this episode is sponsored by kiwiko
dear school today i want to talk about
something that on the surface may seem
trivial but it's actually a huge deal
and that is school start times because
when i tell you that you might not only
be severely impacting your students
mental capacity and intelligence both in
the moment and the future but also
impacting their physical and mental
health i'm not exaggerating let me put
it bluntly school needs to start later
at least for high school and university
age students and i don't mean later as
in later in the year i mean later as in
not so freaking early in the morning
but to understand why we first have to
understand sleep before a baby is even
born and up to around the first year of
its life infants spend much of their
time in rem sleep otherwise known as
rapid eye movement this is a stage we
dream in and it's during this rem sleep
that babies are building up huge amounts
of neural networks and connections in
their brain but soon after this time
period there's a sharp decline in rem
sleep and an exponential rise in deep
non-rem sleep that continues to rise
until around puberty and this non-rem
sleep is actually responsible for
fine-tuning our brains instead of
building up more and more neurons and
connections it actually prunes and makes
the brain more efficient and effective
it's basically taking the mold that
early life created and sculpting it
based on your life experiences and
interactions and studies have shown that
this non-rem sleep is linked to the
development of critical thinking
reasoning and cognitive skills now some
of you might be screaming reasoning
skills critical thinking in genes and
you'd be right in noticing that teens
aren't exactly known for these things
but ironically the development of the
brain during this non-rem increase
happens from back to front literally the
back of the brain which manages visual
and spatial perception develops first
and this growth eventually makes its way
to the front of the brain or the frontal
lobe last which finally enables critical
and rational thought this is why it
sometimes feels that kids brains aren't
exactly working or keeping up with the
rest of their development the thing is
when non-rem is minimized or removed
things can go really wrong in studies of
mice and cats deprived of sleep the
brain development is stopped in fact
many psychiatric disorders like
schizophrenia bipolar and major
depression are considered disorders of
abnormal development studies on
schizophrenia in particular have shown
that there is a two to threefold
reduction in non-rem sleep in teenagers
that suffer from it to top it all off
teens actually need more sleep than
their adult counterparts so if they're
not getting enough hours of sleep then
they aren't going to be getting the
optimal amount of non-rem sleep which
can hamper development now i know what
you're asking how does this correlate to
the time that school starts can't teens
just go to bed early like the rest of us
and get a long enough sleep and if not
what time should school be starting at
before we get to that answer i want to
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asap for your first month free now back
to some sleepy science so why does the
specific time matter so much isn't it
more relevant how much sleep kids are
getting yes and no the first thing you
need to know is that as kids move into
puberty their circadian rhythm
completely shifts our circadian rhythm
is the name given to our internal clock
that controls your body's sleep wake
cycle in other words it helps define
when you feel tired and want to sleep
versus when you feel at your most alert
this rhythm is of course different for
everyone we all have our unique
chronotype which is why some people are
considered early birds and others are
night owls but in general adults share a
propensity to wake and sleep at roughly
the same time the thing is one of the
biggest factors defining our circadian
rhythm is our age young kids before
puberty not only need the most sleep but
tend to have a really early schedule
they become sleepy early in the evening
and wake up earlier than adults
typically but as we hit puberty the
timing is shifted forward past even
their parents by as much as two to four
hours meaning we want to stay up much
later and this change is seen across all
adolescents regardless of culture or
geography where a nine-year-old will
typically fall asleep around 9pm by the
age of 16 that's actually often the hour
of peak wakefulness asking a teenager to
go to bed at 10 pm is like asking an
adult to go to sleep at 7 00 p.m in the
same vein waking up at 7 00 am for a
teen is the same as waking up around 4
a.m for an adult and i'm pretty sure all
of us don't want to be seen at 4am let
alone have to use our brains at 4 am a
lot of parents believe that teens are
making a conscious decision to stay up
later and that if they just went to bed
earlier they wouldn't be so tired but
the truth is even if they do go to bed
earlier chances are they'll just be
lying in bed awake until their body
naturally winds down but not embracing
this biological timing on top of the
fact that teens need more sleep to begin
with risks developmental brain
abnormalities and mental illness and we
have experimental evidence to show it
later start times increase class
attendance reduce behavioral and
psychological problems and decreased
substance and alcohol abuse longer sleep
is directly correlated to better grades
in teens across the board and higher iqs
and studies on identical twins show that
by the age of 10 the twin with the
longer sleep pattern has superior
intellectual abilities with more
expansive vocabulary too and schools
that have tested later start times have
seen a huge shift a school in minnesota
that changed from a 7 25 a.m start to 8
30 a.m found that verbal sat scores rose
by over 150
while math sat scores went up by over
50. and while we talked about the
importance of non-rem quality sleep in
young adults that's not to say rem sleep
isn't also really important studies in
the 1960s that deprived young adults of
rem found that by the third day of
extreme deprivation participants started
to exhibit signs of psychosis they were
anxious moody and started to hallucinate
and became paranoid rem also becomes
longer and more prominent in the later
parts of your sleep meaning if you cut
your sleep short you're
disproportionately impacting the amount
of rem you're getting life expectancy
has also been shown to increase with
later start times so the number one
cause of death in teens is road traffic
accidents which have been linked
directly to sleep deprivation when one
county in wyoming changed their start
time from 7 25 am to 8 55 am they saw a
70 decrease in traffic accidents in the
affected age group so why do circadian
rhythms stray so far in adolescence the
prevailing socio-evolutionary theory
right now is that it allows teens and
young adults to start gaining their
independence from their parents but in
small increments for several hours a day
kids can operate on their own or with
their peer group away from adults but
it's not a full removal from parental
supervision during this stage they get
to practice becoming their own
individual the truth is only a century
ago in america most schools started
around 9 00 am and 95 percent of
students woke up without an alarm now in
the us 80 of schools begin before 8 15
a.m and 50 of those start before 7 20
a.m not to mention the increasing impact
of tvs computers and phones in the
bedroom it's no wonder kids are more
tired than ever at the end of the day
the evidence is overwhelming that later
start times around 9am or so are not
only preferred by students but lead to
improvements in basically every single
metric we're measuring their progress by
in school in the words of dr walker who
wrote the book why we sleep which was
the primary source for this episode
we're too often focused on what sleep is
taking away from our teenagers without
stopping to think about what it may be
adding i hope we can change i hope we
can break the parent-to-child
transmission of sleep neglect and remove
what the exhausted fatigue brains of our
youth are so painfully starved of when
sleep is abundant minds flourish when
it's deficient they don't i hope this
video has been informative and useful
especially if you are a parent or a
teacher or someone who manages a school
and if you're a student send this to
your teachers right now send this to
your administrators and let them know
it's not a joke sleep is a huge part of
our lives and so important for our
intellectual capacities and our physical
health and they would do well to think
about that when they start your school
thanks again for watching make sure you
like the video subscribe if you want
more and we'll see you next time for
some more science peace