hours here!

Anthony here for DNews, and I have always wondered

just why exactly we have to sleep.

Do you know how much I can do if I

never got tired. Scientists wonder about it too.

Every animal participates in

some form of sleep, even though it puts us

all in an incredibly vulnerable state;

Anything can get you, seems wasteful.

So, it must perform some

function that is so important it is worth the

trade-off of being killed by a predator

who is on a slightly different work schedule.

There are a few theories. One is that it

gives us more time to repair our muscles

and cells. One is that it lowers the amount of

energy we need and less energy means less

meals, means less hunting and gathering, which we can't

really do in the dark anyway. One of

the recent and most popular theories

has to do with memory

consolidation. when we sleep, our

brain takes everything we have seen and done

throughout the day and filters through it. Looks

for patterns, sifts through what it finds an essential

and decides what to turn into a memory.

And some experts think that dreams

are a sort of representation of that;

It's like a nightly clean up. We've seen

evidence of it. Studies show that if you get

sleep right after practicing something that takes

fine motor skills, like typing or

playing an instrument, it helps you retain that

knowledge faster. Missing a night of sleep

can mess with attention, awareness

reasoning, problem solving skills. But

the super weird thing is that even

without sleep body repair

happens. So where is the big benefit?

Researchers from the University of Rochester

think they found it. Turns out sleep

isn't just a mental house cleaning for your brain,

it's a physical one. Your body

has got a great system for flushing

all the unneeded stuff out that piles up;

It's called the Lymphatic System. But the Lymphatic

system does not extend to your brain.

And your think box keeps itself

locked up behind something called the Blood Brain

Barrier, which tightly regulates everything

that comes in and out. Your brain controls everything

so it keeps itself in a high security

area where it can't be contaminated.

But it has to get rid of its waste products

somehow, but we have never actually been able to

see how. But using new technology

called Two Photon Microscopy,

the Rochester researchers were able to see the

brain's disposal system. They're calling it

The Glymphatic System. It's this plumbing

system that pumps cerebral spinal

fluid through brain tissue and then flushes

it into your circulatory system and the

Lymphatic system just takes it from there.

And here is where sleep comes in.

The Glymphatic system seem to be about

ten time more active during

sleep in mice. It seems like

pushing all that CSF through its system

requires a lot of energy, so your brain

makes a choice: Run your body

or clean itself. That seems to

be why our brain uses as much energy

when we are asleep as it does when we are

awake. Not only that, it looks like

brain cells shrink up to 60%

during sleep, so all that

CSF can wash over it faster.

So what makes this flushing

process more important that cell

repair or forming memories? Well,

build up of waste is linked to serious

brain diseases, like Alzheimer's. If you

don't shut down every night, your

brain can't clean itself out properly

enough. I don't know, are you guys getting enough

sleep? Let me know down below, but don't brag

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