QI | Why Do We Sleep?

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michael Longford : Sleep was invented to cure being knackered.

Timothy McLean : Why do we sleep? Because we get sleepy. Why do we get sleepy? ...We're working on that.

Patrick Headland : David's wearing his special travel dressing gown!!

Stevie Cole : This is a perfect video for someone perusing YouTube at ungodly hours of the morning

Jacob Seager : Awww Alan got that fact at the start from a previous episode from Stephen

bookashkin : From immortal Bill Hicks: I need my sleep. I need about 8 hours a day... And 10 at night, and then I am good.

Victor Dalloz : To anyone interested in the topic, I highly recommend the book "Why we sleep" by Matthew Walker (former Harvard professor, currently at UC Berkley). It's really a fascinating read.

Rosalie : I'm a simple girl, I see Noel, I click

Arctic IceFox : The description still says Stephen Fry lol

r0bw00d : Oh no, I need my alarm clock. I went an entire summer vacation without using one and wound up staying up later and sleeping later until I was keeping vampiric hours. Then I spent a week using my alarm clock to get myself back on schedule in time for school.

New Message : Sleep is a conspiracy to disable the population for 7 - 9 hours a day, perpetrated by the De-Illuminati.

Widdekuu91 : A better question; Why aren't I sleeping? The answer; This video, I'm watching it.

numbereightyseven : When you can't figure out what to do, it's time for a nap.

Zake Budek : ...perchance to dream - ay, there's the rub, for in this sleep what dreams may come...

Hubert Cumberdale : Noel's starting to look like a tired old woman.

angelstouch92 : A study I read recently showed that during the day things build up in the brain that essentially intoxicates you and sleeping helps clear it away. It's why if you don't sleep you show signs like being drunk.

MeFirst please : I kinda didn’t want this to end

Ben Blackburne : I’ve always imagined that it might have been a way for our ancestors to get through the night, as it was so dark they couldn’t get much done so sleep would essentially they could sleep and then wake up when it’s morning. I’m not saying that this is the reason for sleep as it’s obviously not the main reason, but I’ve always been fascinated as to how sleep seems to be a time machine to the morning time. You can’t feel yourself sleeping, you just sort of wake up and it feels instant to when you went to sleep but really 8 or 9 hours may have passed. I’ve just always found that quite cool

MrWombatty : The weirdest dreams are 'wanting-to-wee' dreams, especially those where I'm searching for a toilet but can't find one anywhere!

Combicon : Was honestly expecting this to be a 'Nobody Knows' answer.

schplengie1 : I've always heard your cells are completely different every 7 years, not 10.

M Standenberg : Can’t even answer the question “does our consciousness continuity break during sleep, in which case, do we effectively die and our bodies generate a new ego as we wake?”

Rosie Clarke : I have dyspraxia which can mess with sleep cycles, so often no matter when I go to bed I wont be asleep until after 3am, sometimes I've even stayed up til 6am (and no I'm not just on my phone) Left on my own during holidays I'll sleep til 10/11 am but idk if that's just because I'm so exhausted from school, as I have to get up at 6:45 to get there on time despite not being able to sleep until past 3 :/ I need to work a night shift I think lmao

The Winspear : 2:34 My brain can't be cleaned because I'm dirty minded.

Fiki Firmansyah : To anyone who interested in this topic, i highly recommend the book "The Republic" by Plato. Its really a fascinating read.

Doctor Witten : The answer's a bit misleading. There's a rather popular book published recently by neuroscientist Matthew Walker, that's literally called Why We Sleep. It talks about how studies have indicated sleep's important role in improving mental functions like learning and memory; maintaining the health of your immune system ; and even helping reduce/prevent serious illnesses like dementia and cancer.

Jethro Watts : I need about 5 hrs and then 10 min awake followed by another 3 hrs

Madam Satan : Why do we sleep? To avoid people

Michael Farrell : I tried the no alarm clock thing and apparently I need 14 hours of sleep a day...

Get the Joke! : My dentist said to me, that my gum has to come out.

Lena Oxton : Your brain cells don't grow back either, and that's both a blessing and a curse. On the downside, you have terrible degenerative neural disorders you can never recover from, but on the upside, you won't have to go every two years for a new skull fitting for that big growing brain of yours!

cloudsRniceC0M3 : Havent slept in month I can see smells Feel colours Touch sound

Veronica Bean : I've had my gums trimmed...

youcometome9 : Why do we sleep ? Cuz U don't got to be WOKE all the time !

WuXiit : Wasn't this a question back when Stephen Fry was hosting? I seem to remember brain cleaning being the answer then.

FutureChaosTV : "gum dresser" ;-)

Alagass : Boosh

Neil Bevan : Why do we sleep? It's the only legitimate excuse a person has to mentally get away from their partner.

sed8me69 : Regenerating, Hence we all wake up with that taste that's like fish fingers and custard 🤣

Yj k : We evolved the ability to sleep as an easy excuse to get out of work

Harry Turner : I hate holly Walsh I’m so sorry 😭😭😭😭😭😭😭 🙃😪🙃🙃😪😪😪🙃

nriab23 : That blond woman on the panal just isn't funny, I don't believe her jokes are supposed to funny rather her presentation of them, but even at that. I don't find either funny

Chriscom28 : I had almost the exact same sleep analogy. Sleep is when our bodies undergo maintenance and repair and is best done while the body is less active.

Ras Putin : When we were a kid we don't like to sleep, now that we're adult we want to sleep all day!

tomdid1 : They now know that sleep cleans the brain. All the little proteins and crap get flushed away.

Jhully Amilly : it has been a long while since I related to a video this much

Yolo Swaggins : Your brain doesn't renew every 10 years

Kendal Smith : The thing is though without an alarm I can sleep for 24hs, that’s not good job wise 😩😫

Audun Paudun : We probably sleep to avoid predators at night. Our ancestors were probably the ones smart enough to stay hidden during night time, when predators where out hunting.

ih8mcfly : You sleep so you can recover and grow