What Is Sleep And Why Do You Need it? (The No-Nonsense Guide)

Have you ever wondered what sleep is?

I mean, what’s the actual point in sleep. It feels like most of our lives are spent sleeping and whacking the snooze button when that annoying alarm goes off.

But seriously… what is sleep?

Well, interestingly enough. Sleep is vital to the survival of the human body.

In fact, without it… well, you’re DEAD (maybe).

To be honest, there’s no evidence that suggests you can die from not sleeping. But it can cause some pretty serious damage to your brain and body over time if you go without it.

Having said that, if you get too much sleep, you can also cause a whole bunch of health problems and sleep disorders, which I’ll get into later.

Below I’m going to look at the different stages of sleep, what influences the quality of your sleep, and the four main reasons you need to sleep.

Oh, and also the reason why we dream (this is very cool).

Sound good? Great, let’s get on with it.

So, what is sleep exactly, and why do you need it?

The simplest answer is that sleep is a full body cleanse.

Erm, a what now?

It’s basically a time for your mind and body to restore itself on a cellular level. Think of it as a complete recharge.

When you sleep, your brain puts your body into a mild sleep paralysis. Now you’re completely safe during this time, and you’re blissfully unaware of what’s going on because you’re dreaming.

Anyway, during this downtime, your body is repairing cells, processing information in the brain, and even fighting off diseases.

What is sleep? Illustration of why sleep is so good for you.

It does a whole lot more than that though…

  • A recent study showed that the brain may actually flush out toxins during sleep. Amazing right?
  • Your body goes into “tissue repair” mode where it fixes damaged or aging tissue and surprisingly even builds muscle.
  • Sleep can help to maintain a healthy metabolism, too (source).
  • The amount of shut-eye you get can directly be linked to how cranky you are and, in some cases, lead to depression. Serious stuff.
  • Some scientists believe sleep is used for survival. As this study suggests, which was carried out on rats who actually died after a few weeks of not sleeping. Yikes!
  • It keeps our immune system and central nervous system healthy.
  • Promotes learning and has even shown to improve memory, how cool is that?

Actually, sleep does so much for us that I can’t list it all here.

Even though scientists are still baffled by sleep (meaning they have no idea what its biological purpose is), they still agree that we need it to stay sane and healthy based on the current evidence.

So now you know what sleep is. Awesome.

But did you know there are 4 separate stages of sleep, known as sleep cycles?

Let me explain…

What are the stages of sleep?

If you woke up this morning feeling half-dead and in a zombie-like haze, then you most likely didn’t cycle through the two main phases of sleep.

REM sleep and Non-REM sleep (or NREM sleep).

The first 3 stages are non-REM, and the final stage is REM.

Illustration of the 4 stages of sleep.

Let me explain:

  • Alpha (Stage 1) – The lightest stage of non-rem sleep. Basically, you’ve just shut your eyes, and you’re fully relaxed. Not awake, but not fully asleep either. Brain waves remain flat.
  • Theta (Stage 2) – Now, you’re asleep. Your brain waves will start to slow down and occasionally spike, known as “sleep spindles”, and your eyes won’t move much (sounds scary, but it’s normal, trust me).
  • Delta (Stage 3) – This stage is where your muscles shut down, your heart rate isa lot slower, and your breathing is shallow. You’re finally in a deep sleep.
  • REM (Stage 4) – This is the freaky REM sleep stage and where most of your dreams happen, your heart rate increases and eye movement becomes rapid. Specifically lucid dreams and you enter a state of paralysis, so you can’t move. You’ll begin this stage, usually within 90 minutes of falling asleep.

In short, to avoid waking up and feeling like crap. Get as much stage 3-4 sleep as possible.

Oh, and try not to wake up during deep sleep. You will feel terrible if you do.

Quick note: Some experts use 4 stages, and others use 5 stages. It really doesn’t matter. What matters is you know the difference between non-REM sleep and REM sleep.

Did you know? At night during sleep, your body temperature drops 1-2 degrees? That’s why you feel a bit chilly. Random I know, but interesting.

5 things that influence the quality and length of sleep

Be brutally honest with me…

When you wake up in the morning after several hours of sleep, do you jump out of bed and feel excited to get to work?

Or do you hit the snooze button on your alarm for the third time, groan at the thought of getting up and close your eyes?

Photo of a guy drinking beer.

Don’t worry if you said #2, most people do. Including me.

But that’s a problem that you need to fix (I’m working on it too).

There are five main reasons why your sleep is being affected, either in length or quality.

The sooner you find out the route cause, the better you will sleep. I promise.

Here they are…

  • Alcohol – If you like a glass of wine or a beer before bed, sorry… but you need to cut that out (not entirely, but obviously drink far less). Alcohol has been proven to mess your sleep up BIG time.
  • Health – Are you carrying an extra love handle or two? The heavier you are, the worse it’s going to be, come bedtime.
  • Age – Not much you can do about this, but as you get older, your sleep gets worse. It’s known as macro sleep changes and means you get less REM sleep, so you’re more groggy all day long. Man, it sucks getting older.
  • Stress – Being stressed can seriously hurt your sleep by messing with your Endocrine system. Not to mention, respiratory, circulatory, digestive, and musculoskeletal problems. Yep, it’s a big one for sure.
  • Food – Some naughty foods, when eaten late at night, can cause acid reflux, indigestion, and gas build-up (better sleep in the spare room, when this one erupts.) All of which mess with your sleep. That means, no more 3am snacks… ok? Ok?

This leads us to the most obvious question…

How many hours of deep sleep do you need?

I have the answer, but you’re not going to like it.


It depends on many factors.

There’s no one-size-fits-all magical time that I can give you. It just doesn’t exist.

Knowing how much sleep YOU specifically need depends on your age, current health., diet, genetics, and lifestyle.

A boring answer, but true none the less.

Sleep deprivation and why it’s dangerous

Here’s a scary fact.

35% of Americans sleep less than the recommended amount of 7 hours per night.

Photo of a tired looking guy.

Now, how do you know if you’re sleep-deprived and part of that group?

Here’s a quick test:

Lay down on a bed or couch, and if you fall asleep in less than 5 minutes (every time you try this), you’re either sleep deprived or have some magical sleep gene. 

I don’t mean a light sleep either, where you could wake up at any minute. I’m talking a DEEP sleep, where someone needs to shake you to wake you up.

If this is you, then you need to understand the negative side effects of sleep deprivation because it’s a lot more worrying than you might think.

Here’s what being deprived of sleep can do:

  • Your hand-eye coordination is impaired (source), so driving, for example, becomes a life-threatening issue for you and others on the road.
  • It can have dangerous effects on your central nervous system. That means you get sick quicker and take longer to recover.
  • You’ll be moodier and instantly angry at the smallest things.
  • Your memory turns to mush, and you won’t be able to focus on anything for longer than a few seconds or retain much.

In a nutshell, it sucks to be sleep deprived!

Oh, and I didn’t even mention the crazier things that can happen, the less sleep you get…

Microsleeping (nodding off at any time), delirium (you start to feel sick), and even hallucinations (you see stuff that isn’t there).

Why do we dream, and what do they mean?

I wish there was a fascinating answer for this, but honestly, there isn’t.

Photo of a woman sleeping in the grass.

Scientists still can’t explain why we dream and if there’s actual meaning behind them. Annoying right?

Sigmund Freud once said that dreaming was used by the brain as a kind of “safety valve” for our unconscious desires. But that doesn’t explain or prove why we dream.

During the night, we actually dream for around 2 hours on average, even though it feels way longer. This happens in the REM stage, the rest of the night is spent in each of the 3 stages.

Basically, dreaming is weird, and it happens to keep our brain active during sleep.

Trying to find meaning in dreams, really will drive you mad. So don’t bother.

One thing I do know is real and absolutely something you can do…

Control your dreams.

It’s called lucid dreaming and has been studied extensively. Just imagine being able to fly or be invisible… it’s actually possible during a controlled dream!

How circadian rhythms work from day to night

Circadian is a Latin word that means “around a day.”

Understanding how your circadian rhythm works can actually be quite confusing.

Illustration of how circadian rhythms work.

So without getting too sciency on you, here’s the important stuff:

  • Your CR is controlled by a natural biological clock.
  • This clock is referred to as the suprachiasmatic nucleus or “SCN.”
  • The SCN can be found in the hypothalamus.
  • Signals sent from the SCN go to a bunch of different areas of the brain. 
  • The pineal gland is one of those crucial areas, and it reacts to light-induced signals by turning off melatonin.
  • Melatonin is known to increase AFTER it’s dark. This makes you feel tired.

Ok, that’s the important circadian rhythm stuff covered.

You still with me?


In other words… your brain knows that light equals awake, and dark equals sleep. Clever right?

That’s why people who use electronics before bed and stay awake, can’t sleep for hours and feel groggy the next day.

If that’s you, then you should maybe try wearing some blue-light blocking glasses at night and set a strict sleep routine.

The 4 most common sleep disorders

Not getting enough sleep because of bad habits is one thing. But what about a disorder which prevents you from getting sleep.

Well, there’s a bunch, and they can impact your life in a big way if you have one.

Here are the most common sleeping disorders:

  • Insomnia – Described as “sleeplessness,” Insomnia can have a dramatic impact on all areas of your life. Those who have it can’t fall asleep or stay asleep regularly.
  • Sleep apnea – A problem where you stop and start breathing repeatedly throughout the night.
  • Restless leg syndrome (RLS) – Doesn’t just apply to sleep, but can affect it. You basically feel a constant urge to move your legs constantly. Unbelievably annoying if you sleep next to someone!
  • Narcolepsy – Overly tired and feel the need to sleep. Throughout the day? Yeah, you might have Narcolepsy. 1 in every 2,000 Americans are reported to have it.

What happens to your brain when you are sleeping?

Your brain cycles through the 4 sleep stages, and you begin to dream once you hit the final stage known as REM sleep.

Why do we sleep talk?

There’s no real reason why we sleep talk, but there outside factors and genetics which can cause someone to talk during sleep. Things like depression, fever, alcohol, and even being sleep deprived.

Conclusion: What is sleep?

Sleep is VERY important.

If you get too much or too little, it can have negative side effects like extreme tiredness, stress, mood swings, and weight gain, to name a few nasties.

So find your sweet spot.

That amount of time in bed that when you wake up, you don’t feel disgusting.

Use sleep apps, eat healthier foods, exercise, and stop binge-watching YouTube at midnight!