Speaker 1: Welcome to Stuff to Blow Your Mind from how Stuff
Speaker 1: Works dot com. Hey, wasn't the stuffed with all your mind?
Speaker 1: My name is Robert Lamb and I'm Julie Douglas. Julie Wins.
Speaker 1: The last time you managed to score a full night
Speaker 1: of sleep last night for the first time in nights glorious,
Speaker 1: Like you wake up feeling like a new person, you do,
Speaker 1: you really wake up feeling refreshed. I was able to
Speaker 1: get a pretty good night's sleep myself last night because
Speaker 1: I slept alone on the couch, um, because the toddlers
Speaker 1: is it still has a cold and ends up sleeping
Speaker 1: in the bed, and so you get the night migration. Yeah.
Speaker 1: And then of course once the toddlers in the bed,
Speaker 1: they just kind of like turn like a like a
Speaker 1: turbine all night. Um. And then this case also coughing,
Speaker 1: So I knew I had the podcast hit the couch.
Speaker 1: Full night's sleep. Woke up so much, so much better,
Speaker 1: like actually able to to think about the topics that
Speaker 1: we were recording today and to some degree articulate those thoughts. Yeah.
Speaker 1: I'm always amazed by what the sort of powers that
Speaker 1: can bestow upon you when you have a good night's sleep,
Speaker 1: and sometimes I wake up thinking, oh I'm back. Oh
Speaker 1: yeah you hey you Julie, I know you. Yeah. It
Speaker 1: really were a different person when we've had a full
Speaker 1: night's sleep. We were we're in a since our best person.
Speaker 1: Like I think back to times where I would try
Speaker 1: to do something either um mentally intense or creatively intense,
Speaker 1: by staying up ridiculously late at night to work on it.
Speaker 1: Be it like you know, school project or you know,
Speaker 1: a bit of fiction I was trying to write. And
Speaker 1: now nowadays I I just I look back and just
Speaker 1: complete disbelief, Like why would I try and do that
Speaker 1: on the last remaining bit of energy that I had
Speaker 1: in my my noggin when I could have had a
Speaker 1: full night's sleep, woken up and tackle the fresh Because
Speaker 1: you're young and foolish. Exactly, That's just what it goes. Um.
Speaker 1: I actually was thinking about those, thinking about how we
Speaker 1: humans require so much sleep. In some ways, it feels
Speaker 1: really ridiculous, right because we're these apex predators. So far,
Speaker 1: we're we're dominating out there among other species. And then
Speaker 1: I think I wonder if tiny dust mites with their
Speaker 1: tiny sharpie scrawl things on my head while I'm sleeping
Speaker 1: at night, like I just pooped on this apex predator's
Speaker 1: head ha ha ha and laugh at us. Why does
Speaker 1: this giant being needs so much sleep? It rules the planet,
Speaker 1: and yet it decides to just shut its eyes and
Speaker 1: drift off into La la land for a large portion
Speaker 1: of its time here on Earth. Yeah, in a very
Speaker 1: vulnerable position. Right, You're immobile, You're vulnerable, and this for
Speaker 1: our ancestors would have been pretty risky business. Yeah. I mean,
Speaker 1: you get into believe we're discussed in the past, like
Speaker 1: the theories about our dreams about falling. It's a leftover
Speaker 1: from days when when falling from your your your perch
Speaker 1: of slumber in the trees would probably mean something would
Speaker 1: eat you. I love that theory. I think it's really interesting.
Speaker 1: Um so, yeah, I mean does bring up this idea
Speaker 1: that is there more to sleep than meets the eye,
Speaker 1: just then consolidating some of our memories or making us
Speaker 1: feel refreshed, as there's something going on in the background
Speaker 1: that is essential to survival. Yeah, and I mean, and
Speaker 1: clearly it's essential. We've talked before about you know, can
Speaker 1: we have a cure for sleep? Are their ways to
Speaker 1: artificially achieve what sleep does for us. And the hard
Speaker 1: answer is no, you can sort of, you can kick
Speaker 1: that can down the street a little bit, but eventually
Speaker 1: you're gonna have to go to sleep or the consences
Speaker 1: are going to grow more and more dire, leading up
Speaker 1: to hallucinations and death right. As we will discover, there
Speaker 1: is no substitute for the night janitors of the brain
Speaker 1: and what they do, and we'll talk about that in
Speaker 1: a minute, but before we get into that, let's talk
Speaker 1: about the awe inspiring an energy draining splendor that is
Speaker 1: the human brain. What sets us apart, why we need
Speaker 1: to rest so much, because if you think about it,
Speaker 1: um our brain is taking up about the energy. So
Speaker 1: if you equate that with like the world energy sources,
Speaker 1: we'd be like the brain would be like the U
Speaker 1: S and China. Yeah, just glowing there in the night.
Speaker 1: Yeah yeah, yeah. To think about the mammalian brain is
Speaker 1: specifically the human brain. I love the analogy that we've
Speaker 1: touched on in the past of the ice cream cun
Speaker 1: You have the basic brain as the scoop of gray
Speaker 1: matter up there on the cone and and for you know,
Speaker 1: most creatures, that's that's all you need. It takes care
Speaker 1: of all ther your your basic functions, but for us,
Speaker 1: humans especially, we need a little more. We need a
Speaker 1: little extra scoop on top of that. Yeah, it's true.
Speaker 1: If we trace the brains evolution from fish to amphibians, too, reptiles,
Speaker 1: to mammals and finally humans, we see that the parts
Speaker 1: of the brain that have grown the most and human
Speaker 1: beings are the neo cortex, specifically the prefrontal cortex, and
Speaker 1: mammals were given this upgrade, the second scoop, if you will,
Speaker 1: that neo cortex, so we could deal with all sorts
Speaker 1: of things parenting, mathematics, language, and humans. So it's really
Speaker 1: important to our survival. So now think about this. As
Speaker 1: reported in the journal Science, researchers who have examined preserved
Speaker 1: samples of cerebral cortex from humans and several species of
Speaker 1: a report that in particular region, in a particular region
Speaker 1: of the prefrontal cortex. Now this is the area that
Speaker 1: contributes to abstract thinking again sophisticated cognition. Neurons have more
Speaker 1: space between them in the human brain than in the
Speaker 1: brains of apes, and this extra space allows for more
Speaker 1: room for connections between neurons and Why is that important
Speaker 1: because we have about I don't know, two hundred billion
Speaker 1: nerve cells which are connected to one another via hundreds
Speaker 1: of trillions of synapsis. Yeah, and these are essentially microprocessors.
Speaker 1: We've discussed how these work out before. They're they're both
Speaker 1: memory storage and information processing elements. Uh, uh and uh
Speaker 1: and they're essential to all this complex uh thoughts, all
Speaker 1: the all these of all this computation that we're able
Speaker 1: to achieve, all the uh this this management of information
Speaker 1: across all of these different parts of the brain. Yeah,
Speaker 1: this is crazy. One synapse may contain on the order
Speaker 1: of one thousand molecular scale switches, and a single human
Speaker 1: brain has more switches than all the computers and routers
Speaker 1: and internet connections on Earth. And that's from Stephen Smith,
Speaker 1: who is a professor of molecular and cellular physiology. So
Speaker 1: what we're saying there is that that is a lot
Speaker 1: of electricity going on in the old noggin and a
Speaker 1: lot of wear and tear. So what is what happens
Speaker 1: with all of that use? Yeah? I like to think
Speaker 1: of think of this in terms of an old house
Speaker 1: that that hasn't had a lot of electrical upgrades. To it,
Speaker 1: but the individuals living inside it, their electrical needs have
Speaker 1: evolved over time. There they have more and more gadgets
Speaker 1: they need to be plugged up. They have more and
Speaker 1: more just just chunks of their entertainment system that need
Speaker 1: to plug into the wall and plug into this, that
Speaker 1: and the other, and so eventually get these overpowered uh
Speaker 1: um outlets where with all these power strips aga into
Speaker 1: power strips. Uh And because that's essentially one of the
Speaker 1: things about about the evolution of the human brain, it
Speaker 1: doesn't as much takeaway old stuff is just pile on more.
Speaker 1: It's just this this ice cream cone that's uh at
Speaker 1: times seems a little toppling. Yeah, and of course you
Speaker 1: have by products from that, and we'll talk a little
Speaker 1: bit more about that, but before we do, we're gonna
Speaker 1: take a quick break, and then we'll find out about
Speaker 1: this night janitor who's coming to clean away the debris
Speaker 1: and positively even the disease. The night Genitor is coming
Speaker 1: for you. All Right, we're back, and I think we
Speaker 1: all have experienced what happens when we over tax our brains.
Speaker 1: Your little nappy poo coming on, or just absolute mental exhaustion. Yeah,
Speaker 1: you just it's harder to string your thoughts together. It's
Speaker 1: harder to uh to prepare for a podcast, much less
Speaker 1: performed one. It's harder to put up with things too.
Speaker 1: It's hard to be patient with people with toddlers, with
Speaker 1: though with whatever your circumstances are. You just feel a
Speaker 1: little more trapped in the maze rather than wandering the labyrinth.
Speaker 1: It's harder to learn new things to write, because that's
Speaker 1: what happens when you're sleeping, and you get the formation
Speaker 1: of new neuronal connections and the pruning of old ones.
Speaker 1: So we know that there is a lot of up
Speaker 1: keep going on, But what about all that mental exercise? Again,
Speaker 1: those byproducts, because if you look at the human body,
Speaker 1: the lymphatic system, you will see that when the body's
Speaker 1: muscles exert sustained energy, they create toxic byproducts in your
Speaker 1: muscle cells. And this is according to Maria Konokov reading
Speaker 1: for The New York Times, the lymphatic system serves as
Speaker 1: the body's custodian. Whenever waste is form, it sweeps it clean.
Speaker 1: The brain, however, is out of reach of this system. Yeah,
Speaker 1: we've we've we've keep adding all of the gear to
Speaker 1: the old brain. But it's shut off from from the
Speaker 1: rest of us. It's a it's it's it's not in
Speaker 1: a position for servicing by the Lympic systems. So what's
Speaker 1: going to clean it up? Who's going to clean it up?
Speaker 1: The old idea is that that the brain rid itself
Speaker 1: of metabolites and beta amyloids, these are actually associated with
Speaker 1: Alzheimer's was that it broke it down and recycled it
Speaker 1: at an individual level. But Mike ken Nindogrod, a Danish
Speaker 1: biologist who has been leading research into sleep function at
Speaker 1: the University of Rochester, didn't think that that made sense.
Speaker 1: She thought, you know, the brain is way too busy
Speaker 1: to be recycling all of its own energy. And she
Speaker 1: suspected that the brain shared the same kind of system
Speaker 1: that muscles and the lymphatic system have. Yeah, and it's
Speaker 1: it makes perfect sense, right. Why would uh, why would
Speaker 1: the brain have a different structure in place? I would
Speaker 1: have a different system entirely. It seems like you would
Speaker 1: have a system more in keeping with what the rest
Speaker 1: of the body is doing to to carry out the
Speaker 1: same task. But it was a mystery, right because you
Speaker 1: know that the brain creates these byproducts. How in the
Speaker 1: world are they ushered out? And why are they sometimes
Speaker 1: sitting in your brain and collecting um. So this system
Speaker 1: that she thought about is again similar to the lymphatic system,
Speaker 1: but this one is predicated on the rebro spinal fluid
Speaker 1: and what near de Guard calls the glymphatic system, and
Speaker 1: that that gly glymphatic system is a nod to the
Speaker 1: brain's cleil cells, which maintain homeostasis and protect neurons. So
Speaker 1: what did she do? What would any good scientists do?
Speaker 1: Go grab a bunch of mice and spy on them
Speaker 1: while they slept. Yeah, that's just what's what they did.
Speaker 1: They injected UM mice with fluescent tracers right into their
Speaker 1: cerebro spinal fluids and this allow them to track where
Speaker 1: the fluids are going during the course of their sleep. Yeah. Now,
Speaker 1: during the mices waking hours, the cerebro spinal fluid barely
Speaker 1: made it into the brain. But once they were asleep
Speaker 1: and the sleep was induced, of course the brain cells
Speaker 1: in in the mice shrunk and that made way for
Speaker 1: a flood of the fluid, essentially hosing down the brain
Speaker 1: of waste products. We're talking the waste products or proteins
Speaker 1: that are toxic to the brain, and so it's turns
Speaker 1: out that the brain's interstitial space, the fluid filled area
Speaker 1: between tissue cells that take up about the brain's total volume,
Speaker 1: is mainly dedicated to physically removing the cells daily waste.
Speaker 1: So it's essentially a flood moving through just washing out
Speaker 1: all the toxins. It's it's it's like the brain is
Speaker 1: a is an office with drains on the floor, and
Speaker 1: when everyone goes home in the evening, they just come
Speaker 1: in with a fire hose and just start just just
Speaker 1: just hose it completely down. It's true. Have you ever
Speaker 1: seen the bathrooms that have like a shower and in
Speaker 1: the toilet in the same area with as you say,
Speaker 1: the drains. It's just a perfect way to kind of
Speaker 1: get rid of all of the waste at the same time. Um. So,
Speaker 1: I mean it's kind of a big deal because it
Speaker 1: gives us a better idea of why humans require so
Speaker 1: much sleep. Okay, it's not just refreshing or memory consolidation,
Speaker 1: the removal of actual toxins from your brain, right, And
Speaker 1: it's also a window into better understanding brain related diseases
Speaker 1: like Alzheimer's because what they've seen at Alzheimer's pay stance
Speaker 1: is that there is a build up of that beta
Speaker 1: amyloid protein in the brains. So is the question, you know,
Speaker 1: Morshley equals less brain disease. Possibly we don't know this yet,
Speaker 1: but it is a It really is a big window
Speaker 1: into this mystery of how the brain rids itself of
Speaker 1: these toxic um byproducts. And again why sleep is so
Speaker 1: incredibly important to our existence? Yeah, and and and again
Speaker 1: I feel like, um, something we can both attest to
Speaker 1: is the the arrival of a child in one's life
Speaker 1: really drives that home for you, especially when you have
Speaker 1: to to make that choice between should I say that
Speaker 1: the kid is asleep, should I go to sleep too,
Speaker 1: or should I try and stay up and carve a
Speaker 1: little me time out of the remainder of the night.
Speaker 1: I would find myself early on trying to do that, thinking, oh,
Speaker 1: I'll just go to bed at you know, an hour
Speaker 1: later and have that hour. But then you cut into
Speaker 1: the amount of sleep you get, any wake up the
Speaker 1: next morning when the toddler wakes up, When the child
Speaker 1: wakes up, and uh, and and you're you're behind. It's
Speaker 1: hard to catch up again. And then you find yourself,
Speaker 1: just less able to process the world around you, less
Speaker 1: able to to to tolerate even the little things to
Speaker 1: annoy you. It's uh, it's definitely been. One of the
Speaker 1: big lessons of getting older is that sleep is magnificent
Speaker 1: and mandatory and and it's so frustrating that the children
Speaker 1: don't don't understand that and don't want to sleep. They like,
Speaker 1: they don't want to do it. It's the greatest thing
Speaker 1: in the world. It's it's the best part of being human.
Speaker 1: And you can pretty much do it all you want.
Speaker 1: You can really sleep as much as you want when
Speaker 1: you're when you're very young, and they inevitably don't want
Speaker 1: to do it. It's the truth, because you know, babies,
Speaker 1: toddlers with their clock in twelve hours or something, they
Speaker 1: don't even think about it. They just pass out. And
Speaker 1: then when you're a teenager, no big deal again, twenties,
Speaker 1: a night of rockest drinking, you can still bound out
Speaker 1: of bed, but at some point your body is going
Speaker 1: to be like, I'm adjusting your sleep clock. Everything from
Speaker 1: here on out matters. Yeah, I'm taking every second time
Speaker 1: is ticking. So again we we we have to be
Speaker 1: thankful for the night janitors. And I do love that
Speaker 1: image of the night janitors moving in because it sounds
Speaker 1: just a little creepy, these strange figures that that move
Speaker 1: in through your brain while you're asleep, and they're they're
Speaker 1: brushing away all the toxins, and it's it's a pretty
Speaker 1: thankless job, right, And we take it for granted, right
Speaker 1: because we think we just wake up at eight am
Speaker 1: and the building is just happened to be cleaned overnight.
Speaker 1: We don't know how it happened. We feel all fresh,
Speaker 1: but yeah, they've been toiling away flushing out the toxins.
Speaker 1: All right, So there you have it now. Sleep is
Speaker 1: something that all of us do. So I know all
Speaker 1: of our listeners out there have some little bit of
Speaker 1: personal information to share about this this uh this idea
Speaker 1: of the night janitors moving through our brains, clearing things out,
Speaker 1: taking the toxins away, and indeed the mandatory nature of sleep. Uh.
Speaker 1: So feel free to share your stories with us. What
Speaker 1: has happened when you have tried to avoid sleep, or
Speaker 1: worse yet, U you've found yourself in a vision where
Speaker 1: you cannot get the sweep that your body needs. Yeah.
Speaker 1: I read recently that Americans are getting an hour less
Speaker 1: of sleep a night than they did something like two
Speaker 1: decades ago, So there's definitely some sleep deprivation going on.
Speaker 1: So you want to reach out to us, you want
Speaker 1: to get in touch, well, you can find us at
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