All language subtitles for NOVA.S47E04.Mysteries.of.Sleep.1080p.AMZN.WEB-DL.DDP.2.0.H.264-GNOME_track3_[eng]

Sleep... we all do it.

But why?

Sleep remains one of
those remarkable puzzles.

We've known the functions

of eating, drinking,
and reproducing

for thousands of years.

However, sleep
remains a mystery.

Why do some people
ruminate all night,

and other people,

they see the
pillow, they're gone?

Cutting-edge research is
now giving us a new view

inside the sleeping brain.

How can we boost and enhance

sleep quality, sleep quantity?

It's really, right now,
the tip of the iceberg.

If you've ever thought of
sleep as a waste of time,

think again.

The more we learn about sleep,

the more we realize
that we can't dismiss it.

Getting a good night's sleep

is possibly the single
most important thing

you can do every day.

"Mysteries of Sleep,"

next, on "NOVA."

I think sleep is

one of the most enduring
mysteries in all of science.

We spend a third
of our lives asleep,

in this kind of unconscious,
unresponsive, immobile state.

I mean, we can't
do any of the things

that we think are important
for our lives, like eat,

care for our young, mate.

Why do we spend
a third of our lives

in such an unproductive
and defenseless state?

What is that thing
that sleep does

to our brain and our
body every single night

is very much an open question.

A question that has baffled
scientists for centuries.

It's like this big black hole.

We don't really understand
why is it that we sleep

and what happens in our
brain when we're asleep.

But in the last decade,

sleep researchers
have started to unravel

the mysteries of sleep,

and what they are
discovering is mind-boggling.

Many people think that when
we sleep, we are unconscious,

so the brain is
sort of shut off.

But the more we explore it,

the more it's clear that
the brain is not shut off.

In fact, we find that
the brain is just as active

when we're asleep
as when we're awake.

It's just active
in different ways.

You're not either
aware or not aware,

you're neither not
conscious or unconscious.

It's a whole spectrum.

So, what exactly is sleep?

And why do we need it?

One thing that is for certain,

when it comes to sleep,
we've got a lot of company.

What we're fast learning

is that sleep isn't a luxury;sleep
is a biological necessity.

I find it fascinating,
because every animal sleeps,

every animal that
we've studied...

from worms to
jellyfish to sea slugs.

Even the octopus, whose
genome is so different from our own,

they sleep about as
much time as we do.

Sleep is one of the most
essential elements of life,

actually.

Sleep and life
evolved hand-in-hand.

Evolution has come
up with a variety of ways

to get some shut-eye.

Some animals are
vulnerable when they sleep.

And other animals are not.

And the animals that are
vulnerable when they sleep

don't sleep very much.

If animals live in the open,
they obviously have to be alert.

And they can't sleep as deeply.

You know, if a giraffe slept
the same way a lion slept,

there wouldn't be any giraffes.

Now, on the other hand,

there are animals
like the big brown bat,

which is the champion
sleeper... sleeps 20 hours a day.

It sleeps on cave walls,

so it's pretty much
invulnerable there.

But perhaps one

of nature's most
innovative sleep solutions

is found under the sea.

One of the really cool
animals that people study

is the dolphin, which actually
has unihemispheric sleep.

Half of the brain
has a sleep-like state

and the other half
has a wake-like state,

so the animal has to have
one hemisphere awake.

In fact, if you anesthetize
dolphins, they stop breathing.

And in the fur seals, such as
the one swimming behind us,

when the right hemisphere
is asleep, the left flipper,

which is controlled by
the right hemisphere,

is inactive,

and the body's
posture is asymmetric.

So by looking at a fur seal,

you can tell which
hemisphere is asleep.

Fur seals and
dolphins aren't alone.

Human sleep is equally
complex, weird, and mysterious.

I would say my favorite animal,
in terms of how animals sleep,

are humans.

Human sleep is very broad.

Each individual has their own
personal experiences with sleep.

So, what exactly is happening
inside our brains when we sleep?

We've really entered a
different world once we're asleep.

I actually think
that the whole night

is a really magical event.

With the help of volunteers
like five-year-old Jaime Lopez,

sleep researcher Rebecca
Spencer gathers clues

to how this magical
event unfolds.

Just slip this on,
just like last time.

To study sleep, we equip
Jaime with a sleep cap...

Shake, shake, shake,
shake, shake, shake, shake.

With an array of electrodes

to record brain activity.

- Yeah.
- There you go.

The way our brain supports
everything that it does,

from controlling our body

to regulating emotion,
having memories,

is through the electrical
activity of neurons.

These are brain cells
connected to one another

via these tiny passages
that are called synapses.

One neuron emits a neurochemical
called a neurotransmitter

to this passage,

and it's picked up
by the next neuron,

much like passing the
baton in the Olympics.

This signal, passed
from neuron to neuron,

can be picked up by the
electrodes in Jaime's cap

with one of the
most powerful tools

in a sleep
researcher's toolbox...

the E.E.G., the
electroencephalogram.

What this screen is
showing is the recordings

from each of those electrodes
in the cap that we put on Jaime.

Right now, in
wake, for instance,

you know, you can see
the brain waves here.

The vertical lines on the chart

represent five seconds
of Jaime's sleep.

What's important is
that as you get drowsy,

those waves slow down,

and they become what
we call alpha waves.

And as the sleep gets deeper,

the waves become
slower and slower,

and in the deepest
parts of sleep,

activity's dominated
by slow waves,

these massive waves
occurring across the brain

that are like a tsunami.

It's almost like a
football stadium,

where all of the
individuals in the stadium

before the game

are all sort of speaking to
each other at different moments,

at different times.

That's what seems to
happen when you're awake.

But when you go into
the deeper stages of sleep,

all of a sudden,
the crowd starts

to synchronize its activity.

They all start to chant in time.

Thousands of
neurons, firing in unison.

That's your deep sleep.

That's when it's
hard to wake you up.

When you wake up someone
who's been in slow-wave sleep,

and we ask them what they
were thinking, they will say,

"I don't know, I wasn't
thinking anything,

"I was asleep... leave me alone,

go away," and
they'll push you off.

But Jaime... along
with the rest of us...

doesn't stay in deep,
slow-wave sleep all night.

At a certain point, his
brain waves change.

After about 50 or 60 minutes,

your brain will
start to rise back up.

And then it will pop up and
have a short REM sleep period.

Turns out that those two types
of sleep, non-REM and REM,

will play out in a battle
for brain domination

throughout the night.

And that sort of cerebral war

is going to be won and
lost every 90 minutes.

We spend most of the
night in non-REM sleep.

The rest of the time we spend

in the mysterious
stage of REM sleep.

It's hard to
investigate REM sleep

without investigating dreams,

because more than 80% of REM
periods would include a dream.

Dreams tend to be emotional.

One idea is that we dream

to simulate potentially
negative events

so that we're prepared for them.

I had a dream, when my
daughter was very young,

that she fell into
the swimming pool...

she was near drowning.

After that, I put my
daughters into swim lessons,

and water safety has
been important to me.

It's not that we do not dream
in the other sleep stages...

we do...

but the most vivid ones
are in, in REM sleep.

REM sleep is named

for the rapid eye movements
we make when we dream.

We believe that every time
the eyes move in a dream,

it's a special moment
where we sort of switch

to the next dream
scene, if you will.

As we switch from
one dream to the next,

our brain waves are doing
something downright strange.

With REM sleep, the brain
waves look just like waves

from when you're awake.

We have this paradox
that it's a state of sleep,

but yet our brain is
in a state of activation.

But perhaps the strangest
feature of this stage of sleep

is what's happening
in your body.

During REM sleep,

our brain actually
sends the instructions

to the different muscles

to move our body
as if we were awake.

But lower down
in the brain stem,

these instructions
are disrupted.

They are not
relayed to the body,

and the body remains paralyzed.

Otherwise, if we had a dream
where we fly above the city,

we would literally
jump out of the window.

From the dreams of REM sleep,

we cycle back into
non-REM sleep,

including the deepest
stage of sleep, slow-wave.

In the first half of the night,
the majority of those cycles

are comprised of
deep, non-REM sleep.

Yet, as you push through to
the second half of the night,

now that ratio balance shifts;

and instead, the
majority of those cycles

are comprised of much more
rapid-eye-movement sleep...

dream sleep...

and a lot less deep,
non-REM sleep.

What is crazy about this is,

the pattern is so
absolutely reliable

in virtually
everybody, every night.

It speaks to a fundamental,
genetically driven program

that is essential for
being a human being.

You have to go through this.

But if every one of us

needs a night full of both
slow-wave and REM sleep,

why is it such a
struggle for so many of us

to get some shut-eye?

The search for answers

has become a
multi-billion-dollar industry,

selling us everything
from sleeping pills

to ergonomic pillows.

And if they don't do the trick,

there are more than 3,000
sleep clinics nationwide,

a number that keeps on growing.

Are you up all night
tossing, turning, mind racing,

trouble getting to sleep,
trouble staying asleep?

Drew Ackerman
has created a podcast

to help the
sleep-deprived get their Zs.

The idea for the
show really sprang

from my childhood insomnia.

When I was a kid, I lost
the ability to fall asleep.

For me, it was anxiety-related.

My parents tried to help,

but because they could sleep,

I think there was,
like, this disconnect.

It's, like, "Oh, try to relax,

try to just think about
something nice,"

and I just couldn't do that.

Whatever's keeping
you awake, thoughts,

you know, things
you're thinking about...

Drew's goal is to be
as boring as possible.

I'm going to tell you
all a bedtime story.

I want you to get comfortable.

The podcast is
not straightforward,

it's full of nonsense.

I have a unique
hobby, my dog and I.

We listen to recordings of
people knocking on doors.

It gives people
permission not to listen,

or to only kind of listen.

I want no social
pressure on the listener

to pay attention to me at all.

And there's no
shortage of people

eager to tune out.

Each month, the
show gets downloaded

a little bit over
three million times.

What I'm going to do is,

I'm going to send my voice
across the deep dark night.

People that listen to the
podcast share that feeling...

I don't know if desperation
might be a strong word...

but that feeling where
you're just lying there in bed,

and you feel alone.

How many people
listen to the podcast

because they have
trouble falling asleep?

Like, if you want,
raise your hand.

Having trouble falling
asleep or staying asleep

are symptoms of the most
common sleep disorder on the planet.

Ten percent of all people
suffer from chronic insomnia.

Insomnia is a 24-hour disorder.

It's not only sleep complaints,

these persons also
feel tensed all day.

It's not that common
that you're a very happy,

completely unanxious insomniac.

Are you ready? Right.

Is there a way to
decode what goes awry

in an insomniac's brain?

On the outskirts of Amsterdam,

at the Netherlands
Institute for Neuroscience,

Eus van Someren
is trying to find out,

with the help of lifelong
insomniacs like Reiny Metz.

I drop off to sleep very easily.

But after two hours, I wake up,

and then it's difficult
to go back to sleep.

If it's one night, well,
I can manage that.

Two nights is okay,

but when it's five
nights in a row,

it's a bit much,

and then you get
very, very tired,

not only physically,
but also mentally.

It makes me anxious, or
angry, or, you know, frightened.

Reiny sleeps in Eus's lab,

wearing a high-tech E.E.G. net

that contains hundreds
of more electrodes

than you'll find in
the standard cap.

We measure sleep overnight

with a special E.E.G. net
with 256 E.E.G. channels,

and they cover all of the head.

The more electrodes he uses,

the more activity
he can record...

more clues to what's
going on in Reiny's brain.

Okay, Reiny,

we recorded your E.E.G...

Yeah... during your sleep.

The next morning,

he shows her the results.

So, you go into REM sleep here.

Yeah. And REM sleep
is the part of sleep

where the most vivid dreams are.

Now, what I wanted to show you

is that, you see that it's not
many seconds into REM sleep,

and then already
something is happening here.

Well, you recognize it.

I don't have to explain that
this looks different than this.

Oh, yes, certainly.

It's just maybe
two seconds or so

that it's really, it's
off, it's different.

And this is what
we call an arousal.

Yeah. Where you exchange sleep

for something that's
really wake-like.

And this is something
that is so typical

for people like
you that sleep bad.

But you do see this in
many patients. Yeah.

Okay.

Usually, if you
had a good sleep,

if you slept on it, as we say,

things feel a bit better.

But if there is this profile,

that there is some
restlessness... Yeah.

Occurring during REM sleep,

then, for some reason...
we try to find out...

this whole process of
feeling better the next day

doesn't work as well.

What we observed,
which was fascinating,

if we add up all
the pieces of sleep

as suggested by the E.E.G.,

many people with insomnia

have about six-and-a-half,
maybe seven hours of sleep,

but this is not how these
people experience it.

Maybe they just experience
large parts of the night

really as ongoing
rumination, worrying, thinking.

So, it may not feel like
a good night of sleep,

but it's not the same as being
completely sleep-deprived.

So, is there a connection

between these
disruptions in REM sleep

and the anxiety so
many insomniacs feel

when they're awake?

To try to find out, Eus comes
up with an out-of-the-box idea,

based on personal experience.

Back in the 1990s,

Eus played guitar in a
popular Dutch rock band.

I remembered a few things
from being in the recording studio.

I heard my own guitar playing,

and even if it was a tiny
little bit, you know, off-tune,

it made me shiver.

Embarrassment is
a powerful emotion.

He decides to put it to a test.

A karaoke test.

We asked people to
sing along karaoke,

but they couldn't
hear themselves sing.

If you don't hear yourself well,

it's also difficult to correct
if you go out of tune.

Um, you hear that
over the headphone,

you have the headphone on...

He does the same
thing with good sleepers.

Next, Eus puts them in an fMRI.

So, in the MRI scanner,

we had them listen to their
own embarrassing singing.

As Reiny listens to her singing,

the fMRI detects activity
in a part of the brain

called the amygdala.

We have two, one
in each hemisphere.

I sometimes call the
amygdala the siren of the brain

or the alarm bell of the brain.

So, if there is something
that we should pay attention to,

because it's
dangerous or important,

then the amygdala activates.

So, they heard themselves

sing really, really out of tune.

Their amygdala was
very upset about that,

so, you know, the
alarms went off.

♪ Gloria

The alarms go off for both
insomniacs and good sleepers.

This is no surprise for Eus.

But his test isn't over yet.

We ask them to stay
all night in the sleep lab,

and we did the same
the next morning.

We again put them
in the MRI scanner.

Good sleepers, it was
not that bad anymore.

A good sleeper's
amygdala calms down.

But that doesn't
happen in the insomniac.

For them, the story
was very different,

because the more
REM sleep they had,

the worse it got.

So, instead of the amygdala
becoming adapted overnight,

many people with
insomnia, the next morning,

the amygdala could
even ring much louder.

You're just loaded with distress
that you take to the next day

and the next day
and the next day.

If we could change
that restless REM sleep,

maybe this will help
people get rid of distress.

But insomniacs
aren't the only ones

to suffer from
restless REM sleep.

Researchers are also
exploring its impact

on post-traumatic
stress disorder.

PTSD is essentially a
memory-based disorder.

An individual has

one or more very stressful,
traumatic experiences,

and they become
fearful of anything

that reminds them
of that trauma.

Like the smell of a wildfire

or the deafening
sounds of combat...

traumas so powerful, they can
even haunt us when we sleep.

People with post-traumatic
stress disorder,

they're afraid to go to sleep,

or they don't sleep very well
because of the nightmares.

Once these nightmares
get established,

they often can persist
for, for decades.

In her lab at U.C.L.A., Gina
Poe is searching for ways

to prevent these recurring
nightmares from taking shape.

One of the things
that we have to do

to study the effects
of trauma on sleep

is, we have to expose
animals to a traumatic stress or.

How you doing?

It's the least favorite
part of my job,

but there's no
other way to study it.

The rats are placed in a chamber

where they hear a tone...

Followed by a shock.

It certainly is not a strong
enough shock to cause them harm

or blister their
feet or anything,

and it only lasts one second,

but it's enough to make
them squeak and jump,

to say, "What, what was that?"

Over the next hour and a half,

the rats hear the tone
and receive the shock.

So they associate that tone

with the fear of being shocked.

Then they're taken
back to their nests

to get some Zs.

But their sleep is
anything but restful.

We have found that the
REM dream state of sleep

after a rat has
experienced a trauma

can be hyperactive.

It's kind of like REM
sleep on steroids

in the way that it is

in people with
post-traumatic stress disorder.

So Gina comes up
with a novel idea.

After the shock, half
the rats go right to sleep.

The other half are kept
awake for about six hours.

In that time, they
eat, they play,

and get a chance to calm down

before they, too,
get some shut-eye.

The next day, we bring them back

into a slightly
different environment.

So, it smells different,

it has different colors,
different lighting.

In fact, the only thing
that remains the same

is the tone that came
before the shock.

When the rat that went
straight to sleep hears the tone,

it freezes.

As soon as they hear the sound,

animals with PTSD will freeze.

But what happens to the rat

that's been allowed to calm
down before going to sleep?

Will it have the same response?

When it hears the tone,
it also freezes... at first.

But then it seems to realize
the shock isn't coming.

And it will start walking
around and sniffing

and exploring, as
rats normally do.

Because they realize they're
not going to be shocked here.

Delaying sleep after a trauma

may lessen the impact
of disturbing experiences

and even prevent the nightmares
of PTSD from taking shape...

that is, in rats.

But will it help us humans?

Gina is taking her
work outside the lab,

conducting a study
with firefighters,

asking them to delay
sleep after a traumatic event.

With firefighters, we
can ask them to do

whatever it is they do

to best relax and calm
themselves after a trauma.

For some, it might be
meditation or prayer.

For others, it might be

listening to music
that they love

or going for a run.

We're going to
see if that helps us

prevent post-traumatic
stress disorder.

I used to be asked a
lot, "Why do you sleep?

What's the function of sleep?"

But I think we should
be asking the question,

"What are the
functions of sleep?"

We spend about 20%
of the night in REM sleep.

The rest of the time, your
brain is in non-REM sleep,

part of which is spent
producing those big, slow waves.

But what are they for?

One of the first scientific
experiments to find clues

was conducted back in
1924 at Cornell University

by psychologists John
Jenkins and Karl Dallenbach.

Using a group of college
students as guinea pigs,

they found that when their
students learned something new,

they had a much better
chance of remembering it

if they slept on it.

So, they found that sleep...

rather than simply
being a dormant state

where nothing too much
happens within the brain...

sleep may be
important for memory.

But then it raised all sorts
of questions about why,

and so we've been trying to
answer the question of why

since then.

At the University of Arizona,

experimental psychologist
Rebecca Gomez,

along with grad student
Katherine Esterline,

search for the "why"

with the help of a younger
generation of students.

Toddlers. Three, four, five.

Are you ready? Yeah!

How does sleep help them
learn and remember new words?

Wow, a zet.

We're teaching
children novel words

for completely novel objects.

Look at these.

We use this completely
new information

so we can measure
the brain's ability

to form completely novel,
completely new memories.

Hey, a beev.

So, in essence,

we're measuring
brute-force memory.

What's this?

The kids are shown four
objects they've never seen before

that have been given
nonsense names like zet...

A zet.

Mup... Cool, a mup.

Beev... Hey, a beev.

And toap.

A toap.

Toap.

They get a chance
to look at the objects.

Look at these.

And even touch them.

Then, half of the toddlers go
home for their afternoon nap,

while the other half
don't nap for hours...

or perhaps not at all.

The next day, they're back.

Where's the zet?

How much do they remember?

What we found is

that the children who
nap soon after learning...

Mup.

Remember the words
about 80% of the time.

Toap.

Where's the zet?

In contrast, the kids who went
through a long period of time

before they napped...

Where's the zet?

Only remembered the
words about 30% of the time.

Where's the toap?

This?

So, you see a huge difference

between 80% of the
time and 30% of the time,

and that's the
difference the nap makes.

Where's the mup?

Right here.

Why did a nap make
all the difference?

The key lays inside a tiny organ
found deep within the brain...

the hippocampus.

We have one in each hemisphere,

and they play a critical role in
helping us learn and remember.

So, think of it this way.

I have a little filing
drawer beside my desk.

And, throughout the
day, as papers come in,

I toss them in this drawer.

It's my mail that came today,

it's some papers that
I had from a class.

That's my temporary storage.

The hippocampus is like
that short-term filing drawer,

a mishmash of information
getting squeezed in,

and there's a limited
amount of room there for that.

But at the end of the day, I
could take that information

and turn around to my
whole huge filing cabinet,

which in this
case is the cortex.

The cortex, it's bigger,

and it has a really
nice sorting mechanism.

You can sort things by
their visual components,

by their auditory components.

That memory
becomes easier to find.

So the role of slow-wave
sleep is to take that information

that's been stuffed
into the hippocampus

and help move it to its
more efficient filing system

out in the cortex.

Things that you
learned yesterday

are now transferred to
a safer storage location.

But second when you
wake up in the morning,

your hippocampus has
now been cleared out,

and you have a
refreshed capacity

for new-file acquisition
all over again.

And that brings us
back to our toddlers

and the power of the midday nap.

Why does it make
such a big difference?

Why is it so
important for toddlers

to clear out that
short-term filing drawer?

Researchers have a theory.

Young children, their
brains are still developing,

and in fact, the
hippocampus is still

in the process of developing
all across the childhood years.

So it does seem
that the hippocampus,

when it's young and immature,

such as in infancy
and early childhood,

perhaps those memories need
to be stored more frequently

or moved to the
cortex more frequently.

But that doesn't mean
naps are just for kids.

It's interesting to think
that as you get older,

you actually see
napping start to return

in a number of individuals.

And there may be
a good reason why.

Most older adults report two
frustrating things about aging...

"I can't remember
things like I used to,

and I can't sleep
like I used to."

Napping could be one way
of helping maintain memories.

There are probably
multiple different reasons

why the aging brain
simply can't learn

and remember as effectively.

And I think we're identifying

that sleep is one of
those critical ingredients.

So, this is the sleep
of an older adult.

You should start seeing
these waves slowing down

and getting higher in amplitude.

That would be what
we're looking for

for slow-wave sleep.

And so far, I'm not seeing any.

Still looking.

They're asleep, but they're
not getting the slow wave

that, in a young adult, you
might expect to see by now.

And it seems to
be that the quality

of the sleeping brain
waves that you have,

the depth of those brain waves,

and the sort of, the
size of those brain waves

accurately predicts how well

you're able to hit the save
button on those memories.

Is there a way to improve
those big, slow waves

to increase our ability
to hit that save button?

Sleep researchers are
exploring a radical idea.

One of the things that
we're most interested in

is, how can we boost and
enhance sleep quality, sleep quantity,

by using, you know, not
pharmacology, but sound.

80-year-old Marion Smith is
participating in a sleep study.

To track the quality
of her slow waves,

a single electrode is
placed on her forehead.

Marion will hear carefully
timed pulses of sound

through this headband
equipped with tiny speakers.

Well, have a good night,
I'll see you tomorrow.

Our patient, Miss Smith,
is now clearly sleeping.

She is now getting deeper sleep.

By examining the brain waves
produced by a single electrode,

Phyllis has all the
information she needs

to assess the quality
of Marion's slow waves.

These are these big, slow waves,

but there are very few of them.

And this is quite typical
of an older person

who has low-amplitude
slow waves,

and they don't
occur, like, in a train.

Next, a specially designed
computer algorithm

measures the waves

to determine the best time
to deliver a particular sound...

The pulsing of pink noise.

And we do very brief,
like, 50 milliseconds

of this very short
burst of pink noise.

And we do it five on, five off

as long as the person
is still in deep sleep.

Think of the sound waves
produced by pink noise

giving Marion's brain
waves a little push,

like a kid on a swing

or the movement of a
ball in a balance pendulum.

And what you try to do is

sing in time with
these brain waves.

But by stimulating them,

you're trying to boost the
size of those brain waves.

It's beautiful.

This is what we want
them all to look like,

these very large, with
strong upstate waves.

Even after you stop stimulating,
you can see the increase

in these slow waves.

Phyllis is finding that a
little push goes a long way.

What we're seeing here

is not only that we can
increase the amplitude...

that means the height
of these slow waves,

which is really important...

but we can also
increase the train.

So, we could prolong
the amount of slow waves.

Which is wonderful,
because it's hopeful

that the brain,
even if you're old,

is capable of boosting
these slow waves.

Not only might boosting
slow waves improve memory,

new research is revealing
that during this stage of sleep,

the brain may be doing
some critical housekeeping.

It was discovered that the brain

is actually actively
flushing out cellular waste

while we sleep.

Just like when we visit Paris,

and we see them clean
the streets at 5:00 a.m.,

our brain, it cleans
out all the waste

during this offline period.

There could be a potential link

between sleep and
neurodegenerative diseases,

like Alzheimer's disease.

And it could all come down
to this brain-cleaning process

that happens specifically
during slow-wave sleep.

We have to do a lot
more work in this area.

It's really, right now,
the tip of the iceberg.

While researchers
explore new ways

to help us get the
sleep we need,

millions of Americans
fight the urge,

staying up way past bedtime,

lured by the trappings
of technology.

Nearly everyone sooner or later

will experience some
sleep loss in their life.

The invasion of television
into the home 50 years ago,

and now computers
and telephones,

basically, we need
to shut that stuff off.

Somewhere between
infancy and even childhood,

we in Western,
industrialized nations,

we start to abandon the
notion that sleep is useful,

and, if anything, take
the opposite approach

and believe that sleep
should be short-changed.

Back in 1964,

17-year-old Randy Gardner
broke the Guinness world record

for staying awake
11 days straight.

One of these young men
holds an unusual world record.

What is your name, please?

My name is Randy Gardner.

My name is Randy Gardner.

The experiment
won him first place

in his high school science fair

and caught the
attention of a nation.

BRUCE McAllister: He
ended up on "To Tell the Truth,"

you know, a TV show.

And supposedly the
most written-about story

in the world

after JFK and the Beatles.

Number Two, how
did you pass the time

when the other
people were sleeping?

Well, there were always, there
was always someone with me,

the two boys that helped
me... one would sleep,

and one would
stay awake with me.

Bruce McAllister was
one of those boys.

It wasn't the science of it
that interested the world.

The world was
interested in the drama.

The experiment moved
beyond high school science

when sleep researcher
William Dement joined the team.

McAllister: And he
brought a portable E.E.G.,

which no one had
ever seen before.

They sent the E.E.Gs.
to a supercomputer,

a Cray computer in Arizona,

and that computer
concluded that his...

Parts of his brain were sleeping

while others were awake.

His brain was
catnapping in pieces.

That is how the human
brain survived this.

While Randy looked wide awake,

parts of his brain weren't...

what neuroscientists
now call a micro sleep.

A micro sleep is
something that may happen

after we've been awake
for a very long time,

and our brain needs
sleep so desperately

that we may fall for
a very short interval

of three to 15 seconds, just...

And we've all seen this
when our eyes shut down,

and we nod to sleep for
just a few seconds like this.

We're all very polite and
sort of pretend we don't see it,

but as we're talking to someone
and they start to fall asleep,

we notice that they're
losing muscle tone,

so they start to slump, and
the head will start to fall over,

and the eye, the
lids are coming down,

and then we'll see the
eyes roll in the head.

If you're holding a
steering wheel and driving,

you might notice that your arms

are starting to slack a
little bit on the wheel.

It only takes 200 milliseconds
when you're not paying attention

that the car is going
in the wrong direction.

When you're sleep-deprived,

your brain will fall asleep...
whether you notice or not.

That's because
biology takes the wheel.

Two different processes
drive you to sleep.

The first is your
circadian rhythm,

your biological clock.

One of the signals

that's keeping you
awake during the day

is the circadian clock.

Think of the circadian clock as
kind of an internal alarm clock.

Back in 1938, in a
landmark experiment,

sleep researcher
Nathaniel Kleitman

takes one of his students to
live in an underground cave.

They spend a month
without sunlight,

testing the power of
that internal alarm clock.

Even without light,
the clock keeps ticking.

But add light, and
the cycle can shift.

Every day, you get a
little light in the morning,

it moves your clock
in one direction.

You get a little
light in the evening,

it moves your clock
in the other direction,

so it can delay and advance.

And by doing this, it
maintains your internal clock

in synchrony with that of
your external environment.

This clock controls the
release of a key chemical

that has the power to
make you feel sleepy:

Melatonin, also known as
the hormone of darkness.

Melatonin goes up at night,

and it stays up
during the entire night

until probably the
early morning hours,

and then begins its decline.

By the time that we
normally would be waking up,

Melatonin levels
are very, very low.

But sleepiness isn't just
controlled by Melatonin.

Another chemical,
called adenosine,

may also play a role.

Some researchers
believe it starts to build

from the moment you wake up,

and, like an hourglass,
fills with the passage of time,

gradually increasing
our need for sleep,

called "sleep pressure."

We see a very strong association

between the levels of
adenosine and being sleepy

and between the level of sleep
and reducing that adenosine.

Sleep is the perfect way to
clear adenosine from the brain

and start fresh.

Many of us are trying

to block the effects of
that adenosine every day

by our consumption of caffeine.

Caffeine binds to these
adenosine receptors,

so it kind of blocks the
effects of sleep pressure,

so that we're,
we're not feeling it.

It's still there, but we're just
not feeling the effects of it.

But drinking coffee
will work for just so long.

If you choose not
to go to sleep tonight,

and you stay up all night,

that sleep pressure
will continue to build.

And as that sleep
pressure builds,

it will impair your
thought processes,

it will impair your memory.

More than 60% of our population

may not be getting
sufficient amount of sleep,

but also sufficient
quality of sleep.

For firefighter Matt Reinhold,

who often works
a 72-hour shift...

A good night's sleep
is hard to come by.

The alarm will go off and
the lights will come on.

It's a, it's a startlement.

You know, right off the
bat, you're woken up.

There's times where
we'll run five, six, seven,

eight calls after midnight.

I have never been
in a deep sleep

here at this firehouse.

Fatigue starts to set in.

All I want to go and
do is go lay down,

but then the alarm's
going off again

for a medical down the street.

Lack of sleep definitely
makes you more snippy,

you become more
agitated, more irritated.

The communication factor
may go out the window,

because you don't want
to talk, because you're tired,

because of what you're
afraid of what you might say.

The irritability takes a toll.

There was a study that
compared a group of participants

only allowed to sleep
for five hours a night,

and then there was another group

that were allowed to sleep
for the whole eight hours,

but were woken up
every now and then

and kept awake for an hour.

And after four days like this,

the effects on mood and anxiety

were actually much stronger
in the interrupted group.

Sleeping in fits and starts

wreaks havoc on
your entire system.

That fragmenting of sleep
is extremely destructive

for wake functioning and health.

It is almost as though
you didn't get sleep.

So, the consolidation of
sleep is easily as important

as the duration of the sleep.

Quality is as
important as quantity.

There's something
about the loss of sleep

that breaks down your
mind and your body.

If you lose sleep, you will
experience memory deficits,

and you will experience
cognitive deficits.

However, there's also an
interesting caveat to that:

losing sleep may affect
one person one way

and another person another way.

There are some individuals
which tend to be resilient

against the negative
effects of sleep loss.

One of the current
focuses of our field

is to understand the
cause of that resilience

and whether there is
a genetic component.

Could the ability to
recover from sleep loss

be determined by our genes?

In 2017, the Nobel Prize
in Physiology or Medicine

was awarded to three scientists
who discovered a group of genes

that drive your
biological clock.

There are genes
such as the clock gene,

the period gene, the
cryptochrome gene.

But the gene that intrigues
neuroscientist Ketema Paul

is called BMAL1.

For those of you that know
that clocks used to have gears,

BMAL1 is the primary
gear of the clock.

In his lab at U.C.L.A.,

Ketema is exploring
the role BMAL1 may play

in our ability to
recover from sleep loss.

To do it, he makes use
of a classic memory test.

You put a mouse
in an environment

and present two objects.

In this case, two orange blocks.

The mouse spends time
getting familiar with them.

After that, we take them out

and sleep-deprive
them for six hours.

While the mouse is kept awake,

one of the orange blocks is
replaced with a new object,

a blue cylinder.

After six hours,

the sleep-deprived mouse
is put back in the chamber.

Like humans, mice
are naturally curious...

they're drawn to new things.

So a well-rested mouse
will spend more time

exploring the new
object, the blue cylinder.

But that doesn't happen
with this sleepy mouse.

If you sleep-deprive a mouse,

and you put it in the
same environment,

it will spend equal
amounts of time

between the familiar
object and the novel object,

because its memory
of the familiar object

was impaired by the sleep loss.

It seems not to remember
the orange block.

But what happens if Ketema
repeats the memory test

with a mouse that has
been genetically modified

to express higher
levels of BMAL1?

Will this dialed-up mouse
have a better memory?

Or will the results be the same?

The mouse is now

exploring the area in
which the novel object is in.

Another approach
to the novel object.

More exploration
around the arena.

A third approach
to the novel object,

sniffing, exploring
the novel object.

So the mouse is clearly spending
more time with the novel object,

and it suggests that
the sleep deprivation

did not impair the
memory of this mouse,

which suggests that
over expressing BMAL1

does make that mouse
resilient to sleep loss,

and it preserves its memory
after sleep deprivation.

But this is not
the only surprise,

because it turns out BMAL1
works in mysterious ways.

So the B in BMAL1
stands for "brain,"

the M in BMAL1
stands for "muscle."

BMAL1 is a gene
that's found in the brain

and in skeletal muscle.

And the resilient mice were
ones that had BMAL1 boosted

in their muscles,
not in their brains.

The result we got
was really a surprise.

Sleep is a mental process.

And that's kind of, as
a trained neurobiologist,

how I had been
looking at it before that.

As Ketema continues
his research,

he will try to find out how
genes in skeletal muscle

could influence how we
sleep and store memories.

Hopefully this will lead

to more effective therapies

for people that are unable
to get sufficient sleep

and people that need to function

in spite of not
getting enough sleep.

Because when it comes
to not getting enough sleep,

the people hardest-hit are often
the ones we depend on the most.

Sleep deprivation
of first responders

leads to issues of increased
isolation and depression

and has enormous impacts,
not on just your psychology,

but on your physical
well-being, as well.

Former E.M.S.
worker Susan Farren

and retired
firefighter Ron Shull

are working with
first responders,

educating them on ways
to manage their sleep,

on and off the job.

We want to give you guys
some tools and some techniques

and modalities to kind
of help you sleep better.

In the last ten or 20 years,

we've discovered
that sleep is essential

for proper brain function.

It's important for our
health, for our immunity,

for our memory... Toap.

And for our well-being.

I think that's where the
phrase "sleep on it" comes from,

is that we wake up, and we
think differently about a problem.

We think differently about that
person that we were angry at.

We just generally feel
better about our day

if we've had a really
good night's sleep.

I think sleep's one of the
sweetest things you can get.

It's like a great meal
or seeing a good friend.

As a citizen in our society
that wants people to be safe,

the best thing I can say is,
"Don't sacrifice your sleep.

"Protect your sleep like
you protect your food,

"like you protect
your resources,

"like you protect
your environment.

It may save your life."