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now there is a
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sound ah it worked a a sound that is
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desperately desperately familiar to most
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of us and of course it's the sound of
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the alarm clock and what that truly
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ghastly awful sound does is stop the
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single most important behavioral
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experience that we have and that's
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sleep if you're an average sort of
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person 36% of your life will be spent
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asleep which means that if you live to
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90 then 32 years 32 years will have been
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spent entirely asleep now what that 32
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years is telling us that sleep at some
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level is important what do we do in the
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20th century about sleep well of course
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we used Thomas Edison's light bulb to
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invade the night and we occupied the
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dark and and and in the process of this
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occupation we've treated sleep as an
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illness almost we we've treated it as an
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enemy an enemy why is it why do we
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abandon sleep in our thoughts well it's
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because you don't do anything much while
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you're asleep it seems you don't eat you
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don't drink and you don't have sex well
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most of us anyway um and so therefore
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it's sorry it it's a complete waste of
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time right wrong when you're asleep this
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thing doesn't shut down in fact some
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areas of the brain are actually more
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active during the Sleep State than
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during the Wake state so why do we sleep
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and it won't surprise any of you that of
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course the scientists we don't have a
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consensus there are dozens of different
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ideas about why we sleep and I'm going
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to outline three of those the first is
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sort of the restoration idea and it's
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somewhat intuitive essentially all the
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stuff we've burnt up during the day we
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restore we replace we rebuild during the
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night what about energy conservation
00:01:58
again perhaps intuitive um um you
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essentially sleep to save calories now
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when you do the sums though it doesn't
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really pan out but the third idea I'm
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quite attracted to which is brain
00:02:11
processing and memory consolidation what
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we know is that if after you've tried to
00:02:16
learn a task and you sleep deprive
00:02:18
individuals the ability to learn that
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task is smashed it's it's really hugely
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uh attenuated so sleep and memory
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consolidation is also very important
00:02:28
however it's not just the laying down a
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memory and recalling it what's turned
00:02:32
out to be really exciting is that our
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ability to come up with novel solutions
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to complex problems is hugely enhanced
00:02:40
by night of sleep in fact it's been
00:02:42
estimated to give us a three-fold
00:02:44
Advantage sleeping at night um enhances
00:02:46
our creativity and what seems to be
00:02:48
going on is that in the brain those
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neural connections that are important
00:02:53
those synaptic connections that are
00:02:54
important are linked and strengthened
00:02:56
while those that are less important tend
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to sort of fade away way and be less
00:03:00
important so let's now look at sleep
00:03:03
deprivation huge sectors of society are
00:03:05
sleep deprived and let's look at our
00:03:08
sleep ometer so in the 1950s good data
00:03:11
suggests that most of us were getting
00:03:13
around about 8 hours of sleep a night
00:03:16
nowadays we sleep 1 and a half to two
00:03:18
hours less every night so we're in the
00:03:20
sort of 6 and 1/ half hours every night
00:03:23
league for teenagers it's it's worse
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much worse they need 9 hours for full
00:03:29
brain per performance and many of them
00:03:31
on a school night are only getting 5
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hours of sleep it's simply not enough
00:03:35
one of the things that the brain does is
00:03:38
indulge in microsleeps this involuntary
00:03:41
falling asleep and you have essentially
00:03:43
no control over it now microsleeps can
00:03:46
be sort of somewhat embarrassing but
00:03:47
they can also be deadly it's been
00:03:50
estimated that 31% of drivers will fall
00:03:54
asleep at the wheel at least once in
00:03:56
their life and in the US the statistics
00:03:59
are pretty good 100,000 accidents on the
00:04:02
freeway have been associated with
00:04:04
tiredness loss of vigilance and falling
00:04:06
asleep 100,000 of years extraordinary at
00:04:09
another level of Terror we dip into the
00:04:13
tragic accidents at Chernobyl and indeed
00:04:15
the space shuttle Challenger which was
00:04:17
so tragically lost and in the
00:04:20
investigations that followed those
00:04:21
disasters poor judgment as a result of
00:04:24
extended shift work and loss of
00:04:26
vigilance and tiredness was attributed
00:04:28
to be a a big chunk of of those those
00:04:31
disasters
00:04:32
so when you're tired and you lack sleep
00:04:36
you have poor memory you have poor
00:04:38
creativity you have increased
00:04:40
impulsiveness and you have overall poor
00:04:43
judgment but my friends it's so much
00:04:46
worse than
00:04:48
that if you are a tired brain the brain
00:04:52
is craving things to make it up so drugs
00:04:56
stimulants caffeine represents the
00:04:59
stimulant of choice across much of the
00:05:01
Western World much of the day is fueled
00:05:03
by caffeine and if you're really naughty
00:05:05
tired brain nicotine and of course
00:05:07
you're fueling the waking state with
00:05:09
these uh stimulants and then of course
00:05:11
it gets to 11:00 at night and the Brain
00:05:12
says to itself ah well actually I need
00:05:14
to be asleep fairly shortly what do we
00:05:16
do about that when I'm feeling
00:05:18
completely wired well of course you then
00:05:20
resort to alcohol now alcohol short term
00:05:24
you know once or twice to use to mildly
00:05:26
sedate you can be very useful it can
00:05:28
actually EAS the the Sleep transition
00:05:31
but what you must be so aware of is that
00:05:34
alcohol doesn't provide sleep a
00:05:36
biological mimic for sleep it sedates
00:05:38
you so it actually harms some of those
00:05:41
neural processing that's going on during
00:05:42
memory consolidation and memory recall
00:05:45
so it's it's a short-term acute measure
00:05:47
but for goodness sake don't become
00:05:49
addicted to alcohol as a way of getting
00:05:51
to sleep every night another connection
00:05:54
between Lo loss of sleep is weight gain
00:05:57
if you sleep around about 5 hours of
00:05:59
less every night then you have a 50%
00:06:02
likelihood of being obese what's the
00:06:05
connection here well sleep loss seems to
00:06:08
give rise to the release of the hormone
00:06:10
gin the hunger hormone gin is released
00:06:13
it gets gets to the brain the brain says
00:06:15
I need carbohydrates and what it does is
00:06:18
seek out carbohydrates and particularly
00:06:20
sugars so there's our link between
00:06:22
tiredness and the metabolic
00:06:24
predisposition for weight gain stress
00:06:27
tired people are massively stressed
00:06:30
um and one of the things of stress of
00:06:32
course is loss of memory which is uh
00:06:34
what I'm sort of just then had a little
00:06:36
lapse of um and and and but stress is so
00:06:39
much more um so if you're if you're
00:06:41
acutely stressed not a great problem uh
00:06:44
but it sustains stress associated with
00:06:46
sleep loss that's the problem so
00:06:48
sustained stress leads leads to
00:06:50
suppressed immunity and so tired people
00:06:53
tend to have higher rates of overall
00:06:54
infection and there's some very good
00:06:56
studies showing that shift workers for
00:06:58
example have high rates of cancer
00:07:00
um increased levels of stress throw
00:07:02
glucose into the circulation uh glucose
00:07:05
becomes a dominant part of the
00:07:07
vasculature and essentially become
00:07:09
glucose intolerant therefore diabetes 2
00:07:13
uh stress increases cardiovascular
00:07:16
disease as a result of raising raising
00:07:18
blood pressure well how do I know
00:07:19
whether I'm getting enough sleep well
00:07:20
it's not rocket science if you need an
00:07:22
alarm clock to get you out of bed in the
00:07:24
morning um if you are taking a long time
00:07:27
to get up if you need lots of stimulants
00:07:29
if you're GR grumpy if you're irritable
00:07:31
if you're told by your work colleagues
00:07:33
that you're looking tired and irritable
00:07:35
chances are you are sleep-deprived
00:07:37
listen to them listen to yourself what
00:07:39
do you do well and this is slightly
00:07:42
offensive sleep for dummies
00:07:45
um make your bedroom a Haven for Sleep
00:07:49
the first critical thing is make it as
00:07:51
dark as you possibly can and also make
00:07:53
it slightly cool very important actually
00:07:56
reduce your amount of light exposure at
00:07:58
least half an hour before you go to bed
00:08:01
light increases levels of alertness and
00:08:02
will delay sleep what's the last thing
00:08:04
that most of us do before we go to bed
00:08:06
we stand in a massively lit bathroom um
00:08:09
with looking into the mirror cleaning
00:08:10
our teeth it's the worst thing we could
00:08:12
possibly do to to to before we went to
00:08:14
sleep turn off those mobile phones turn
00:08:16
off those computers turn off all of
00:08:18
those things that are also going to
00:08:19
excite the
00:08:20
brain try not to drink caffeine too late
00:08:23
in the day um ideally not after lunch
00:08:27
now we said about reducing light
00:08:28
exposure before you go to bed but light
00:08:31
exposure in the morning is very good at
00:08:33
setting the biological clock to the
00:08:35
light dark cycle so seek out Morning
00:08:37
Light okay that's some facts what about
00:08:39
some myths teenagers are lazy no poor
00:08:43
things they have a biological
00:08:45
predisposition to go to bed late and get
00:08:46
up late so give them a break so let me
00:08:48
just finish what I started by saying is
00:08:51
take sleep seriously our attitudes
00:08:53
towards sleep are so very different from
00:08:55
a pre-industrial age when we were almost
00:08:57
wrapped in a duvet we used to
00:08:59
understand intuitively importance of
00:09:01
sleep and this isn't some sort of
00:09:04
Crystal waving nonsense this is a
00:09:06
pragmatic response to Good Health if you
00:09:09
have good sleep it increases your
00:09:10
concentration attention decision-making
00:09:13
creativity social skills Health if you
00:09:16
get sleep it reduces your mood changes
00:09:18
your stress your levels of anger your
00:09:21
impulsivity and your tendency to drink
00:09:23
and take drugs
