After reading “The Sleep Revolution,”
which is all about the importance of a good night’s sleep… I found it really hard to… fall asleep. Before that I didn’t have much difficulty
with it, but after being bombarded with endless statistics and research results illustrating
the detriments of inadequate sleep, I became very anxious about how long I was lying awake
in my bed. “What? …What the hell?” When we’re trying to get more out of life,
sleep is usually the first thing that gets cut to make room in our schedules. Ironically, it can be hard to realize that
by cutting back on sleep, we are decreasing productivity, creativity, concentration, patience,
communication skills and a lot of what makes a good… human. That’s because less sleep results in a less
effective brain and less healthy body. Pretty much whatever you’re doing, you end
up doing it worse. Of course there are some cases where you have
no choice but to stay up late or wake up early. But I’d like to spend this video looking
over why sleep is so important. By getting a new perspective on sleep, hopefully
you’ll enjoy getting more of it rather than just feeling like you’re wasting 8 hours
of your life. First, let’s take a look at what happens
to your mind when you’re not completing the process of sleep properly. ★. In 1999, two professors at Loughborough
University wanted to test how sleep affects the brain’s ability to react to changing
conditions. They developed a computer game set in the
business world, and MBA students had to promote sales of a virtual product. Then, halfway through the game, the dynamics
of the virtual marketplace suddenly changed. Now strategies that used to work resulted
in terrible sales. Only students who could quickly change and
adapt could survive. Students were split into two groups, one with
restricted sleep and another where they could sleep as much as they liked. Most of the students who slept well quickly
adapted to the changes and maintained their sales. On the other hand, the sleep-deprived students
were unable to modify their strategy appropriately and very quickly became bankrupt. The conclusion was that without sleep, their
brains lost the ability to consider alternative solutions to problems. Brain scans have shown that when you’re
lacking sleep, the neurons firing in the prefrontal cortex begin to slow down. The prefrontal cortex is particularly important
for the behaviors that make us… human. This region is associated with planning, personality
expression, decision making, attention control, reasoning, and problem solving. When you lack sleep, it’s harder for us
to complete a thought or see a problem in a new way. In a talk on the role of sleep in learning
and creativity, Robert Stickgold discusses an experiment where subjects were supposed
to come up with a string of numbers based on a different set of numbers they were provided
with. The instructions were complicated, but after
several trials everyone got the hang of it and could slowly but consistently solve the
number puzzle. However, there was a trick to make the process
much faster. The last three numbers in the sequence always
ended up being a mirror image of the 3 numbers before it. They wanted to see how long it would take
people to pick up on the trick. So, after everyone got a hang of the instructions,
they had them wait 12 hours and then try it again. But, they were split into three groups: those
who learned how to do the puzzle in the morning and got tested at night, those who learned
how to do it at night and then stayed awake all night before trying in the morning, and
those who tried in the morning but had gotten a good night’s rest. The first two groups showed about the same
chance of discovering the trick in the puzzle. But with the 3rd group, and again the only
difference is that they got to sleep, they were 2.5 times more likely to gain the insight
into the puzzle and catch the trick. “So you can gain these insights when you
didn’t even know there was an insight to find, just by sleeping on it. ” Two big things on the sleep to-do list that
allow for such insights are memory consolidation and information processing. While asleep, your brain looks at the information
you picked up throughout the day, prunes out the useless junk and keeps the things worth
remembering. Of the four stages of sleep, slow wave sleep
and rapid eye movement have been shown to move electrical impulses between the brain
stem, hippocampus, thalamus and cortex. These four areas serve as relay stations for
memory formation. During this process, your brain takes the
information in the short term memory and moves the important bits to long term memory. In this World Science Festival program, Neurobiology
professor Matthew Wilson describes an experiment designed to gain insight into this information
processing step. They analyzed the brain activity of rats while
they were making their way through a maze, and then compared that to their brain activity
while sleeping. What they saw was that as the rat went into
non-REM deep sleep, its brain was lighting up as if it was actually back in the maze…
except it was replaying the information about 10 times faster than normal, and it was playing
the events backwards and forwards and skipping around. The idea is that during this non-REM deep
sleep phase, your brain is quickly reviewing the information you’ve gained throughout
the day and taking notes. It’s kind of like flipping around in your
textbook before you take the test the next day. REM sleep however is played out at normal
speed. This is why your dreams, however ridiculous,
will follow some sequence of events. While you dream, your brain is seeing how
unrelated pieces of information fit together and simulating scenarios you might need to
be prepared for. What if my boss turns into the monster from
Pan’s Labyrinth, what would I do!? Because your brain is playing around with
information like this, some of our most creative insights can come to us in the form of dreams. August Kekulé in 1865 came up with the structure
of the Benzene molecule in a dream. Elias Howe owes the invention of the sewing
machine to a dream. Paul McCartney came up with the melody for
Yesterday in a dream, and there’s all kinds of examples like this. So insufficient sleep interferes with creativity
and memory, but it can also interfere with your personality and competence in general. As mentioned earlier, the more “human”
part of your brain, the prefrontal cortex shows less activity when you’re sleep deprived. The Amygdala on the other hand, shows more
activity. The amygdala is associated with processing
emotional information and, as this study has found, “a lack of sleep inappropriately
modulates the human emotional brain response to negative aversive stimuli.” Essentially, the less sleep you get, the more
likely you are to interpret situations negatively, overreact to things and be more moody in general. This can manifest itself as more fights with
your spouse as illustrated by this article, or much more drastic behavior. In 2009, a band of American soldiers from
the 172nd infantry found themselves in court martial for murdering two men in Baghdad against
a superior’s orders. Their lawyers’ defense was that the soldiers
were too sleep deprived to make rational decisions. David Randall’s book Dreamland discusses
how in the early 80’s military studies found that sleep deprived air force pilots “changed
their vocal patterns, no longer enunciating or speaking loudly enough [to be understood]”
by their co pilots. Maybe that didn’t bother the military that
much because in 1996 ”…crew fatigue was blamed for thirty-two accidents that destroyed
American military aircraft, including three F-14 jetfighters that cost $38 million each.” The military has spent millions of dollars
testing all kinds of methods to keep soldiers awake longer, but in 2007 they concluded that
the only way to recover from lost sleep was to …sleep. Now some of you may say “I’m operating
just fine on my 6 hours of sleep a night, thank you very much” And you could be one
of the 5% of the population with the genetic mutation that lets you get by on only 6 hours
of sleep. But as we discussed earlier, activity in the
prefrontal cortex lessens when you lack sleep. And The prefrontal cortex is the only part
of the brain that has the power of self-assessment, to think about how it is thinking. So if you’re not getting enough sleep, would
your prefrontal cortex properly recognize that it’s working at sub-optimal capacity? It’s not only your brain that needs sleep,
also on the sleep to do list is tissue repair, maintenance of metabolic pathways and the
balancing of hormones. Sleep is also very important for your body. A study at the University of Chicago put participants
on a calorie restricted diet and then randomly assigned them to sleep 5.5 hours or 8.5 hours
each night. Those who slept only 5.5 hours lost 55% less
body fat. Again, they were on the same diets. The sleep deprived group did lose weight,
but they were losing more muscle. They lost 60% more fat-free mass compared
to those who slept well. They also reported feeling hungrier. An important factor in this was that the sleep
deprived group were shown to have much higher ghrelin levels. Ghrelin is a hormone that causes you to retain
fat and feel more hungry. It has been shown that just one night of poor
sleep leads to a 15% increase in this “hunger hormone.” Now ghrelin isn’t the only hormone is disrupted. Lack of sleep also means lowered levels of
the satiety hormone leptin, and less melatonin. Melatonin has some very powerful anti-aging
and anti-cancer properties, and as the Journal of pineal research found, melatonin increases
weight loss by increasing brown adipose tissue. Brown adipose tissue or BAT Fat actually acts
a lot like muscle in that it increases your metabolic rate and burns white adipose tissue. Inadequate sleep also increases Cortisol,
which has been shown to increase the worst type of fat -visceral fat, the stuff that
surrounds your organs. Cortisol also encourages your body to break
down muscle for fuel through a process called gluconeogenesis. So whether you are trying to make some “gains”
or just want to lose a bit of fat, your time in the gym needs to be complemented with proper
sleep. One more key hormone secreted during sleep
is Human Growth Factor (HGH), otherwise known as “the youth hormone”. As the name suggests, it stimulates growth,
cell reproduction and cell regeneration, which means increased muscle, more fat loss, and
other things like improved skin elasticity. Human growth hormone even plays a role in
improving cognitive function and a deficiency in it has been linked with depression. It’s important to get enough sleep, but
also to get it at the right time. While it depends on each individual’s circadian
rhythm, in general 10PM to 2AM is when your body secretes the most growth hormone (that
is- IF you’re asleep at that time). The other thing on the sleep to do list is
waste cleanup. Throughout the course of the day, the brain
produces a decent amount of waste. The brain handles this waste cleanup task
during sleep via something called the glymphatic system in which brain cells shrink to allow
for cerebrospinal fluid to flood into the brain and flush out the waste. One thing that needs to be flushed out is
the compound adenosine. Adenosine is a byproduct of your neurons and
other cells when they burn up adenosine triphosphate, the main molecule that our bodies use to store
energy. As adenosine builds up, you start to slow
down and accumulate a “sleep pressure”. When your adenosine levels reach a certain
point, your body sends you signals to go to sleep. Caffeine works by bonding to the same receptors
as adenosine, tricking the body into thinking it’s not tired. While caffeine will wake you up, it will interfere
with your sleep cycle if taken too late in the day. Cristopher Drake, associate professor of behavioral
neurosciences at Wayne State University School of Medicine led a study that found that taking
caffeine even 6 hours before bed can lead to a measureable objective loss of 1 hour
of sleep. What this means is that it may seem like you
got say 7 hours of sleep after having a coffee mid day, but a sleep monitor would show that
you’re not properly dipping into the normal ranges of REM and deep sleep, leading to an
actual sleep total of 6 hours. For this reason it’s recommended to finish
your caffeine at least 8 or more hours before bedtime. Like adenosine, Amyloid beta is another waste
product that is created in the brain. Unfortunately, excess amyloid beta is toxic
to the brain and Amyloid plaques have been thoroughly linked to Alzheimer’s disease. It’s understood that Alzheimer’s patients
don’t create more amyloid beta than other people, but they simply were not clearing
it out enough. Of course other lifestyle factors like diet
play a role here, but sleep could be particularly critical for avoiding neurodegenerative disease. Artificial intelligence, robots, and all kinds
of automation are already replacing jobs nowadays and the technology is only expected to get
better and better. Machine intelligence may be the last invention
humanity will ever need to make, but at least until that point we need to set ourselves
up access our creative insights and take advantage of the more human faculties of our brains. As Daniel Pink says in A Whole New Mind, it’s
the “creative and emphatic ‘right-brain’ oriented thinkers whose abilities mark the
fault line between who gets ahead and who doesn’t.” Without enough sleep, our bodies as well as
these creative, insightful and emotionally adept human faculties of our brains suffer. Now, I’m sure you’re thinking “OK, so we should
get more quality sleep, but how?” this is what I’ll be talking about next week so make
sure to stick around for sleep part 2.

100 thoughts on “WHY Sleep is critical for the Body and Brain | Science of Sleep”

  1. Dwayne the rock Johnson
    And mark Walberg must be lowley monsters

    In this case they not really human they sleep like 4-5hrs per day

  2. We need to sleep because our brain can't store more information than one day. Meaning that after you've slept the brain has stored only valuable information from the previous day, arranged it in the storage and is ready for the next. You can see this if you skip sleeping one night. You will not manage to process information quickly enough the next day.

    We are all a part of a Matrix

  3. I can barely sleep in this neighborhood I moved into a year or so ago and it’s making me sick and irritable. I started this video at 2am and closed it immediately to sleep then finished it in the morning

  4. I honestly can't sleep for longer than ~5-6 hours. If I fall asleep around 10pm, I'll wake up at around 4 am or sometimes 3am.

  5. Sleep is important huh? Well, I guess I need to tell that to my 6th grade self who had to catch the bus at 6:30 am for school. Same with highschool, except in highschool it was common for me to do homework until midnight. Then in college, 4-6 hours was the norm, with frequent all-nighters. And I wonder why I get sick so easily and have an absolutely shitty memory that's getting worse. I'm 22 and I feel like I have dementia.

  6. It's fine to listen to you talk about it but I am a chronic insomniac and I don't get any sleep maybe a half hour a night because of chronic pain. My brain is fried. And I won't take Ambien to do it

  7. What if you sleep for 10-14 hours?? I'm pregnant and we get tired more easily and that has made me sleep more. Also if I get nauseous or a headache I like to sleep and make them go away that way. When I wake up I feel like I wake up with a headache and not sure if it's because I sleep more or if it's the hormones that are causing it.

  8. Sometimes, similar to the rat test, I'll have these weird half-conscious dreams where a certain piece of information will replay over and over in my mind. It's like I'm able to visualize my brain looking for a solution to a specific problem or my brain improving on something that's been learned. But it drives me crazy when this happens because I'm basically seeing the same thing over and over for what feels like an eternity before I finally wake up

  9. The percentage of people who can get by on only 6 hours of sleep a night is much lower than 5% (the number stated in the video). In Matthew Walker's book "Why We Sleep", he says "The number of people who can survive on 6 hours of sleep or less without showing any impairment rounded to a whole number and expressed as a percent of the population is 0". In fact, you are more likely to develop schizophrenia (which is also linked to sleep deprivation) than to be one of the people who can legitimately get by on only 6 hours of sleep. Don't kid yourself.

  10. Watching this at 5:39am….. I haven't slept yet and I was about to when I saw this……. and when I sleep now,I will certainly wake up at 5:00pm or earlier because my mom might wake me up 😂😂

  11. Question
    I sleep 6-6:30 hours a day and I always feel refreshed and easier to think
    But when I sleep 7:30 or more I feel sleepy
    The brain is slog-ish, hard to think straight and it feel likes the blood is clogged in the brain
    Someone explains please

  12. Wait, sleep is important? Holy hell I had no idea, here i am on my 8th day binge of adderall thinking i could stay awake for a few decades. Groundbreaking information

  13. I have noticed this effect with video games.often I will be unable to beat a certain boss/scenario even after many tries, but often I will pass it on the first try when I try again on a different day (after having slept)

  14. I only had 6 hours of sleep last night and I fell asleep during the church sermon and had a hard time staying awake during the times I wasn't sleeping.

  15. I forgot ab’t Matrix computer messages on sleep deprivation. Forgot Anderson lived in Rm 101 (binary). Orwell’s 1984 was written in 1948. WWII computers ran on transistors & punch cards. Imagine torture of transistor upkeep & coding? Rm 101. 1984 “inspired” by E German Stalinist KGB & Stasi secret police hell in the monstrously named German Democratic Republic. Where Col. Putin was assigned. The movie Atomic Blonde had a character named Merkel & KGB Putin like character.

  16. 10:33 Gluconeogensis is mainly dietary protein, not so much muscle tissue. The body won't touch muscle if dietary protein is adequate. Higher stress hormones might impact this, but not much. Maintaining muscle mass is a high priority for survival. So much so that even short periods of fasting elevates human growth hormone (so it's muscle sparing).

  17. if less sleep meant less human
    then Leonardo da vinci and nikola tesla and Winston Churchill, etc.. would have been turned to monkeys.

  18. "prunes out the useless junk and keeps the things worth remembering" Not my brain. I remember mostly useless information.

  19. For me I can only sleep 5-6 hours max. Not that I don't want sleep but I just wake up once I get those hours. I want to sleep 8 hours or so but my body just wakes itself up lol am I weird? xD

  20. So basically, if someone is very, very sleep deprived, they likely won't be able to help themselves because they can't assess that they are sleep deprived themselves and likely wouldn't be able to retain this information.

  21. Can you do a video how weed affects the prefrontal cortex? It can actually cause people a lot of issues, and it also affects sleep by shortening the REM cycle

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