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But why?

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MATTHEW WALKER:
Sleep remains one of
those remarkable puzzles.

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We've known the functions

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of eating, drinking,
and reproducing

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for thousands of years.

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However, sleep
remains a mystery.

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EUS VAN SOMEREN:
Why do some people ruminate
all night,

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and other people,

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they see the pillow,
they're gone?

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NARRATOR:
Cutting-edge research is
now giving us a new view

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inside the sleeping brain.

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PHYLLIS ZEE:
How can we boost and enhance

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sleep quality,
sleep quantity?

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

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

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think again.

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RAVI ALLADA:
The more we learn about sleep,

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

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DAVID DINGES:
Getting a good night's sleep

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is possibly the single
most important thing

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you can do every day.

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NARRATOR:
"Mysteries of Sleep,"

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next, on "NOVA."

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♪ ♪

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Major funding for "NOVA"
is provided by the following:

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one of the most enduring
mysteries in all of science.

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We spend a third of our lives
asleep,

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in this kind of unconscious,
unresponsive, immobile state.

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

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

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care for our young, mate.

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NARRATOR:
Why do we spend
a third of our lives

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in such an unproductive
and defenseless state?

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ETI BEN-SIMON:
What is that thing
that sleep does

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to our brain and our body
every single night

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is very much an open question.

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NARRATOR:
A question that has baffled
scientists for centuries.

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YUVAL NIR:
It's like this big black hole.

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

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

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NARRATOR:
But in the last decade,

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sleep researchers
have started to unravel

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the mysteries of sleep,

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and what they are discovering
is mind-boggling.

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♪ ♪

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

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so the brain is
sort of shut off.

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But the more we explore it,

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

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

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

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's just active
in different ways.

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MICHAEL CRAMER BORNEMANN:
You're not either aware
or not aware,

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you're neither not conscious
or unconscious.

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It's a whole spectrum.

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NARRATOR:
So, what exactly is sleep?

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And why do we need it?

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One thing that is for certain,

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

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WALKER:
What we're fast learning

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

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POE:
I find it fascinating,
because every animal sleeps,

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every animal
that we've studied--

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from worms to jellyfish
to sea slugs.

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

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they sleep about as much time
as we do.

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(yawning)

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BEN-SIMON:
Sleep is one of the most
essential elements of life,

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actually.

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Sleep and life evolved
hand-in-hand.

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NARRATOR:
Evolution has come up
with a variety of ways

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to get some shut-eye.

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JERRY SIEGEL:
Some animals are vulnerable
when they sleep.

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And other animals are not.

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And the animals that are
vulnerable when they sleep

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don't sleep very much.

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

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And they can't sleep as deeply.

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

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there wouldn't be any giraffes.

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Now, on the other hand,

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there are animals
like the big brown bat,

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

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It sleeps on cave walls,

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so it's pretty much
invulnerable there.

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(dolphins clicking)

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NARRATOR:
But perhaps one

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of nature's most innovative
sleep solutions

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is found under the sea.

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ALLADA:
One of the really cool animals
that people study

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is the dolphin, which actually
has unihemispheric sleep.

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Half of the brain has
a sleep-like state

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and the other half has
a wake-like state,

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so the animal has to have
one hemisphere awake.

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

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

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when the right hemisphere
is asleep, the left flipper,

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which is controlled
by the right hemisphere,

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is inactive,

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and the body's posture
is asymmetric.

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So by looking at a fur seal,

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you can tell
which hemisphere is asleep.

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NARRATOR:
Fur seals and dolphins
aren't alone.

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Human sleep is equally complex,
weird, and mysterious.

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

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are humans.

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Human sleep is very broad.

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Each individual has their own
personal experiences with sleep.

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♪ ♪

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

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

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I actually think
that the whole night

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is a really magical event.

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♪ ♪

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

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sleep researcher Rebecca Spencer
gathers clues

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to how this magical event
unfolds.

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Just slip this on,
just like last time.

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

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

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SPENCER:
...with an array of electrodes

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to record brain activity.

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Yeah.
SPENCER:
There you go.

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NIR:
The way our brain supports
everything that it does,

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from controlling our body

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to regulating emotion,
having memories,

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is through the electrical
activity of neurons.

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These are brain cells
connected to one another

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via these tiny passages
that are called synapses.

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One neuron emits a neurochemical
called a neurotransmitter

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to this passage,

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and it's picked up
by the next neuron,

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much like passing the baton
in the Olympics.

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NARRATOR:
This signal,
passed from neuron to neuron,

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

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with one of the
most powerful tools

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in a sleep researcher's
toolbox--

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the E.E.G.,
the electroencephalogram.

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What this screen is
showing is the recordings

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

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Right now, in wake,
for instance,

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you know, you can see
the brain waves here.

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NARRATOR:
The vertical lines on the chart

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represent five seconds
of Jaime's sleep.

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What's important is
that as you get drowsy,

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those waves slow down,

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and they become
what we call alpha waves.

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NIR:
And as the sleep gets deeper,

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the waves become
slower and slower,

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and in the deepest parts
of sleep,

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activity's dominated
by slow waves,

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these massive waves
occurring across the brain

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that are like a tsunami.

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(crowd cheering)

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WALKER:
It's almost
like a football stadium,

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where all of the individuals
in the stadium

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before the game

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

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at different times.

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

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But when you go into
the deeper stages of sleep,

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all of a sudden,
the crowd starts

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to synchronize its activity.

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They all start to chant in time.

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NARRATOR:
Thousands of neurons,
firing in unison.

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SPENCER:
That's your deep sleep.

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

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

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

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

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"I was asleep--
leave me alone,

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

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NARRATOR:
But Jaime--
along with the rest of us--

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

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At a certain point,
his brain waves change.

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WALKER:
After about 50 or 60 minutes,

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your brain will start
to rise back up.

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

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

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will play out in a battle
for brain domination

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throughout the night.

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And that sort of cerebral war

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is going to be won and lost
every 90 minutes.

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

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The rest of the time we spend

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in the mysterious stage
of REM sleep.

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It's hard to investigate
REM sleep

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without investigating dreams,

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

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SPENCER:
Dreams tend to be emotional.

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One idea is that we dream

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to simulate potentially
negative events

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so that we're prepared for them.

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♪ ♪

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

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that she fell
into the swimming pool--

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she was near drowning.

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After that, I put my daughters
into swim lessons,

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and water safety has been
important to me.

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VAN SOMEREN:
It's not that we do not dream
in the other sleep stages--

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we do--

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

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NARRATOR:
REM sleep is named

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for the rapid eye movements
we make when we dream.

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

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it's a special moment
where we sort of switch

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to the next dream scene,
if you will.

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NARRATOR:
As we switch
from one dream to the next,

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our brain waves are doing
something downright strange.

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SPENCER:
With REM sleep, the brain waves
look just like waves

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from when you're awake.

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

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but yet our brain is
in a state of activation.

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NARRATOR:
But perhaps the strangest
feature of this stage of sleep

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is what's happening
in your body.

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NIR:
During REM sleep,

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our brain actually sends
the instructions

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to the different muscles

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to move our body
as if we were awake.

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But lower down
in the brain stem,

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these instructions
are disrupted.

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They are not relayed
to the body,

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and the body remains paralyzed.

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

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we would literally
jump out of the window.

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NARRATOR:
From the dreams of REM sleep,

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we cycle back
into non-REM sleep,

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including the deepest stage
of sleep, slow-wave.

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

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are comprised
of deep, non-REM sleep.

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

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now that ratio balance shifts;

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and instead, the majority
of those cycles

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

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dream sleep--

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and a lot less
deep, non-REM sleep.

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DINGES:
What is crazy about this is,

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the pattern is
so absolutely reliable

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in virtually everybody,
every night.

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It speaks to a fundamental,
genetically driven program

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that is essential
for being a human being.

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You have to go through this.

243
00:12:03,390 --> 00:12:05,924
NARRATOR:
But if every one of us

244
00:12:05,926 --> 00:12:10,528
needs a night full
of both slow-wave and REM sleep,

245
00:12:10,530 --> 00:12:13,898
why is it such a struggle
for so many of us

246
00:12:13,900 --> 00:12:17,402
to get some shut-eye?

247
00:12:17,404 --> 00:12:19,037
The search for answers

248
00:12:19,039 --> 00:12:22,307
has become
a multibillion-dollar industry,

249
00:12:22,309 --> 00:12:25,110
selling us everything
from sleeping pills

250
00:12:25,112 --> 00:12:27,779
to ergonomic pillows.

251
00:12:27,781 --> 00:12:29,748
And if they don't do the trick,

252
00:12:29,750 --> 00:12:33,752
there are more than 3,000
sleep clinics nationwide,

253
00:12:33,754 --> 00:12:36,955
a number that keeps on growing.

254
00:12:36,957 --> 00:12:40,125
Are you up all night tossing,
turning, mind racing,

255
00:12:40,127 --> 00:12:43,461
trouble getting to sleep,
trouble staying asleep?

256
00:12:43,463 --> 00:12:48,233
NARRATOR:
Drew Ackerman has
created a podcast

257
00:12:48,235 --> 00:12:51,603
to help the sleep-deprived
get their Zs.

258
00:12:51,605 --> 00:12:53,872
The idea for the show
really sprang

259
00:12:53,874 --> 00:12:55,640
from my childhood insomnia.

260
00:12:55,642 --> 00:13:00,311
When I was a kid, I lost
the ability to fall asleep.

261
00:13:00,313 --> 00:13:02,647
For me, it was anxiety-related.

262
00:13:02,649 --> 00:13:05,150
My parents tried to help,

263
00:13:05,152 --> 00:13:06,251
but because they could sleep,

264
00:13:06,253 --> 00:13:07,852
I think there was,
like, this disconnect.

265
00:13:07,854 --> 00:13:09,754
It's, like, "Oh, try to relax,

266
00:13:09,756 --> 00:13:11,322
try to just think
about something nice,"

267
00:13:11,324 --> 00:13:12,590
and I just couldn't do that.

268
00:13:12,592 --> 00:13:15,426
Whatever's keeping you awake,
thoughts,

269
00:13:15,428 --> 00:13:16,928
you know,
things you're thinking about...

270
00:13:16,930 --> 00:13:21,666
NARRATOR:
Drew's goal is to be
as boring as possible.

271
00:13:21,668 --> 00:13:24,402
I'm going to tell you all
a bedtime story.

272
00:13:24,404 --> 00:13:26,337
I want you to get
comfortable.

273
00:13:26,339 --> 00:13:28,106
ACKERMAN:
The podcast is not
straightforward,

274
00:13:28,108 --> 00:13:30,375
it's full of nonsense.

275
00:13:30,377 --> 00:13:32,677
I have a unique hobby,
my dog and I.

276
00:13:32,679 --> 00:13:34,679
We listen to recordings
of people knocking on doors.

277
00:13:34,681 --> 00:13:36,447
ACKERMAN:
It gives people permission
not to listen,

278
00:13:36,449 --> 00:13:38,249
or to only kind of listen.

279
00:13:38,251 --> 00:13:40,952
I want no social pressure
on the listener

280
00:13:40,954 --> 00:13:43,655
to pay attention to me at all.

281
00:13:43,657 --> 00:13:46,524
NARRATOR:
And there's no shortage
of people

282
00:13:46,526 --> 00:13:49,394
eager to tune out.

283
00:13:49,396 --> 00:13:52,096
Each month,
the show gets downloaded

284
00:13:52,098 --> 00:13:54,165
a little bit
over three million times.

285
00:13:54,167 --> 00:13:55,800
What I'm going to do
is,

286
00:13:55,802 --> 00:13:58,870
I'm going to send my voice
across the deep dark night.

287
00:13:58,872 --> 00:14:02,841
ACKERMAN:
People that listen to the
podcast share that feeling--

288
00:14:02,843 --> 00:14:05,343
I don't know if desperation
might be a strong word--

289
00:14:05,345 --> 00:14:07,512
but that feeling where
you're just lying there in bed,

290
00:14:07,514 --> 00:14:09,514
and you feel alone.

291
00:14:09,516 --> 00:14:11,282
How many people listen
to the podcast

292
00:14:11,284 --> 00:14:15,053
because they have trouble
falling asleep?

293
00:14:15,055 --> 00:14:17,188
Like, if you want,
raise your hand.

294
00:14:19,226 --> 00:14:22,694
NARRATOR:
Having trouble falling asleep
or staying asleep

295
00:14:22,696 --> 00:14:26,431
are symptoms of the most common
sleep disorder on the planet.

296
00:14:26,433 --> 00:14:31,870
Ten percent of all people suffer
from chronic insomnia.

297
00:14:31,872 --> 00:14:35,673
VAN SOMEREN:
Insomnia is a 24-hour disorder.

298
00:14:35,675 --> 00:14:37,075
It's not only sleep complaints,

299
00:14:37,077 --> 00:14:39,777
these persons also feel tensed
all day.

300
00:14:39,779 --> 00:14:44,048
It's not that common
that you're a very happy,

301
00:14:44,050 --> 00:14:45,750
completely unanxious insomniac.

302
00:14:45,752 --> 00:14:48,319
LAB ASSISTANT:
Are you ready?
Right.

303
00:14:48,321 --> 00:14:51,789
NARRATOR:
Is there a way
to decode what goes awry

304
00:14:51,791 --> 00:14:54,425
in an insomniac's brain?

305
00:14:54,427 --> 00:14:56,761
On the outskirts of Amsterdam,

306
00:14:56,763 --> 00:14:59,163
at the Netherlands Institute
for Neuroscience,

307
00:14:59,165 --> 00:15:03,701
Eus van Someren
is trying to find out,

308
00:15:03,703 --> 00:15:07,505
with the help of lifelong
insomniacs like Reiny Metz.

309
00:15:07,507 --> 00:15:10,008
METZ:
I drop off to sleep very easily.

310
00:15:10,010 --> 00:15:12,844
But after two hours, I wake up,

311
00:15:12,846 --> 00:15:14,746
and then it's difficult
to go back to sleep.

312
00:15:14,748 --> 00:15:18,449
If it's one night,
well, I can manage that.

313
00:15:18,451 --> 00:15:19,817
Two nights is okay,

314
00:15:19,819 --> 00:15:21,719
but when it's five nights
in a row,

315
00:15:21,721 --> 00:15:22,787
it's a bit much,

316
00:15:22,789 --> 00:15:25,223
and then you get
very, very tired,

317
00:15:25,225 --> 00:15:30,028
not only physically,
but also mentally.

318
00:15:30,030 --> 00:15:36,167
It makes me anxious, or angry,
or, you know, frightened.

319
00:15:36,169 --> 00:15:39,103
NARRATOR:
Reiny sleeps in Eus's lab,

320
00:15:39,105 --> 00:15:41,572
wearing a high-tech E.E.G. net

321
00:15:41,574 --> 00:15:44,642
that contains hundreds
of more electrodes

322
00:15:44,644 --> 00:15:46,444
than you'll find
in the standard cap.

323
00:15:46,446 --> 00:15:49,480
VAN SOMEREN:
We measure sleep overnight

324
00:15:49,482 --> 00:15:54,419
with a special E.E.G. net
with 256 E.E.G. channels,

325
00:15:54,421 --> 00:15:56,788
and they cover all of the head.

326
00:15:56,790 --> 00:15:59,590
NARRATOR:
The more electrodes he uses,

327
00:15:59,592 --> 00:16:02,360
the more activity
he can record--

328
00:16:02,362 --> 00:16:06,431
more clues to what's going on
in Reiny's brain.

329
00:16:06,433 --> 00:16:08,099
VAN SOMEREN:
Okay, Reiny,

330
00:16:08,101 --> 00:16:09,634
we recorded your E.E.G....

331
00:16:09,636 --> 00:16:11,035
Yeah.
...during your sleep.

332
00:16:11,037 --> 00:16:12,637
NARRATOR:
The next morning,

333
00:16:12,639 --> 00:16:14,238
he shows her the results.

334
00:16:14,240 --> 00:16:18,509
So, you go into
REM sleep here.

335
00:16:18,511 --> 00:16:21,245
Yeah.
And REM sleep is
the part of sleep

336
00:16:21,247 --> 00:16:23,414
where the most vivid
dreams are.

337
00:16:23,416 --> 00:16:26,217
Now, what I wanted
to show you

338
00:16:26,219 --> 00:16:30,521
is that, you see that it's not
many seconds into REM sleep,

339
00:16:30,523 --> 00:16:33,391
and then already something
is happening here.

340
00:16:33,393 --> 00:16:34,826
Well, you recognize it.

341
00:16:34,828 --> 00:16:37,662
I don't have to explain that
this looks different than this.

342
00:16:37,664 --> 00:16:39,097
Oh, yes, certainly.

343
00:16:39,099 --> 00:16:41,532
It's just maybe
two seconds or so

344
00:16:41,534 --> 00:16:44,102
that it's really,
it's off, it's different.

345
00:16:44,104 --> 00:16:46,504
And this is what
we call an arousal.

346
00:16:46,506 --> 00:16:49,807
Yeah.
Where you exchange sleep

347
00:16:49,809 --> 00:16:52,010
for something that's
really wake-like.

348
00:16:52,012 --> 00:16:54,412
And this is something
that is so typical

349
00:16:54,414 --> 00:16:57,482
for people like you
that sleep bad.

350
00:16:57,484 --> 00:17:00,018
But you do see this
in many patients.
Yeah.

351
00:17:00,020 --> 00:17:02,153
METZ:
Okay.

352
00:17:02,155 --> 00:17:03,755
VAN SOMEREN:
Usually, if you had
a good sleep,

353
00:17:03,757 --> 00:17:06,024
if you slept on it,
as we say,

354
00:17:06,026 --> 00:17:07,859
things feel a bit better.

355
00:17:07,861 --> 00:17:10,028
But if there is
this profile,

356
00:17:10,030 --> 00:17:12,063
that there is some
restlessness...
Yeah.

357
00:17:12,065 --> 00:17:13,831
...occurring during
REM sleep,

358
00:17:13,833 --> 00:17:17,201
then, for some reason--
we try to find out--

359
00:17:17,203 --> 00:17:20,238
this whole process
of feeling better the next day

360
00:17:20,240 --> 00:17:21,439
doesn't work as well.

361
00:17:21,441 --> 00:17:23,408
♪ ♪

362
00:17:23,410 --> 00:17:26,644
VAN SOMEREN:
What we observed,
which was fascinating,

363
00:17:26,646 --> 00:17:28,479
if we add up
all the pieces of sleep

364
00:17:28,481 --> 00:17:30,114
as suggested by the E.E.G.,

365
00:17:30,116 --> 00:17:32,717
many people with insomnia

366
00:17:32,719 --> 00:17:37,155
have about six-and-a-half,
maybe seven hours of sleep,

367
00:17:37,157 --> 00:17:40,291
but this is not
how these people experience it.

368
00:17:40,293 --> 00:17:43,261
Maybe they just experience
large parts of the night

369
00:17:43,263 --> 00:17:47,999
really as ongoing rumination,
worrying, thinking.

370
00:17:48,001 --> 00:17:51,803
So, it may not feel
like a good night of sleep,

371
00:17:51,805 --> 00:17:56,207
but it's not the same as being
completely sleep-deprived.

372
00:17:56,209 --> 00:17:57,742
NARRATOR:
So, is there a connection

373
00:17:57,744 --> 00:18:00,845
between these disruptions
in REM sleep

374
00:18:00,847 --> 00:18:04,082
and the anxiety
so many insomniacs feel

375
00:18:04,084 --> 00:18:05,516
when they're awake?

376
00:18:05,518 --> 00:18:10,822
To try to find out, Eus comes up
with an out-of-the-box idea,

377
00:18:10,824 --> 00:18:15,760
based on personal experience.

378
00:18:15,762 --> 00:18:17,862
Back in the 1990s,

379
00:18:17,864 --> 00:18:22,800
Eus played guitar
in a popular Dutch rock band.

380
00:18:22,802 --> 00:18:25,937
VAN SOMEREN:
I remembered a few things from
being in the recording studio.

381
00:18:25,939 --> 00:18:29,040
I heard my own guitar playing,

382
00:18:29,042 --> 00:18:32,677
and even if it was a tiny
little bit, you know, off-tune,

383
00:18:32,679 --> 00:18:33,978
it made me shiver.

384
00:18:33,980 --> 00:18:38,015
NARRATOR:
Embarrassment is
a powerful emotion.

385
00:18:38,017 --> 00:18:41,419
He decides to put it
to a test.

386
00:18:41,421 --> 00:18:44,789
(singing out of tune)

387
00:18:44,791 --> 00:18:48,426
NARRATOR:
A karaoke test.

388
00:18:48,428 --> 00:18:52,530
VAN SOMEREN:
We asked people
to sing along karaoke,

389
00:18:52,532 --> 00:18:54,732
but they couldn't hear
themselves sing.

390
00:18:54,734 --> 00:18:56,100
If you don't hear yourself well,

391
00:18:56,102 --> 00:18:59,537
it's also difficult to correct
if you go out of tune.

392
00:18:59,539 --> 00:19:02,173
Um, you hear that
over the headphone,

393
00:19:02,175 --> 00:19:03,608
you have the headphone on...

394
00:19:03,610 --> 00:19:06,177
NARRATOR:
He does the same thing
with good sleepers.

395
00:19:06,179 --> 00:19:11,115
Next, Eus puts them in an fMRI.

396
00:19:11,117 --> 00:19:12,950
VAN SOMEREN:
So, in the MRI scanner,

397
00:19:12,952 --> 00:19:17,488
we had them listen to
their own embarrassing singing.

398
00:19:17,490 --> 00:19:22,093
(Metz singing out of tune
on speaker)

399
00:19:22,095 --> 00:19:24,762
NARRATOR:
As Reiny listens to her singing,

400
00:19:24,764 --> 00:19:27,965
the fMRI detects activity
in a part of the brain

401
00:19:27,967 --> 00:19:30,501
called the amygdala.

402
00:19:30,503 --> 00:19:34,705
We have two,
one in each hemisphere.

403
00:19:34,707 --> 00:19:38,142
VAN SOMEREN:
I sometimes call the amygdala
the siren of the brain

404
00:19:38,144 --> 00:19:41,379
or the alarm bell of the brain.

405
00:19:41,381 --> 00:19:44,115
So, if there is something
that we should pay attention to,

406
00:19:44,117 --> 00:19:47,051
because it's dangerous
or important,

407
00:19:47,053 --> 00:19:48,386
then the amygdala activates.

408
00:19:48,388 --> 00:19:52,089
(Metz singing out of tune
on speakers)

409
00:19:52,091 --> 00:19:53,457
VAN SOMEREN:
So, they heard themselves

410
00:19:53,459 --> 00:19:56,027
sing really,
really out of tune.

411
00:19:56,029 --> 00:19:58,896
Their amygdala
was very upset about that,

412
00:19:58,898 --> 00:20:00,831
so, you know,
the alarms went off.

413
00:20:00,833 --> 00:20:02,867
METZ (on recording):
♪ Gloria ♪

414
00:20:02,869 --> 00:20:07,939
NARRATOR:
The alarms go off for both
insomniacs and good sleepers.

415
00:20:07,941 --> 00:20:10,575
This is no surprise for Eus.

416
00:20:10,577 --> 00:20:13,611
But his test isn't over yet.

417
00:20:13,613 --> 00:20:15,980
VAN SOMEREN:
We ask them to stay
all night in the sleep lab,

418
00:20:15,982 --> 00:20:19,250
and we did the same
the next morning.

419
00:20:19,252 --> 00:20:22,987
We again put them
in the MRI scanner.

420
00:20:22,989 --> 00:20:27,225
Good sleepers,
it was not that bad anymore.

421
00:20:27,227 --> 00:20:31,696
NARRATOR:
A good sleeper's amygdala
calms down.

422
00:20:31,698 --> 00:20:34,632
But that doesn't happen
in the insomniac.

423
00:20:34,634 --> 00:20:37,501
VAN SOMEREN:
For them, the story
was very different,

424
00:20:37,503 --> 00:20:41,072
because the more REM sleep
they had,

425
00:20:41,074 --> 00:20:42,740
the worse it got.

426
00:20:42,742 --> 00:20:48,679
So, instead of the amygdala
becoming adapted overnight,

427
00:20:48,681 --> 00:20:51,449
many people with insomnia,
the next morning,

428
00:20:51,451 --> 00:20:57,255
the amygdala could even
ring much louder.

429
00:20:57,257 --> 00:21:00,391
You're just loaded with distress
that you take to the next day

430
00:21:00,393 --> 00:21:02,093
and the next day
and the next day.

431
00:21:02,095 --> 00:21:03,527
♪ ♪

432
00:21:03,529 --> 00:21:06,564
If we could change
that restless REM sleep,

433
00:21:06,566 --> 00:21:11,335
maybe this will help people
get rid of distress.

434
00:21:11,337 --> 00:21:13,604
NARRATOR:
But insomniacs
aren't the only ones

435
00:21:13,606 --> 00:21:17,708
to suffer
from restless REM sleep.

436
00:21:17,710 --> 00:21:20,544
Researchers are also exploring
its impact

437
00:21:20,546 --> 00:21:24,048
on post-traumatic
stress disorder.

438
00:21:24,050 --> 00:21:27,151
GEHRMAN:
PTSD is essentially
a memory-based disorder.

439
00:21:27,153 --> 00:21:28,519
An individual has

440
00:21:28,521 --> 00:21:32,256
one or more very stressful,
traumatic experiences,

441
00:21:32,258 --> 00:21:35,126
and they become fearful
of anything

442
00:21:35,128 --> 00:21:37,561
that reminds them
of that trauma.

443
00:21:37,563 --> 00:21:41,866
NARRATOR:
Like the smell of a wildfire

444
00:21:41,868 --> 00:21:44,969
or the deafening sounds
of combat--

445
00:21:44,971 --> 00:21:51,342
traumas so powerful, they can
even haunt us when we sleep.

446
00:21:51,344 --> 00:21:54,378
POE:
People with post-traumatic
stress disorder,

447
00:21:54,380 --> 00:21:56,247
they're afraid to go to sleep,

448
00:21:56,249 --> 00:21:59,684
or they don't sleep very well
because of the nightmares.

449
00:21:59,686 --> 00:22:02,486
♪ ♪

450
00:22:02,488 --> 00:22:04,789
GEHRMAN:
Once these nightmares
get established,

451
00:22:04,791 --> 00:22:07,024
they often can persist
for, for decades.

452
00:22:08,695 --> 00:22:12,396
NARRATOR:
In her lab at U.C.L.A.,
Gina Poe is searching for ways

453
00:22:12,398 --> 00:22:17,134
to prevent these recurring
nightmares from taking shape.

454
00:22:17,136 --> 00:22:19,904
POE:
One of the things
that we have to do

455
00:22:19,906 --> 00:22:22,707
to study the effects
of trauma on sleep

456
00:22:22,709 --> 00:22:27,878
is, we have to expose animals
to a traumatic stressor.

457
00:22:27,880 --> 00:22:29,947
How you doing?

458
00:22:29,949 --> 00:22:32,249
POE:
It's the least favorite
part of my job,

459
00:22:32,251 --> 00:22:36,721
but there's no other way
to study it.

460
00:22:36,723 --> 00:22:39,023
NARRATOR:
The rats are placed in a chamber

461
00:22:39,025 --> 00:22:40,424
where they hear a tone...

462
00:22:40,426 --> 00:22:41,625
(tone beeps)

463
00:22:41,627 --> 00:22:44,195
Followed by a shock.

464
00:22:44,197 --> 00:22:47,298
It certainly is not a strong
enough shock to cause them harm

465
00:22:47,300 --> 00:22:49,600
or blister their feet
or anything,

466
00:22:49,602 --> 00:22:51,068
and it only lasts one second,

467
00:22:51,070 --> 00:22:53,404
but it's enough to make them
squeak and jump,

468
00:22:53,406 --> 00:22:54,839
to say, "What, what was that?"

469
00:22:54,841 --> 00:22:58,642
NARRATOR:
Over the next hour and a half,

470
00:22:58,644 --> 00:23:03,414
the rats hear the tone
and receive the shock.

471
00:23:03,416 --> 00:23:05,850
POE:
So they associate that tone

472
00:23:05,852 --> 00:23:07,284
with the fear of being shocked.

473
00:23:07,286 --> 00:23:09,987
NARRATOR:
Then they're taken back
to their nests

474
00:23:09,989 --> 00:23:12,923
to get some Zs.

475
00:23:12,925 --> 00:23:15,960
But their sleep is anything
but restful.

476
00:23:15,962 --> 00:23:21,232
POE:
We have found that
the REM dream state of sleep

477
00:23:21,234 --> 00:23:23,367
after a rat has
experienced a trauma

478
00:23:23,369 --> 00:23:26,404
can be hyperactive.

479
00:23:26,406 --> 00:23:28,806
It's kind of like REM sleep
on steroids

480
00:23:28,808 --> 00:23:31,041
in the way that it is

481
00:23:31,043 --> 00:23:33,077
in people with post-traumatic
stress disorder.

482
00:23:33,079 --> 00:23:37,948
NARRATOR:
So Gina comes up
with a novel idea.

483
00:23:37,950 --> 00:23:41,619
After the shock,
half the rats go right to sleep.

484
00:23:41,621 --> 00:23:45,790
The other half are kept awake
for about six hours.

485
00:23:45,792 --> 00:23:48,993
In that time,
they eat, they play,

486
00:23:48,995 --> 00:23:51,662
and get a chance to calm down

487
00:23:51,664 --> 00:23:54,398
before they, too,
get some shut-eye.

488
00:23:56,035 --> 00:23:57,368
POE:
The next day, we bring them back

489
00:23:57,370 --> 00:23:59,837
into a slightly
different environment.

490
00:23:59,839 --> 00:24:01,038
So, it smells different,

491
00:24:01,040 --> 00:24:03,441
it has different colors,
different lighting.

492
00:24:03,443 --> 00:24:07,878
NARRATOR:
In fact, the only thing
that remains the same

493
00:24:07,880 --> 00:24:10,581
is the tone that came
before the shock.

494
00:24:10,583 --> 00:24:11,982
(tone beeps)

495
00:24:11,984 --> 00:24:15,085
When the rat that went straight
to sleep hears the tone,

496
00:24:15,087 --> 00:24:18,289
it freezes.

497
00:24:18,291 --> 00:24:19,990
POE:
As soon as they hear the sound,

498
00:24:19,992 --> 00:24:22,460
animals with PTSD will freeze.

499
00:24:22,462 --> 00:24:25,663
NARRATOR:
But what happens to the rat

500
00:24:25,665 --> 00:24:29,166
that's been allowed to calm down
before going to sleep?

501
00:24:29,168 --> 00:24:34,104
Will it have the same response?

502
00:24:34,106 --> 00:24:39,543
(tone beeps)
When it hears the tone,
it also freezes-- at first.

503
00:24:39,545 --> 00:24:43,881
But then it seems to realize
the shock isn't coming.

504
00:24:43,883 --> 00:24:45,483
And it will start walking around
and sniffing

505
00:24:45,485 --> 00:24:48,419
and exploring,
as rats normally do.

506
00:24:48,421 --> 00:24:51,856
Because they realize they're
not going to be shocked here.

507
00:24:51,858 --> 00:24:54,458
NARRATOR:
Delaying sleep after a trauma

508
00:24:54,460 --> 00:24:57,995
may lessen the impact
of disturbing experiences

509
00:24:57,997 --> 00:25:03,467
and even prevent the nightmares
of PTSD from taking shape--

510
00:25:03,469 --> 00:25:06,670
that is, in rats.

511
00:25:06,672 --> 00:25:10,040
But will it help us humans?

512
00:25:10,042 --> 00:25:12,576
Gina is taking her work
outside the lab,

513
00:25:12,578 --> 00:25:16,413
conducting a study
with firefighters,

514
00:25:16,415 --> 00:25:20,751
asking them to delay sleep
after a traumatic event.

515
00:25:20,753 --> 00:25:23,087
POE:
With firefighters,
we can ask them to do

516
00:25:23,089 --> 00:25:24,321
whatever it is they do

517
00:25:24,323 --> 00:25:28,425
to best relax and
calm themselves after a trauma.

518
00:25:28,427 --> 00:25:32,563
For some, it might be
meditation or prayer.

519
00:25:32,565 --> 00:25:33,864
For others, it might be

520
00:25:33,866 --> 00:25:36,033
listening to music
that they love

521
00:25:36,035 --> 00:25:38,702
or going for a run.

522
00:25:38,704 --> 00:25:40,504
We're going to see
if that helps us

523
00:25:40,506 --> 00:25:42,740
prevent post-traumatic
stress disorder.

524
00:25:42,742 --> 00:25:45,509
♪ ♪

525
00:25:45,511 --> 00:25:48,779
ZEE:
I used to be asked a lot,
"Why do you sleep?

526
00:25:48,781 --> 00:25:50,881
What's the function of sleep?"

527
00:25:50,883 --> 00:25:54,118
But I think we should
be asking the question,

528
00:25:54,120 --> 00:25:57,855
"What are the functions
of sleep?"

529
00:25:57,857 --> 00:26:02,092
NARRATOR:
We spend about 20% of the night
in REM sleep.

530
00:26:02,094 --> 00:26:05,729
The rest of the time,
your brain is in non-REM sleep,

531
00:26:05,731 --> 00:26:11,135
part of which is spent producing
those big, slow waves.

532
00:26:11,137 --> 00:26:15,306
But what are they for?

533
00:26:15,308 --> 00:26:18,409
One of the first scientific
experiments to find clues

534
00:26:18,411 --> 00:26:23,314
was conducted back in 1924
at Cornell University

535
00:26:23,316 --> 00:26:28,085
by psychologists John Jenkins
and Karl Dallenbach.

536
00:26:28,087 --> 00:26:30,955
Using a group of college
students as guinea pigs,

537
00:26:30,957 --> 00:26:34,325
they found that when their
students learned something new,

538
00:26:34,327 --> 00:26:37,094
they had a much better
chance of remembering it

539
00:26:37,096 --> 00:26:40,197
if they slept on it.

540
00:26:40,199 --> 00:26:42,566
WALKER:
So, they found that sleep--

541
00:26:42,568 --> 00:26:44,935
rather than simply being
a dormant state

542
00:26:44,937 --> 00:26:47,204
where nothing too much happens
within the brain--

543
00:26:47,206 --> 00:26:51,842
sleep may be important
for memory.

544
00:26:51,844 --> 00:26:54,411
But then it raised all sorts
of questions about why,

545
00:26:54,413 --> 00:26:57,982
and so we've been trying
to answer the question of why

546
00:26:57,984 --> 00:26:59,083
since then.

547
00:26:59,085 --> 00:27:01,452
NARRATOR:
At the University of Arizona,

548
00:27:01,454 --> 00:27:03,954
experimental psychologist
Rebecca Gomez,

549
00:27:03,956 --> 00:27:07,958
along with grad student
Katherine Esterline,

550
00:27:07,960 --> 00:27:10,227
search for the "why"

551
00:27:10,229 --> 00:27:12,596
with the help of a younger
generation of students.

552
00:27:12,598 --> 00:27:14,365
(crying)

553
00:27:14,367 --> 00:27:16,800
NARRATOR:
Toddlers.
Three, four, five.

554
00:27:16,802 --> 00:27:19,036
ESTERLINE:
Are you ready?
Yeah!

555
00:27:19,038 --> 00:27:22,773
NARRATOR:
How does sleep help them learn
and remember new words?

556
00:27:22,775 --> 00:27:24,975
Wow, a zet.

557
00:27:24,977 --> 00:27:26,877
GOMEZ:
We're teaching children
novel words

558
00:27:26,879 --> 00:27:29,747
for completely novel objects.

559
00:27:29,749 --> 00:27:31,081
Look at these.

560
00:27:31,083 --> 00:27:34,485
GOMEZ:
We use this completely
new information

561
00:27:34,487 --> 00:27:36,720
so we can measure
the brain's ability

562
00:27:36,722 --> 00:27:40,624
to form completely novel,
completely new memories.

563
00:27:40,626 --> 00:27:42,860
Hey, a beev.

564
00:27:42,862 --> 00:27:45,896
GOMEZ:
So, in essence,

565
00:27:45,898 --> 00:27:48,832
we're measuring
brute-force memory.

566
00:27:48,834 --> 00:27:50,701
What's this?

567
00:27:50,703 --> 00:27:53,437
NARRATOR:
The kids are shown four objects
they've never seen before

568
00:27:53,439 --> 00:27:58,275
that have been given nonsense
names like zet...

569
00:27:58,277 --> 00:27:59,343
A zet.

570
00:27:59,345 --> 00:28:01,779
NARRATOR:
Mup...
Cool, a mup.

571
00:28:01,781 --> 00:28:04,682
NARRATOR:
Beev...
Hey, a beev.

572
00:28:04,684 --> 00:28:06,083
NARRATOR:
And toap.

573
00:28:06,085 --> 00:28:07,284
A toap.

574
00:28:07,286 --> 00:28:08,786
Toap.

575
00:28:08,788 --> 00:28:11,588
NARRATOR:
They get a chance
to look at the objects.

576
00:28:11,590 --> 00:28:12,890
Look at these.

577
00:28:12,892 --> 00:28:16,927
NARRATOR:
And even touch them.

578
00:28:16,929 --> 00:28:21,932
Then, half of the toddlers
go home for their afternoon nap,

579
00:28:21,934 --> 00:28:25,703
while the other half
don't nap for hours--

580
00:28:25,705 --> 00:28:27,371
or perhaps not at all.

581
00:28:27,373 --> 00:28:30,207
The next day, they're back.

582
00:28:30,209 --> 00:28:31,709
ESTERLINE:
Where's the zet?

583
00:28:31,711 --> 00:28:35,112
NARRATOR:
How much do they remember?

584
00:28:35,114 --> 00:28:36,780
GOMEZ:
What we found is

585
00:28:36,782 --> 00:28:38,816
that the children who nap
soon after learning...

586
00:28:38,818 --> 00:28:41,085
ESTERLINE:
Mup.

587
00:28:41,087 --> 00:28:42,386
GOMEZ:
...remember the words
about 80% of the time.

588
00:28:42,388 --> 00:28:43,420
Toap.

589
00:28:43,422 --> 00:28:46,323
Where's the zet?

590
00:28:46,325 --> 00:28:49,059
GOMEZ:
In contrast, the kids who went
through a long period of time

591
00:28:49,061 --> 00:28:51,161
before they napped...

592
00:28:51,163 --> 00:28:53,931
Where's the zet?

593
00:28:53,933 --> 00:28:56,667
GOMEZ:
...only remembered the words
about 30% of the time.

594
00:28:56,669 --> 00:28:59,903
Where's the toap?

595
00:28:59,905 --> 00:29:01,338
This?

596
00:29:01,340 --> 00:29:03,507
GOMEZ:
So, you see a huge difference

597
00:29:03,509 --> 00:29:05,609
between 80% of the time
and 30% of the time,

598
00:29:05,611 --> 00:29:07,277
and that's the difference
the nap makes.

599
00:29:07,279 --> 00:29:09,813
Where's the mup?

600
00:29:09,815 --> 00:29:12,950
Right here.

601
00:29:12,952 --> 00:29:17,488
NARRATOR:
Why did a nap
make all the difference?

602
00:29:17,490 --> 00:29:22,159
The key lays inside a tiny organ
found deep within the brain--

603
00:29:22,161 --> 00:29:24,461
the hippocampus.

604
00:29:24,463 --> 00:29:27,331
We have one in each hemisphere,

605
00:29:27,333 --> 00:29:32,636
and they play a critical role in
helping us learn and remember.

606
00:29:32,638 --> 00:29:34,104
So, think of it this way.

607
00:29:34,106 --> 00:29:35,839
I have a little filing drawer
beside my desk.

608
00:29:35,841 --> 00:29:39,576
And, throughout the day,
as papers come in,

609
00:29:39,578 --> 00:29:41,411
I toss them in this drawer.

610
00:29:41,413 --> 00:29:43,647
It's my mail that came today,

611
00:29:43,649 --> 00:29:46,583
it's some papers
that I had from a class.

612
00:29:46,585 --> 00:29:49,419
That's my temporary storage.

613
00:29:49,421 --> 00:29:51,655
The hippocampus is like
that short-term filing drawer,

614
00:29:51,657 --> 00:29:55,692
a mishmash of information
getting squeezed in,

615
00:29:55,694 --> 00:29:59,663
and there's a limited amount
of room there for that.

616
00:29:59,665 --> 00:30:02,266
But at the end of the day,
I could take that information

617
00:30:02,268 --> 00:30:04,568
and turn around to
my whole huge filing cabinet,

618
00:30:04,570 --> 00:30:07,271
which in this case
is the cortex.

619
00:30:07,273 --> 00:30:09,239
The cortex, it's bigger,

620
00:30:09,241 --> 00:30:11,809
and it has a really nice
sorting mechanism.

621
00:30:11,811 --> 00:30:14,978
You can sort things
by their visual components,

622
00:30:14,980 --> 00:30:16,780
by their auditory components.

623
00:30:16,782 --> 00:30:20,184
That memory becomes
easier to find.

624
00:30:20,186 --> 00:30:22,686
So the role of slow-wave sleep
is to take that information

625
00:30:22,688 --> 00:30:25,088
that's been stuffed
into the hippocampus

626
00:30:25,090 --> 00:30:28,859
and help move it to
its more efficient filing system

627
00:30:28,861 --> 00:30:31,862
out in the cortex.

628
00:30:31,864 --> 00:30:34,031
WALKER:
Things that you learned
yesterday

629
00:30:34,033 --> 00:30:37,601
are now transferred
to a safer storage location.

630
00:30:37,603 --> 00:30:39,736
But second when you wake up
in the morning,

631
00:30:39,738 --> 00:30:42,539
your hippocampus has
now been cleared out,

632
00:30:42,541 --> 00:30:44,775
and you have
a refreshed capacity

633
00:30:44,777 --> 00:30:47,878
for new-file acquisition
all over again.

634
00:30:47,880 --> 00:30:51,915
NARRATOR:
And that brings us back
to our toddlers

635
00:30:51,917 --> 00:30:54,484
and the power
of the midday nap.

636
00:30:56,255 --> 00:31:00,557
Why does it make
such a big difference?

637
00:31:00,559 --> 00:31:02,826
Why is it so important
for toddlers

638
00:31:02,828 --> 00:31:06,930
to clear out
that short-term filing drawer?

639
00:31:06,932 --> 00:31:10,267
Researchers have a theory.

640
00:31:10,269 --> 00:31:12,269
GOMEZ:
Young children, their brains
are still developing,

641
00:31:12,271 --> 00:31:15,539
and in fact,
the hippocampus is still

642
00:31:15,541 --> 00:31:19,877
in the process of developing
all across the childhood years.

643
00:31:19,879 --> 00:31:22,145
So it does seem
that the hippocampus,

644
00:31:22,147 --> 00:31:24,414
when it's young and immature,

645
00:31:24,416 --> 00:31:27,618
such as in infancy
and early childhood,

646
00:31:27,620 --> 00:31:31,321
perhaps those memories need
to be stored more frequently

647
00:31:31,323 --> 00:31:33,390
or moved to the cortex
more frequently.

648
00:31:33,392 --> 00:31:35,759
♪ ♪

649
00:31:35,761 --> 00:31:39,596
NARRATOR:
But that doesn't mean
naps are just for kids.

650
00:31:39,598 --> 00:31:42,099
SPENCER:
It's interesting to think
that as you get older,

651
00:31:42,101 --> 00:31:44,034
you actually see napping
start to return

652
00:31:44,036 --> 00:31:45,302
in a number of individuals.

653
00:31:45,304 --> 00:31:49,840
NARRATOR:
And there may be
a good reason why.

654
00:31:49,842 --> 00:31:53,710
SPENCER:
Most older adults report two
frustrating things about aging--

655
00:31:53,712 --> 00:31:56,213
"I can't remember things
like I used to,

656
00:31:56,215 --> 00:31:57,915
and I can't sleep
like I used to."

657
00:31:57,917 --> 00:32:04,521
Napping could be one way
of helping maintain memories.

658
00:32:06,091 --> 00:32:08,592
There are probably multiple
different reasons

659
00:32:08,594 --> 00:32:10,961
why the aging brain
simply can't learn

660
00:32:10,963 --> 00:32:13,363
and remember as effectively.

661
00:32:13,365 --> 00:32:14,631
And I think we're identifying

662
00:32:14,633 --> 00:32:19,002
that sleep is one
of those critical ingredients.

663
00:32:19,004 --> 00:32:20,938
So, this is the sleep
of an older adult.

664
00:32:20,940 --> 00:32:24,808
You should start seeing
these waves slowing down

665
00:32:24,810 --> 00:32:26,443
and getting higher in amplitude.

666
00:32:26,445 --> 00:32:27,911
That would be
what we're looking for

667
00:32:27,913 --> 00:32:29,913
for slow-wave sleep.

668
00:32:29,915 --> 00:32:32,883
And so far, I'm not seeing any.

669
00:32:32,885 --> 00:32:34,618
Still looking.

670
00:32:34,620 --> 00:32:37,387
They're asleep, but they're not
getting the slow wave

671
00:32:37,389 --> 00:32:39,723
that, in a young adult,
you might expect to see by now.

672
00:32:39,725 --> 00:32:44,161
WALKER:
And it seems to be
that the quality

673
00:32:44,163 --> 00:32:46,630
of the sleeping brain waves
that you have,

674
00:32:46,632 --> 00:32:48,265
the depth of those brain waves,

675
00:32:48,267 --> 00:32:51,635
and the sort of,
the size of those brain waves

676
00:32:51,637 --> 00:32:53,704
accurately predicts how well

677
00:32:53,706 --> 00:32:58,675
you're able to hit the save
button on those memories.

678
00:32:58,677 --> 00:33:02,612
NARRATOR:
Is there a way to improve
those big, slow waves

679
00:33:02,614 --> 00:33:06,583
to increase our ability
to hit that save button?

680
00:33:06,585 --> 00:33:11,088
Sleep researchers are
exploring a radical idea.

681
00:33:11,090 --> 00:33:14,691
ZEE:
One of the things
that we're most interested in

682
00:33:14,693 --> 00:33:20,998
is, how can we boost and enhance
sleep quality, sleep quantity,

683
00:33:21,000 --> 00:33:26,536
by using, you know,
not pharmacology, but sound.

684
00:33:26,538 --> 00:33:32,476
NARRATOR:
80-year-old Marion Smith is
participating in a sleep study.

685
00:33:32,478 --> 00:33:35,145
To track the quality
of her slow waves,

686
00:33:35,147 --> 00:33:39,182
a single electrode is placed
on her forehead.

687
00:33:39,184 --> 00:33:43,020
Marion will hear carefully timed
pulses of sound

688
00:33:43,022 --> 00:33:47,591
through this headband
equipped with tiny speakers.

689
00:33:47,593 --> 00:33:50,727
Well, have a good night,
I'll see you tomorrow.

690
00:33:50,729 --> 00:33:53,163
♪ ♪

691
00:33:53,165 --> 00:33:58,268
ZEE:
Our patient, Miss Smith,
is now clearly sleeping.

692
00:33:58,270 --> 00:34:00,704
She is now getting deeper sleep.

693
00:34:00,706 --> 00:34:06,243
NARRATOR:
By examining the brain waves
produced by a single electrode,

694
00:34:06,245 --> 00:34:09,179
Phyllis has all the information
she needs

695
00:34:09,181 --> 00:34:12,883
to assess the quality
of Marion's slow waves.

696
00:34:12,885 --> 00:34:15,252
ZEE:
These are these big, slow waves,

697
00:34:15,254 --> 00:34:17,988
but there are very few of them.

698
00:34:17,990 --> 00:34:20,057
And this is quite typical
of an older person

699
00:34:20,059 --> 00:34:23,193
who has low-amplitude
slow waves,

700
00:34:23,195 --> 00:34:25,228
and they don't occur,
like, in a train.

701
00:34:25,230 --> 00:34:29,433
NARRATOR:
Next, a specially designed
computer algorithm

702
00:34:29,435 --> 00:34:30,801
measures the waves

703
00:34:30,803 --> 00:34:34,404
to determine the best time
to deliver a particular sound...

704
00:34:34,406 --> 00:34:36,473
(sound pulsing)

705
00:34:36,475 --> 00:34:40,444
...the pulsing of pink noise.

706
00:34:40,446 --> 00:34:44,081
ZEE:
And we do very brief,
like, 50 milliseconds

707
00:34:44,083 --> 00:34:47,984
of this very short burst
of pink noise.

708
00:34:47,986 --> 00:34:51,688
And we do it five on, five off

709
00:34:51,690 --> 00:34:54,958
as long as the person
is still in deep sleep.

710
00:34:54,960 --> 00:34:57,494
(sound pulsing)

711
00:34:57,496 --> 00:35:00,297
NARRATOR:
Think of the sound waves
produced by pink noise

712
00:35:00,299 --> 00:35:04,167
giving Marion's brain waves
a little push,

713
00:35:04,169 --> 00:35:06,203
like a kid on a swing

714
00:35:06,205 --> 00:35:09,573
or the movement of a ball
in a balance pendulum.

715
00:35:09,575 --> 00:35:12,342
WALKER:
And what you try to do is

716
00:35:12,344 --> 00:35:15,145
sing in time
with these brain waves.

717
00:35:15,147 --> 00:35:16,546
But by stimulating them,

718
00:35:16,548 --> 00:35:19,616
you're trying to boost
the size of those brain waves.

719
00:35:19,618 --> 00:35:22,052
ZEE:
It's beautiful.

720
00:35:22,054 --> 00:35:24,654
This is what we want them
all to look like,

721
00:35:24,656 --> 00:35:29,559
these very large,
with strong upstate waves.

722
00:35:29,561 --> 00:35:34,898
Even after you stop stimulating,
you can see the increase

723
00:35:34,900 --> 00:35:37,400
in these slow waves.

724
00:35:37,402 --> 00:35:43,140
NARRATOR:
Phyllis is finding that
a little push goes a long way.

725
00:35:43,142 --> 00:35:44,407
ZEE:
What we're seeing here

726
00:35:44,409 --> 00:35:48,778
is not only that we can
increase the amplitude--

727
00:35:48,780 --> 00:35:50,547
that means the height
of these slow waves,

728
00:35:50,549 --> 00:35:52,149
which is really important--

729
00:35:52,151 --> 00:35:55,585
but we can also increase
the train.

730
00:35:55,587 --> 00:35:59,322
So, we could prolong
the amount of slow waves.

731
00:35:59,324 --> 00:36:02,159
Which is wonderful,
because it's hopeful

732
00:36:02,161 --> 00:36:04,928
that the brain,
even if you're old,

733
00:36:04,930 --> 00:36:07,697
is capable of boosting
these slow waves.

734
00:36:07,699 --> 00:36:14,004
NARRATOR:
Not only might boosting
slow waves improve memory,

735
00:36:14,006 --> 00:36:17,607
new research is revealing
that during this stage of sleep,

736
00:36:17,609 --> 00:36:20,911
the brain may be doing
some critical housekeeping.

737
00:36:20,913 --> 00:36:22,979
It was discovered that the brain

738
00:36:22,981 --> 00:36:26,516
is actually actively
flushing out cellular waste

739
00:36:26,518 --> 00:36:27,450
while we sleep.

740
00:36:27,452 --> 00:36:29,753
Just like when we visit Paris,

741
00:36:29,755 --> 00:36:34,090
and we see them
clean the streets at 5:00 a.m.,

742
00:36:34,092 --> 00:36:37,093
our brain, it cleans out
all the waste

743
00:36:37,095 --> 00:36:39,362
during this offline period.

744
00:36:39,364 --> 00:36:42,766
SPENCER:
There could be a potential link

745
00:36:42,768 --> 00:36:45,902
between sleep and
neurodegenerative diseases,

746
00:36:45,904 --> 00:36:47,804
like Alzheimer's disease.

747
00:36:47,806 --> 00:36:52,409
And it could all come down
to this brain-cleaning process

748
00:36:52,411 --> 00:36:56,513
that happens specifically
during slow-wave sleep.

749
00:36:56,515 --> 00:36:59,316
ZEE:
We have to do a lot more work
in this area.

750
00:36:59,318 --> 00:37:01,351
It's really, right now,
the tip of the iceberg.

751
00:37:02,988 --> 00:37:05,322
NARRATOR:
While researchers
explore new ways

752
00:37:05,324 --> 00:37:08,525
to help us get
the sleep we need,

753
00:37:08,527 --> 00:37:12,429
millions of Americans
fight the urge,

754
00:37:12,431 --> 00:37:16,833
staying up way past bedtime,

755
00:37:16,835 --> 00:37:19,836
lured by the trappings
of technology.

756
00:37:19,838 --> 00:37:23,173
DINGES:
Nearly everyone sooner or later

757
00:37:23,175 --> 00:37:25,775
will experience some sleep loss
in their life.

758
00:37:25,777 --> 00:37:30,013
The invasion of television
into the home 50 years ago,

759
00:37:30,015 --> 00:37:33,216
and now computers
and telephones,

760
00:37:33,218 --> 00:37:37,153
basically, we need to shut
that stuff off.

761
00:37:37,155 --> 00:37:40,924
WALKER:
Somewhere between infancy
and even childhood,

762
00:37:40,926 --> 00:37:43,660
we in Western,
industrialized nations,

763
00:37:43,662 --> 00:37:47,097
we start to abandon the notion
that sleep is useful,

764
00:37:47,099 --> 00:37:49,866
and, if anything,
take the opposite approach

765
00:37:49,868 --> 00:37:52,902
and believe that sleep
should be short-changed.

766
00:37:52,904 --> 00:37:57,107
NARRATOR:
Back in 1964,

767
00:37:57,109 --> 00:38:00,577
17-year-old Randy Gardner broke
the Guinness world record

768
00:38:00,579 --> 00:38:03,813
for staying awake
11 days straight.

769
00:38:03,815 --> 00:38:09,753
ANNOUNCER:
One of these young men holds
an unusual world record.

770
00:38:09,755 --> 00:38:11,821
What is your name, please?

771
00:38:11,823 --> 00:38:13,690
My name is Randy Gardner.

772
00:38:15,060 --> 00:38:16,726
My name is Randy Gardner.

773
00:38:16,728 --> 00:38:18,862
NARRATOR:
The experiment won him
first place

774
00:38:18,864 --> 00:38:21,231
in his high school science fair

775
00:38:21,233 --> 00:38:24,334
and caught the attention
of a nation.

776
00:38:24,336 --> 00:38:27,570
BRUCE McALLISTER:
He ended up on "To Tell
the Truth,"

777
00:38:27,572 --> 00:38:29,939
you know, a TV show.

778
00:38:29,941 --> 00:38:31,975
And supposedly
the most written-about story

779
00:38:31,977 --> 00:38:34,044
in the world

780
00:38:34,046 --> 00:38:36,713
after JFK and the Beatles.

781
00:38:36,715 --> 00:38:39,482
Number Two,
how did you pass the time

782
00:38:39,484 --> 00:38:41,117
when the other people
were sleeping?

783
00:38:41,119 --> 00:38:43,887
Well, there were always, there
was always someone with me,

784
00:38:43,889 --> 00:38:45,689
the two boys that helped me--
one would sleep,

785
00:38:45,691 --> 00:38:46,790
and one would stay awake
with me.

786
00:38:46,792 --> 00:38:48,325
(chuckles)

787
00:38:48,327 --> 00:38:53,463
NARRATOR:
Bruce McAllister was
one of those boys.

788
00:38:53,465 --> 00:38:55,999
It wasn't the science of it
that interested the world.

789
00:38:56,001 --> 00:38:57,834
The world was interested
in the drama.

790
00:38:57,836 --> 00:38:59,803
♪ ♪

791
00:38:59,805 --> 00:39:03,306
NARRATOR:
The experiment moved beyond
high school science

792
00:39:03,308 --> 00:39:09,112
when sleep researcher
William Dement joined the team.

793
00:39:09,114 --> 00:39:11,281
McALLISTER:
And he brought
a portable E.E.G.,

794
00:39:11,283 --> 00:39:14,551
which no one had ever seen
before.

795
00:39:14,553 --> 00:39:18,054
They sent the E.E.Gs.
to a supercomputer,

796
00:39:18,056 --> 00:39:20,457
a Cray computer in Arizona,

797
00:39:20,459 --> 00:39:22,692
and that computer concluded
that his...

798
00:39:22,694 --> 00:39:25,128
Parts of his brain
were sleeping

799
00:39:25,130 --> 00:39:27,297
while others were awake.

800
00:39:27,299 --> 00:39:30,600
His brain was catnapping
in pieces.

801
00:39:30,602 --> 00:39:33,370
That is how the human brain
survived this.

802
00:39:33,372 --> 00:39:37,207
NARRATOR:
While Randy looked wide awake,

803
00:39:37,209 --> 00:39:39,109
parts of his brain weren't--

804
00:39:39,111 --> 00:39:43,880
what neuroscientists now call
a microsleep.

805
00:39:43,882 --> 00:39:46,750
NIR:
A microsleep is
something that may happen

806
00:39:46,752 --> 00:39:49,319
after we've been awake
for a very long time,

807
00:39:49,321 --> 00:39:52,188
and our brain needs sleep
so desperately

808
00:39:52,190 --> 00:39:55,125
that we may fall
for a very short interval

809
00:39:55,127 --> 00:39:58,428
of three to 15 seconds, just...

810
00:39:58,430 --> 00:40:01,998
And we've all seen this
when our eyes shut down,

811
00:40:02,000 --> 00:40:06,169
and we nod to sleep for
just a few seconds like this.

812
00:40:06,171 --> 00:40:08,405
♪ ♪

813
00:40:08,407 --> 00:40:10,940
DINGES:
We're all very polite and sort
of pretend we don't see it,

814
00:40:10,942 --> 00:40:13,343
but as we're talking to someone
and they start to fall asleep,

815
00:40:13,345 --> 00:40:14,978
we notice that they're losing
muscle tone,

816
00:40:14,980 --> 00:40:17,714
so they start to slump, and the
head will start to fall over,

817
00:40:17,716 --> 00:40:19,616
and the eye,
the lids are coming down,

818
00:40:19,618 --> 00:40:21,985
and then we'll see
the eyes roll in the head.

819
00:40:21,987 --> 00:40:25,021
If you're holding a steering
wheel and driving,

820
00:40:25,023 --> 00:40:26,790
you might notice that your arms

821
00:40:26,792 --> 00:40:29,259
are starting to slack
a little bit on the wheel.

822
00:40:29,261 --> 00:40:34,998
BEN-SIMON:
It only takes 200 milliseconds
when you're not paying attention

823
00:40:35,000 --> 00:40:37,834
that the car is going
in the wrong direction.

824
00:40:37,836 --> 00:40:40,904
NARRATOR:
When you're sleep-deprived,

825
00:40:40,906 --> 00:40:45,475
your brain will fall asleep--
whether you notice or not.

826
00:40:45,477 --> 00:40:47,710
♪ ♪

827
00:40:47,712 --> 00:40:51,681
That's because biology
takes the wheel.

828
00:40:51,683 --> 00:40:55,051
Two different processes
drive you to sleep.

829
00:40:55,053 --> 00:40:57,854
The first is
your circadian rhythm,

830
00:40:57,856 --> 00:41:00,223
your biological clock.

831
00:41:00,225 --> 00:41:01,624
ALLADA:
One of the signals

832
00:41:01,626 --> 00:41:03,726
that's keeping you awake
during the day

833
00:41:03,728 --> 00:41:05,395
is the circadian clock.

834
00:41:05,397 --> 00:41:08,565
Think of the circadian clock as
kind of an internal alarm clock.

835
00:41:08,567 --> 00:41:14,070
NARRATOR:
Back in 1938,
in a landmark experiment,

836
00:41:14,072 --> 00:41:16,206
sleep researcher
Nathaniel Kleitman

837
00:41:16,208 --> 00:41:21,177
takes one of his students
to live in an underground cave.

838
00:41:21,179 --> 00:41:24,881
They spend a month
without sunlight,

839
00:41:24,883 --> 00:41:27,484
testing the power
of that internal alarm clock.

840
00:41:27,486 --> 00:41:30,053
♪ ♪

841
00:41:30,055 --> 00:41:34,357
Even without light,
the clock keeps ticking.

842
00:41:34,359 --> 00:41:38,161
But add light,
and the cycle can shift.

843
00:41:38,163 --> 00:41:41,097
ZEE:
Every day, you get
a little light in the morning,

844
00:41:41,099 --> 00:41:43,166
it moves your clock
in one direction.

845
00:41:43,168 --> 00:41:44,901
You get a little light
in the evening,

846
00:41:44,903 --> 00:41:46,903
it moves your clock
in the other direction,

847
00:41:46,905 --> 00:41:48,771
so it can delay and advance.

848
00:41:48,773 --> 00:41:53,176
And by doing this,
it maintains your internal clock

849
00:41:53,178 --> 00:41:58,281
in synchrony with that
of your external environment.

850
00:41:58,283 --> 00:42:01,885
NARRATOR:
This clock controls the release
of a key chemical

851
00:42:01,887 --> 00:42:05,555
that has the power
to make you feel sleepy:

852
00:42:05,557 --> 00:42:10,193
melatonin, also known
as the hormone of darkness.

853
00:42:10,195 --> 00:42:12,629
ZEE:
Melatonin goes up at night,

854
00:42:12,631 --> 00:42:15,899
and it stays up
during the entire night

855
00:42:15,901 --> 00:42:18,601
until probably
the early morning hours,

856
00:42:18,603 --> 00:42:21,604
and then begins its decline.

857
00:42:21,606 --> 00:42:24,307
By the time that we normally
would be waking up,

858
00:42:24,309 --> 00:42:27,010
melatonin levels are
very, very low.

859
00:42:27,012 --> 00:42:28,811
♪ ♪

860
00:42:28,813 --> 00:42:33,683
NARRATOR:
But sleepiness isn't just
controlled by melatonin.

861
00:42:33,685 --> 00:42:36,452
Another chemical,
called adenosine,

862
00:42:36,454 --> 00:42:39,188
may also play a role.

863
00:42:39,190 --> 00:42:41,591
Some researchers believe
it starts to build

864
00:42:41,593 --> 00:42:43,660
from the moment you wake up,

865
00:42:43,662 --> 00:42:48,932
and, like an hourglass,
fills with the passage of time,

866
00:42:48,934 --> 00:42:52,035
gradually increasing
our need for sleep,

867
00:42:52,037 --> 00:42:55,838
called "sleep pressure."

868
00:42:55,840 --> 00:42:57,674
BEN-SIMON:
We see a very strong association

869
00:42:57,676 --> 00:43:01,010
between the levels of adenosine
and being sleepy

870
00:43:01,012 --> 00:43:04,280
and between the level of sleep
and reducing that adenosine.

871
00:43:04,282 --> 00:43:08,418
Sleep is the perfect way to
clear adenosine from the brain

872
00:43:08,420 --> 00:43:11,721
and start fresh.

873
00:43:11,723 --> 00:43:13,423
Many of us are trying

874
00:43:13,425 --> 00:43:16,426
to block the effects
of that adenosine every day

875
00:43:16,428 --> 00:43:20,396
by our consumption of caffeine.

876
00:43:20,398 --> 00:43:23,132
Caffeine binds
to these adenosine receptors,

877
00:43:23,134 --> 00:43:26,436
so it kind of blocks
the effects of sleep pressure,

878
00:43:26,438 --> 00:43:28,838
so that we're,
we're not feeling it.

879
00:43:28,840 --> 00:43:31,608
It's still there, but we're just
not feeling the effects of it.

880
00:43:31,610 --> 00:43:33,509
♪ ♪

881
00:43:33,511 --> 00:43:38,181
NARRATOR:
But drinking coffee will work
for just so long.

882
00:43:38,183 --> 00:43:40,316
PAUL:
If you choose
not to go to sleep tonight,

883
00:43:40,318 --> 00:43:41,884
and you stay up all night,

884
00:43:41,886 --> 00:43:44,153
that sleep pressure
will continue to build.

885
00:43:44,155 --> 00:43:45,521
And as that sleep pressure
builds,

886
00:43:45,523 --> 00:43:47,357
it will impair
your thought processes,

887
00:43:47,359 --> 00:43:50,193
it will impair your memory.

888
00:43:50,195 --> 00:43:53,129
ZEE:
More than 60% of our population

889
00:43:53,131 --> 00:43:55,698
may not be getting
sufficient amount of sleep,

890
00:43:55,700 --> 00:43:59,936
but also sufficient quality
of sleep.

891
00:43:59,938 --> 00:44:02,605
NARRATOR:
For firefighter Matt Reinhold,

892
00:44:02,607 --> 00:44:05,308
who often works a 72-hour
shift...
(alarm chiming)

893
00:44:05,310 --> 00:44:08,611
...a good night's sleep
is hard to come by.

894
00:44:08,613 --> 00:44:11,381
REINHOLD:
The alarm will go off
and the lights will come on.

895
00:44:11,383 --> 00:44:13,016
(snaps fingers):
It's a, it's a startlement.

896
00:44:13,018 --> 00:44:16,319
You know, right off the bat,
you're woken up.

897
00:44:16,321 --> 00:44:20,390
There's times where we'll run
five, six, seven,

898
00:44:20,392 --> 00:44:23,326
eight calls after midnight.

899
00:44:23,328 --> 00:44:26,896
I have never been
in a deep sleep

900
00:44:26,898 --> 00:44:29,766
here at this firehouse.

901
00:44:29,768 --> 00:44:31,134
Fatigue starts to set in.

902
00:44:31,136 --> 00:44:34,237
All I want to go and do
is go lay down,

903
00:44:34,239 --> 00:44:36,673
but then the alarm's
going off again

904
00:44:36,675 --> 00:44:40,176
for a medical down the street.

905
00:44:40,178 --> 00:44:43,713
Lack of sleep definitely
makes you more snippy,

906
00:44:43,715 --> 00:44:46,282
you become more agitated,
more irritated.

907
00:44:46,284 --> 00:44:49,819
The communication factor
may go out the window,

908
00:44:49,821 --> 00:44:52,422
because you don't want to talk,
because you're tired,

909
00:44:52,424 --> 00:44:55,391
because of what you're afraid
of what you might say.

910
00:44:55,393 --> 00:45:00,129
The irritability takes a toll.

911
00:45:00,131 --> 00:45:02,999
There was a study that compared
a group of participants

912
00:45:03,001 --> 00:45:06,235
only allowed to sleep
for five hours a night,

913
00:45:06,237 --> 00:45:07,837
and then there was another group

914
00:45:07,839 --> 00:45:10,073
that were allowed to sleep
for the whole eight hours,

915
00:45:10,075 --> 00:45:13,142
but were woken up
every now and then

916
00:45:13,144 --> 00:45:15,845
and kept awake for an hour.

917
00:45:15,847 --> 00:45:17,814
And after four days like this,

918
00:45:17,816 --> 00:45:19,716
the effects on mood and anxiety

919
00:45:19,718 --> 00:45:22,351
were actually much stronger
in the interrupted group.

920
00:45:22,353 --> 00:45:25,521
NARRATOR:
Sleeping in fits and starts

921
00:45:25,523 --> 00:45:28,958
wreaks havoc
on your entire system.

922
00:45:28,960 --> 00:45:32,662
DINGES:
That fragmenting of sleep
is extremely destructive

923
00:45:32,664 --> 00:45:34,230
for wake functioning and health.

924
00:45:34,232 --> 00:45:38,134
It is almost as though
you didn't get sleep.

925
00:45:38,136 --> 00:45:41,637
So, the consolidation of sleep
is easily as important

926
00:45:41,639 --> 00:45:46,409
as the duration of the sleep.

927
00:45:46,411 --> 00:45:50,146
NARRATOR:
Quality is as important
as quantity.

928
00:45:50,148 --> 00:45:52,348
PAUL:
There's something
about the loss of sleep

929
00:45:52,350 --> 00:45:56,185
that breaks down
your mind and your body.

930
00:45:56,187 --> 00:45:58,921
If you lose sleep, you will
experience memory deficits,

931
00:45:58,923 --> 00:46:02,425
and you will experience
cognitive deficits.

932
00:46:02,427 --> 00:46:06,195
However, there's also
an interesting caveat to that:

933
00:46:06,197 --> 00:46:09,031
losing sleep may affect
one person one way

934
00:46:09,033 --> 00:46:11,234
and another person another way.

935
00:46:11,236 --> 00:46:14,470
There are some individuals
which tend to be resilient

936
00:46:14,472 --> 00:46:17,974
against the negative effects
of sleep loss.

937
00:46:17,976 --> 00:46:20,910
One of the current focuses
of our field

938
00:46:20,912 --> 00:46:23,379
is to understand
the cause of that resilience

939
00:46:23,381 --> 00:46:25,815
and whether there is
a genetic component.

940
00:46:25,817 --> 00:46:30,553
NARRATOR:
Could the ability
to recover from sleep loss

941
00:46:30,555 --> 00:46:33,556
be determined by our genes?

942
00:46:33,558 --> 00:46:38,294
In 2017, the Nobel Prize
in Physiology or Medicine

943
00:46:38,296 --> 00:46:42,532
was awarded to three scientists
who discovered a group of genes

944
00:46:42,534 --> 00:46:45,368
that drive
your biological clock.

945
00:46:45,370 --> 00:46:47,370
PAUL:
There are genes
such as the clock gene,

946
00:46:47,372 --> 00:46:49,605
the period gene,
the cryptochrome gene.

947
00:46:49,607 --> 00:46:55,745
NARRATOR:
But the gene that intrigues
neuroscientist Ketema Paul

948
00:46:55,747 --> 00:46:58,381
is called BMAL1.

949
00:46:58,383 --> 00:47:00,850
For those of you that know
that clocks used to have gears,

950
00:47:00,852 --> 00:47:04,620
BMAL1 is the primary gear
of the clock.

951
00:47:04,622 --> 00:47:08,291
NARRATOR:
In his lab at U.C.L.A.,

952
00:47:08,293 --> 00:47:11,761
Ketema is exploring
the role BMAL1 may play

953
00:47:11,763 --> 00:47:16,632
in our ability to recover
from sleep loss.

954
00:47:16,634 --> 00:47:19,635
To do it, he makes use
of a classic memory test.

955
00:47:19,637 --> 00:47:23,072
PAUL:
You put a mouse
in an environment

956
00:47:23,074 --> 00:47:25,374
and present two objects.

957
00:47:25,376 --> 00:47:30,112
NARRATOR:
In this case, two orange blocks.

958
00:47:30,114 --> 00:47:32,915
The mouse spends time
getting familiar with them.

959
00:47:32,917 --> 00:47:35,885
PAUL:
After that, we take them out

960
00:47:35,887 --> 00:47:38,120
and sleep-deprive them
for six hours.

961
00:47:38,122 --> 00:47:40,923
NARRATOR:
While the mouse is kept awake,

962
00:47:40,925 --> 00:47:44,126
one of the orange blocks
is replaced with a new object,

963
00:47:44,128 --> 00:47:47,563
a blue cylinder.

964
00:47:47,565 --> 00:47:48,998
After six hours,

965
00:47:49,000 --> 00:47:52,435
the sleep-deprived mouse is
put back in the chamber.

966
00:47:52,437 --> 00:47:56,639
Like humans, mice are
naturally curious--

967
00:47:56,641 --> 00:47:59,275
they're drawn to new things.

968
00:47:59,277 --> 00:48:01,911
So a well-rested mouse
will spend more time

969
00:48:01,913 --> 00:48:06,682
exploring the new object,
the blue cylinder.

970
00:48:06,684 --> 00:48:10,119
But that doesn't happen
with this sleepy mouse.

971
00:48:10,121 --> 00:48:11,621
PAUL:
If you sleep-deprive a mouse,

972
00:48:11,623 --> 00:48:14,690
and you put it
in the same environment,

973
00:48:14,692 --> 00:48:16,225
it will spend
equal amounts of time

974
00:48:16,227 --> 00:48:19,428
between the familiar object
and the novel object,

975
00:48:19,430 --> 00:48:21,831
because its memory
of the familiar object

976
00:48:21,833 --> 00:48:24,033
was impaired by the sleep loss.

977
00:48:24,035 --> 00:48:28,871
NARRATOR:
It seems not to remember
the orange block.

978
00:48:28,873 --> 00:48:31,874
But what happens if Ketema
repeats the memory test

979
00:48:31,876 --> 00:48:34,110
with a mouse that has been
genetically modified

980
00:48:34,112 --> 00:48:38,014
to express higher levels
of BMAL1?

981
00:48:38,016 --> 00:48:42,351
Will this dialed-up mouse
have a better memory?

982
00:48:42,353 --> 00:48:45,388
Or will the results be the same?

983
00:48:45,390 --> 00:48:46,656
PAUL:
The mouse is now

984
00:48:46,658 --> 00:48:49,992
exploring the area in which
the novel object is in.

985
00:48:49,994 --> 00:48:52,361
Another approach
to the novel object.

986
00:48:52,363 --> 00:48:56,732
More exploration
around the arena.

987
00:48:56,734 --> 00:48:58,534
A third approach
to the novel object,

988
00:48:58,536 --> 00:49:00,469
sniffing,
exploring the novel object.

989
00:49:00,471 --> 00:49:04,373
So the mouse is clearly spending
more time with the novel object,

990
00:49:04,375 --> 00:49:06,709
and it suggests
that the sleep deprivation

991
00:49:06,711 --> 00:49:09,445
did not impair
the memory of this mouse,

992
00:49:09,447 --> 00:49:13,282
which suggests
that overexpressing BMAL1

993
00:49:13,284 --> 00:49:16,452
does make that mouse
resilient to sleep loss,

994
00:49:16,454 --> 00:49:18,454
and it preserves its memory
after sleep deprivation.

995
00:49:18,456 --> 00:49:22,358
NARRATOR:
But this is not
the only surprise,

996
00:49:22,360 --> 00:49:28,297
because it turns out
BMAL1 works in mysterious ways.

997
00:49:28,299 --> 00:49:30,199
PAUL:
So the B in BMAL1
stands for "brain,"

998
00:49:30,201 --> 00:49:33,703
the M in BMAL1
stands for "muscle."

999
00:49:33,705 --> 00:49:36,739
NARRATOR:
BMAL1 is a gene
that's found in the brain

1000
00:49:36,741 --> 00:49:39,241
and in skeletal muscle.

1001
00:49:39,243 --> 00:49:43,379
And the resilient mice were
ones that had BMAL1 boosted

1002
00:49:43,381 --> 00:49:47,616
in their muscles,
not in their brains.

1003
00:49:47,618 --> 00:49:50,453
PAUL:
The result we got
was really a surprise.

1004
00:49:50,455 --> 00:49:52,755
Sleep is a mental process.

1005
00:49:52,757 --> 00:49:54,423
And that's kind of,
as a trained neurobiologist,

1006
00:49:54,425 --> 00:49:57,593
how I had been looking at it
before that.

1007
00:49:57,595 --> 00:50:00,229
NARRATOR:
As Ketema continues
his research,

1008
00:50:00,231 --> 00:50:04,567
he will try to find out
how genes in skeletal muscle

1009
00:50:04,569 --> 00:50:07,937
could influence how we sleep
and store memories.

1010
00:50:07,939 --> 00:50:10,172
PAUL:
Hopefully this will lead

1011
00:50:10,174 --> 00:50:11,407
to more effective therapies

1012
00:50:11,409 --> 00:50:13,509
for people that are unable
to get sufficient sleep

1013
00:50:13,511 --> 00:50:14,910
and people that need to function

1014
00:50:14,912 --> 00:50:18,748
in spite
of not getting enough sleep.

1015
00:50:18,750 --> 00:50:22,051
NARRATOR:
Because when it comes
to not getting enough sleep,

1016
00:50:22,053 --> 00:50:27,456
the people hardest-hit are often
the ones we depend on the most.

1017
00:50:27,458 --> 00:50:29,158
Sleep deprivation
of first responders

1018
00:50:29,160 --> 00:50:33,195
leads to issues of increased
isolation and depression

1019
00:50:33,197 --> 00:50:36,565
and has enormous impacts,
not on just your psychology,

1020
00:50:36,567 --> 00:50:38,300
but on your physical well-being,
as well.

1021
00:50:38,302 --> 00:50:41,871
NARRATOR:
Former E.M.S. worker
Susan Farren

1022
00:50:41,873 --> 00:50:45,374
and retired firefighter
Ron Shull

1023
00:50:45,376 --> 00:50:46,942
are working
with first responders,

1024
00:50:46,944 --> 00:50:50,546
educating them on ways
to manage their sleep,

1025
00:50:50,548 --> 00:50:52,281
on and off the job.

1026
00:50:52,283 --> 00:50:54,517
SHULL:
We want to give you guys
some tools and some techniques

1027
00:50:54,519 --> 00:50:57,053
and modalities to kind of
help you sleep better.

1028
00:50:57,055 --> 00:50:59,321
NIR:
In the last ten or 20 years,

1029
00:50:59,323 --> 00:51:01,457
we've discovered
that sleep is essential

1030
00:51:01,459 --> 00:51:03,092
for proper brain function.

1031
00:51:03,094 --> 00:51:06,862
It's important for our health,
for our immunity,

1032
00:51:06,864 --> 00:51:08,764
for our memory...
Toap.

1033
00:51:08,766 --> 00:51:11,667
NIR:
...and for our well-being.

1034
00:51:11,669 --> 00:51:14,537
SPENCER:
I think that's where the phrase
"sleep on it" comes from,

1035
00:51:14,539 --> 00:51:18,541
is that we wake up, and we think
differently about a problem.

1036
00:51:18,543 --> 00:51:22,178
We think differently about that
person that we were angry at.

1037
00:51:22,180 --> 00:51:24,613
We just generally
feel better about our day

1038
00:51:24,615 --> 00:51:28,017
if we've had
a really good night's sleep.

1039
00:51:28,019 --> 00:51:29,885
I think sleep's one of the
sweetest things you can get.

1040
00:51:29,887 --> 00:51:33,656
It's like a great meal
or seeing a good friend.

1041
00:51:33,658 --> 00:51:36,992
PAUL:
As a citizen in our society
that wants people to be safe,

1042
00:51:36,994 --> 00:51:39,962
the best thing I can say is,
"Don't sacrifice your sleep.

1043
00:51:39,964 --> 00:51:42,598
"Protect your sleep
like you protect your food,

1044
00:51:42,600 --> 00:51:44,300
"like you protect
your resources,

1045
00:51:44,302 --> 00:51:45,668
"like you protect
your environment.

1046
00:51:45,670 --> 00:51:48,704
It may save your life."

1047
00:51:48,706 --> 00:51:53,476
♪ ♪

1048
00:52:16,934 --> 00:52:19,602
To order this program on DVD,

1049
00:52:19,604 --> 00:52:24,940
visit ShopPBS
or call 1-800-PLAY-PBS.

1050
00:52:24,942 --> 00:52:27,610
Episodes of "NOVA" are available
with Passport.

1051
00:52:27,612 --> 00:52:30,279
"NOVA" is also available
on Amazon Prime Video.

1052
00:52:30,281 --> 00:52:35,718
♪ ♪