Horizon

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.