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Interrupted Sleep: The Dangers Of Restricted -

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Interrupted Sleep: The dangers of restricted sleep (19/08/2010)

TRANSCRIPT

Dr Maryanne Demasi

We all love a good night's sleep and let's face it, not enough makes us grumpy and drowsy. Now
sleep researchers are showing that restricted or interrupted sleep may be more harmful than you
think.

Professor Ron Grunstein

What we know about sleep is if you don't get it, you start to suffer.

Associate Professor Peter Liu

There's a relationship between disrupted sleep and the risk of obesity, the risk of diabetes, and
the risk of heart attack.

NARRATION

These researchers are looking at how disrupted or restricted sleep affects metabolism as well as
brain function. Graham and I are about to spend a night in a sleep lab to feel the effects for
ourselves. First we're both put through a series of tests to check our baseline reflexes.

Researcher

As soon as you see the red light you press the button and then that'll give you your reaction time
in milliseconds.

Dr Graham Phillips

It's quite stressful.

Dr Maryanne Demasi

Ooh God I am so slow.

NARRATION

Then came the test for vigilance.

Shaun

Just pull the lever when you're ready and then you'll be off.

Dr Graham Phillips

Right, see you in an hour and a half.

Dr Maryanne Demasi

This is a long road to nowhere.

NARRATION

With the baseline testing out of the road, the fun part begins... getting wired up.

Kerri Melehan

Just like getting your hair done.

Dr Graham Phillips

Hey, look at that.

Dr Maryanne Demasi

All done, all wired up.

NARRATION

This experiment will investigate our cognitive function after each of us experiences a bad night's
sleep.

Dr Graham Phillips

Well I think it's my bedtime, right.

NARRATION

Graham will be getting a full eight hours. But the bad news is he'll be disrupted every time he
gets into a deep sleep.

Dr Graham Phillips

I'm not going to sleep. (lights go out) Hm. It's dark.

NARRATION

While Graham drifts off under the gaze of the night vision cameras, we monitor his progress in the
control room.

Kerri Melehan

These black lines here are his brainwave activity so we look at the patterns in that brainwave
activity to see what sort of sleep he's having, whether he's awake or asleep.

Professor Ron Grunstein

People a hundred years ago thought it was sort of like your brain just went dead. Um, and didn't
understand about different stages of sleep. I mean the, the understanding of stages of sleep wasn't
really refined till the fifties.

NARRATION

Essentially, sleep is divided into Rapid Eye Movement or REM which is when we dream and Non-REM
which includes the slow wave sleep.

Professor Ron Grunstein

Slow wave sleep by its name, is when the brain wave activity starts to slow, and you get these
waves that are slower than the standard sort of faster frequencies that you see.

Dr Maryanne Demasi

So essentially you're going to stay here all night and wait for him to get into that deep sleep and
then wake him up.

Kerri Melehan

Yes.

NARRATION

Now I have time to kill. As part of the experiment I'm being restricted to only four hours sleep so
I have to try and stay awake until 2am. But at least when I do get to bed, my sleep will be
uninterrupted. So unlike Graham, I should get some deep sleep. Finally, it's 2am.

Dr Maryanne Demasi

At last. Bed.

Associate Professor Peter Liu

As one falls into sleep, one falls into deeper and deeper sleep, and this deep sleep, or slow wave
sleep, is thought to be very important for the secretion of a number of very metabolically active
hormones. And so we therefore believe that sleep is intimately related to metabolic health through
these hormones.

NARRATION

This could have a serious impact on people with sleep disorders, such as sleep apnoea sufferers who
have breathing difficulties during the night.

Michael Fung

I was waking up forty-eight times per hour. These are awakenings that you're not aware of. They're
not conscious awakenings. It's just, you're falling out of deep sleep, so you're not getting any
quality sleep.

Professor Ron Grunstein

Many patients with sleep apnoea get very broken down slow wave sleep. They'll still have a bit of
it, but it's chopped up when they snore and stop breathing and wake up. So we're looking at the
importance of that in those sort of patients.

NARRATION

Getting a bad night's sleep also affected Michael's metabolism.

Associate Professor Peter Liu

During sleep, certain metabolically active hormones are secreted. So for example growth hormone is
secreted during slow wave sleep, this deep sleep. And if you don't have slow wave sleep, then you
don't get this growth hormone being secreted.

NARRATION

This could increase the risk of diabetes and obesity and it also affects lipid processing. Once
Michael's sleep apnoea was successfully treated he saw a remarkable improvement in his metabolism.

Michael Fung

My body processed the lipids 25 per cent better.

George Dungan

Lights on, good morning, how are you doing?

Dr Graham Phillips

That was awful.

George Dungan

We'll get you unplugged and then we'll do some driving tests.

Dr Maryanne Demasi

I definitely want more hours sleep.

Dr Graham Phillips

That was perhaps the worst night's sleep I've ever had...

NARRATION

Now in our sleep stupor, it's time to get tested again.

Dr Graham Phillips

I can barely focus on the numbers.

Dr Maryanne Demasi

This is not going to be good.

Dr Graham Phillips

See how we go with this.

Dr Maryanne Demasi

This is so bad. Oh my God.

Dr Graham Phillips

Almost hit the truck.

NARRATION

An hour and a half later...

Dr Maryanne Demasi

Yes! Finished!

Dr Graham Phillips

That was awful. I'm never doing that again.

NARRATION

Now for the results.

Professor Ron Grunstein

You go into this stage of sleep, which is slow wave sleep. You can see the wave brain wave activity
is a lot sort of slower.

Dr Maryanne Demasi

Alright, so how does this compare to Graham's?

Professor Ron Grunstein

The moment we saw a hint of slow wave sleep, we'd hit him with sound. And you can see here, these
are the sound hits.

Dr Maryanne Demasi

So how many times would you hit him with a noise burst?

Professor Ron Grunstein

Ah, lots. It looks like up to three hundred times across the night.

Dr Maryanne Demasi

Three hundred, wow!

NARRATION

While Graham had twice as much sleep as I did, he had virtually no deep sleep. So how did this
affect our ability to think?

Associate Professor Peter Liu

Well this is the most interesting graph I think. And what this shows us is that for fatigue and
your ability to drive straight...

Dr Maryanne Demasi

I did worse...

Associate Professor Peter Liu

Much, much worse compared to Graham. Well what this tells us is that for driving ability the slow
wave sleep component is not important.

NARRATION

Surprisingly, slow wave sleep wasn't crucial for Graham to maintain his concentration, but what
would've been the effect on his metabolism?

Associate Professor Peter Liu

What we predict is that the glucose metabolism, the metabolism that's important for diabetes risk
will be affected by the deepness of sleep.

NARRATION

Until the study is complete, there's one thing we do know... nothing feels better than a good
night's sleep.