On a clifftop in Devon, one brave volunteer is about to take part
in a unique experiment into the workings of our body clock.
Good luck.
See you in ten days.
He'll live deep inside an abandoned nuclear bunker without sunlight,
human contact or any way of telling the time.
It's bloody tough.
Argh!
My name's Ella Al-Shamahi.
As an evolutionary biologist, I've always been curious
about the rhythms of our everyday lives.
So I've teamed up with scientists and experts to monitor the bunker
24 hours a day.
And learn more about a fascinating new science that could improve
our sleep, lift our mood and even help us fight disease.
Now, we all know that what we choose to eat or whether we exercise
affects our wellbeing, but I'm going to find out
how the choices we make about our biological clock
could improve our health.
I'll use the bunker experiment to discover exactly
how our body clock works and test it to its limits.
And with the help of two couples who are out of sync
with their internal clocks, I'll look at how we can
take back control.
I'm exhausted.
Now I've got a 12-hour night shift coming.
It's now half four.
I don't know why I can't sleep.
At every stage, I'll use the latest scientific research to uncover
practical advice that we can all take on board,
and the results could help us all transform our lives.
As a busy scientist who travels a lot,
I don't have the best relationship with my own internal clock.
So, I work really weird hours. I'm in work quite late.
Now, this is the lab, but this is the sofa,
and the truth is, I crash here a lot.
In fact, I probably spend more time on this sofa
than I do at my desk, and the problem is, whenever I sleep here,
it messes up my sleep, and I feel dreadful.
Altering our daily rhythms is bad for our health.
Studies on shift workers show that if we regularly disrupt our sleep
we're at a greater risk of diabetes, heart disease and cancer.
So understanding our biological clock couldn't be more important.
To do that, we need to strip away the trappings of modern life,
and even the natural rhythms of sunrise and sunset.
Our volunteer, former Commando Aldo Kane, is well used to
tough situations, but life in the bunker will be hard going,
even for him.
Ten days in isolation, it's a huge challenge.
I don't know what it's like to spend ten days in my own head
without another human voice or interaction.
It's completely unknown to me.
See, in the bunker,
the temperature doesn't change between night and day.
There's no sunlight, there's no other people to give away the time,
and there's definitely no phone signal.
See, Aldo is about to experience something most of us never will -
what life is like completely outside of time.
We've rigged the bunker with remote cameras to monitor Aldo
day and night.
Inside, he'll complete a barrage of tests seven times a day
that measure everything, from his mood,
to his reaction time and memory.
We want to find out what drives our internal clock,
how it affects us, and how well it keeps ticking
when we've no idea what the real time is.
I need to find routine in the silent chaos that's going to be down there,
I need to somehow find a way of making sense of it.
Probably a good point for me to take your watch off you, actually.
Yeah!
I'm going to replace that with this.
It's a special monitoring watch
and it will basically monitor your movements,
your body temperature.
This has to stay on... Yeah... 24/7? Well, except for the shower.
Can I ask if you've got a phone on you...? Yes.
Do you have anything else on you that might...?
No, just the feeling of impending doom.
Without phone or watch, the only clock Aldo has now
is the one inside his body.
Deep within his brain, in the hypothalamus,
a small group of cells tick along with a regular 24-hour rhythm.
This biological clock uses nerves and hormones to transmit
this rhythm to his internal organs, keeping them in sync
and regulating body functions.
We want to find out what happens to the system
when it's shut off from the outside world.
Good luck. See you in ten days.
Godspeed.
Experiments like this have driven participants out of their minds.
So while Aldo's in the bunker, we'll have a psychologist on standby
24 hours a day.
If Aldo copes with the isolation, we'll get valuable insight
into managing our internal clocks better and improving our lives.
It took me all of about four minutes to unpack.
These are my shelves,
and a fine selection of strange underwear.
I actually now have nothing to do.
The experiment will get more difficult as we try
to interfere with Aldo's body clock.
But in this first phase, he will follow and normal daily routine
and have full control of the lights.
The question is, will he keep to his usual schedule
or go completely out of sync with the outside world?
So, this is day one in... the bunker.
I am underground.
I've been in for... How long?
That's an interesting question already.
He is going to try and live his rhythmic life
because we have daily set patterns.
Some people stick to routines more than others.
So it will be interesting to see how he copes with that.
Debra Skene is helping me oversee the experiment.
She's a leading body clock scientist who has studied
the rhythms of the human body for over 25 years.
She'll work in shifts with Vikki Revell,
a sleep science specialist who has overseen dozens
of clinical sleep experiments.
As a society, we're quite good at saying, "I can survive
"on four hours' sleep, I can survive on six hours' sleep.
"Look at me, I'm very tough, I'm very British. Look at me, I'm fine."
"Margaret Thatcher did it." Exactly. "We can do it!"
But it's not a good idea.
Experiments into the human body clock are mostly done
in a tightly controlled lab.
Here, Aldo will live relatively freely,
so we don't know exactly how he'll respond.
We want to know what happens to your body clock,
what happens when we disrupt it, what happens when it goes wrong.
Really, I'm spending ten days in complete silence with myself.
That, potentially, is quite alarming.
Looks like you can get underneath there.
To fill some of his spare time, Aldo's exploring
the more inaccessible parts of the bunker.
I might have to put this on higher, actually, see if that works.
Strange, it's such a big place, and quiet.
Come into this room, and it has old maps.
Look at that!
The bunker was built to house the entire regional government
in the event of a nuclear war.
No-one was supposed to be down here alone.
That's probably the most ironic thing I've seen
since I've been in here.
The experiment will give us masses of information
on how our body clocks work.
But I also want to find out how we can change our lives
and sleep patterns to manage our clocks better.
So I've come to Manchester to meet some people
who can definitely do with some help.
We've asked two couples to monitor their own daily rhythms,
to see if we can help them improve their lives.
Because, at the moment, their internal clocks are
not exactly on the same page.
Like lots of couples, Naomi and Greg run on very different schedules.
Naomi's out as soon as her head hits the pillow.
But for Greg, it's a very different story.
I've been awake for the past four hours.
It's now half four.
I don't know why I can't sleep.
I've not eaten any... anything,
not had any caffeine, that I can think of, that would've kept me up,
but I just feel like... just pumped full of adrenaline all of a sudden.
Come morning, Naomi's up and about...
..while Greg is fast asleep.
So it sounds like we've got an early bird and a night owl -
would I be right in thinking that?
We tend to go to bed around the same time,
but I won't actually get to sleep for a couple of hours
after we've got into bed.
Greg teaches guitar, so he doesn't have to keep
a normal nine-to-five schedule.
But like many night owls, he's desperate to improve his sleep.
You're struggling to shift to an earlier timetable,
but how does it affect you, other than kind of struggling to
wake up in the morning?
Just any personal problems I have, anything I find difficult,
whether it's, you know, anxiety or anything like that,
I think it probably all boils down to sleep, for me.
I think if I could get a consistently good night's sleep,
I think it would solve a lot of issues for me.
Say I've got, like, a job coming up and I'm really stressed,
I will be like, "I need to go to bed now."
If he's pottering about because he's not tired,
so he's like, "I'll come up with you," but he's pottering about,
he's turning the light on and stuff like that.
I think it's... When you're in a stressed time,
that's when it becomes a problem.
I want to see what we can do to help night owls like Greg
go to bed earlier and get more sleep.
To do that, I need some hard data on his internal clock.
What we've got in here is these Actiwatches.
Feel free to open them.
The instructions are in here.
These watches use sensors to record how much Naomi and Greg moved.
It means we can accurately track when they're active
and when they're asleep.
Knowing where you are on that spectrum, from early bird
to night owl, is the first step in learning how to hack your clock.
If you're always up early with a smile on your face,
you're part of the 25% of the population who are early birds.
If you dread your alarm and only
come to life in the evening,
you're a night owl, like me, Greg and another 25% of the population.
50% of us fall somewhere in between.
Whether we're early birds or night owls shifts as we get older,
so when we're young kids, we tend to be early birds.
As teenagers, most of us are serious night owls.
But by our early 20s, we settle into our adult patterns.
We can't change where we fall on the early bird to night owl spectrum
as it's mostly determined by our genes.
The second couple I'm going to meet has a different set of problems.
They both work nights, and it's making them miserable.
Hello?
Hi, it's Ella. Oh, hiya. Come on up.
Did you guys intentionally start picking night-time jobs?
No, it was just kind of fell upon it, didn't we?
Yeah, I think we kind of had the option of nights and we've thought
"If we both do nights, it might be OK cos we can both sleep
"during the day and both still see each other."
But it didn't go to plan. So it wasn't OK? No.
Connor works in security, and Chloe does shifts in a local care home.
Currently 20 past six, and I'm just getting ready for work.
I woke up at about half five, and I'm exhausted.
I am completely drained.
I think I've had about a two-hour jip on the sofa again.
So... Now I've got a 12-hour night shift coming.
Over three million people across the UK do some sort of night shift work.
Long-term, this can seriously affect their physical and mental health.
It's been linked to heart disease, stomach disorders and depression.
She can't sleep, I, like, sleep way too much.
After the Saturday shift, I've slept from seven o'clock Sunday morning
to seven o'clock Monday morning -
I've literally slept 24 hours.
Wow!
Using the data from our watches, I want to see if we can help them
sleep better and take back control of their topsy-turvy routines.
Sure, each of these couples have their own problems,
but I reckon they stem from the same issue -
their lives seem out of whack with their body clocks.
So I suppose the question is, can we improve their lives
and help them live more in sync?
Back in the bunker, Aldo is getting used to life in isolation.
Day three.
All well, I think.
I'd love to hear another person speak,
even just for a few minutes.
Everyone's so obsessed now with
telling everyone else what they're up to.
It kind of gives you that feeling that you're missing out,
when actually, maybe I'm not missing out.
Maybe I'm having an amazing time in a bunker, deep underground.
During the first phase of this experiment,
we want to see how well Aldo's body clock keeps him a 24-hour rhythm.
As he settles in, his attempt to keep track of time doesn't seem
to be going that well.
I think it's probably somewhere
about seven or eight o'clock in the morning.
What time do I think it is?
Round about... three o'clock in the afternoon.
I'm hungry, so I'm eating, so it's now dinner time.
The sound of silence is deafening, and the sound of my own voice,
already, is starting to annoy me.
"Strips of tender steak in a classic creamy sauce"!
Mm-hmm...
Aldo can only guess what time he thinks it is.
He can't know the timing of his internal clock,
which simply ticks along in his subconscious.
I need to take my... monitoring watch off.
We're using his wrist monitor to unmask the timing of his body clock.
It's custom-built to measure movement,
light and, crucially, his temperature.
Body temperature drops during the night and rises
in the morning, so these measurements will give
an accurate picture of his internal clock cycle.
We downloaded the data from the watch, and we're giving it
back cos we don't want it off him for too long.
The results show that his body clock keeps much better time than him.
Combining his temperature and movement data
tells us the midpoint of his sleep.
This is the clearest marker for his body clock's timing
and sits halfway between when he went to sleep and when he woke up.
We're ignoring the first day, because Aldo was catching up
on his sleep.
But for the next three nights,
the middle of his sleep was always at a quarter to five in the morning.
His body clock kept to an almost perfect 24-hour schedule.
There is a real internal clock in your brain that's driving
these 24-hour rhythms.
And that's what we are seeing,
that when we put him in there with no access to clocks,
no access to outdoor light, that clock still persists,
those body rhythms still persist, they're a real thing.
There's a reason we need an accurate internal clock.
Our body changes in hundreds of different ways
over the course of a day.
And this has a real impact on our lives.
I'm just about to start the first set of experiments.
Back against the wall, wait for the light.
Seven times a day, Aldo has been doing tests
that measure his mental and physical performance.
One.
Get in!
After a few days, the results are in.
Two, three...
Intriguingly, his performance depends on where he is
in his daily cycle.
There are clear 24-hour rhythms in Aldo's ability to perform,
so both tasks when we're using our brain, so, like,
processing speed, reaction time tasks, but also physical task -
there's a change in the 24-hour day.
His reaction time is over a tenth of a second faster in the afternoon
than in the early morning.
That's a 20% improvement.
His grip strength too peaks in the afternoon...
I don't know if you can see that there?
That says 66.6.
Oh, 666!
..before dropping 10% to 60 kilos late in the evening.
Almost all of Aldo's experiments show a clear, daily variation,
even in his memory and mood.
Everything has a time-of-day variation, every single part
of our physiology and our behaviour is changing,
you know, minute by minute, literally.
Even within our normal days, our normal lives, we have
different times when we're better at things than others.
All of these daily changes are coordinated by our internal clock.
So how does this affect our daily lives
and is there a way of organising our days
so that we're doing the right thing
at the right time?
Overnight, to save energy, our temperature and blood pressure
are low, which makes us sluggish.
Day two.
This means early morning isn't the best time for exercise
or complicated mental activities.
Aw, sh...!
Mornings are a great time to eat a big meal,
as our stomachs are more active and our metabolism, more efficient.
Look at that.
Late morning is the best time to do things that require
lots of brainpower, like writing and planning.
For physical exercise, it's late afternoon.
Athletes should be faster and stronger than in the morning.
Big evening meals aren't a great idea,
as our stomachs are slowing down for the night.
While we sleep, our bodies repair any damage.
These daily cycles make us better equipped to move around
and eat during the day and rest at night.
This is the reason we have an internal clock at all.
We know that in our brain,
we have what we call our master clock.
That can be seen as a conductor, and then all the rest of the cells
within your body are like the orchestra.
Those different organs in different parts of the body
are all very carefully co-ordinated.
We all think that it's our watches that control our daily routines.
But phase one of the bunker has shown us that our bodies
are doing their own thing and following their own rhythms.
Our internal clock keeps its own time.
So, how do we take control of this clock
and shift it earlier or later?
First, we have to understand how it works -
something that, up until recently, was a complete mystery.
I've come to America to meet a man who shared a Nobel Prize
for figuring out how our body clock keeps time.
It's all about our genes.
Now, as a geneticist by training, I'm really excited to meet him
because it's not everyday that you get to go
to a cabin in Maine to meet a Nobel Prize winner.
And apparently he's quite a recluse and a bit of a character.
On the attack here... Good girl, look at you.
You little worm. You worm-like dog.
Oh, my gosh.
Hey! Hey!
Stop it!
The dogs are amazing,
but they've just gone and destroyed my tights.
So I'm currently trying to show you a Nobel Prize medal
with the professor screaming at all the dogs
because they are uncontrollable.
They just clearly run the show.
Easy! Easy!
Stop it!
There is one really interesting thing to me, though,
and it's that he says that... Get out of there!
..when he says to people that he's a biologist, they might glaze over,
but when he says that he's a biologist who studies rhythm,
suddenly they all connect.
I think it's cos we all identify with that,
we've all... we've all got clocks, right?
So, how do you feel about having won the Nobel Prize?
I never mention it to anybody around here
cos I assume nobody would've heard of it.
But even in rural Maine, they've heard of this.
I couldn't believe it.
You know, a kindly woman who works the cash register
at the supermarket, she said congratulations.
I said, "About what?"
She said, "The Nobel Prize."
I said, "How in the world...?"
She said, "Facebook."
I said, "Oh, God..."
Before he moved to Maine, Jeff was a geneticist
fascinated by the fruit fly.
These tiny flies live according to a regular 24-hour rhythm,
just like us.
Along with two other scientists, Jeff started using the flies to try
and answer the long-held mystery of how biological clocks keep time.
He thought it might be some sort of chemical clock driven by genes.
It would take him ten long years to prove that he was right.
We found, eventually, maybe five or six key core clock genes.
Every animal on the planet possesses these genes
discovered in fruit flies.
What the products of most genes are is proteins.
What are the proteins doing?
We eventually figured that out.
Jeff and his colleagues had discovered an elegant system
that works a bit like a chemical pendulum.
It all starts with a gene called period.
Inside the cells that make up the fly's body clock,
molecular machinery copies the DNA
that makes up the period gene.
These copies move out to the main body of the cell
and start making the period protein.
Next, a second protein transports period back inside the cell nucleus.
When its concentration gets high enough, it acts like a master
switch, shutting down production of the period protein itself.
The proteins break down and the whole thing starts again.
From start to finish, each cycle takes roughly 24 hours.
It's a very effective chemical clock.
Other scientists went on to prove that it wasn't just flies -
the human body clock works in exactly the same way.
And it turns out it's a mechanism conserved in animal evolution
going back zillion, eleventy zillion years or something.
It's one of the... perhaps one the earliest things that evolved
on behalf of animal evolution,
is the existence of a circadian clock,
an internal clock, a biological clock,
operating mechanistically in a similar way amongst all animals
on the third rock from the Sun.
Circadian clocks have a 24-hour rhythm
and keep in time with the cycles of night and day.
This means they have a key feature that affects us all.
Circadian clocks are not very accurate, by definition.
Circadian, but they're easily reset.
Mm...! They get reset every day, and that's a crucial feature
of any rhythm system, is a reset mechanism.
Our own body clock gets reset every day to keep it in sync
with the outside world by using daylight as the trigger.
We're about to enter phase two of the bunker experiment.
To find out how lack of light affects our body clock,
I'm going to plunge Aldo into near darkness 24 hours a day.
Hello. Hey, Aldo, it's Ella here.
We're about to go dim,
but I thought I'd check up on you first. How are you doing?
Um, yeah, good.
Just, um... Yeah, just trying to make use of my time.
I'm wishing you well, and we're all rooting for you out here.
All right, mate. Take care, bye-bye.
I've just had a phone call, and that was from Ella up on the top and
all she had to tell me, basically, was that they are going dim,
whatever that means, so I guess the lights are going off.
So, guys, can we go dim?
I may be in the dark for...
Yeah. So it's just happened there, so I am...
Let me flick to...
I've switched to IR on the camera.
And the shadow that you can see on the wall here,
that's not actually from a light, that's from this here,
which is an infrared light.
If I switch back to normal, you'll see that light disappears.
So, that's normal.
This is how dark it is in the room.
So that light, I can't see.
For the next few days, this is as bright as the bunker will get.
It does give the impression somehow
that I'm more on my own
and that I'm more isolated from humanity.
So, Vikki, why exactly are we dimming the lights?
So, we know that we have a body clock in our brain
and we know that that body clock doesn't run at exactly 24 hours,
but to live on a 24-hour day, as we do, with the Earth rotating,
we need to synchronise that body clock on a daily basis.
And it is the light-dark cycle that we see,
that's what synchronises our body clock to the 24-hour day.
So what happens is, if we put someone
into continuous dim light levels,
the body clock doesn't have any signal to hang on to.
Up to now, the bright lights inside the bunker have acted
like a false day, resetting Aldo's body clock.
Now we'll find out how it works without the daily dose of light.
Oh. One...
I already feel tired... because it's very, very dim and dark.
It feels like...
It feels like, um... a winter's night at home
with the hatches battened down -
that's what it feels like in here.
Except it's not cosy and warm.
I noticed today that, just because I'm not busy and I'm not active,
that as soon as I sit down my eyes are heavy and I'm drifting off.
I think again, today, I fell asleep on the bed,
which I never, ever do, I never sleep during the day.
If it is the day.
It could be the night.
He's wearing a head torch cos he's reading.
It kind of shows just how little light we've got him in right now.
It really, really is dim lighting.
This is candlelight level, it's very dim.
Aldo is struggling because our bodies haven't evolved
to live underground.
They've evolved in the world where, without fail,
every day, the sun rises and sets.
We know that light is detected in our eyes,
it passes down a specific pathway to the area of our brain,
where our body clock is located,
and it's that light signal that keeps us synchronised.
Deep inside our brains, our body clock ticks
to roughly a 24-hour rhythm.
But, like an old watch, it doesn't keep perfect time.
To counteract this, special cells in our eyes detect
the overall amount of light coming in
and pass that information to the clock.
These signals reset our clock every single day,
keeping it in time with the outside world.
I've just woken up after... my...
..fourth sleep-wake cycle, which puts me...
..I think, in day five. Um...
Since it's been dark down here, I've completely lost track of time.
I've just got... I've just got absolutely no idea
how long I've been sleeping,
whether I've been asleep for four hours,
whether I've been asleep for ten.
The light levels do have a really profound impact
on how alert you're feeling
and how sort of happy or positive you're feeling,
so he's struggling against that as well.
Aldo's finding living in darkness hard enough.
But I want to understand the real-world impact
of what life is like without light.
Hi. Hi, Ella. Pleased to meet you, Ella. Mark.
Thank you so much for having us. You're more than welcome.
Can I come in? Thank you. You're welcome.
Mark lost his sight whilst serving in the British Army.
He hasn't seen a sunrise or sunset for almost 20 years.
Most blind people would have some residual vision
so they'd have a grasp of whether it's day or night.
I had a head injury, and I've, with the brain surgery and everything,
they gave me good looks back, I always say.
But, yeah, after the brain surgery,
I was left with severed optic nerves,
so even if the eyes were working, the wiring's gone.
So everything is utterly black, totally black, black blind.
Mark's mastered how to live without sight.
He competes in triathlons, goes scuba diving
and climbs mountains.
He even holds a powerboat speed record.
But losing his eyesight has caused his body clock massive problems.
I tend to lose about an hour a day.
So instead of waking up at six in the morning,
you start waking up at five in the morning.
The next day, you're up at four,
until you're completely upside down.
And you just know the sleepless nights are coming,
and it's soul destroying.
You're permanently tired, you know,
you're permanently crabby with people.
Mark wants to live a normal life where he sleeps at night
and is awake during the day.
For much of the month, his body wants to do the opposite,
so he's forced to live against his internal clock.
So what you've actually described there is free running,
and you're actually one of the few people that does this.
When you get that one week where you are actually in sync
in the month with everything, it's just so much better.
What this really rams home to me is that our eyes aren't just
the organs of vision - they're also organs of time.
Light is massively important for our internal clocks,
and that single fact has huge implications for our everyday lives.
This is a light meter.
It tells us something which is surprisingly hard
to judge with the naked eye -
exactly how much light is falling on a certain area.
So it's quite a bright day today, and it's coming in at 614,000 lux.
A lux is just a measure of how much light hits a certain area.
The key thing is, over half a million is a lot.
It's why we often sleep well
when we spend the whole day outside or go camping.
Our body clocks are exposed to a huge dose of light,
making us more alert during the day and sleep better at night.
Now, inside this car, which you'd think is quite bright
because of all the glass, the light level drops to...
..514.
So that's a thousand times less than a sunny day.
Inside cars, homes and buildings, light levels are often many hundreds
of times lower than outside, even on a cloudy day.
This gives our clocks a weaker signal.
It means that because so many of us spend so much of our lives in a car
on a train, on a bus, and then in an office,
we're not getting the right amount of light
that our bodies have evolved for,
and that's why so many of us have body clocks out of whack.
We're enjoying plenty of sunshine above ground, here in Devon.
But inside the bunker, with no light to reset his clock,
Aldo's slipping further and further out of sync.
I estimated around about 8:30 going to bed.
I'm not sure if that's right...
..right or not.
It's just so difficult to tell.
I actually have no idea where I am in my cycle now of...
..asleep and awake.
In the constant gloom, Aldo is finding it quite hard to concentrate
and even do things he normally enjoys, like working out.
It's amazing how much...
..motivation it's taking to actually do
even simply just an hour's worth of training.
It's bloody tough.
With every single rep I do, I'm wanting to quit.
Two new freezer meals.
Proper porridge oats.
Uh... Some batteries.
My watch.
And a load of new folders.
To work out exactly how the lack of light
has affected Aldo's body clock,
we need to look at his wrist monitoring device again.
What's been plotted here in the red
is the midpoint of his sleep pattern.
And you can clearly see that shifting
later and later each day.
After 168 hours inside the bunker,
Aldo's slipped three hours and 16 minutes out of sync.
Without light resetting his biological clock,
it's gaining 30 minutes every day.
The body clock is running at its own speed,
and as it's running at slightly longer than 24 hours,
each day, he's going to get up a little bit later,
go to bed a little bit later.
And so what we're seen here is the underlying timing of his clock.
This is an important clue to the timing of all of our clocks.
We don't know why, but most people's clocks run
slightly longer than 24 hours.
What's really nice about the data Aldo's given us is that
he is basically showing us what the average person's clock looks like.
Up in Manchester, we've got even more data coming in.
Our couples have been filling in sleep diaries
and wearing their monitoring devices for over a week.
I've asked Till Roenneberg,
one of the world's leading body clock experts,
to look at their results and give them some advice.
Many people have problems to coincide their internal timing
of their body clocks and the times they have to spend at work.
So they have sleeping problems, they have eating problems
and so forth.
The best thing is to start talking to people and making them aware
of what body clock type they are, if they are early or late.
Till believes passionately that we should all pay more attention
to our body's inner clock.
And from what he's seen, our couples need help.
Hi, welcome. Hello. Come on in.
At the moment, I see you being an extreme late sleeper.
What you are living we call social jet lag.
You could fall asleep as late as five o'clock in the morning
and then you will probably sleep quite well.
But you try to synchronise with your partner, and then you lie wake.
Social jet lag mostly affects late sleepers, or night owls,
like Greg, whose clock runs slow.
They go to bed late, but still have to try and get up at the same time
as the rest of us, meaning they're often chronically deprived of sleep.
Now, the question is, do we want to treat your lateness -
and there are possibilities to do so -
but you have to be aware of the fact that, if we do so,
you have to do it all the time.
Till's solutions are all to do with light.
To become an earlier sleeper, there are two things that you have to do.
Expose yourself to as much light as you can when you get up,
because that light will allow you to get up earlier the next day.
And in addition, avoid any blue light after sunset.
You might try something that we call blue light blockers.
So no blue light... And you may try them on.
No blue light after sunset.
It feels like the sun's about to go down for the night.
So, yeah, this makes... Yeah, it makes a huge difference.
You can even start earlier, in the afternoon, if you want.
Our clock responds to blue light more than any other colour.
By blocking it, the glasses fool our clock into thinking
it's far darker than it really is.
Perfect for the evening, when we're getting ready to sleep.
What time our clock is exposed to light is important.
So more light in the morning shifts our clock earlier,
but more light in the afternoon shifts it later.
And that can come in handy.
Night owls, like me and Greg, need to shift our clocks earlier.
To catch plenty of light first thing, we should sleep in rooms
that have light curtains or with the curtains open.
And get outside in the daylight during the morning.
If we night owls spend two hours outside in bright light every day -
let's say we cycle into work instead of getting the train -
we can shift our clock by up to an hour.
That's an entire hour's more sleep every night.
For that to work, we also have to cut down on light late at night.
So tablets and mobile phones in bed are out,
unless we use the night shift function
that turns the screens orange.
Early birds have an easier time fitting in with the nine to five.
But if they do want to wake up later, they should get bright light
in the afternoon and evening and sleep with thick blinds.
Or eye masks, to block the morning light.
Till's meeting night shift worker Connor next.
His partner Chloe is in bed with a nasty bug.
It is very important for your health that your daily rhythms
and your body clock are regular.
Trying to adhere to a very strict schedule, even if it's not
the natural one is, in your case, very good,
and for both you and Chloe, it would probably
improve your health in many ways.
Connor and Chloe's wrist monitors show Till that their sleep
is all over the place, especially on their days off
when they revert to sleeping at night.
Till wants them to stick to sleeping during the day
and keep more regular patterns.
For anyone like Connor and Chloe, whose shifts don't change,
sticking to a schedule based around the timings of your shift
is the way to go.
But here's the important bit -
you need to be doing this, even on your days off.
It's chopping and changing routines that really messes with your clock
and your health.
Till also suggests night shift workers use eye masks
or blackout blinds to block out the light when they're trying to sleep.
And wear blue light-blocking glasses
on their way home in the morning light,
as long as they don't drive.
It's important for you to expose yourself to as little blue light
as possible on your way home. Right.
So... It will help you fall asleep. Right.
Because the blue light of the daylight in the bus
and the blue light that comes
from computers or from television screens,
will make you wake up.
We're about to enter phase three of the bunker experiment.
So far, Aldo's been living according to his own natural rhythm
to uncover the underlying timing of his internal clock.
Now I'm going to force him to live out of sync with his clock
to see how this affects his body and his mind.
I'm going to wake him up early
and give him the equivalent of five hours of jet lag.
So it's six in the morning, I'm half asleep,
but Aldo is fast asleep.
He actually went to sleep at 2:30 in the morning
thinking it was 8:30 in the evening,
so this is very much in the middle of his sleep,
and we're sending him into jet lag by switching all the lights on,
and I feel sorry for him.
He's still not moving.
Love this. Our attempt at waking Aldo up is not really working.
There we go, that worked.
The poor guy.
Aw... I feel for him actually.
Hello. Hey, Aldo.
So we're... we've gone into the jet lag phase,
so we've switched all the lights on, so just what your eyes there.
And if it's all right,
we'd like you to operate as if it's the morning.
OK, no problem.
I think we underestimate just how much jet lag affects us.
It's actually a really unpleasant phenomenon.
The question is, how will it affect Aldo?
I think I'd just got to sleep.
I've no idea what the time is,
I don't know how long I've been asleep for.
For the next few days, we'll carry on waking Aldo at 6am,
right in the middle of his night.
It's as if he's flown from New York to London.
Good morning, it's, erm...
Uh, I went to sleep at... round about...
..nine o'clock, I think.
Then, when I eventually got to sleep...
His wrist monitoring device and the daily tests will tell us
exactly how living out of sync affects him.
This is a vital question - and not just for people who travel.
This situation doesn't just happen in jet lag.
People doing shift work. for example, or, you know, the majority
of us when the clocks go back or go forwards.
It's only an hour's change, but you're out by an hour,
so all of us are going to experience this.
Jet lag and night shift workers is a more extreme example,
but a lot of us will experience
slight misalignment on a daily basis.
Up in Manchester, our sleep-deprived couples have been following
our advice and trying to get their own body clocks back in sync.
So has it actually helped?
Naomi and her night-owl fiance Greg
have been spending more time outside,
and Greg's been religiously wearing his orange glasses in the evening.
So trying out the different...
Naomi's controlling all this on her phone right now
so there's different light colours.
Kind of... I've got the glasses on, so I don't actually know
what colour that actually is - everything looks orange.
How has your sleep been in the last week?
It's been noticeably better, definitely.
I'm finding it easier to actually sort of get my body
into the sleep process.
I don't necessarily feel like I'm going to drop off right now,
but I close my eyes and they feel like they lock,
and I felt really comfortable just lying there still
with my eyes closed, and I think, "OK, I can do this."
In just a week, Greg's managed to shift his clock noticeably earlier.
It's a great result.
But also, for me, I think there's such an important point
about realising that Greg's normal, he's fine.
It feels like that was such a realisation for both of you.
Definitely. Feels like it.
So it's not so weird now if I go to bed by myself,
it doesn't bother me.
Before, it bothered me a little bit,
but now I'm like, "Well, it's not his bedtime."
We can really understand each other now.
Night shift workers Connor and Chloe have been using their glasses,
eye masks and only sleeping during the day for over a week.
We're using this tonight.
I've been using my glasses tonight too while I've been watching telly.
I've just had to take them off cos I've, like...
..I've just literally just got in bed.
So I'm going to use my mask tonight and hope for a good night's sleep.
So, one can only hope.
So, Till told you guys to essentially follow a routine,
so be nocturnal, really.
Yeah. Pretty much.
And also to wear these funky glasses. Yeah.
And you feel that there's been some positive effects?
Yeah, definitely. Oh, yeah.
You've just got to kind of like take your orange glasses off
and put the eye mask on quickly, otherwise it really messes with you.
It's definitely made a difference, but cos I've been using this mask,
it's blocked every bit of light out and I've been sleeping through.
It has made a massive difference. That's great!
They're simple techniques, but you saw how much
our couples were struggling.
And this really seems to have helped them improve their lives.
So I have hope that any of us can hack our body clocks
and make them work for us.
It's day nine.
Aldo's finding the jet lag phase of the experiments tough.
I'm bored.
Four hours into his sleep, you woke him up.
That was a big shock to his system and, you know,
we've got mood data, we've got sleepiness data.
We can see what a shock that was to his system
beautifully, in the data.
This was when... the first point that he did after being woken up
so early in the morning,
and you can see his reaction time is a lot slower.
Aldo's tests show that his reaction speed, physical performance
and even mental ability have taken a nosedive.
That's because his body is completely out of sync.
He's active when he should be resting
and resting when his body is ready to be active.
We have clocks all over our bodies, and nearly all the cells
in our bodies have a clock, and all of our different systems
are synchronised to make us really functional during the day.
And we know the different parts of our body and the different clocks,
they will all catch up at a slightly different rate.
So, for example, you know, our brain clock might be shifted
and might be there, but our stomach clock or our lung clock
might take a different number of days to readjust.
Long-term, this misalignment can harm the health of shift workers
and regular jet lag sufferers.
There's a strong link to mental health too.
Aldo's definitely feeling the strain.
Still day nine.
Or it should be renamed the longest day in history.
I have a small, niggling worry
that I may not actually be in day nine.
If I had to do another few days of this, I would probably sack it.
It is doing my head in.
Argh!
It's really having an impact on him mentally.
It's actually... It's actually a little bit uncomfortable to watch.
Remember, it hasn't been an easy experiment.
I mean, he's on his own, losing track of time.
Perhaps the jet lag experiment,
where we, you know, cut his sleep short...
I mean, he had four hours of sleep, and then he was abruptly woken up.
You know, maybe this was just a stress too far.
You can see how easy it would be to psychologically unwind
and unwind fairly spectacularly.
Aldo's is free to leave the bunker if he wants,
but as a former Commando who survived tours in Iraq
and Afghanistan, he's determined to tough it out.
His exhaustion will be familiar
if you've ever travelled across time zones.
If you've got jet lag, you can't shift your clock
by more than one hour a day,
but you can use light and the absence of light
to shift it as fast as possible in the right direction.
Fly east, and on arrival, you should catch strong daylight
in the morning.
This will shift your clock earlier and closer to the local time.
Go west, it's the opposite.
On arrival, get light in the evening to shift your clock later.
Fly more than a few hours and the timings can vary,
but apps and websites will help you calculate the best time to catch
the light for wherever you're going to.
It's the morning of day ten.
I've had one, two, three, four, five,
six, seven, eight, nine sleep cycles.
And I've just had a phone call which woke me up,
asking if I could do one round of experiments and then pack my bags.
Which I am ecstatic about.
The thing is, his jet lag phase, which he's been in for
the last few days, has really taken its toll on him,
and his mood and everything, really, has just been getting worse for him.
So I think it's really time to get him out, the poor guy.
And, yeah, I'm happy.
Aldo's experience has shown how important the body clock is
for every single one of us.
How it defines our daily rhythms far more than the watch on our wrist.
And the impact these rhythms have on our health,
happiness and performance.
He's drifted more than three hours out of sync with the outside world
in just a few days.
And shown how we can all make better choices about our body clocks
in our everyday lives.
Now, after ten days hidden from the sun,
he's about to catch his first glimpse of daylight.
Wow!
How are you? So happy to see you.
Not as happy as I am you. It is super bright.
We felt, you know, here's a man who really wants to keep track of time.
You know, you never estimated the clock time correctly.
2:30 in the morning... Yeah.
..going to bed. I never go to bed that late.
But you didn't think it was that time.
I have no idea what time it is, or when I am.
I have no idea in space and time where I am,
which is quite a nice place to be.
What's Aldo's put himself through inside the bunker
is completely extreme.
But from an evolutionary perspective,
the way most of us live now is also extreme.
Think about it - you spend all day inside dingy offices
and use artificial light way into the night.
What's worse, we live by schedules which force us all - all of us -
whether we're early birds or night owls,
to live by the same clock.
It's really just not how we're built.
And it's why our body clocks get confused and have problems.
But what I've learnt is that we can take back control,
and if we do that, we can be happier and healthier.
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