Shadowing Practice: Why Do We Actually Need Sleep?? - Learn English Speaking with Video

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Sleeping.

Every day you go to your bed, lie down and do nothing.

For like eight hours.

This is stupid.

The time you spend doing literally nothing could be spent on so many other things.

Like eating, drinking, exercise, getting a job, spending time remembering that time you accidentally called your teacher mum.

But instead you're doing this.

Why?

Why haven't we figured out a way to not need to do this?

What does sleep even do?

And why do you feel sleepy?

What is sleepy?

Two things.

First is the suprachiasmatic nucleus, which is just your body clock.

It relies on light to get an idea of what time it is.

When it's day, it's chillin'.

But when it becomes night though, your retinas in your eyes see this

and then send messages to your body clock and it goes.. bed and then allows the release of melatonin,

which pretty much tells the brain it's nighttime.

And second is adenosine.

The heck is that?

Well all of your cells use this thing called ATP as energy, but as your body uses it, adenosine accumulates.

This accumulation increases sleep pressure, which makes you more tired.

So you finally climb into your bed and then you just lie there?

Don't worry, even

Even though you might feel like you're just lying there like a useless blob,

your part of the brain called the hypothalamus is getting ready to send

you into your dreamy state where you ride unicorns and eat fluffy clouds.

During the day, your brain is constantly sending messages using all these different chemicals in your brain called neurotransmitters,

but it's being extra sure to use these special neurotransmitters to stay awake.

But as your sleepiness builds,

it gets to a point where it lets this thing out of the cage the ventrolateral preoptic area inside the hypothalamus,

or VELPO for short.

What this does is blocks all the systems in the brain

that are making sure that it's using these neurotransmitters to stay awake, and thus gets you to fall asleep.

So now you're sleeping like a baby.

But again, why have we even evolved to need this absolute waste of time?

We'll get to that.

But first, what's happening while you're asleep?

It's called the sleep cycle, which you've probably heard of before.

And there's four parts to it.

First is stage one.

This is when you're barely asleep.

Your awareness goes down and muscle activity relaxes.

This is also the stage where this happens.

That was what the pros call a hypnic jerk.

So why does your own body give you a jump scare?

Well, researchers think that it could be your brain reacting to a sudden relaxation in the muscles and because it's stupid,

it interprets that as we're falling and jolts your muscles to double check.

But they aren't actually certain, so it could be something else.

Anyway, next is stage two, which is a light sleep.

This is where your heart rate slows, your body temperature decreases, and muscles relax even more.

But two other really interesting things happen here.

Sleep spindles, which are short bursts of brain activity, and K -complexes, which are big distinctive brainwaves.

Why?

Well, they seem to both have roles in protecting sleep and memory processing, but again, meh.

Then you get to stage three, deep sleep.

This is where activity is at its lowest, and your body takes advantage of that, increasing growth hormone secretion, tissue repair,

immune function support, and metabolic regulation.

It also takes that opportunity to use the glymphatic systems, which is a nerdy way of saying a waste clearing system for the brain as well.

And this is the stage where you're the most dead to the world.

You're just there, in your bed, catching your Z's, sleeping like a baby.

BOOM!

REM sleep.

All of a sudden your heart rate starts going up and down, brain activity jumps, and irregular breathing increases as well.

REM, or rapid eye movement, is where the most vivid of your dreams happen.

And yes, it's called rapid eye movement because your eyes are literally darting around while you sleep.

But, if you're having a dream that you're running away from the scariest thing you can imagine,

a job application, why don't you move in real life?

It's called REM -a -tonia.

Pretty much, your brainstem literally stops messages going from your brain to your skeletal muscles, while other messages for vital muscles such as your heart,

lungs and yes your eyes are allowed through.

But on the odd occasion it goes over time and is still stopping you from moving even when you wake up.

That's what causes sleep paralysis.

The thing where you're awake but you can't move.

And yes, because of this mix -up, dreamlike processes can still intrude your awakeness.

Hence why you sometimes can start hallucinating really scary things.

Like that job application.

Then you finish the cycle.

So, you do it again.

This whole cycle takes roughly 90 minutes.

But that can vary depending on the person.

And they're not even lengths either.

Usually, earlier in the night you actually get more deep sleep, whereas later in the night you get more REM sleep.

But then you wake up in the morning and think to yourself, why?

Think about it though, every night you're putting yourself in a state where you are extremely vulnerable to enemies, you can't eat, you can't drink,

you can't care for your children, you can't look for a girlfriend, you can't even fill out that job application.

And yet evolution has gone to extreme lengths in order to preserve this strange routine.

And when I say extreme, I mean extreme.

Think about dolphins for instance.

They need air to survive, but if they slept they would drown.

So they evolved to not need sleep right?

Nope.

They evolved so that to sleep they shut down half of their brain

and let that side sleep and just use the awake side and then just swap it over.

And not just dolphins, but many birds also do this too.

So why hasn't evolution just gotten rid of it altogether?

Why is it so persistent on keeping sleeping?

Well, we do know the important stuff that sleep does do.

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First, the brain needs maintenance, and it can't do it as effectively while it's awake.

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It's like trying to do maintenance in a warehouse.

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It's much easier to do it while it's empty rather than when it's full of customers.

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Second, the brain also needs to manage and sort what it learnt that day.

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Organise memories, new skills and get rid of old ones.

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Again, it seems that it can't do it as effectively while it's awake.

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And third is body repair.

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Yet again, it does it better when it's asleep.

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But I still have a problem with that.

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Why do we need to actually be asleep?

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As in unconscious?

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We could have just evolved to be able to repair, sort and maintain ourselves while awake.

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And yet evolution has been determined to keep it,

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and has clearly decided that it's worth the risk of not being conscious for 8 hours every day, than not to sleep at all.

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And that's the real mystery of sleep that no one has been able to really answer.

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Why do we really need sleep?

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And if you want to get a good night's sleep,

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a little birdie told me that hitting the subscribe button and show it two cold sides to your pillow for a week.

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Vocabulary and speaking notes for this lesson

This speaking lesson is built on the video “Why Do We Actually Need Sleep??”. The speaker keeps coming back to these words: sleep, brain, awake, muscle, asleep. This video has 118 sentences and 1262 words to shadow. The speech runs for 7:47. The speaker talks at a natural 162 words per minute, close to everyday conversation. 84% of the words are among the 3,000 most common in English; the rest is worth studying before you start. 19 of its 118 sentences are questions, so it is good practice for question intonation and short answers.

Key vocabulary in this video

15 words from the video worth learning, with pronunciation and meaning:

Word	Pronunciation	Meaning
awake verb	/əˈweɪk/	To become conscious after having slept.
muscle noun	/ˈmʌs.əl/	A contractile form of tissue which animals use to effect movement.
asleep adjective	/əˈsliːp/	In a state of sleep; also, broadly, resting.
evolve verb	/ɪˈvɑlv/	To move (something) in regular procession through a system.
evolution noun	/ˌiːvəˈluːʃ(ə)n/	A manoeuvre of troops or ships.
repair verb	/ˈɹiːpɛɚ/	To restore to good working order, fix, or improve damaged condition; to mend; to remedy.
clock noun	/klɑk/	A chronometer, an instrument that measures time, particularly the time of day.
sudden adjective	/ˈsʌd.ən/	Occurring quickly with little or no warning or expectation; instantly.
rapid adjective	/ˈɹæp.ɪd/	Very swift or quick.
scary adjective	/ˈskɛə.ɹi/	Causing fear or anxiety
relax verb	/ɹɪˈlæks/	To make something loose.
sleepy adjective	/ˈsliːpi/	Tired; feeling the need for sleep.
dolphin noun	/ˈdɑlf.ɪn/	A carnivorous cetacean, typically with a beak-like snout, famed for their intelligence and occasional willingness to approach humans.
cloud noun	/ˈklaʊ̯d/	A visible mass of water droplets suspended in the air.
mystery noun	/ˈmɪs.t(ə.)ɹi/	Something secret or unexplainable; an unknown.

Phrasal verbs you will hear

Word	Pronunciation	Meaning
figure out verb		To come to understand; to discover or find a solution; to deduce.
fill out verb	/fɪl ˈaʊt/	To complete a form or questionnaire with requested information.
go down verb		To descend; to move from a higher place to a lower one.
go over verb		To look at carefully; to scrutinize; to analyze.
go up verb		To move upwards.
lie down verb		To assume a horizontal position.
mix up verb		To mix or blend thoroughly and completely.
run away from verb		To avoid or shirk a problem or consequences; to rush to back away from or disclaim responsibility for something.

Sentences worth repeating

Short, complete lines from the video that you can reuse in everyday conversation:

But first, what's happening while you're asleep?
This is when you're barely asleep.
The thing where you're awake but you can't move.
Why do we need to actually be asleep?
Why do we really need sleep?

Grammar in this video

The structures the speaker uses most, with the exact words from the video:

Structure	In the video
Present perfect have/has + past participle — a past action that still matters now	haven't we figured · have we even evolved · you've probably heard
Relative clauses who / which + clause — extra information about a person or thing	nucleus, which is · pressure, which makes · two, which is
Passive voice be + past participle — the focus is on what happens, not who does it	could be spent · are allowed

Pronunciation to watch

The speaker uses 28 contractions and reduced forms, such as you're, can't, don't. Say them the short way, as you hear them.

The “th” sounds: breathe /bɹiːð/, altogether /ɔl.tuˈɡɛð.ɚ/
The “sh” and “zh” sounds: evolution /ˌiːvəˈluːʃ(ə)n/, occasion /əˈkeɪ̯ʒən/, regulation /ˌɹɛɡjʊˈleɪʃən/, tissue /ˈtɪʃ.(j)u/, conscious /ˈkɑn.ʃəs/
Long words — get the stress right: evolution /ˌiːvəˈluːʃ(ə)n/, regulation /ˌɹɛɡjʊˈleɪʃən/, accidentally /ˌæk.sɪˈdɛnt(ə)li/, altogether /ɔl.tuˈɡɛð.ɚ/, irregular /ɪˈɹɛɡ.jə.lɚ/

How to practise with this video

Listen to the whole video once without speaking and note the words you do not know.
Start at 0.75× speed, shadow it sentence by sentence, then go back to normal speed once it feels easy.
Record yourself and compare with the original, paying attention to words like awake, muscle, asleep.

What is the Shadowing Technique?

Shadowing is a science-backed language learning technique originally developed for professional interpreter training and popularized by polyglot Dr. Alexander Arguelles. The method is simple but powerful: you listen to native English audio and immediately repeat it out loud — like a shadow following the speaker with just a 1–2 second delay. Unlike passive listening or grammar drills, shadowing forces your brain and mouth muscles to simultaneously process and reproduce real speech patterns. Research shows it significantly improves pronunciation accuracy, intonation, rhythm, connected speech, listening comprehension, and speaking fluency — making it one of the most effective methods for IELTS Speaking preparation and real-world English communication.

Shadowing technique: read the full step-by-step guide →

Shadowing Practice: Why Do We Actually Need Sleep?? - Learn English Speaking with Video

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