bastardTED英语演讲稿：我们为什么要睡觉

2021年1月21日发(作者：blend)

TED
英语演讲稿：我们为什么要睡觉



简 介：一生中，我们有三分之一的时间都在睡眠中度过。关于睡
眠，
你又了解多少
?睡眠专家
Russell Foster
为我们解答为什么要睡觉，
以及睡眠对健康的影响。



What I'd like to do today is talk about one of my favorite subjects,
and that is the neuroscience of sleep.


Now, there is a sound -- (Alarm clock) -- aah, it worked -- a sound
that is desperately, desperately familiar to most of us, and of course it's
the sound of the alarm clock. And what that truly ghastly, awful sound
does
is
stop
the
single
most
important
behavioral
experience
that
we
have, and that's sleep. If you're an average sort of person, 36 percent of
your life will be spent asleep, which means that if you live to 90, then 32
years will have been spent entirely asleep.


Now
what
that 32
years
is
telling
us
is
that
sleep
at
some
level
is
important. And yet, for most of us, we don't give sleep a second thought.
We throw it away. We really just don't think about sleep. And so what I'd
like
to
do
today
is
change
your
views,
change
your
ideas
and
your
thoughts
about
sleep.
And
the
journey
that
I
want
to
take
you
on,
we
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need to start by going back in time.



Shakespeare's Julius Caesar. Yes, let me give you a few more quotes.
sleep,
O
gentle
sleep,
nature's
soft
nurse,
how
have
I
frighted
thee?
Shakespeare again, from -- I won't say it -- the Scottish play. [Correction:
Henry
IV,
Part
2]
(Laughter)
From
the
same
time:

is
the
golden
chain that ties health and our bodies together.
Thomas Dekker, another Elizabethan dramatist.


But
if
we
jump
forward
400
years,
the
tone
about
sleep
changes
somewhat. This is from Thomas Edison, from the beginning of the 20th
century.
days.
may
remember
that
Margaret
Thatcher
was
reported
to
have
said,

--
the
infamous
Gordon
Gekko
from

Street
said,

never
sleeps.


What do we do in the 20th century about sleep? Well, of course, we
use Thomas Edison's light bulb to invade the night, and we occupied the
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dark,
and
in
the
process
of
this
occupation,
we've
treated
sleep
as
an
illness, almost. We've treated it as an enemy. At most now, I suppose, we
tolerate
the
need
for
sleep,
and
at
worst
perhaps
many
of
us
think
of
sleep
as
an
illness
that
needs
some
sort
of
a
cure.
And
our
ignorance
about sleep is really quite profound.


Why
is
it?
Why
do
we
abandon
sleep
in
our
thoughts?
Well,
it's
because you don't do anything much while you're asleep, it seems. You
don't
eat.
You
don't
drink.
And
you
don't
have
sex.
Well,
most
of
us
anyway. And so therefore it's -- Sorry. It's a complete waste of time, right?
Wrong. Actually, sleep is an incredibly important part of our biology, and
neuroscientists
are
beginning
to
explain
why
it's
so
very
important.
So
let's move to the brain.


Now, here we have a brain. This is donated by a social scientist, and
they
said
they
didn't
know
what
it
was,
or
indeed
how
to
use
it,
so
--
(Laughter)
Sorry.
So
I
borrowed
it.
I
don't
think
they
noticed.
Okay.
(Laughter)


The point I'm trying to make is that when you're asleep, this thing
doesn't
shut
down.
In
fact,
some
areas
of
the
brain
are
actually
more
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active during the sleep state than during the wake state. The other thing
that's really important about sleep is that it doesn't arise from a single
structure within the brain, but is to some extent a network property, and
if we flip the brain on its back -- I love this little bit of spinal cord here --
this bit here is the hypothalamus, and right under there is a whole raft of
interesting structures, not least the biological clock. The biological clock
tells us when it's good to be up, when it's good to be asleep, and what
that structure does is interact with a whole raft of other areas within the
hypothalamus,
the
lateral
hypothalamus,
the
ventrolateral
preoptic
nuclei.
All
of
those
combine,
and
they
send
projections
down
to
the
brain
stem
here.
The
brain
stem
then
projects
forward
and
bathes
the
cortex,
this
wonderfully
wrinkly
bit
over
here,
with
neurotransmitters
that keep us awake and essentially provide us with our consciousness. So
sleep arises from a whole raft of different interactions within the brain,
and essentially, sleep is turned on and off as a result of a range of


Okay.
So
where
have
we
got
to?
We've
said
that
sleep
is
complicated and it takes 32 years of our life. But what I haven't explained
is what sleep is about. So why do we sleep? And it won't surprise any of
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you that, of course, the scientists, we don't have a consensus. There are
dozens of different ideas about why we sleep, and I'm going to outline
three of those.


The first is sort of the restoration idea, and it's somewhat intuitive.
Essentially, all the stuff we've burned up during the day, we restore, we
replace,
we
rebuild
during
the
night.
And
indeed,
as
an
explanation,
it
goes back to Aristotle, so that's, what, 2,300 years ago. It's gone in and
out
of
fashion.
It's
fashionable
at
the
moment
because
what's
been
shown is that within the brain, a whole raft of genes have been shown to
be
turned
on
only
during
sleep,
and
those
genes
are
associated
with
restoration
and
metabolic
pathways.
So
there's
good
evidence
for
the
whole restoration hypothesis.


What
about
energy
conservation?
Again,
perhaps
intuitive.
You
essentially sleep to save calories. Now, when you do the sums, though, it
doesn't
really
pan
out.
If
you
compare
an
individual
who
has
slept
at
night, or stayed awake and hasn't moved very much, the energy saving
of sleeping is about 110 calories a night. Now, that's the equivalent of a
hot dog bun. Now, I would say that a hot dog bun is kind of a meager
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return for such a complicated and demanding behavior as sleep. So I'm
less convinced by the energy conservation idea.


But the third idea I'm quite attracted to, which is brain processing
and memory consolidation. What we know is that, if after you've tried to
learn a task, and you sleep-deprive individuals, the ability to learn that
task
is
smashed.
It's
really
hugely
attenuated.
So
sleep
and
memory
consolidation
is
also
very
important.
However,
it's
not
just
the
laying
down of memory and recalling it. What's turned out to be really exciting
is that our ability to come up with novel solutions to complex problems is
hugely enhanced by a night of sleep. In fact, it's been estimated to give
us a threefold advantage. Sleeping at night enhances our creativity. And
what seems to be going on is that, in the brain, those neural connections
that
are
important,
those
synaptic
connections
that
are
important,
are
linked
and
strengthened,
while
those
that
are
less
important
tend
to
fade away and be less important.


Okay. So we've had three explanations for why we might sleep, and
I think the important thing to realize is that the details will vary, and it's
probable
we
sleep
for
multiple
different
reasons.
But
sleep
is
not
an
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indulgence. It's not some sort of thing that we can take on board rather
casually. I think that sleep was once likened to an upgrade from economy
to business class, you know, the equiavlent of. It's not even an upgrade
from
economy
to
first
class.
The
critical
thing
to
realize
is
that
if
you
don't
sleep,
you
don't
fly.
Essentially,
you
never
get
there,
and
what's
extraordinary
about
much
of
our
society
these
days
is
that
we
are
desperately sleep-deprived.


So let's now look at sleep deprivation. Huge sectors of society are
sleep-deprived, and let's look at our sleep-o- meter. So in the 1950s, good
data suggests that most of us were getting around about eight hours of
sleep a night. Nowadays, we sleep one and a half to two hours less every
night,
so
we're
in
the
six-and-a- half-hours-every-night
league.
For
teenagers,
it's
worse,
much
worse.
They
need
nine
hours
for
full
brain
performance, and many of them, on a school night, are only getting five
hours of sleep. It's simply not enough. If we think about other sectors of
society, the aged, if you are aged, then your ability to sleep in a single
block is somewhat disrupted, and many sleep, again, less than five hours
a night. Shift work. Shift work is extraordinary, perhaps 20 percent of the
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working population, and the body clock does not shift to the demands of
working at night. It's locked onto the same light-dark cycle as the rest of
us.
So
when
the
poor
old
shift
worker
is
going
home
to
try
and
sleep
during
the
day,
desperately
tired,
the
body
clock
is
saying,

up.
This is the time to be awake.
night
shift
worker
is
usually
very
poor,
again
in
that
sort
of
five-hour
region. And then, of course, tens of millions of people suffer from jet lag.
So
who
here
has
jet
lag?
Well,
my
goodness
gracious.
Well,
thank
you
very much indeed for not falling asleep, because that's what your brain is
craving.


One of the things that the brain does is indulge in micro-sleeps, this
involuntary
falling
asleep,
and
you
have
essentially
no
control
over
it.
Now, micro-sleeps can be sort of somewhat embarrassing, but they can
also
be
deadly.
It's
been
estimated
that
31
percent
of
drivers
will
fall
asleep
at
the
wheel
at
least
once
in
their
life,
and
in
the
U.S.,
the
statistics are pretty good: 100,000 accidents on the freeway have been
associated with tiredness, loss of vigilance, and falling asleep. A hundred
thousand a year. It's extraordinary. At another level of terror, we dip into
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the
tragic
accidents
at
Chernobyl
and
indeed
the
space
shuttle
Challenger,
which
was
so
tragically
lost.
And
in
the
investigations
that
followed
those
disasters,
poor
judgment
as
a
result
of
extended
shift
work and loss of vigilance and tiredness was attributed to a big chunk of
those disasters.


So when you're tired, and you lack sleep, you have poor memory,
you
have
poor
creativity,
you
have
increased
impulsiveness,
and
you
have overall poor judgment. But my friends, it's so much worse than that.


(Laughter)


If you are a tired brain, the brain is craving things to wake it up. So
drugs,
stimulants.
Caffeine
represents
the
stimulant
of
choice
across
much of the Western world. Much of the day is fueled by caffeine, and if
you're a really naughty tired brain, nicotine. And of course, you're fueling
the waking state with these stimulants, and then of course it gets to 11
o'clock at night, and the brain says to itself,
be
asleep
fairly
shortly.
What
do
we
do
about
that
when
I'm
feeling
completely
wired?
Well,
of
course,
you
then
resort
to
alcohol.
Now
alcohol, short-term, you know, once or twice, to use to mildly sedate you,
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