

I don't know, they could have. They probably still

37:35

be something we'll find

37:37

out. Yeah, well we'll look into it. But

37:39

it just speaks to how important these

37:41

rhythms are. But

37:44

why why would it.

37:45

Be so crucial to partition our

37:47

activity or our physiology across a

37:50

twenty four.

37:50

Hour period, That's my question?

37:51

Why does it matter?

37:53

In a word, optimization, Our

37:55

external environment changes in many

37:58

ways every day, availability,

38:01

predator activity, temperature, When

38:03

other members of your species are also

38:05

out and about, you want

38:07

to spend your energy where it counts. If

38:10

you're a bird who relies on color

38:12

vision for foraging for berries,

38:15

you probably want to do that during the day, when

38:17

the light actually helps you pick out

38:19

those colorful berries.

38:21

See them, you can actually see helps.

38:24

But if you're a small prey mammal

38:26

species like this flying squirrel, maybe

38:29

running around at night is your best bet

38:31

to escape predators or flying around.

38:33

You also don't want to be active all the time.

38:36

It will be exhausting.

38:37

Our sleep is incredibly important

38:40

for housekeeping tasks that our body

38:42

can't do while we're running around, and

38:44

circadian rhythms help us optimize

38:46

how we spend our energy and when

38:48

it's safe to get the rest that we need to

38:50

recuperate.

38:52

Anyone who has pulled an.

38:53

All nighter or who has had to run

38:55

on a few stolen hours of sleep after welcoming

38:57

a newborn knows the pain of being

39:00

out of sync with the world.

39:02

But for the most part, we can easily.

39:04

Recover from these one time or short term

39:06

disruptions. But what happens

39:08

when there is a constant mismatch between

39:10

your internal clock and the external environment.

39:13

Well, we know from what you.

39:14

Just told us, Aaron, that it's really not great,

39:17

not good for humans at the least, not good for

39:19

most, if not all, of the animals we've studied,

39:22

and decades of research have shown that

39:24

it's not great for really anything.

39:26

So let's take a minute to get into the story

39:28

of how we came to understand these rhythms

39:31

of our lives and the consequences

39:33

of their disruption. Humans

39:35

have recognized circadian rhythms in ourselves

39:38

and other creatures for millennia. Aristotle

39:41

in the fourth century BCE noted

39:43

that bees slept bees,

39:46

bees slept fourth

39:48

century BCE.

39:50

I love that they're just cutting open hives, being like,

39:52

oh, that one's asleep.

39:53

Oh yeah, I'm sure. Sorry, you're disturbing up

39:56

like this. Very's so cute.

40:00

And around the same time and Rosthenes

40:02

observed the leaves of the tamarin tree curling

40:05

and uncurling over a day. The

40:07

famous ancient Greek and Roman physicians Hippocrates

40:10

and Galen described fevers that

40:12

peaked at certain times of day.

40:14

What do we think that might be?

40:15

I love this, it's malaria, it's larious, probably,

40:18

yeah.

40:19

And one of the leading hypotheses for why

40:21

these cyclic fevers exist is

40:24

that the parasites match the circadian rhythm

40:26

of their host or their mosquito vector

40:28

for more likely transmission. Like is,

40:30

do they go into the bloodstream at certain times a

40:33

day so that that's when the mosquitoes are biting.

40:34

It's really that's not

40:37

malaria.

40:38

It's horrible.

40:38

Yeah,

40:41

but they and the parasites

40:43

are like going to be active at certain times to maximize

40:46

transmission.

40:46

That's I know, mind blowing evolution.

40:49

Man, it's pretty cool.

40:51

But for centuries, all of these observations

40:54

remained just that observations.

40:57

No one attempted to answer the question of

40:59

why until them seventeen twenties,

41:02

when a French scientist by the name of de Meran

41:05

decided to take a closer look at a plant,

41:08

specifically Mimosa pudica,

41:10

which also goes by the adorable

41:12

common name of sensitive plants or.

41:14

Shy plant or shype so I used to call it.

41:17

And anyone who is interacted with this plant

41:19

can see where it got its nickname. When

41:21

you touch its delicate leaves, they fold

41:24

in on themselves like ah, don't touch me,

41:27

and then a few minutes later they'll open back up, though

41:29

they calm back down. But it turns out

41:31

that the plants also do this folding

41:33

and unfolding routine throughout the day,

41:35

folding up at night.

41:37

Day.

41:37

Moron, observing this, thought to himself,

41:40

what if the two words at

41:42

the heart of every scientist, what

41:44

if they aren't exposed to light?

41:46

Then what happens?

41:48

And so he plopped the plant into a dark cupboard

41:50

and saw that it still opened

41:52

and closed its leaves over that twenty four

41:54

hour period.

41:55

Wow, even in complete darkness.

41:57

And so if light wasn't driving this pattern,

42:00

what was In

42:02

eighteen thirty two, about one hundred

42:04

years after day Morn's experiments, Swiss

42:07

botanist Augusta. Kendall took

42:09

this question further, placing MOMSA

42:11

plants under continuous light. Initially,

42:14

the plants still show their daily leaf movements,

42:17

but as the days went on, the

42:19

candle watched as this pattern grew

42:21

out of sync with day and night. Something

42:24

internal, like an internal clock,

42:26

perhaps it seemed to be

42:29

driving these movements, governed

42:31

by a cycle slightly shorter than a day,

42:33

around twenty two hours compared to twenty

42:35

four to Kandle's

42:37

experiment was the first to demonstrate the

42:39

concept of a free running rhythm,

42:42

where an organism's internal clock is slightly

42:44

longer or shorter than a full twenty four hour

42:46

day, and in the absence of external

42:48

cues, their rhythms will eventually decouple

42:51

from that twenty four hour cycle and instead

42:53

be guided by their internal ones humans,

42:56

for instance, twenty.

42:57

Four and twenty four hours then nine to

43:00

eleven minutes.

43:02

But, as it often goes Dick, Kendal's conclusion

43:04

that organisms are guided by an internal

43:07

clock as opposed to responding solely

43:09

due to external stimuli was not

43:11

immediately embraced.

43:13

Shock imagine that.

43:14

We learned something new and not everyone believes.

43:17

The debate on whether these daily patterns

43:19

were directed by internal or external

43:22

forces continued basically

43:24

up to the middle of the twentieth century, coinciding

43:27

with the peak of the nature versus nurture

43:29

debate, But while nature versus

43:31

nurture seemed to be only increasing in

43:34

contentiousness, research on

43:36

rats, plants, birds,

43:39

bees, even humans demonstrated clear

43:41

evidence for an internal clock cut

43:44

off from external cues. Mice

43:46

and rats kept running on their wheel or sleeping

43:49

right on schedule.

43:50

Chickens who had been incubated at.

43:52

Constant conditions still hatched with

43:54

an innate biological rhythm. Bees

43:57

demonstrated a keen sense of time

44:00

and an ability to communicate that time.

44:02

These are just an amazing example.

44:05

Rhythms and flower time in really

44:07

good I have to.

44:08

Like schedule, like have a little schedule calendar

44:11

for oh, ta this flower then, because that's

44:13

when it's producing nectar.

44:14

Right.

44:14

They have it all in a little notebook.

44:15

I just imagine getting there a little early and they're like, oh.

44:18

My gosh, you'll wait, wait, this is

44:20

where's the nectar?

44:21

Yeah, got places

44:23

to be. Next

44:25

one opens in five.

44:29

And humans turned out to be no exception to

44:31

this, as a series of cave, Arctic

44:33

and.

44:33

Underground bunker experiments demonstrated.

44:36

The first of these took place in nineteen

44:38

thirty eight when physiologist Nathaniel

44:41

Kleitman called his graduate student

44:43

Bruce Richardson into his office one.

44:45

Day this is how I imagining how it went,

44:47

and.

44:47

Said, hey, Bruce, can I interest

44:49

you in an all expenses paid, thirty

44:52

two day trip to Mammoth Cave, Kentucky

44:54

where we'll hang out in a cavern and try to adjust

44:56

our bodies to a twenty eight hour day. The

44:58

nearby hotel will take care of our gourmet

45:01

meals. You can bring whatever books you'd

45:03

like.

45:03

I've got a deck of cards to play bridge. It'll

45:05

be great.

45:06

One deck of cards, thirty two days.

45:08

Yeah cool, Well that's all you need really really,

45:11

but bridge, just bridge.

45:12

I don't even know how to play bridge me either.

45:14

Two conditions though.

45:16

You've got to record your sleep movements and

45:18

your temperature at regular intervals.

45:21

Richardson said, yes, I mean, who wouldn't

45:23

like I would do this? That sounds fun.

45:26

I tried his advisor and he's like, well,

45:28

I can't say no.

45:29

That's true.

45:29

Yeah.

45:30

I tried to do it with ticks. Do you remember this.

45:32

I was sampling in Panama and I tried to measure

45:34

see if there was like a diurnal pattern

45:37

of tick abundance. And then the rainy

45:39

seasons a three

45:41

am. Yeah, and I got rained out and I had.

45:43

To leave and this is over.

45:44

Yeah.

45:45

It was exhausting new experiment. Yeah,

45:47

I never I never did it again though. Oh

45:50

well, opportunities for the future. But

45:53

while the scientific.

45:54

Conclusions drawn from this end of two experiment

45:57

just Kleiittman and.

45:57

Richardson, they were a little vague, right.

46:00

Richardson apparently readjusted to twenty

46:02

eight hours, but Kleitmann did not. It

46:04

made quite an impact on the budding

46:06

field of chronobiology, drawing

46:09

the attention of journalists who sketched a

46:11

story of scientific adventure, as

46:13

well as researchers who wanted to try it

46:15

for themselves, like Michel

46:17

Sifrey, who spent two months in a cave

46:19

in the Italian Alps in nineteen sixty

46:21

two, waking and sleeping when

46:24

he felt like it. Ultimately, when

46:26

he emerged, he was shocked to find

46:28

that he had lost two weeks.

46:31

He thought I'll just it'll be exactly where I

46:33

think.

46:33

But no, no, he lost two weeks because he's too long.

46:36

And this work helped to incite interest

46:39

into the study of circadian rhythms, and

46:41

by the early nineteen sixties the field

46:43

of chronobiology was born, with one

46:45

of its leaders, Franz Hallberg, introducing

46:47

the term circadian rhythm in nineteen fifty

46:50

nine.

46:51

Seems so recent, I know it

46:53

is. I mean internal clock. I think was at

46:55

least from the eighteen hundred. This this is the term rhythm

46:58

more recent, Okay.

47:00

Since then, researcher has examined the

47:02

process of entreatment which you described,

47:05

and I was thinking about zeit Gabers

47:08

Again, apologies for the pronunciation as

47:10

kind of like right now, how you're giving a talk and

47:13

you think, oh, I'm right on time, I'm doing great,

47:15

and then someone at the back holds up like a five minute warning

47:17

and you're like, whoops, I'm only halfway

47:19

through my presentation.

47:20

I feel like that sign is a psyche Gaberah.

47:22

It's a good analogy. I like it.

47:24

Researchers have examined the mechanistic

47:27

basis of how these external signals

47:29

are received by the hypothalamist eyes,

47:31

pineal gland, or by some other means.

47:34

They've attempted to decipher the genetic basis

47:36

of biological clocks, identifying clock

47:39

genes and observing how these genes

47:41

synchronize across our body to orchestrate

47:44

broad physiological and behavioral

47:46

changes during a.

47:47

Twenty four hour period.

47:48

They've done a lot, Yeah, a lot,

47:51

and this research has been integral

47:54

to understanding what drives

47:56

the rhythms of our life, why they're

47:58

important, and what happened when

48:00

they're disrupted, which brings me toune

48:03

dune.

48:03

Dune shift work.

48:05

Shift work has been around forever,

48:08

or at least for thousands of years, standing

48:10

guard, keeping the fire lit, watching

48:13

over your flock of sheep, caring for the

48:15

sick or wounded. The military

48:18

and certain trades have long required

48:20

irregular hours, like shipbuilders who

48:22

had to work with the tides, or rope

48:24

makers. I found a quote by a rope

48:26

maker from seventeen forty two.

48:29

We cannot make ropes when the sun shines.

48:31

We begin at eight o'clock at night and work

48:33

till eight in the morning, and sometimes we work

48:35

all day if we can hold it. I

48:38

don't know why I tried

48:40

to look into it. And I even asked like blue

48:42

Sky, and I got varied answers

48:44

and some fun hypotheses. But if anyone knows

48:46

or is an idea they have to work at night, please

48:49

reach out, come find me. But

48:51

until the late eighteen hundreds, shift work was a fairly

48:54

uncommon occurrence. Then let

48:56

there be light, specifically

48:59

electrical life. In

49:01

eighteen ninety two, just three years

49:04

after the invention of the light bulb, the first

49:06

power plant in New York opened, supplying

49:08

continuous powder to those who could receive

49:11

it. The effect on industry

49:13

was immediate. Factories

49:16

that had to shutter their doors shortly after

49:18

the sunset, or who used lanterns

49:20

or gas lights for overnight work, could

49:22

now operate around the clock, bathe

49:25

in the glow of artificial light. For

49:27

the heads of industry, the benefits of

49:29

around the clock operation were clear

49:32

again, the word optimization comes to mind.

49:35

Factories could be more efficient while maximizing

49:37

production, and a twenty four hour workday

49:40

broken down into shifts became the

49:42

new norm for many industries, even

49:44

those that had not previously required

49:46

continuous labor. Shiftwork

49:49

was not just something to give them a leg up,

49:51

but it was becoming necessary to survive

49:53

the competition. It was apparent that

49:55

industry was enjoying an economic boom

49:57

from this increased productivity.

49:59

But how were workers faring

50:01

in this brave, new, well lit

50:03

world? Doing

50:06

great? I'm sure doing wonderful.

50:09

Interest in this question grew in earnest

50:11

over the first couple decades of the twentieth century,

50:14

and a new concept term industrial

50:16

fatigue was introduced to describe

50:19

the exhaustion caused by over exertion

50:21

to long working hours and insufficient

50:23

rest, often measured by a

50:26

decline in productivity.

50:28

About productivity, Aran, yeah,

50:30

I mean so.

50:31

Under this framework, human health was reimagined

50:34

as or equated to the body's

50:36

capacity for productivity. So,

50:38

in other words, if you're sick, that means diminished

50:41

output. If you're exhausted, that

50:43

means more mistakes, which means diminished

50:45

output. And this concern with worker

50:47

health and productivity, especially when

50:49

it came to industrial fatigue, led

50:51

to the formation of committees such

50:53

as the Health of Munition Workers Committee

50:55

in Great Britain, who sought to get a sense

50:58

of the scope of the problem. One

51:00

thing became clear people

51:02

working on night shift were especially prone

51:04

to industrial fatigue. So I'm going to

51:06

read you a quote from a nineteen eighteen

51:09

report by the Health of Munition Workers

51:11

Committee about night shift. The

51:14

objections to night shift may be shortly

51:16

summarized as follows. Number

51:18

one, it is uneconomical,

51:21

owing to the higher cost of wages, lighting

51:23

and heating.

51:24

Number two.

51:25

Supervision at night is not always so

51:27

good as by day, owing to less effective

51:30

lighting or to the employment of fewer or less

51:32

experienced foremen.

51:34

Number three.

51:34

The inferiority of lighting may make

51:37

work, and especially fine work, more

51:39

difficult. Number four. The workers

51:41

may be unable to obtain adequate sleep

51:43

by day. This may be the result

51:45

of the dislocation of the ordinary habits

51:48

of life, or of social causes e g.

51:50

Noises and disturbances, or the care of children.

51:53

Workers are tempted to curtail their period

51:55

of sleep through rising to join the

51:58

family midday meal, or to some

52:00

recreation and enjoyment.

52:02

Number five.

52:03

Social intercourse, recreation and amusement may

52:05

be seriously interfered with, and number

52:07

six. Finally, it is

52:09

not natural to turn the night

52:12

into day and to deprive the body

52:14

of the beneficial effects of sunlight.

52:17

Not natural, not natural, not natural,

52:19

not wrong.

52:21

So as far back as nineteen eighteen

52:23

people recognize the harm that night shift

52:25

work could cause, But the

52:27

next line in this report reveals

52:30

the stark reality facing this kind

52:32

of work.

52:33

Under existing conditions.

52:35

Night work at any rate for men and

52:37

women is inevitable. And

52:39

those existing conditions that are referenced

52:42

in that happened to be World War One, and

52:44

then they happened to be World War Two, and

52:47

then night shift work and shift work in general

52:49

stopped being discussed as something that was an

52:51

exception to the rule and slowly became

52:53

the rule, a normal part of many industries,

52:56

from transportation to hospitality.

53:00

To entertainment.

53:01

Round the clock work became a fact

53:03

of life. Many countries introduced

53:06

pieces of legislature that limited the harsh

53:08

working conditions, especially like long

53:10

and irregular hours that had become

53:12

so widespread during the late eighteenth and early

53:14

nineteen hundreds, but shift work

53:17

remained a staple of industry, growing

53:20

in prevalence, particularly through the mid twentieth

53:22

century. I can share a couple of old

53:24

stats here if you please.

53:25

Kind of stats.

53:26

Okay, So these are from a nineteen eighty one

53:28

symposium in France. Between

53:31

nineteen fifty seven and nineteen seventy four,

53:33

the percent of shift work across the workforce

53:35

more than doubled, from ten point three percent.

53:37

To twenty two percent.

53:39

Wow, and in some industries that

53:41

percentage shot up to fifty percent.

53:42

Are over.

53:44

In Great Britain, full time night work was estimated

53:46

to increase by one percent every

53:49

year from the end of World War II to the

53:51

late nineteen seventies, which one percent

53:53

doesn't sound like much.

53:54

But I have Yeah.

53:57

The bottom line is that over the course of the twentieth

53:59

century, we've got more people

54:01

than we ever have doing shift work.

54:05

And accompanying this growth in shift work

54:07

was heightened interest in its health effects

54:09

on shift workers, as opposed to

54:12

solely the effects that it had on accidents,

54:14

injuries, or lost productivity.

54:17

Partly driving this change in research interest

54:19

was the growing field of chronobiology. While

54:22

researchers were uncovering the

54:24

physiological basis of the internal clocks

54:26

that guide circadian rhythms, they were

54:28

also exploring what could happen

54:31

if or when those rhythms were

54:33

disrupted purpose intentionally

54:36

and as you might expect, this research

54:39

held great interest to both industry

54:41

as well as the military. Can a person

54:43

ever truly adjust and switch

54:45

from diurnal to nocturnal spoilers,

54:49

not so much, not so much much?

54:52

And if so, how long does that switch take

54:55

and how easy is it to reverse it go

54:57

back to normal?

54:59

Can you switch? Is it every two weeks? Is

55:01

it every three weeks? Is it a month? Can

55:03

it be done? Can it be done?

55:06

How do shift work alter physiology of

55:08

different systems in the short term, and

55:10

what are some potential implications for

55:12

the long term.

55:13

By the nineteen eighties and the.

55:15

Nineteen nineties, some of these long term health

55:17

effects of shift work were coming into focus.

55:19

Digestion issues, which had long been

55:22

recognized to be a part of shift work,

55:24

cardiovascular disease, cancer immune

55:26

system issues, diabetes, mood disorders,

55:28

and a host of social and lifestyle risk

55:31

factors emerged as possible consequences

55:33

of shift work, or, more generally,

55:35

a disrupted circadian rhythm and poor

55:37

sleep. We have made

55:40

great strides in our ability

55:42

to evaluate the links between shift work,

55:45

circadian rhythm, and health from epidemiological,

55:48

physiological, genetic, psychological,

55:50

and sociological perspectives.

55:52

All the perspectives.

55:53

We've also come a long way towards understanding

55:55

how we can control those risks in the

55:57

workplace. But as everyone

56:00

in this room, everyone listening can

56:02

attest we've still got some ways

56:04

to go to put what we've learned into

56:06

practice for sustained improvement and

56:08

prevention. We've recognized

56:10

the negative effects of shift work for

56:13

over one hundred years since it

56:15

became a feature of our everyday lives, and

56:17

there are some brilliant minds working

56:19

on innovative solutions to address

56:21

and reduce the impact of circadian rhythm

56:24

disruptions at both individual and

56:26

systemic levels, and

56:29

we are so excited

56:31

to have with us here today one of those

56:33

brilliant minds, Doctor Ian Dunican.

56:36

Like doctor Eilef the provider of our first hand

56:38

account, Doctor Ian Duncan is also

56:40

originally from Ireland but moved to Perth

56:42

where he completed his many degrees, including

56:45

his PhD in Sleep and Performance,

56:48

which he earned at the University of Western Australia.

56:51

Doctor Dunicin is the director and Chief Advisor

56:53

of Melia's Consulting, a scientific consultancy

56:56

undertaking research consulting and education,

56:58

and he also hosts an produces the

57:00

Sleep for Performance podcast fellow

57:02

podcaster. On top of all

57:05

of that, Doctor Duncan is also an adjunct

57:07

Senior Research Fellow at the University of Western

57:09

Australia and is involved in numerous

57:12

research projects related to sport, shift

57:14

work, nutrition, safety, death and psychology.

57:17

So please join me in welcoming doctor Duncan.

57:19

Thanks so much for coming.

57:26

We made this meme just for you.

57:28

Yeah, so just first time I ever heard my name.

57:30

I'm brilliant. Together, so we

57:33

can retract afterwards, INDI da do

57:35

where.

57:35

We can cut.

57:37

Thank you so much. We're really really excited to chat

57:39

with you. We're going to just pepper you with questions

57:42

ready. So, like Aaron

57:44

kind of has described already, we've known for a

57:46

really long time that work that disrupts

57:48

circadian rhythms can be pretty detrimental to

57:50

human health. So if we look first

57:52

from a system's perspective, what

57:54

measures can organizations or companies

57:57

take to help reduce the impact of shift

57:59

work.

58:00

Yeah, it's a good question. I think it's really important

58:02

to take a systematic view. Many companies

58:05

to just chase one thing and go ooh,

58:07

let's get technology, let's look at

58:09

rosters. So we always advocate

58:11

a system view, and we have this paper

58:14

that we published a couple of years ago in Safety

58:16

and Health at Work, which has fourteen elements

58:18

and it's very holistic. Some of those key

58:20

elements of obviously include things like

58:22

shifts and rosters, sleep

58:25

disorders, which many people really don't focus

58:27

on. I know you spoke about sleep happening earlier on.

58:29

There's over seventy seven zero

58:32

recognize disorders by the American Academy

58:34

of Sleep Medicine that we follow here in Australia.

58:36

But typically many companies just administer

58:39

a questionnaire like the Airport

58:41

Sleeping Scale, and I think that's an actual

58:43

sleep disorder program when it's not, So we need to look

58:45

more holistically there. Other components

58:48

include educating our workforce and that's not just

58:50

a few slides and induction, that's actually spending

58:52

two to three hours, you know, like what you've done

58:54

here today in more detail about how

58:56

to manage shift work at a personal level

58:59

around sleep path and diet, nutrition, commuting

59:01

to work if travels involved as well.

59:04

So these are just some of the elements that we would take

59:06

in a system view as well. But another

59:08

crucial aspect not to be overlooked is actually

59:10

staffing, because if we don't have enough

59:12

people to do the job, we're just going to lead to more and over

59:14

time, more stress on the individuals

59:17

and more rework, and so it's very

59:19

important at the first level that we have the staff

59:21

incorrect before we start trying to implement the

59:23

system. And finally, on this point, you

59:26

don't actually have to have a system that stands alone.

59:28

That system could be integrated in your health,

59:30

your safety, or other sort of systems

59:32

there in a business, So it doesn't have to

59:34

be a standalone or a newly constructed system.

59:37

It may exist in other ones

59:39

as well.

59:39

Okay, that makes sense.

59:40

Yeah, yeah, And so maybe you're lucky

59:43

enough to work at one of these places that does incorporate

59:45

a more holistic view of sleep and

59:47

shift work.

59:48

Or maybe you're not.

59:49

But what can anyone do at an individual

59:52

level to kind of reduce the negative

59:54

impacts of shift work?

59:56

Yeah? I think at the individual level, I think you've

59:59

done a really good job, say, highlighting some of the negative

1:00:01

impacts. But what a lot of studies haven't done is

1:00:03

look that what is the benefit of some

1:00:05

of the interventions or case

1:00:07

controlled studies where people are doing something going forward.

1:00:10

The first thing I would say to anybody undertaking shift

1:00:12

work is keeping your own physical

1:00:14

fitness and mental health and check is number

1:00:17

one. So you know, excessive

1:00:19

alcohol consumption that we see excessive nicotine

1:00:22

caffeins that we see in shift workers, we

1:00:24

need to bring that back into normal tolerable levels.

1:00:27

When we start increasing our body weight, that's

1:00:29

going to lead to things like sleep with their breeding disorders,

1:00:31

it's going to lead to more like generalized fatigue that

1:00:34

you define that will start as well. So it's

1:00:36

really important that your own physical fitness and mental

1:00:38

health and well being is in checking and shape. And

1:00:41

that's really key, I would say for individuals

1:00:43

and also as well when you are away

1:00:45

undertaking shift work, whether it's here in Western Australia

1:00:48

elsewhere, like in the classic fly and flyout,

1:00:50

is having a routine. And that routine doesn't

1:00:52

mean going to the pub every night and having things.

1:00:54

That routine may involves some exercise, connecting

1:00:58

with other people, family and friends back home as

1:01:00

well. So it needs to be holistic

1:01:02

in nature as well.

1:01:03

For the individual just being healthy.

1:01:05

You mean, yes, which is difficult over

1:01:08

twelve thirteen hour days, but you go to mag

1:01:10

time. And I would say to people as well, don't think about

1:01:12

going to the gym as a one or two hour exercise. Even

1:01:14

fifteen to twenty minutes of high intensity exercise

1:01:16

can be really good for you and.

1:01:18

Just having that routine right there were just such

1:01:20

a hard part to maintained.

1:01:21

But it's recially.

1:01:22

Important if you're on those rotating shifts

1:01:24

or things like that. But that makes a lot of sense. Yeah,

1:01:26

So a hot topic, hot button.

1:01:28

Topic these days.

1:01:29

Why we made you this meme is

1:01:32

our screens, especially our personal devices,

1:01:34

and especially the use of those at night. So

1:01:37

I want to ask you what do we actually

1:01:39

know about how much these devices

1:01:42

are disrupting our sleep or disrupting our circadian

1:01:44

rhythms and contributing to things like fatigue,

1:01:47

and how much of it is the light or

1:01:49

the things that we're doing with our devices.

1:01:51

So do you want the scientific answer or do you want to

1:01:53

clickbdswer.

1:01:55

I don't any more answers that I want.

1:01:57

Because I don't give you a klick answer. It's really interesting

1:02:00

because we did discuss this a few weeks ago. However,

1:02:02

over the last few days there has been a bill introduced

1:02:04

in Australia to band social media. Why

1:02:07

yes, so this was past their day. I believe

1:02:10

I'm not getting into politics and good that's as far as

1:02:12

I'll going. So if we

1:02:14

look at electronic device use and its impact on

1:02:16

sleep. There's two ways of looking at this. One

1:02:18

is the subjective evidence, how do people

1:02:21

report their feel with electrinic devices?

1:02:23

And two is the objective evidence. What's

1:02:25

happening in laboratories with polysymnography,

1:02:27

what's happening with actigraphy of risk warned devices.

1:02:30

The subjective stuff is saying, Ooh, this is really

1:02:32

impacted my sleep. The objective stuff is

1:02:34

saying it's not. So.

1:02:37

The science and the data and the quantitative method

1:02:39

actually is showing very little of

1:02:41

how it's out there. We're currently undertaking a systematic

1:02:44

review in a meta analysis a few scientists

1:02:47

around that from around the world. Russell Foster, who you may

1:02:49

know who actually discovered the SCN he's

1:02:51

on that paper with us as well. And so

1:02:53

what we're finding so far self reported

1:02:56

stuff, very influenced I think by the

1:02:58

media and the general population. I've ran

1:03:00

two studies and athletes no impact

1:03:02

onto sleep. However, there's

1:03:05

three mechanisms how they're trying devices may be impact

1:03:07

on sleep. One is the light emitting from

1:03:09

these devices that could be TV, iPad,

1:03:11

social media, could be anything or gaming. Two,

1:03:14

the nature or the stimulate and activity. And

1:03:17

many of us in this room do this we get home,

1:03:19

put the kids to bed, do or exercise whatever it might be, and

1:03:22

then we go, oh, a bit of me time. I put on Netflix,

1:03:24

open up my laptop, do some me melts. I check

1:03:26

Instagram as well while I'm having a glass wine and healthy

1:03:29

dark chocolate. And it's always like stimulation

1:03:32

plus alcohol plus caffeine, and then

1:03:34

you wonder why you can't sleep.

1:03:38

A single explanation there, and as.

1:03:39

You've explained in your in your reviewerer

1:03:42

on is in the in the graph is

1:03:44

when court sool is high, melatonin can't be

1:03:46

released. So we're doing all the stimulate and activity, we

1:03:48

cannot release melatonin or it delays

1:03:50

the time of melatonin. And but also

1:03:53

what artificial light may have that impact, as we said,

1:03:55

and the final thing is that we're replacing sleep

1:03:58

time with other times. See

1:04:00

example is I'll just watch one more and tonight Yellowstone

1:04:02

as that as well. But

1:04:05

the bad part about Yellowstone at the moment, which is also

1:04:07

good, is there's not one more episode because it comes out

1:04:09

weekly.

1:04:10

That's the trick. That's why streaming services.

1:04:13

Yeah, so that's what we can actually blame is Netflix.

1:04:16

Yeah, no, we can't blame Netflix. Yeah, it's

1:04:18

on stand here in Australia anyway. So that's

1:04:22

why I'm wearing my Ora William's boots and belt today.

1:04:24

And for Yellowstone I was

1:04:26

going to my wife said no, I

1:04:30

recently bought my scuba So

1:04:32

it's it's those three mechanisms, delight the

1:04:35

type of activity and then replacing sleep

1:04:37

time. But so far we are not seeing at the finite

1:04:39

of link. A couple of weeks ago we had the Australasian Sleep

1:04:41

Association conference in the Gold Coast

1:04:44

and even a massive study looking at body motion

1:04:46

cameras with kids, no results, no

1:04:48

impact on sleep.

1:04:49

Wow, it's so interesting because all of

1:04:51

the like recommendations are still like no screen

1:04:53

time one hour two hours before bed, even like

1:04:55

all the sleep you know, organizations

1:04:58

still like recommend that blanket statement,

1:05:01

which is so interesting but.

1:05:02

It's not definitive. But I would say the people is, if you're

1:05:04

having troubled sleeping, shift work disorder,

1:05:06

sleep on set, insomnia and trouble winding

1:05:09

down, eliminate that activity before

1:05:11

bed. Yeah, lessen that light and

1:05:14

just basically use that time to basically just

1:05:16

wind down and candown, which probably

1:05:18

leads into the recommendations

1:05:20

on light yep, yeah, exact this is something

1:05:22

that we're really saying.

1:05:23

Now, Yeah, that makes a lot of sense.

1:05:25

That makes a lot of sense.

1:05:26

And so this may or may not be

1:05:28

a question of personal interest, seeing as

1:05:31

we just traveled across nine and ten

1:05:33

times a.

1:05:34

Million time zones. That is what it feels like sometimes.

1:05:36

But what can we do to minimize

1:05:39

or escape the effects of jet lag?

1:05:41

Like, are there any are there any tips

1:05:44

or tricks?

1:05:44

Or are we all just doomed to be sleep deprived

1:05:47

and brain fog and groggy when we cross

1:05:49

more than a couple of time zones?

1:05:51

Yeah? You you really are. But you can't

1:05:53

lessen to that. You can you can? Yeah, the answer is yes,

1:05:56

you're going to be. You're going to be impacted by jet lag. There's

1:05:58

no escape now, there is no biohack. Regardless

1:06:00

of who you listen to on a podcast. You cannot buy a hackle

1:06:02

a jet like. And then people go who happened

1:06:04

years ago? And people came to Australia, they came on a slow

1:06:07

moving shit it's UK six weeks so slowly

1:06:09

or justice. But now we have this rapid

1:06:11

transmittitian travel which leads to jet like.

1:06:14

So you can do some preadaptation like with shift

1:06:16

work, but a lot of people can't do that because they're trying to work

1:06:18

before they go. And then you've got to really

1:06:20

kind of use rapid adaption when you get there, and

1:06:22

going east and west will have different effects like

1:06:24

switching from days to nights or nights to days

1:06:27

and shift work, and so there's

1:06:29

many things you can do. The number one thing I would

1:06:31

say is light. Light is key.

1:06:33

So for you two here today trying to get

1:06:35

over jet like this is the worst environment

1:06:38

you come be in. Nice and dark. Nice

1:06:40

include artificial light, no Zeitgerber's

1:06:43

no time givers. It's a bit like a casino,

1:06:45

and that's what they do when a casino, they use all

1:06:48

those things against you to keep you in there.

1:06:50

What's going on?

1:06:51

And now at twelveth midnight that we are now, we've

1:06:55

got no idea what time it is, and so

1:06:57

that's that's what's happening there as well. But with that,

1:06:59

I would say people trying to overcome jet

1:07:01

light is light and natural

1:07:04

light as key. So today I would recommend as much

1:07:06

natural light as possible. That's the number one

1:07:08

mechanism you can do. So you need to get and

1:07:10

go straight because you sign get

1:07:13

some fresh air and get some movement.

1:07:14

Oh, I love it. We have one

1:07:16

last question for you. It seems like a very

1:07:18

exciting time to be working in these fields

1:07:20

in coronibiology and sleep science. What

1:07:23

are you most excited about or most

1:07:25

hopeful for in the future of this field of

1:07:27

research.

1:07:28

I think some of the most interesting research is

1:07:30

coming out of Flinders University and Adelette at

1:07:32

the moment, and it's looking at light. Now. I'm

1:07:34

separating the word light from social media

1:07:36

and I'm looking at the impact of light

1:07:39

on our health. Like you spoke about artificial

1:07:41

light, people working a nighttime and so on, Sean

1:07:44

Ken, Andrew Phillips, Angus Burns, some of those

1:07:46

guys there are doing some really interesting work

1:07:48

around the long term impact of light, and

1:07:50

you're using the UK Biobank data to

1:07:52

show the impact on cardiovascular

1:07:55

disease, mortality, all of these

1:07:57

things as well. And as you said earlier on,

1:07:59

in this in this research space, still

1:08:02

lots to do. But we know that so far at

1:08:04

less than three percent of people can fully adapt

1:08:06

to permanent night shift. And

1:08:09

that's very very few people, but

1:08:11

most people think they can. So you

1:08:13

cannot buy or hack your way out of this.

1:08:15

There is no free ride and you've really displayed

1:08:17

that today. So what I would say is that

1:08:20

the sort of the light and this science is really key

1:08:22

going forward. And the final part is I

1:08:24

think using individual sleep

1:08:27

tracking metrics is really key for the future because

1:08:29

we have to individualize this, and we're starting

1:08:31

to look at individualizing light as well, because

1:08:34

people have different sensitivities to like some people

1:08:36

can be in a brightly lit room go straight to sleep,

1:08:38

other people can. So looking at more an individual

1:08:41

level of sleep and weight patterns and individual

1:08:43

light sensitivity as well as the next phase I think

1:08:45

we're going to get into that's fascinating.

1:08:48

I now have a million more questions. Yeah,

1:08:50

but I know that we do have to wrap this up.

1:08:52

So thank you so much for sharing

1:08:54

your expertise with us today. That was super

1:08:56

fun.

1:08:57

Yeah, we were really excited if everyone here

1:08:59

also got really stoked about this and

1:09:01

wants to learn a lot more about circadian

1:09:03

rhythms about shift work. We have a very

1:09:05

long list of the sources that we used

1:09:07

to put together this episode.

1:09:09

There's another page. There's a lot just

1:09:11

come and find us.

1:09:12

So yeah,

1:09:14

and I've got a ton of sources for this, but we always

1:09:17

shout out just a couple that we want to specifically

1:09:19

highlight, so two in particular. One

1:09:21

is a book by Russell Foster and Leon Kreutzman

1:09:24

titled Circadian Rhythms, a very short introduction

1:09:26

published in twenty seventeen, and on

1:09:28

the history of shift work side of things, there

1:09:30

was a great nineteen eighty six paper

1:09:33

by Gordon at All titled the Prevalence

1:09:35

and Health Impact of Shift Work from the American

1:09:37

Journal of Public Health.

1:09:39

And then I also had a number of sources

1:09:41

a couple really great overview papers

1:09:43

about circadian rhythm that I loved. One was from

1:09:45

the Lancet twenty twenty two by Meyer had

1:09:47

All titled Circadian Rhythms and Disorders

1:09:50

of the Timing of Sleep, and

1:09:52

that was part of a four part series that was also really

1:09:54

really great. And then another one from the New

1:09:56

England Journal of Medicine by Eleda and Bass

1:09:59

in twenty twenty one, Circadian Rhythms in Medicine.

1:10:01

But we had a lot. We always post them on our

1:10:03

website, This podcast will Kill You dot com. Under

1:10:05

the episodes tab, you'll be able to find this list of

1:10:07

all of our sources.

1:10:09

I was going to say, please and your

1:10:11

session.

1:10:11

Yeah, yeah, I just released a book today for pre

1:10:14

order on and it's called

1:10:16

Thank You very Much. It's a ghostwriter

1:10:21

and it's called a Guide for Sleep, Health and Shipwork.

1:10:23

I love it and it's got over two.

1:10:25

Hundred and forty references in it and as designed

1:10:27

for people doing shift work organizing sleep

1:10:29

and shift work patterns. It's available for pre

1:10:32

order, it's up on LinkedIn, It's on our website Mellia's

1:10:34

Consulting. Fantastic over there and do it. And

1:10:36

tomorrow we have a Fatigue Management symposium

1:10:38

from Holt Past one to Holt Past two and

1:10:41

we'll be delving more into this with five

1:10:43

session, five speakers in that session.

1:10:45

Excellent, that's going to be great.

1:10:47

Thank you well, and a big thank you again

1:10:49

to doctor Ilf and also you doctor

1:10:51

Dunikan for sharing experience and expertise

1:10:53

with us.

1:10:54

We really appreciate it.

1:10:55

Yeah, and thank you again to Zach Bentley,

1:10:57

Kelly Piper's, David Lowry and everybody

1:11:00

body else here at AI Oh.

1:11:02

I can't say it, I know, and I say

1:11:04

the H wrong.

1:11:05

I know.

1:11:07

No, Thank you everyone

1:11:10

for inviting us and for organizing this

1:11:12

conference.

1:11:12

We're really really excited to be.

1:11:14

Here and we've got a couple

1:11:16

more of our usual outro episode

1:11:18

thank yous, which is thank you to Bloodmobile for

1:11:20

providing the music for this episode and all of our

1:11:22

episodes.

1:11:23

Thank you to Leona.

1:11:24

Sculacchi and Tom Bryfocal for their amazing

1:11:26

audio mixing. Thank you to everyone at

1:11:28

Exactly Right, and a huge thank you to

1:11:30

our amazing listeners, including everyone

1:11:33

here today. Thank you, thank you, thank you, and

1:11:35

until next time, wash your hands, you

1:11:38

filthy animals.

1:11:39

I've never send that to people

1:11:41

in real life. Sorry.

1:12:02

Oh um

1:12:09

um

1:12:13

Uh