Speaker 1: Good morning, Erinds.
Speaker 2: Good morning everyone, and thank you for the invitation to
Speaker 2: come and share a story that I went through my career.
Speaker 2: In twenty twelve, I was an intern back in Dublin
Speaker 2: in a large teaching hospital. I was six months after
Speaker 2: finishing my intern year, aged twenty three, and I was
Speaker 2: working in a busy surgical unit. It was January and
Speaker 2: I was woken up about six am to go and
Speaker 2: start my journey to work. As I've gone to work,
Speaker 2: I've where in mind.
Speaker 1: It's a Thursday.
Speaker 2: I've already undertaken about thirty six hours of work within
Speaker 2: this work week from Monday, and I'm about to go
Speaker 2: and start on another Thursday. I feel I'm relatively well rested,
Speaker 2: but I know that I'm not feeling particularly good going
Speaker 2: in to start a very large shift, which I'm going
Speaker 2: to elaborate on a little bit now. At six point thirty,
Speaker 2: I arrive into work and I undertake results checking. We
Speaker 2: look at all the results of our patients from the
Speaker 2: day before, recent blood tests, recent scan results, and ultimately
Speaker 2: to prepare for the ward round when our surgeons and
Speaker 2: the consultants and the senior doctors will start undertaking looking
Speaker 2: at every patient on their list. At seven o'clock, we
Speaker 2: start sharp and we finish about eight o'clock. And at
Speaker 2: eight o'clock those senior surgeons will head off to surgery,
Speaker 2: and us as the junior doctors, will then undertake.
Speaker 1: The tasks of the day.
Speaker 2: We'll look at organizing consultations, We'll be writing letters, discharging patients,
Speaker 2: admitting new ones, and then deal with problems as they
Speaker 2: occur on the wards. It's fast paced. It's a busy unit,
Speaker 2: but it's something.
Speaker 1: That I thrive.
Speaker 2: I enjoy the challenges as they present. I really am
Speaker 2: passionate about the work and I'm very happy to work
Speaker 2: in such a busy environment. Even though you might only
Speaker 2: be getting twenty minutes for a quick lunch break, you
Speaker 2: feel very valued, You feel wanted and a key cog
Speaker 2: in that machine of the hospital. But there's very much
Speaker 2: a drive. You have to have the work done and
Speaker 2: it has to be done correctly. It's got to be
Speaker 2: done with precision, because at the end of the day,
Speaker 2: patient care depends on it. As the day continues, we
Speaker 2: tick over to about quarter to six in the evening,
Speaker 2: and then the surgeons are starting to come out of
Speaker 2: theater and then we start doing a further round through
Speaker 2: the hospital again of all the patients that have been
Speaker 2: under the lists, of the surgeons whom have operated, and
Speaker 2: those who are still waiting after their operations. These rounds
Speaker 2: then can finish about quarter past seven. So bear in
Speaker 2: minds I've been in the hospital since six point thirty
Speaker 2: and it's now quarter past seven at night, and then
Speaker 2: start the next part of my shift. And back in
Speaker 2: twenty twelve, we were routinely rostered to do twenty four hours,
Speaker 2: So I will then move from my day job to
Speaker 2: then providing night cover in the tertiary hospital, of which
Speaker 2: there are only four interns. All of us have only
Speaker 2: done six months prior, and we're all fresh out of college,
Speaker 2: maybe twenty three, twenty four to twenty five. We each
Speaker 2: cover in the region about one hundred and eighty patients,
Speaker 2: each with one senior doctor to call upon for assistance
Speaker 2: as we go.
Speaker 1: Through the night.
Speaker 2: Now, usually you would get a scattering of sleep here
Speaker 2: or there of a few hours, maybe hold each other's pages.
Speaker 2: This particular night in question, that was not going to
Speaker 2: be one of those cases. We were dealing with six
Speaker 2: patients across the hospital and in my particular area that
Speaker 2: I was looking after I know offhand I was dealing
Speaker 2: with the patient who was having an acute stroke on
Speaker 2: the middle of the ward, as well as a patient
Speaker 2: who was bleeding post operatively on the ward and trying
Speaker 2: to get them back to theater for emergency surgery. Jobs
Speaker 2: kept creeping up as we went through the night, and
Speaker 2: they did not stop. But then we were getting to
Speaker 2: six point thirty in the morning, and I was then
Speaker 2: starting to get set for the next ward round, which my.
Speaker 1: Team were getting prepared for.
Speaker 2: And it's at that point that I've been notified that
Speaker 2: we have a sick doctor on and I'm going to
Speaker 2: be required to stay, and my boss has asked me
Speaker 2: to stay and conduct surgery with them. Now, I'm not
Speaker 2: a surgeon, and I'm working under complete supervision of very
Speaker 2: senior surgeons at the time. I'm not putting any patient
Speaker 2: within risk because I'm simply holding a retractor. I'm not
Speaker 2: doing anything that's going to be compromising them. It is
Speaker 2: simply to be able to hold something in theater and
Speaker 2: provide that extra bit of support so the surgeon and
Speaker 2: their assistant can do their work under full supervision. At
Speaker 2: that time, I finished and wrapped up about eleven thirty
Speaker 2: in the morning and I'm excused, at which point I've
Speaker 2: probably been awake for about twenty nine hours and scatterings
Speaker 2: of sleep here or there. I make the decision to
Speaker 2: drive home, and nobody forced me to make this decision.
Speaker 2: I took that completely on myself. And as I'm driving
Speaker 2: down the Grand Canal in Dublin, I fall asleep at
Speaker 2: the wheel and I wake up with a jolt and
Speaker 2: I've put my car into the back of a large
Speaker 2: Dublin bus. I get out of the car, look at
Speaker 2: the smashed windscreen, completely obliterated bonnet, and smoke coming up
Speaker 2: the engine. I'm shaking. I'm uninjured, but really fraught with
Speaker 2: anxiety and just fear of what's happened. I call my dad,
Speaker 2: who's been a fantastic wealth of wealth of advice and
Speaker 2: support for me over the years, who helps me to
Speaker 2: navigate the situation in relation to getting insurance, calling retrieval authorities, etc.
Speaker 2: To get the cars off the road. He slowly makes
Speaker 2: his way to come and see me on the Grand
Speaker 2: Canal dock, and as traffic starts to move on, we
Speaker 2: get the daggered looks of the frustrated drivers whose days
Speaker 2: have been interrupted by my accident. But my dad has
Speaker 2: been a wealth of advice over the years, says to
Speaker 2: me is that this has been a very valuable learning
Speaker 2: curve for you, and you've gone through it without anybody
Speaker 2: being injured. And for me, that was what was really interesting,
Speaker 2: was because now as I reflect back on that, my
Speaker 2: life could have taken a very different turn. Not only
Speaker 2: was I uninjured, but I did not injure anybody else.
Speaker 2: And it's something that it really does strike fear in
Speaker 2: me that I didn't only put myself in a position
Speaker 2: of danger, but I put others in danger and it
Speaker 2: only cost me the price of my car, not the
Speaker 2: cost of someone's life or my own life, and leaving
Speaker 2: a family potentially having an injured family member or even
Speaker 2: my own family where they would have to have dealt
Speaker 2: with my debt because of the decision I made. But
Speaker 2: in reality, I was far too fatigued to make that
Speaker 2: decision correctly. And as I said, no one forced me
Speaker 2: to do this. This was something that I did on
Speaker 2: my own bat and it's something I reflect on every
Speaker 2: day as I go to work, whether I'm making sure
Speaker 2: that I am not in a position where I can
Speaker 2: make an error like.
Speaker 3: That again, that is just a terrifying and very relatable story.
Speaker 1: And I'm glad that you were okay.
Speaker 3: I'm glad everything turned out okay, and just thank you
Speaker 3: very much for sharing the story with us.
Speaker 4: Yeah, thank you. We're so glad, like you said that
Speaker 4: the accident wasn't worse than it was, and we really
Speaker 4: appreciate you sharing it with everybody here today. I think
Speaker 4: it's something that unfortunately a lot of us can probably
Speaker 4: relate to. So thank you so much, thank.
Speaker 5: You for having me. Thank you. Hi.
Speaker 4: I'm Aaron Welsh and I'm a'm an update and.
Speaker 3: This is this podcast will kill You and we are
Speaker 3: coming to you live with our very first recorded live
Speaker 3: episode from Perth, Australia, The Lovely Perth. We're here at
Speaker 3: the twenty twenty four AIOH Annual Scientific Conference and Exhibition
Speaker 3: and we are just thrilled to be here.
Speaker 1: We really are.
Speaker 4: Thank you all so much for having us. A huge
Speaker 4: thank you to Zach and Kelly and David and everybody
Speaker 4: who helped organize this conference. We are truly honored to
Speaker 4: be up here today speaking with you all.
Speaker 3: Really and in light of the fact that we are
Speaker 3: at the annual meeting of the Australian Institute of Occupational Hygienists,
Speaker 3: and we just flew across one million time zones to
Speaker 3: get here, not an exaggeration. We decided to focus on
Speaker 3: a topic that is of central importance to pretty much
Speaker 3: every industry, and that is fatigue, specifically fatigue caused by
Speaker 3: disruption in our circadian rhythms in the context of shift work.
Speaker 4: And because that alone is such a huge topic that
Speaker 4: there's no way that we could fit it all into
Speaker 4: a ninety minute plenary, We're not going to make you
Speaker 4: sit here for one hundred hours. Don't worry, We're going
Speaker 4: to take you through just a few parts of that.
Speaker 4: So first I'm going to focus on what do we
Speaker 4: mean by fatigue, how do we define that, and what
Speaker 4: does that actually mean, how our circadian rhythms actually work,
Speaker 4: and how disruption in circadian rhythms can lead to symptoms
Speaker 4: like fatigue, excessive daytime sleepiness, and so many other chronic
Speaker 4: health conditions.
Speaker 3: And then I'll get into how our understanding of circadian
Speaker 3: rhythms has evolved over time, the changes that led to
Speaker 3: shift work becoming as widespread as it is today, and
Speaker 3: how we came to recognize those negative effects of shift work.
Speaker 3: And then we're going to bring on a subject matter expert,
Speaker 3: doctor Ian Dunkin, who will share some of the current
Speaker 3: exciting research that's going on on circadian rhythms and how
Speaker 3: to combat the negative effects of things like shift work
Speaker 3: and jet lag.
Speaker 4: Yes, but first, no episode of our podcast this pla
Speaker 4: I Guess We'll kill you would be complete without a
Speaker 4: beverage that we call a quarantinie or in our case
Speaker 4: of place berta, because we don't have any alcoholic spirits
Speaker 4: in it.
Speaker 1: But we are drinking one today. Today we're drinking TikTok.
Speaker 1: You don't stop get it because it's like a clock. Yes,
Speaker 1: it'll be funny. We explain jokes so that they're not
Speaker 1: funny anymore. But in TikTok, you don't stop.
Speaker 4: There.
Speaker 3: It's a delicious beverage consisting of one ingredient, which is
Speaker 3: Australian ginger beer.
Speaker 1: So thank you.
Speaker 3: It's delicious and also easily modified. You can add whatever
Speaker 3: spirit you would like or just leave.
Speaker 1: It with a little bit of lime in there. Delicious.
Speaker 4: Sorry, we should have really had the foresight to make
Speaker 4: a drink for everyone, like under your seats you can
Speaker 4: find oh, my gosh, very Oprah.
Speaker 1: Cheers to you all.
Speaker 4: Okay, now, drinks are drunk, shall we We'll get into
Speaker 4: the biology of are circadian with us?
Speaker 1: I can't wait. Yeah, tell me all about it.
Speaker 4: It's going to be fun. So we decided to do
Speaker 4: this talk today on fatigue because it's kind of this
Speaker 4: universal experience that also happens to be an occupational hazard
Speaker 4: in so many different industries.
Speaker 1: Everyone has at.
Speaker 4: Some point been fatigued experienced fatigue. But when we talk
Speaker 4: about this idea, what do we actually mean, Like, how
Speaker 4: do we define fatigue?
Speaker 5: Right?
Speaker 1: It's super easy to define, right, Right, there's not a definition.
Speaker 4: There is not a single definition of fatigue, but there
Speaker 4: are a lot of different definitions. Most of them use
Speaker 4: a lot of synonyms, things like tiredness or exhaustion. Most
Speaker 4: of the definitions include something like the decreased ability to
Speaker 4: function at your normal capacity or something of decreased capacity
Speaker 4: for mental or physical work.
Speaker 1: Okay, So overall we're.
Speaker 4: Looking at fatigue as this generalized lack of energy that
Speaker 4: overall has some kind of impairment on your ability to function,
Speaker 4: be that your physical function or your cognitive function.
Speaker 1: All right, makes sense?
Speaker 4: Okay, And following but in that definition, what's important about
Speaker 4: it is that we then have to intentionally separate fatigue
Speaker 4: from sleepiness.
Speaker 1: Right, right, And how does one do that?
Speaker 4: How does one do that by defining sleepiness?
Speaker 1: Okay, more definitions, more definitions.
Speaker 4: So we can do this by defining sleepiness as directly
Speaker 4: related to the physiologic phenomenon that is the act of
Speaker 4: falling asleep, okay, because that means that it's something that
Speaker 4: we can measure, okay, at least to a better degree
Speaker 4: than we can fatigue, which is so nebulous. Right, And
Speaker 4: we do this. We can measure sleepiness with a couple
Speaker 4: of different tests. There's one called the multiple sleep latency test,
Speaker 4: which is I'm going to put you in a dark
Speaker 4: room and you're going to lay down and fall asleep.
Speaker 4: How long does it take you?
Speaker 1: Wow? Not stressful at all, right.
Speaker 4: And then there's also the maintenance of wakefulness test, which
Speaker 4: is how long can you stay awake if we sit
Speaker 4: to you in a dark room and ask you to
Speaker 4: not sleep.
Speaker 1: We have to be sitting just sitting with your thoughts
Speaker 1: in a dark room. No, I don't like that idea.
Speaker 4: Now, sleepiness itself like falling asleep, It's not a bad thing.
Speaker 1: Inherently, we have to sleep.
Speaker 4: It is required of all humans, and as humans are
Speaker 4: diurnal species, we have evolved to sleep.
Speaker 1: At night when it is dark and be awake when
Speaker 1: it is light.
Speaker 4: So being sleepy at night time itself is not a
Speaker 4: bad thing, but if that sleepiness is happening when we
Speaker 4: shouldn't be asleep, then it can lead to what's called
Speaker 4: excessive daytime sleepiness, or this inability to stay awake during
Speaker 4: hours when you should be awake, and that can be
Speaker 4: bad or, as we heard in our first hand account,
Speaker 4: even downright dangerous. Both excessive sleepiness and fatigue, though they
Speaker 4: are different, and these definitions are important, also kind of
Speaker 4: two halves of a story, and they both contribute to
Speaker 4: the kinds of accidents and workplace events like we heard
Speaker 4: about in our first hand account. And while circadian rhythm
Speaker 4: disruptions themselves are by no means the only things that
Speaker 4: can cause excessive daytime sleepiness or fatigue, these are two
Speaker 4: of the most immediate consequences that we see from circadian dysfunction.
Speaker 4: So having a basic understanding of what our circadian rhythms
Speaker 4: are and how they work can go a really long
Speaker 4: way to understanding what happens if they get pushed out
Speaker 4: of sync, which then can lead us to better anticipate
Speaker 4: the hazards that might be inherent to some professions, or
Speaker 4: recognize these symptoms when they start to crop up during
Speaker 4: certain phases of life. Hello newborns, Gotta love them. And
Speaker 4: then evaluating and understanding these consequences of this type of
Speaker 4: circadian disruption can help us to actually implement strategies in
Speaker 4: the future to help mitigate some of these.
Speaker 1: Hopefully we'll get there. Yeah, can it be done?
Speaker 5: Can it? So?
Speaker 4: Then, first we have to start with what really is
Speaker 4: circadian rhythm? And I think most people probably have a
Speaker 4: sense of what this.
Speaker 1: Means in their mind right.
Speaker 4: It comes from the Latin circa means about and ds
Speaker 4: or DM means.
Speaker 1: Day stole my line, Yeah, thank you, I try so.
Speaker 4: When we talk about a circadian rhythm, we're talking about
Speaker 4: cycles that are happening in our bodies on an about
Speaker 4: twenty four hour timeframe. And Aaron, I know later you're
Speaker 4: going to talk about why we have these rhythms. Yeah,
Speaker 4: like from an evolutionary perspective, yep, what are they.
Speaker 1: Doing for us? It's they're important? Are they? Let's find
Speaker 1: out yeah.
Speaker 4: But I'm going to focus first on how they actually work.
Speaker 4: And everyone is probably most familiar with a circadian rhythm
Speaker 4: in the context of sleep and our sleep wake cycle,
Speaker 4: because our sleep wake cycle is one of the most
Speaker 4: classic examples of our circadian rhythm in action. So we
Speaker 4: can see a few different things that oscillate in our
Speaker 4: sleep wake cycles. One of them is something like melotone
Speaker 4: in secretion. So our melotonin peaks in the couple of
Speaker 4: hours before we go to sleep, and then we'll go
Speaker 4: to sleep, our corticol levels will peak in the morning
Speaker 4: right about the time that we tend to wake up.
Speaker 4: We also see oscillations in our body temperature, with the
Speaker 4: lowest body temperature happening in the wee hours of the
Speaker 4: night while you're still asleep.
Speaker 1: I just want to ask why for each one of these.
Speaker 4: I don't have great answers, but I can tell you
Speaker 4: that what these like the why is that these processes
Speaker 4: together are what are driving our drive for wakefulness okay,
Speaker 4: and our pressure for sleep okay. So these three things,
Speaker 4: they're not the only things that are involved in what's
Speaker 4: literally keeping us awake during the day and telling our
Speaker 4: bodies we need to go to sleep at night.
Speaker 1: But these are three of the big.
Speaker 4: Drivers of that drive for wakefulness that happens during the
Speaker 4: day and that pressure for sleep that happens through like.
Speaker 1: Towards the night. But what's the deal with temperature?
Speaker 5: Oh?
Speaker 1: I don't know? And also what is.
Speaker 3: That so use the body? But are changes by how
Speaker 3: many degrees?
Speaker 4: I knew you were going to ask that, and I
Speaker 4: meant to like look it up again to try and
Speaker 4: get in. I don't know.
Speaker 3: I don't know that it's twenty it's just the fool Yes,
Speaker 3: like a proportions of a degree.
Speaker 1: Yeah, yeah, yeah, Okay, we're little changes.
Speaker 4: But it's enough that it's sort of in that period
Speaker 4: when we're close to waking up. That drop in temperature
Speaker 4: is what helps our bodies stay asleep essentially, right, it's colder,
Speaker 4: stay asleep, et cetera.
Speaker 3: Rkay, Okay, explain why didn't sleep well when I have
Speaker 3: that power?
Speaker 4: Yeah, we're going off track. So, as humans, because we're diurnal,
Speaker 4: we see these particular cycles again on this twenty four
Speaker 4: hour clock where sleep is happening at dark and a
Speaker 4: week time is happening during the light. So this is
Speaker 4: what we all think of when we think of circadian rhythm.
Speaker 4: But it is not just this our circadian rhythm, like
Speaker 4: literally every single function and process in our bodies from
Speaker 4: the cellular level, like the genes that are controlling which
Speaker 4: cells are going to divide, when the genes that are
Speaker 4: controlling DNA repair, does it happen in what cells? And
Speaker 4: when things like our immune system, our metabolism, our hunger cues,
Speaker 4: our bowel movements, our libidos, every function in our body
Speaker 4: is controlled to one degree or another by circadian processes.
Speaker 1: It's like the ultimate but weight. There's more. It's not
Speaker 1: just sleepwake, it's everything.
Speaker 4: Everything, and these all are our circadian rhythms. It's not
Speaker 4: just sleep, but sleep is a big part of our
Speaker 4: circadian rhythm. And these circadian rhythms are mechoganized internally in
Speaker 4: our bodies by what's called an intrinsic circadian clock. But
Speaker 4: not just one clock. We have multiple clocks. We have
Speaker 4: a main clock in the part of our brain that's
Speaker 4: called the super chismatic nucleus.
Speaker 3: I'm really glad that you pronounced this because I just
Speaker 3: wrote SCN over and over again.
Speaker 1: I don't even know if I talk about SCN. But no,
Speaker 1: now I.
Speaker 4: Know how to pronounce the SCN or the super chismatic nucleus,
Speaker 4: and this region in our brain functions as like a
Speaker 4: master regulator of our internal clock. But all of our
Speaker 4: peripheral cells and tissues, they all have clocks of their own,
Speaker 4: and together all these clocks drive our many many circadian rhythms,
Speaker 4: in large part by the build up and then the
Speaker 4: breakdown of specific proteins whose literal job it is to
Speaker 4: be made build up and then break down on a
Speaker 4: twenty four hour cycle to keep these clocks all in
Speaker 4: sync with each other.
Speaker 1: Okay, does that make sense?
Speaker 4: Yeah, it's like pretty basic, right, super simple.
Speaker 1: I'm sure it took no time at all to figure
Speaker 1: that out.
Speaker 4: No, no, no, So that's how these circadian clocks are working
Speaker 4: on like a cellular level. And I said that these
Speaker 4: are intrinsic, and we know that these are intrinsic because
Speaker 4: these cycles will persist on an.
Speaker 1: About twenty four hour basis.
Speaker 4: In humans, it's a little long. We tend to run
Speaker 4: about twenty four hours and ten minutes.
Speaker 1: I got eleven in here.
Speaker 4: Eleven minutes, eleven minutes, nine to eleven is what the
Speaker 4: literature says.
Speaker 3: We can have a rate anywhere from nine to eleven
Speaker 3: minutes and twenty four hours.
Speaker 4: And twenty four hours and eleven minutes nine to eleven
Speaker 4: and our clocks keep doing this even if we put
Speaker 4: someone in a dark room with absolutely no external environmental
Speaker 4: clue cues like in absence of the environment, our clocks
Speaker 4: still run. However, these environmental cues are in fact an
Speaker 4: essential part of our circadian rhythm because a lot like clocks,
Speaker 4: old tiny clocks, not new fangled watches which work by magic.
Speaker 1: Is how my magic I watch works.
Speaker 4: Okay, old tiny clocks mechanical ones you used to have
Speaker 4: to wind in order for them to keep correct time.
Speaker 4: Our circadian clocks also have to be wound in order
Speaker 4: to keep them on as close to a twenty four
Speaker 4: hour cycle as possible, and this happens through a process
Speaker 4: called entrainment. And the environmental cues that we use for
Speaker 4: entrainment in our circadian clocks are called zight gabers. Which
Speaker 4: is my attempt at German, and that is German for timegiver.
Speaker 1: How'd she do?
Speaker 4: Did anyone speak German?
Speaker 1: And not?
Speaker 5: Great?
Speaker 4: I can tell I tried really hard.
Speaker 1: Zight gabers.
Speaker 4: In humans, it is light, predominantly light from the sun
Speaker 4: that acts as our number one zyp giver or time giver,
Speaker 4: and the sun light from the sun is detected by
Speaker 4: these specialized cells in the back of our eyeballs that
Speaker 4: project directly to that SCN, the super chismatic nucleus, and
Speaker 4: that part of our brain again is this pacemaker that
Speaker 4: coordinates the cycles in all of the rest of our body.
Speaker 4: And they do this, they coordinate the timing of like
Speaker 4: so many different processes, right through direct and indirect pathways
Speaker 4: to keep us on this twenty four hour cycle in
Speaker 4: sync with the sun or the light around us. Now,
Speaker 4: light is by no means our only zight gaper. Food
Speaker 4: can be a powerful one, especially for other mammals other
Speaker 4: than humans.
Speaker 1: We also can.
Speaker 4: See, exercise, social activity, other things can serve as zitkeepers,
Speaker 4: but light is by far the primary one that our
Speaker 4: particular clocks use, which means that although these rhythms are
Speaker 4: generated internally, they do require entrainment, mostly via light in
Speaker 4: order for so many of our biological processes to match
Speaker 4: our environment. So when our environment changes, like when we
Speaker 4: travel across exactly nine time zones I counted between California
Speaker 4: and Western Australia to come to a conference ten for me,
Speaker 4: suffice to say, our internal clock no longer matches our
Speaker 4: external environment.
Speaker 6: I'm feeling okay, though I will say thank you caffeine.
Speaker 4: Yeah, that's a big part of it, right, And we
Speaker 4: all know this particular phenomenon very well. This is jetlag.
Speaker 4: And with jet lag, because of this discrepancy between your
Speaker 4: external environment, the timing of light exposure, and where your
Speaker 4: internal circadian clock was set before you left, you end
Speaker 4: up feeling pretty terrible. Right, not myself, not today right now,
Speaker 4: we feel great, but you can end up feeling pretty terrible.
Speaker 4: You might have symptoms like a really hard time falling
Speaker 4: asleep when it's time to fall asleep, or maybe you
Speaker 4: simply cannot keep your eyes open for like an afternoon
Speaker 4: meeting when you get to where you're going. And because again,
Speaker 4: this malagested timing is affecting every body system that we have,
Speaker 4: not just sleep, it's not just being fatigued or being
Speaker 4: excessively sleepy, you might also have gi upset, mood changes,
Speaker 4: brain fog, and so much more. Now, in addition to
Speaker 4: regular old jet lag, there's also a phenomenon called social
Speaker 4: jet lag.
Speaker 1: We'll separate it all.
Speaker 4: Right, and social jetla is basically this idea that we
Speaker 4: all as like a society at large, not us in
Speaker 4: this room here. We have all decided that our day
Speaker 4: starts at like eight am, right, or whatever we can
Speaker 4: say for it, and that is where the day is
Speaker 4: supposed to start for everyone across the board.
Speaker 1: But a lot of us.
Speaker 4: Maybe end up relying on like our alarm clocks to
Speaker 4: wake us up on the weekdays to be able to
Speaker 4: get ready for work on time.
Speaker 3: A lot of us, I mean of us who doesn't
Speaker 3: that would be amazing?
Speaker 4: Yeah, And then when that happens, many of us might
Speaker 4: perhaps on weekends, when our schedule permits it, sleep in later,
Speaker 4: go to bed later, stay up later. So we have
Speaker 4: this shift in what our schedule looks like between weekdays
Speaker 4: and weekends. And it turns out that different people might
Speaker 4: feel differently. Some of you might be like, oh, yeah,
Speaker 4: I do that, and others are like, noth dude, six am, I'm.
Speaker 1: Ready to go.
Speaker 4: That's because we all have different chronotypes, and a chronotype
Speaker 4: is like different natural tendencies to either sleep early or
Speaker 4: sleep late, like early bird, night owl. It's a real thing.
Speaker 4: Which are I'm an early bird.
Speaker 1: You're an early bird? Like so what is the threshold? Like?
Speaker 1: What a fun question? I don't know. I don't know.
Speaker 4: I don't know if there's like a specific thing.
Speaker 1: And can you be neither or can you be like
Speaker 1: a light early?
Speaker 4: You can be neither, you can be whatever you want
Speaker 4: to be.
Speaker 1: Okay, are you an early bird? I think about mild
Speaker 1: early bird.
Speaker 4: Mild early bird?
Speaker 1: Ye like and not too early? Yeah bird?
Speaker 3: Yeah, I don't want the first word.
Speaker 1: One would be fuels.
Speaker 3: Are still left at the book and want them all gone.
Speaker 4: I love that I'm an early very early No, No,
Speaker 4: probably not.
Speaker 1: Maybe I wish I was. It's too much.
Speaker 4: But for people, especially who veer more night owl, then
Speaker 4: they might have an especially hard time waking up for
Speaker 4: that eight am start every day.
Speaker 5: Right.
Speaker 4: This is especially true for teenagers. And that's not just
Speaker 4: a stereotype teenagers. Actually we see shifts in their intrinsic
Speaker 4: circadian clocks during the teen years, and like.
Speaker 3: Most teenagers at least in the US, start their days
Speaker 3: at like.
Speaker 1: Before seven, right, which is do we do it? It
Speaker 1: was miserable.
Speaker 4: It wasn't my idea. And so this system of forcing
Speaker 4: these early wakings on some days and then maybe seeing
Speaker 4: a shift in what your patterns are like on the weekends,
Speaker 4: it can end up causing chronic sleep deprivation. And so
Speaker 4: that's what we see in this phenomenon of social jet lag,
Speaker 4: and that's something that a lot of us have probably
Speaker 4: experienced to one degree or another. But we also then
Speaker 4: have even more severe or persistent disruptions in our circadian
Speaker 4: cycle that can result from a more chronic forced mismatch
Speaker 4: between our environmental cues and our intrinsic clocks. And this
Speaker 4: is what we can see in shift work. So across
Speaker 4: the globe, it's estimated that anywhere between ten and thirty
Speaker 4: percent of all adults in industrialized countries.
Speaker 1: Which is a lot.
Speaker 4: That's a lot, work in shift work. And often if
Speaker 4: you work in shift work, then you might end up
Speaker 4: working outside of a traditional eight to five of like
Speaker 4: a regular old job, and that might mean you're working
Speaker 4: night shifts. And night shifts, of course, are going to
Speaker 4: require a complete flip of your circadian.
Speaker 1: Cycle where you have to adapt to working.
Speaker 4: Entirely during the dark hours and being asleep during the
Speaker 4: light hours.
Speaker 1: Right, But it might not just be night shift. It
Speaker 1: can also mean rotating shifts.
Speaker 4: It can mean late afternoon shifts that bleed into night time,
Speaker 4: or it can mean early early morning shifts that require
Speaker 4: you to start your day before the dawn.
Speaker 3: My mom was an afternoon night shift work, or an
Speaker 3: afternoon worker as a nurse. But she loved it because
Speaker 3: she would just lay out at the pool until three pm.
Speaker 3: She said, she was like, I loved it, and then
Speaker 3: I would go home. And maybe she is she a
Speaker 3: night owl, not anymore.
Speaker 1: Because that would track.
Speaker 4: But so all of any of these scenarios can serve
Speaker 4: to end up disrupting our circadian clock because they're disrupting
Speaker 4: the typical timing of our light dark exposure. In a
Speaker 4: lot of cases, it might be exposing our eyes and
Speaker 4: thus our brains to light essentially twenty four hours a day.
Speaker 4: And while sometimes people can adjust the timing of when
Speaker 4: they're asleep and when they're awake, like maybe they sleep
Speaker 4: just fine during the day, they like sleeping in late
Speaker 4: and then laying out in the sun or whatever, what
Speaker 4: we do see is that the vast majority of shift
Speaker 4: workers do not show a complete shift in all of
Speaker 4: their circadian rhythms, meaning things like their melatonin secretion, as
Speaker 4: an example, will still happen at night time, and in
Speaker 4: some cases can be up to twelve hours out of
Speaker 4: phase from when they're actually sleeping. Wow right.
Speaker 5: Yeah.
Speaker 4: There was one paper I read that estimated that only
Speaker 4: about twenty five percent of people who work night shift
Speaker 4: long term actually show evidence of having a lot of
Speaker 4: these circadian rhythms actually being shifted in line with their
Speaker 4: real life. Wow right, it's a pretty low percentage, okay.
Speaker 3: And this is like continuous night shift work, not like
Speaker 3: rotating shift work or like two weeks on two week
Speaker 3: two exactly.
Speaker 4: This was a people who are like night shift for
Speaker 4: the long term. Yeah yeah, And so this can unsurprisingly
Speaker 4: result in what's called shift work disorder, which is a
Speaker 4: disorder that can be characterized by things like insomnia, which
Speaker 4: is difficulty falling asleep or staying asleep, or it might
Speaker 4: be excessive sleepiness like falling asleep when you shouldn't be
Speaker 4: at work or micronapping. But it can also lead to
Speaker 4: increased irritability, it can lead to mood changes like depression
Speaker 4: or anxiety, and it overall can lead to this mental
Speaker 4: fog that can lead to increases in mistakes because of
Speaker 4: all of this fatigue and sleepiness. So some studies suggest
Speaker 4: that working during the night alone increases the risk of
Speaker 4: workplace accidents by forty to one hundred percent.
Speaker 1: WHOA, which is huge.
Speaker 4: It's a huge range also, but it's also huge, like
Speaker 4: very significant. And shift work disorder alone is not that uncommon.
Speaker 4: Some papers estimate up to twenty seven percent of shift
Speaker 4: workers meet the formal definition of shift work shift work disorder.
Speaker 1: But on a practical.
Speaker 4: Level, everyone who has work shift work has probably experienced,
Speaker 4: to one degree or another, this negative effects of this
Speaker 4: circadian disruption. Yeah, but again, it's not just fatigue and
Speaker 4: sleepiness at work or outside of work, because especially what
Speaker 4: we see with time spent working night shifts having really
Speaker 4: significant impacts on long term health. Shift workers are at
Speaker 4: about a twenty to thirty five percent increased risk of
Speaker 4: breast cancer, prostate cancer, colorectal cancers, but also type two diabetes,
Speaker 4: coronary artery disease, and depression and many other chronic health
Speaker 4: conditions as well.
Speaker 3: Eric, But like, what is the mechanism for that? Like why, Yeah,
Speaker 3: what do we know about that?
Speaker 4: We don't know everything, which is a classic line, and
Speaker 4: I will say that there has in the literature been
Speaker 4: some pushback as to like how causal is this relationship
Speaker 4: because a lot of these disorders also have a lot
Speaker 4: of other lifestyle factors that influence them as well, and
Speaker 4: so sometimes you might see difference in lifestyle between people
Speaker 4: who work shift work or night shift work specifically compared
Speaker 4: to day shift workers and things like that. But the evidence,
Speaker 4: especially for cancers in animal studies, is so significant that
Speaker 4: circadian rhythm destruction in animal studies leads to cancer formation,
Speaker 4: tumor growth. And it is such overwhelming evidence that the
Speaker 4: International Agency for Research on Cancer named night shift work
Speaker 4: a probable carcinogen all the way back in.
Speaker 1: Two thousand and seven. Wow, this is like a new information.
Speaker 4: But then if we dig even deeper on like what
Speaker 4: is the mechanisms, we know that our circadian rhythms are
Speaker 4: affecting so much of our overall body functions, and what
Speaker 4: we see is that disynchrony of our sleep wake cycles
Speaker 4: and our endogenous circadian rhythms ends up leading to things
Speaker 4: like increases in blood pressure, reduced insulin sensitivity, elevated lipid concentration,
Speaker 4: and so all of these might put us at risk
Speaker 4: for things like diabetes, hypertension.
Speaker 1: Cardiovascular disease.
Speaker 4: There's also some evidence between like timing of and amount
Speaker 4: of melatonin secretion and the effects on uncogenesis or cancer formation.
Speaker 1: That's interesting exactly.
Speaker 4: So at like a basic level, what it's thought to
Speaker 4: be is that all of these increases in risk are
Speaker 4: a result of the fact that so many of us
Speaker 4: working night shifts. Our endogenous circadian rhythms do not adapt
Speaker 4: to this forced pattern of being a weak.
Speaker 1: At night and being asleep during the day.
Speaker 4: So it's a mismatch between our internal cycles and the environment.
Speaker 1: So that's the best answer I've got. I mean, I
Speaker 1: think that's a pretty good awer.
Speaker 4: Parts it is, yeah, and probably a lot of specific
Speaker 4: mechanisms that go into each of the different disorders and
Speaker 4: things like that, But on the whole, I think I've
Speaker 4: convinced you all that it's abundantly clear that our circadian
Speaker 4: rhythms are very, very integral, not just in our sleeping
Speaker 4: and our weakness and our alertness or fatigue, but also
Speaker 4: in so much of our health. So circadian rhythms are
Speaker 4: an important thing to consider in the context of a
Speaker 4: lot of our stages of life, a lot of our professions.
Speaker 1: So I have a question for you erin uh huh,
Speaker 1: ask go ahead.
Speaker 4: If this thing, these things, these circadian rhythms that seem
Speaker 4: today to be it's so easy for us to disrupt them,
Speaker 4: to get get messed up. You just hop on a plane,
Speaker 4: just change.
Speaker 1: Your clocks back, just go into a grocery store at night.
Speaker 5: Right.
Speaker 4: If it's so easy for them to get disrupted, and
Speaker 4: when they get disrupted, they can cause so much trouble,
Speaker 4: why do we have them? What do they do for
Speaker 4: us as humans or creatures like you?
Speaker 1: And when?
Speaker 4: How did we know all of this? Tell me everything?
Speaker 3: Okay, I'll tell you as much as I can tell you,
Speaker 3: maybe not everything. Wherever you are, whether you're here in
Speaker 3: this room in Perth, Australia at this conference, or you're
Speaker 3: tuning in from across the world. I want you to
Speaker 3: imagine yourself as a dot on the globe, as a
Speaker 3: pin on the map I've.
Speaker 1: Marked Perth here.
Speaker 3: Now, let's rewind time, let's say two hundred million years
Speaker 3: or so, keeping that pin in its original coordinates, and
Speaker 3: I want you to picture a time lapse of the
Speaker 3: continents shifting, colliding, separating, oceans, expanding and shrinking, mountains forming
Speaker 3: and crumbling.
Speaker 1: What is your pin witnessing in all of this?
Speaker 3: Has it mostly been a drift in a vast ocean,
Speaker 3: or has it been at the center of continental action,
Speaker 3: witness to collisions and separations, or maybe your pin has
Speaker 3: seen it all. As our time lapse comes to an
Speaker 3: end eventually and the continents have settled into the familiar positions,
Speaker 3: let's take a minute to marvel at the incredible dynamic
Speaker 3: changes that our planet has seen over those two hundred
Speaker 3: million years, which is just a fraction of the Earth's
Speaker 3: four and a half billion year existence. Grasslands turned to deserts,
Speaker 3: rainforests turned to freshwater lakes, and temperature rainfall and atmospheric
Speaker 3: composition shifting tremendously over these millennia. Life on Earth has
Speaker 3: had to deal with a lot of change, even just
Speaker 3: over those two hundred million years. But throughout those transformations,
Speaker 3: there has remained one near constant. The sun always rises
Speaker 3: and the sun always sets.
Speaker 1: I love that so profound.
Speaker 3: And while the time between sunrise and sunset varies across
Speaker 3: latitudes and seasons, the existence of a day has always
Speaker 3: been a feature of life on Earth. So let's go
Speaker 3: back to your pain the map the two hundred million
Speaker 3: years ago, the day you'd experience outside of like having
Speaker 3: to fight and hide from dinosaurs, is nearly identical to
Speaker 3: the one that you'll experience today, just about an hour
Speaker 3: shorter thanks to the Earth's s gradual slow down. In
Speaker 3: a world filled with so much uncertainty, it can be
Speaker 3: reassuring to have that one constant. And this sentiment is
Speaker 3: shared across much of life on Earth. Most organisms have
Speaker 3: evolved to anticipate these daily changes. Plants, animals, fungi, algae,
Speaker 3: even cyanobacteria all possess internal clocks that control the timing
Speaker 3: of biological, physiological, and behavioral responses.
Speaker 4: We love that we see it, even in bacteria, likely fascinating.
Speaker 1: It's so cool. I also love that someone looked for that.
Speaker 4: Right They're like, we've got to find it here.
Speaker 3: It's not just us, It's not just us, it's everyone.
Speaker 3: Or is it? Is it that I don't know.
Speaker 1: Rhetorical question.
Speaker 3: But these behavioral responses, or these biological responses, things like sleep,
Speaker 3: like the release of certain hormones, or like feeding that
Speaker 3: occurs at certain times of day or night, and we
Speaker 3: call these rhythms that are these responses that repeat over
Speaker 3: a roughly twenty four hour period, of course, are circadian rhythms.
Speaker 3: The ubiquity of these rhythms across all or almost all
Speaker 3: of life. I guess I don't know what's going on
Speaker 3: in like the worms that live in the deep sea events.
Speaker 1: Whether they have they always mess things up.
Speaker 6: I don't know, they could have. They probably still be
Speaker 6: something we'll find out. Yeah, well we'll look into it.
Speaker 6: But it just speaks to how important these rhythms are.
Speaker 6: But why why would it.
Speaker 3: Be so crucial to partition our activity or our physiology
Speaker 3: across a twenty four.
Speaker 4: Hour period, That's my question?
Speaker 1: Why does it matter?
Speaker 3: In a word, optimization, Our external environment changes in many
Speaker 3: ways every day, availability, predator activity, temperature, When other members
Speaker 3: of your species are also out and about, you want
Speaker 3: to spend your energy where it counts. If you're a
Speaker 3: bird who relies on color vision for foraging for berries,
Speaker 3: you probably want to do that during the day, when
Speaker 3: the light actually helps you pick out those colorful berries.
Speaker 4: See them, you can actually see helps.
Speaker 3: But if you're a small prey mammal species like this
Speaker 3: flying squirrel, maybe running around at night is your best
Speaker 3: bet to escape predators or flying around.
Speaker 1: You also don't want to be active all the time.
Speaker 1: It will be exhausting.
Speaker 3: Our sleep is incredibly important for housekeeping tasks that our
Speaker 3: body can't do while we're running around, and circadian rhythms
Speaker 3: help us optimize how we spend our energy and when
Speaker 3: it's safe to get the rest that we need to recuperate.
Speaker 1: Anyone who has pulled an.
Speaker 3: All nighter or who has had to run on a
Speaker 3: few stolen hours of sleep after welcoming a newborn knows
Speaker 3: the pain of being out of sync with the world.
Speaker 1: But for the most part, we can easily.
Speaker 3: Recover from these one time or short term disruptions. But
Speaker 3: what happens when there is a constant mismatch between your
Speaker 3: internal clock and the external environment.
Speaker 1: Well, we know from what you.
Speaker 3: Just told us, Aaron, that it's really not great, not
Speaker 3: good for humans at the least, not good for most,
Speaker 3: if not all, of the animals we've studied, and decades
Speaker 3: of research have shown that it's not great for really anything.
Speaker 3: So let's take a minute to get into the story
Speaker 3: of how we came to understand these rhythms of our
Speaker 3: lives and the consequences of their disruption. Humans have recognized
Speaker 3: circadian rhythms in ourselves and other creatures for millennia. Aristotle
Speaker 3: in the fourth century BCE noted that bees slept bees,
Speaker 3: bees slept fourth century BCE.
Speaker 4: I love that they're just cutting open hives, being like, oh,
Speaker 4: that one's asleep.
Speaker 1: Oh yeah, I'm sure. Sorry, you're disturbing up like this.
Speaker 1: Very's so cute.
Speaker 3: And around the same time and Rosthenes observed the leaves
Speaker 3: of the tamarin tree curling and uncurling over a day.
Speaker 3: The famous ancient Greek and Roman physicians Hippocrates and Galen
Speaker 3: described fevers that peaked at certain times of day.
Speaker 1: What do we think that might be?
Speaker 4: I love this, it's malaria, it's larious, probably, yeah.
Speaker 3: And one of the leading hypotheses for why these cyclic
Speaker 3: fevers exist is that the parasites match the circadian rhythm
Speaker 3: of their host or their mosquito vector for more likely transmission.
Speaker 3: Like is, do they go into the bloodstream at certain
Speaker 3: times a day so that that's when the mosquitoes are biting.
Speaker 4: It's really that's not malaria.
Speaker 1: It's horrible.
Speaker 4: Yeah, but they and the parasites are like going to
Speaker 4: be active at certain times to maximize transmission.
Speaker 1: That's I know, mind blowing evolution. Man, it's pretty cool.
Speaker 3: But for centuries, all of these observations remained just that observations.
Speaker 3: No one attempted to answer the question of why until
Speaker 3: them seventeen twenties, when a French scientist by the name
Speaker 3: of de Meran decided to take a closer look at
Speaker 3: a plant, specifically Mimosa pudica, which also goes by the
Speaker 3: adorable common name of sensitive plants or.
Speaker 1: Shy plant or shype so I used to call it.
Speaker 3: And anyone who is interacted with this plant can see
Speaker 3: where it got its nickname. When you touch its delicate leaves,
Speaker 3: they fold in on themselves like ah, don't touch me,
Speaker 3: and then a few minutes later they'll open back up,
Speaker 3: though they calm back down. But it turns out that
Speaker 3: the plants also do this folding and unfolding routine throughout
Speaker 3: the day, folding up at night.
Speaker 2: Day.
Speaker 3: Moron, observing this, thought to himself, what if the two
Speaker 3: words at the heart of every scientist, what if they
Speaker 3: aren't exposed to light?
Speaker 1: Then what happens?
Speaker 3: And so he plopped the plant into a dark cupboard
Speaker 3: and saw that it still opened and closed its leaves
Speaker 3: over that twenty four hour period.
Speaker 1: Wow, even in complete darkness.
Speaker 3: And so if light wasn't driving this pattern, what was
Speaker 3: In eighteen thirty two, about one hundred years after day
Speaker 3: Morn's experiments, Swiss botanist Augusta. Kendall took this question further,
Speaker 3: placing MOMSA plants under continuous light. Initially, the plants still
Speaker 3: show their daily leaf movements, but as the days went on,
Speaker 3: the candle watched as this pattern grew out of sync
Speaker 3: with day and night. Something internal, like an internal clock,
Speaker 3: perhaps it seemed to be driving these movements, governed by
Speaker 3: a cycle slightly shorter than a day, around twenty two
Speaker 3: hours compared to twenty four to Kandle's experiment was the
Speaker 3: first to demonstrate the concept of a free running rhythm,
Speaker 3: where an organism's internal clock is slightly longer or shorter
Speaker 3: than a full twenty four hour day, and in the
Speaker 3: absence of external cues, their rhythms will eventually decouple from
Speaker 3: that twenty four hour cycle and instead be guided by
Speaker 3: their internal ones humans, for instance, twenty.
Speaker 1: Four and twenty four hours then nine to eleven minutes.
Speaker 3: But, as it often goes Dick, Kendal's conclusion that organisms
Speaker 3: are guided by an internal clock as opposed to responding
Speaker 3: solely due to external stimuli was not immediately embraced.
Speaker 1: Shock imagine that.
Speaker 4: We learned something new and not everyone believes.
Speaker 3: The debate on whether these daily patterns were directed by
Speaker 3: internal or external forces continued basically up to the middle
Speaker 3: of the twentieth century, coinciding with the peak of the
Speaker 3: nature versus nurture debate, But while nature versus nurture seemed
Speaker 3: to be only increasing in contentiousness, research on rats, plants, birds, bees,
Speaker 3: even humans demonstrated clear evidence for an internal clock cut
Speaker 3: off from external cues. Mice and rats kept running on
Speaker 3: their wheel or sleeping right on schedule.
Speaker 1: Chickens who had been incubated at.
Speaker 3: Constant conditions still hatched with an innate biological rhythm. Bees
Speaker 3: demonstrated a keen sense of time and an ability to
Speaker 3: communicate that time.
Speaker 1: These are just an amazing example.
Speaker 4: Rhythms and flower time in really good I have to.
Speaker 3: Like schedule, like have a little schedule calendar for oh,
Speaker 3: ta this flower then, because that's when it's producing nectar.
Speaker 5: Right.
Speaker 4: They have it all in a little notebook.
Speaker 1: I just imagine getting there a little early and they're like, oh.
Speaker 3: My gosh, you'll wait, wait, this is where's the nectar?
Speaker 1: Yeah, got places to be. Next one opens in five.
Speaker 3: And humans turned out to be no exception to this,
Speaker 3: as a series of cave, Arctic and.
Speaker 1: Underground bunker experiments demonstrated.
Speaker 3: The first of these took place in nineteen thirty eight
Speaker 3: when physiologist Nathaniel Kleitman called his graduate student Bruce Richardson
Speaker 3: into his office one.
Speaker 1: Day this is how I imagining how it went, and.
Speaker 3: Said, hey, Bruce, can I interest you in an all
Speaker 3: expenses paid, thirty two day trip to Mammoth Cave, Kentucky
Speaker 3: where we'll hang out in a cavern and try to
Speaker 3: adjust our bodies to a twenty eight hour day. The
Speaker 3: nearby hotel will take care of our gourmet meals. You
Speaker 3: can bring whatever books you'd like.
Speaker 1: I've got a deck of cards to play bridge. It'll
Speaker 1: be great.
Speaker 4: One deck of cards, thirty two days.
Speaker 1: Yeah cool, Well that's all you need really really, but bridge,
Speaker 1: just bridge.
Speaker 4: I don't even know how to play bridge me either.
Speaker 1: Two conditions though.
Speaker 3: You've got to record your sleep movements and your temperature
Speaker 3: at regular intervals.
Speaker 1: Richardson said, yes, I mean, who wouldn't like I would
Speaker 1: do this? That sounds fun.
Speaker 4: I tried his advisor and he's like, well, I can't
Speaker 4: say no.
Speaker 1: That's true.
Speaker 5: Yeah.
Speaker 1: I tried to do it with ticks. Do you remember this.
Speaker 3: I was sampling in Panama and I tried to measure
Speaker 3: see if there was like a diurnal pattern of tick abundance.
Speaker 3: And then the rainy seasons a three am. Yeah, and
Speaker 3: I got rained out and I had.
Speaker 4: To leave and this is over.
Speaker 5: Yeah.
Speaker 1: It was exhausting new experiment. Yeah, I never I never
Speaker 1: did it again though. Oh well, opportunities for the future.
Speaker 1: But while the scientific.
Speaker 3: Conclusions drawn from this end of two experiment just Kleiittman and.
Speaker 1: Richardson, they were a little vague, right.
Speaker 3: Richardson apparently readjusted to twenty eight hours, but Kleitmann did not.
Speaker 3: It made quite an impact on the budding field of chronobiology,
Speaker 3: drawing the attention of journalists who sketched a story of
Speaker 3: scientific adventure, as well as researchers who wanted to try
Speaker 3: it for themselves, like Michel Sifrey, who spent two months
Speaker 3: in a cave in the Italian Alps in nineteen sixty two,
Speaker 3: waking and sleeping when he felt like it. Ultimately, when
Speaker 3: he emerged, he was shocked to find that he had
Speaker 3: lost two weeks. He thought I'll just it'll be exactly
Speaker 3: where I think.
Speaker 1: But no, no, he lost two weeks because he's too long.
Speaker 3: And this work helped to incite interest into the study
Speaker 3: of circadian rhythms, and by the early nineteen sixties the
Speaker 3: field of chronobiology was born, with one of its leaders,
Speaker 3: Franz Hallberg, introducing the term circadian rhythm in nineteen fifty nine.
Speaker 1: Seems so recent, I know it is. I mean internal clock.
Speaker 1: I think was at least from the eighteen hundred. This
Speaker 1: this is the term rhythm more recent, Okay.
Speaker 3: Since then, researcher has examined the process of entreatment which
Speaker 3: you described, and I was thinking about zeit Gabers Again,
Speaker 3: apologies for the pronunciation as kind of like right now,
Speaker 3: how you're giving a talk and you think, oh, I'm
Speaker 3: right on time, I'm doing great, and then someone at
Speaker 3: the back holds up like a five minute warning and
Speaker 3: you're like, whoops, I'm only halfway through my presentation.
Speaker 1: I feel like that sign is a psyche Gaberah. It's
Speaker 1: a good analogy. I like it.
Speaker 3: Researchers have examined the mechanistic basis of how these external
Speaker 3: signals are received by the hypothalamist eyes, pineal gland, or
Speaker 3: by some other means. They've attempted to decipher the genetic
Speaker 3: basis of biological clocks, identifying clock genes and observing how
Speaker 3: these genes synchronize across our body to orchestrate broad physiological
Speaker 3: and behavioral changes during a.
Speaker 1: Twenty four hour period.
Speaker 3: They've done a lot, Yeah, a lot, and this research
Speaker 3: has been integral to understanding what drives the rhythms of
Speaker 3: our life, why they're important, and what happened when they're disrupted,
Speaker 3: which brings me toune dune.
Speaker 1: Dune shift work.
Speaker 3: Shift work has been around forever, or at least for
Speaker 3: thousands of years, standing guard, keeping the fire lit, watching
Speaker 3: over your flock of sheep, caring for the sick or wounded.
Speaker 3: The military and certain trades have long required irregular hours,
Speaker 3: like shipbuilders who had to work with the tides, or
Speaker 3: rope makers. I found a quote by a rope maker
Speaker 3: from seventeen forty two. We cannot make ropes when the
Speaker 3: sun shines. We begin at eight o'clock at night and
Speaker 3: work till eight in the morning, and sometimes we work
Speaker 3: all day if we can hold it. I don't know
Speaker 3: why I tried to look into it. And I even
Speaker 3: asked like blue Sky, and I got varied answers and
Speaker 3: some fun hypotheses. But if anyone knows or is an
Speaker 3: idea they have to work at night, please reach out,
Speaker 3: come find me. But until the late eighteen hundreds, shift
Speaker 3: work was a fairly uncommon occurrence. Then let there be light,
Speaker 3: specifically electrical life. In eighteen ninety two, just three years
Speaker 3: after the invention of the light bulb, the first power
Speaker 3: plant in New York opened, supplying continuous powder to those
Speaker 3: who could receive it. The effect on industry was immediate.
Speaker 3: Factories that had to shutter their doors shortly after the sunset,
Speaker 3: or who used lanterns or gas lights for overnight work,
Speaker 3: could now operate around the clock, bathe in the glow
Speaker 3: of artificial light. For the heads of industry, the benefits
Speaker 3: of around the clock operation were clear again, the word
Speaker 3: optimization comes to mind. Factories could be more efficient while
Speaker 3: maximizing production, and a twenty four hour workday broken down
Speaker 3: into shifts became the new norm for many industries, even
Speaker 3: those that had not previously required continuous labor. Shiftwork was
Speaker 3: not just something to give them a leg up, but
Speaker 3: it was becoming necessary to survive the competition. It was
Speaker 3: apparent that industry was enjoying an economic boom from this
Speaker 3: increased productivity.
Speaker 1: But how were workers faring in this brave, new, well
Speaker 1: lit world? Doing great? I'm sure doing wonderful.
Speaker 3: Interest in this question grew in earnest over the first
Speaker 3: couple decades of the twentieth century, and a new concept
Speaker 3: term industrial fatigue was introduced to describe the exhaustion caused
Speaker 3: by over exertion to long working hours and insufficient rest,
Speaker 3: often measured by a decline in productivity.
Speaker 1: About productivity, Aran, yeah, I mean so.
Speaker 3: Under this framework, human health was reimagined as or equated
Speaker 3: to the body's capacity for productivity. So, in other words,
Speaker 3: if you're sick, that means diminished output. If you're exhausted,
Speaker 3: that means more mistakes, which means diminished output. And this
Speaker 3: concern with worker health and productivity, especially when it came
Speaker 3: to industrial fatigue, led to the formation of committees such
Speaker 3: as the Health of Munition Workers Committee in Great Britain,
Speaker 3: who sought to get a sense of the scope of
Speaker 3: the problem. One thing became clear people working on night
Speaker 3: shift were especially prone to industrial fatigue. So I'm going
Speaker 3: to read you a quote from a nineteen eighteen report
Speaker 3: by the Health of Munition Workers Committee about night shift.
Speaker 3: The objections to night shift may be shortly summarized as follows.
Speaker 3: Number one, it is uneconomical, owing to the higher cost
Speaker 3: of wages, lighting and heating.
Speaker 1: Number two.
Speaker 3: Supervision at night is not always so good as by day,
Speaker 3: owing to less effective lighting or to the employment of
Speaker 3: fewer or less experienced foremen.
Speaker 1: Number three.
Speaker 3: The inferiority of lighting may make work, and especially fine work,
Speaker 3: more difficult. Number four. The workers may be unable to
Speaker 3: obtain adequate sleep by day. This may be the result
Speaker 3: of the dislocation of the ordinary habits of life, or
Speaker 3: of social causes e g. Noises and disturbances, or the
Speaker 3: care of children. Workers are tempted to curtail their period
Speaker 3: of sleep through rising to join the family midday meal,
Speaker 3: or to some recreation and enjoyment.
Speaker 1: Number five.
Speaker 3: Social intercourse, recreation and amusement may be seriously interfered with,
Speaker 3: and number six. Finally, it is not natural to turn
Speaker 3: the night into day and to deprive the body of
Speaker 3: the beneficial effects of sunlight.
Speaker 1: Not natural, not natural, not natural, not wrong.
Speaker 3: So as far back as nineteen eighteen people recognize the
Speaker 3: harm that night shift work could cause, But the next
Speaker 3: line in this report reveals the stark reality facing this
Speaker 3: kind of work.
Speaker 1: Under existing conditions.
Speaker 3: Night work at any rate for men and women is inevitable.
Speaker 3: And those existing conditions that are referenced in that happened
Speaker 3: to be World War One, and then they happened to
Speaker 3: be World War Two, and then night shift work and
Speaker 3: shift work in general stopped being discussed as something that
Speaker 3: was an exception to the rule and slowly became the rule,
Speaker 3: a normal part of many industries, from transportation to hospitality.
Speaker 1: To entertainment.
Speaker 3: Round the clock work became a fact of life. Many
Speaker 3: countries introduced pieces of legislature that limited the harsh working conditions,
Speaker 3: especially like long and irregular hours that had become so
Speaker 3: widespread during the late eighteenth and early nineteen hundreds, but
Speaker 3: shift work remained a staple of industry, growing in prevalence,
Speaker 3: particularly through the mid twentieth century. I can share a
Speaker 3: couple of old stats here if you please.
Speaker 4: Kind of stats.
Speaker 3: Okay, So these are from a nineteen eighty one symposium
Speaker 3: in France. Between nineteen fifty seven and nineteen seventy four,
Speaker 3: the percent of shift work across the workforce more than doubled,
Speaker 3: from ten point three percent.
Speaker 1: To twenty two percent.
Speaker 3: Wow, and in some industries that percentage shot up to
Speaker 3: fifty percent.
Speaker 1: Are over.
Speaker 3: In Great Britain, full time night work was estimated to
Speaker 3: increase by one percent every year from the end of
Speaker 3: World War II to the late nineteen seventies, which one
Speaker 3: percent doesn't sound like much.
Speaker 1: But I have Yeah.
Speaker 3: The bottom line is that over the course of the
Speaker 3: twentieth century, we've got more people than we ever have
Speaker 3: doing shift work. And accompanying this growth in shift work
Speaker 3: was heightened interest in its health effects on shift workers,
Speaker 3: as opposed to solely the effects that it had on accidents, injuries,
Speaker 3: or lost productivity. Partly driving this change in research interest
Speaker 3: was the growing field of chronobiology. While researchers were uncovering
Speaker 3: the physiological basis of the internal clocks that guide circadian rhythms,
Speaker 3: they were also exploring what could happen if or when
Speaker 3: those rhythms were disrupted purpose intentionally and as you might expect,
Speaker 3: this research held great interest to both industry as well
Speaker 3: as the military. Can a person ever truly adjust and
Speaker 3: switch from diurnal to nocturnal spoilers, not so much, not
Speaker 3: so much much? And if so, how long does that
Speaker 3: switch take and how easy is it to reverse it
Speaker 3: go back to normal?
Speaker 1: Can you switch? Is it every two weeks? Is it
Speaker 1: every three weeks? Is it a month? Can it be done?
Speaker 1: Can it be done?
Speaker 3: How do shift work alter physiology of different systems in
Speaker 3: the short term, and what are some potential implications for
Speaker 3: the long term.
Speaker 1: By the nineteen eighties and the.
Speaker 3: Nineteen nineties, some of these long term health effects of
Speaker 3: shift work were coming into focus. Digestion issues, which had
Speaker 3: long been recognized to be a part of shift work,
Speaker 3: cardiovascular disease, cancer immune system issues, diabetes, mood disorders, and
Speaker 3: a host of social and lifestyle risk factors emerged as
Speaker 3: possible consequences of shift work, or, more generally, a disrupted
Speaker 3: circadian rhythm and poor sleep. We have made great strides
Speaker 3: in our ability to evaluate the links between shift work,
Speaker 3: circadian rhythm, and health from epidemiological, physiological, genetic, psychological, and
Speaker 3: sociological perspectives.
Speaker 1: All the perspectives.
Speaker 3: We've also come a long way towards understanding how we
Speaker 3: can control those risks in the workplace. But as everyone
Speaker 3: in this room, everyone listening can attest we've still got
Speaker 3: some ways to go to put what we've learned into
Speaker 3: practice for sustained improvement and prevention. We've recognized the negative
Speaker 3: effects of shift work for over one hundred years since
Speaker 3: it became a feature of our everyday lives, and there
Speaker 3: are some brilliant minds working on innovative solutions to address
Speaker 3: and reduce the impact of circadian rhythm disruptions at both
Speaker 3: individual and systemic levels, and we are so excited to
Speaker 3: have with us here today one of those brilliant minds,
Speaker 3: Doctor Ian Dunican. Like doctor Eilef the provider of our
Speaker 3: first hand account, Doctor Ian Duncan is also originally from
Speaker 3: Ireland but moved to Perth where he completed his many degrees,
Speaker 3: including his PhD in Sleep and Performance, which he earned
Speaker 3: at the University of Western Australia. Doctor Dunicin is the
Speaker 3: director and Chief Advisor of Melia's Consulting, a scientific consultancy
Speaker 3: undertaking research consulting and education, and he also hosts an
Speaker 3: produces the Sleep for Performance podcast fellow podcaster. On top
Speaker 3: of all of that, Doctor Duncan is also an adjunct
Speaker 3: Senior Research Fellow at the University of Western Australia and
Speaker 3: is involved in numerous research projects related to sport, shift work, nutrition, safety,
Speaker 3: death and psychology. So please join me in welcoming doctor Duncan.
Speaker 3: Thanks so much for coming.
Speaker 4: We made this meme just for you.
Speaker 5: Yeah, so just first time I ever heard my name.
Speaker 5: I'm brilliant. Together, so we can retract afterwards, INDI da
Speaker 5: do where.
Speaker 1: We can cut.
Speaker 4: Thank you so much. We're really really excited to chat
Speaker 4: with you. We're going to just pepper you with questions ready. So,
Speaker 4: like Aaron kind of has described already, we've known for
Speaker 4: a really long time that work that disrupts circadian rhythms
Speaker 4: can be pretty detrimental to human health. So if we
Speaker 4: look first from a system's perspective, what measures can organizations
Speaker 4: or companies take to help reduce the impact of shift work.
Speaker 5: Yeah, it's a good question. I think it's really important
Speaker 5: to take a systematic view. Many companies to just chase
Speaker 5: one thing and go ooh, let's get technology, let's look
Speaker 5: at rosters. So we always advocate a system view, and
Speaker 5: we have this paper that we published a couple of
Speaker 5: years ago in Safety and Health at Work, which has
Speaker 5: fourteen elements and it's very holistic. Some of those key
Speaker 5: elements of obviously include things like shifts and rosters, sleep disorders,
Speaker 5: which many people really don't focus on. I know you
Speaker 5: spoke about sleep happening earlier on. There's over seventy seven
Speaker 5: zero recognize disorders by the American Academy of Sleep Medicine
Speaker 5: that we follow here in Australia. But typically many companies
Speaker 5: just administer a questionnaire like the Airport Sleeping Scale, and
Speaker 5: I think that's an actual sleep disorder program when it's not,
Speaker 5: So we need to look more holistically there. Other components
Speaker 5: include educating our workforce and that's not just a few
Speaker 5: slides and induction, that's actually spending two to three hours,
Speaker 5: you know, like what you've done here today in more
Speaker 5: detail about how to manage shift work at a personal
Speaker 5: level around sleep path and diet, nutrition, commuting to work
Speaker 5: if travels involved as well. So these are just some
Speaker 5: of the elements that we would take in a system
Speaker 5: view as well. But another crucial aspect not to be
Speaker 5: overlooked is actually staffing, because if we don't have enough
Speaker 5: people to do the job, we're just going to lead
Speaker 5: to more and over time, more stress on the individuals
Speaker 5: and more rework, and so it's very important at the
Speaker 5: first level that we have the staff incorrect before we
Speaker 5: start trying to implement the system. And finally, on this point,
Speaker 5: you don't actually have to have a system that stands alone.
Speaker 5: That system could be integrated in your health, your safety,
Speaker 5: or other sort of systems there in a business, So
Speaker 5: it doesn't have to be a standalone or a newly
Speaker 5: constructed system. It may exist in other ones as well.
Speaker 4: Okay, that makes sense.
Speaker 3: Yeah, yeah, And so maybe you're lucky enough to work
Speaker 3: at one of these places that does incorporate a more
Speaker 3: holistic view of sleep and shift work.
Speaker 1: Or maybe you're not.
Speaker 3: But what can anyone do at an individual level to
Speaker 3: kind of reduce the negative impacts of shift work?
Speaker 5: Yeah? I think at the individual level, I think you've
Speaker 5: done a really good job, say, highlighting some of the
Speaker 5: negative impacts. But what a lot of studies haven't done
Speaker 5: is look that what is the benefit of some of
Speaker 5: the interventions or case controlled studies where people are doing
Speaker 5: something going forward. The first thing I would say to
Speaker 5: anybody undertaking shift work is keeping your own physical fitness
Speaker 5: and mental health and check is number one. So you know,
Speaker 5: excessive alcohol consumption that we see excessive nicotine caffeins that
Speaker 5: we see in shift workers, we need to bring that
Speaker 5: back into normal tolerable levels. When we start increasing our
Speaker 5: body weight, that's going to lead to things like sleep
Speaker 5: with their breeding disorders, it's going to lead to more
Speaker 5: like generalized fatigue that you define that will start as well.
Speaker 5: So it's really important that your own physical fitness and
Speaker 5: mental health and well being is in checking and shape.
Speaker 5: And that's really key, I would say for individuals and
Speaker 5: also as well when you are away undertaking shift work,
Speaker 5: whether it's here in Western Australia elsewhere, like in the
Speaker 5: classic fly and flyout, is having a routine. And that
Speaker 5: routine doesn't mean going to the pub every night and
Speaker 5: having things. That routine may involves some exercise, connecting with
Speaker 5: other people, family and friends back home as well. So
Speaker 5: it needs to be holistic in nature as well.
Speaker 4: For the individual just being healthy.
Speaker 5: You mean, yes, which is difficult over twelve thirteen hour days,
Speaker 5: but you go to mag time. And I would say to
Speaker 5: people as well, don't think about going to the gym
Speaker 5: as a one or two hour exercise. Even fifteen to
Speaker 5: twenty minutes of high intensity exercise can be really good
Speaker 5: for you and.
Speaker 3: Just having that routine right there were just such a
Speaker 3: hard part to maintained.
Speaker 5: But it's recially.
Speaker 4: Important if you're on those rotating shifts or things like that.
Speaker 4: But that makes a lot of sense. Yeah, So a
Speaker 4: hot topic, hot button.
Speaker 1: Topic these days.
Speaker 4: Why we made you this meme is our screens, especially
Speaker 4: our personal devices, and especially the use of those at night.
Speaker 4: So I want to ask you what do we actually
Speaker 4: know about how much these devices are disrupting our sleep
Speaker 4: or disrupting our circadian rhythms and contributing to things like fatigue,
Speaker 4: and how much of it is the light or the
Speaker 4: things that we're doing with our devices.
Speaker 5: So do you want the scientific answer or do you
Speaker 5: want to clickbdswer.
Speaker 4: I don't any more answers that I want.
Speaker 5: Because I don't give you a klick answer. It's really
Speaker 5: interesting because we did discuss this a few weeks ago. However,
Speaker 5: over the last few days there has been a bill
Speaker 5: introduced in Australia to band social media. Why yes, so
Speaker 5: this was past their day. I believe I'm not getting
Speaker 5: into politics and good that's as far as I'll going.
Speaker 5: So if we look at electronic device use and its
Speaker 5: impact on sleep. There's two ways of looking at this.
Speaker 5: One is the subjective evidence, how do people report their
Speaker 5: feel with electrinic devices? And two is the objective evidence.
Speaker 5: What's happening in laboratories with polysymnography, what's happening with actigraphy
Speaker 5: of risk warned devices. The subjective stuff is saying, Ooh,
Speaker 5: this is really impacted my sleep. The objective stuff is
Speaker 5: saying it's not. So. The science and the data and
Speaker 5: the quantitative method actually is showing very little of how
Speaker 5: it's out there. We're currently undertaking a systematic review in
Speaker 5: a meta analysis a few scientists around that from around
Speaker 5: the world. Russell Foster, who you may know who actually
Speaker 5: discovered the SCN he's on that paper with us as well.
Speaker 5: And so what we're finding so far self reported stuff,
Speaker 5: very influenced I think by the media and the general population.
Speaker 5: I've ran two studies and athletes no impact onto sleep. However,
Speaker 5: there's three mechanisms how they're trying devices may be impact
Speaker 5: on sleep. One is the light emitting from these devices
Speaker 5: that could be TV, iPad, social media, could be anything
Speaker 5: or gaming. Two, the nature or the stimulate and activity.
Speaker 5: And many of us in this room do this we
Speaker 5: get home, put the kids to bed, do or exercise
Speaker 5: whatever it might be, and then we go, oh, a
Speaker 5: bit of me time. I put on Netflix, open up
Speaker 5: my laptop, do some me melts. I check Instagram as
Speaker 5: well while I'm having a glass wine and healthy dark chocolate.
Speaker 5: And it's always like stimulation plus alcohol plus caffeine, and
Speaker 5: then you wonder why you can't sleep.
Speaker 1: A single explanation there, and as.
Speaker 5: You've explained in your in your reviewerer on is in
Speaker 5: the in the graph is when court sool is high,
Speaker 5: melatonin can't be released. So we're doing all the stimulate
Speaker 5: and activity, we cannot release melatonin or it delays the
Speaker 5: time of melatonin. And but also what artificial light may
Speaker 5: have that impact, as we said, and the final thing
Speaker 5: is that we're replacing sleep time with other times. See
Speaker 5: example is I'll just watch one more and tonight Yellowstone
Speaker 5: as that as well. But the bad part about Yellowstone
Speaker 5: at the moment, which is also good, is there's not
Speaker 5: one more episode because it comes out weekly.
Speaker 1: That's the trick. That's why streaming services.
Speaker 4: Yeah, so that's what we can actually blame is Netflix.
Speaker 5: Yeah, no, we can't blame Netflix. Yeah, it's on stand
Speaker 5: here in Australia anyway. So that's why I'm wearing my
Speaker 5: Ora William's boots and belt today. And for Yellowstone I
Speaker 5: was going to my wife said no, I recently bought
Speaker 5: my scuba So it's it's those three mechanisms, delight the
Speaker 5: type of activity and then replacing sleep time. But so
Speaker 5: far we are not seeing at the finite of link.
Speaker 5: A couple of weeks ago we had the Australasian Sleep
Speaker 5: Association conference in the Gold Coast and even a massive
Speaker 5: study looking at body motion cameras with kids, no results,
Speaker 5: no impact on sleep.
Speaker 4: Wow, it's so interesting because all of the like recommendations
Speaker 4: are still like no screen time one hour two hours
Speaker 4: before bed, even like all the sleep you know, organizations
Speaker 4: still like recommend that blanket statement, which is so interesting but.
Speaker 5: It's not definitive. But I would say the people is,
Speaker 5: if you're having troubled sleeping, shift work disorder, sleep on set,
Speaker 5: insomnia and trouble winding down, eliminate that activity before bed. Yeah,
Speaker 5: lessen that light and just basically use that time to
Speaker 5: basically just wind down and candown, which probably leads into
Speaker 5: the recommendations on light yep, yeah, exact this is something
Speaker 5: that we're really saying.
Speaker 4: Now, Yeah, that makes a lot of sense.
Speaker 1: That makes a lot of sense.
Speaker 3: And so this may or may not be a question
Speaker 3: of personal interest, seeing as we just traveled across nine
Speaker 3: and ten times a.
Speaker 1: Million time zones. That is what it feels like sometimes.
Speaker 3: But what can we do to minimize or escape the
Speaker 3: effects of jet lag?
Speaker 1: Like, are there any are there any tips or tricks?
Speaker 3: Or are we all just doomed to be sleep deprived
Speaker 3: and brain fog and groggy when we cross more than
Speaker 3: a couple of time zones?
Speaker 5: Yeah? You you really are. But you can't lessen to that.
Speaker 5: You can you can? Yeah, the answer is yes, you're
Speaker 5: going to be. You're going to be impacted by jet lag.
Speaker 5: There's no escape now, there is no biohack. Regardless of
Speaker 5: who you listen to on a podcast. You cannot buy
Speaker 5: a hackle a jet like. And then people go who
Speaker 5: happened years ago? And people came to Australia, they came
Speaker 5: on a slow moving shit it's UK six weeks so
Speaker 5: slowly or justice. But now we have this rapid transmittitian
Speaker 5: travel which leads to jet like. So you can do
Speaker 5: some preadaptation like with shift work, but a lot of
Speaker 5: people can't do that because they're trying to work before
Speaker 5: they go. And then you've got to really kind of
Speaker 5: use rapid adaption when you get there, and going east
Speaker 5: and west will have different effects like switching from days
Speaker 5: to nights or nights to days and shift work, and
Speaker 5: so there's many things you can do. The number one
Speaker 5: thing I would say is light. Light is key. So
Speaker 5: for you two here today trying to get over jet
Speaker 5: like this is the worst environment you come be in.
Speaker 5: Nice and dark. Nice include artificial light, no Zeitgerber's no
Speaker 5: time givers. It's a bit like a casino, and that's
Speaker 5: what they do when a casino, they use all those
Speaker 5: things against you to keep you in there.
Speaker 4: What's going on?
Speaker 5: And now at twelveth midnight that we are now, we've
Speaker 5: got no idea what time it is, and so that's
Speaker 5: that's what's happening there as well. But with that, I
Speaker 5: would say people trying to overcome jet light is light
Speaker 5: and natural light as key. So today I would recommend
Speaker 5: as much natural light as possible. That's the number one
Speaker 5: mechanism you can do. So you need to get and
Speaker 5: go straight because you sign get some fresh air and
Speaker 5: get some movement.
Speaker 4: Oh, I love it. We have one last question for you.
Speaker 4: It seems like a very exciting time to be working
Speaker 4: in these fields in coronibiology and sleep science. What are
Speaker 4: you most excited about or most hopeful for in the
Speaker 4: future of this field of research.
Speaker 5: I think some of the most interesting research is coming
Speaker 5: out of Flinders University and Adelette at the moment, and
Speaker 5: it's looking at light. Now. I'm separating the word light
Speaker 5: from social media and I'm looking at the impact of
Speaker 5: light on our health. Like you spoke about artificial light,
Speaker 5: people working a nighttime and so on, Sean Ken, Andrew Phillips,
Speaker 5: Angus Burns, some of those guys there are doing some
Speaker 5: really interesting work around the long term impact of light,
Speaker 5: and you're using the UK Biobank data to show the
Speaker 5: impact on cardiovascular disease, mortality, all of these things as well.
Speaker 5: And as you said earlier on, in this in this
Speaker 5: research space, still lots to do. But we know that
Speaker 5: so far at less than three percent of people can
Speaker 5: fully adapt to permanent night shift. And that's very very
Speaker 5: few people, but most people think they can. So you
Speaker 5: cannot buy or hack your way out of this. There
Speaker 5: is no free ride and you've really displayed that today.
Speaker 5: So what I would say is that the sort of
Speaker 5: the light and this science is really key going forward.
Speaker 5: And the final part is I think using individual sleep
Speaker 5: tracking metrics is really key for the future because we
Speaker 5: have to individualize this, and we're starting to look at
Speaker 5: individualizing light as well, because people have different sensitivities to
Speaker 5: like some people can be in a brightly lit room
Speaker 5: go straight to sleep, other people can. So looking at
Speaker 5: more an individual level of sleep and weight patterns and
Speaker 5: individual light sensitivity as well as the next phase I
Speaker 5: think we're going to get into that's fascinating.
Speaker 3: I now have a million more questions. Yeah, but I
Speaker 3: know that we do have to wrap this up.
Speaker 1: So thank you so much for sharing your expertise with
Speaker 1: us today. That was super fun.
Speaker 4: Yeah, we were really excited if everyone here also got
Speaker 4: really stoked about this and wants to learn a lot
Speaker 4: more about circadian rhythms about shift work. We have a
Speaker 4: very long list of the sources that we used to
Speaker 4: put together this episode.
Speaker 1: There's another page. There's a lot just come and find us.
Speaker 3: So yeah, and I've got a ton of sources for this,
Speaker 3: but we always shout out just a couple that we
Speaker 3: want to specifically highlight, so two in particular. One is
Speaker 3: a book by Russell Foster and Leon Kreutzman titled Circadian Rhythms,
Speaker 3: a very short introduction published in twenty seventeen, and on
Speaker 3: the history of shift work side of things, there was
Speaker 3: a great nineteen eighty six paper by Gordon at All
Speaker 3: titled the Prevalence and Health Impact of Shift Work from
Speaker 3: the American Journal of Public Health.
Speaker 4: And then I also had a number of sources a
Speaker 4: couple really great overview papers about circadian rhythm that I loved.
Speaker 4: One was from the Lancet twenty twenty two by Meyer
Speaker 4: had All titled Circadian Rhythms and Disorders of the Timing
Speaker 4: of Sleep, and that was part of a four part
Speaker 4: series that was also really really great. And then another
Speaker 4: one from the New England Journal of Medicine by Eleda
Speaker 4: and Bass in twenty twenty one, Circadian Rhythms in Medicine.
Speaker 4: But we had a lot. We always post them on
Speaker 4: our website, This podcast will Kill You dot com. Under
Speaker 4: the episodes tab, you'll be able to find this list
Speaker 4: of all of our sources.
Speaker 1: I was going to say, please and your session.
Speaker 5: Yeah, yeah, I just released a book today for pre
Speaker 5: order on and it's called Thank You very Much. It's
Speaker 5: a ghostwriter and it's called a Guide for Sleep, Health
Speaker 5: and Shipwork.
Speaker 1: I love it and it's got over two.
Speaker 5: Hundred and forty references in it and as designed for
Speaker 5: people doing shift work organizing sleep and shift work patterns.
Speaker 5: It's available for pre order, it's up on LinkedIn, It's
Speaker 5: on our website Mellia's Consulting. Fantastic over there and do it.
Speaker 5: And tomorrow we have a Fatigue Management symposium from Holt
Speaker 5: Past one to Holt Past two and we'll be delving
Speaker 5: more into this with five session, five speakers in that session.
Speaker 4: Excellent, that's going to be great.
Speaker 3: Thank you well, and a big thank you again to
Speaker 3: doctor Ilf and also you doctor Dunikan for sharing experience
Speaker 3: and expertise with us.
Speaker 1: We really appreciate it.
Speaker 4: Yeah, and thank you again to Zach Bentley, Kelly Piper's,
Speaker 4: David Lowry and everybody body else here at AI Oh.
Speaker 4: I can't say it, I know, and I say the
Speaker 4: H wrong.
Speaker 1: I know.
Speaker 4: No, Thank you everyone for inviting us and for organizing
Speaker 4: this conference.
Speaker 1: We're really really excited to be.
Speaker 3: Here and we've got a couple more of our usual
Speaker 3: outro episode thank yous, which is thank you to Bloodmobile
Speaker 3: for providing the music for this episode and all of
Speaker 3: our episodes.
Speaker 1: Thank you to Leona.
Speaker 3: Sculacchi and Tom Bryfocal for their amazing audio mixing. Thank
Speaker 3: you to everyone at Exactly Right, and a huge thank
Speaker 3: you to our amazing listeners, including everyone here today. Thank you,
Speaker 3: thank you, thank you, and until next time, wash your hands,
Speaker 3: you filthy animals.
Speaker 1: I've never send that to people in real life. Sorry.
Speaker 6: Oh um um
Speaker 4: Uh