The disturbing things that happen to your brain when you don't get enough sleep.

I’ve never been a particularly good sleeper. I get a burst of energy at about 10pm, which means I’ll stay up far too late and then very much regret it when I wake up.

At work the following day I feel… uncomfortable. If I’ve had a particularly bad night’s sleep, I feel as though I’m in a dream – not quite connected to the world around me.

My mind becomes slower and my motivation drops off in the middle of the afternoon. Often I’m grouchy and slightly irritable.

But what does the brain actually do when we haven’t had enough sleep? Why do I feel so uncomfortable? And how quickly does my brain recover from it?

Why do I feel so uncomfortable? Image via iStock.

Here are the seven things your brain does after a bad night's sleep.

You become highly emotional/angry

You're not imagining it — a bad night's sleep makes you moody and angry.

The amygdala, the part of the brain responsible for processing emotions, takes over when we're tired. A lack of sleep disrupts the amygdala's connection with other regions of the brain that ensure our emotions are regulated.

A study published by the US National Library of Medicine found that when a sleep deprived subject was shown emotionally negative images, the activity levels in the amygdala were up to 60 per cent higher than participants who were well rested.

Simply, the likelihood of losing your temper, or having a good cry, is greatly increased if you didn't get a good night's sleep.


Robin Bailey's trick to getting more sleep. Post continues below. 

Your memory is impaired

Have you ever got to the end of a big day following a bad night's sleep, and felt like you can't remember any of it?

That "fuzzy" feeling we seem to get when we haven't slept well is really common, and it's all because of the hippocampus.

Referred to as the "memory centre", the hippocampus acts like a record skipping when it's not been properly rested. Hence why pulling an all-nighter before an exam is never a good idea.

One study found that tired participants struggled to memorise a set of pictures, and the activity level in their hippocampus was significantly reduced compared to well rested subjects.

It's almost as though the hippocampus is unable to embed any new information. It's just too damn tired.

Serious sleep deprivation has been used as an interrogation method in the past, as we find it more difficult to separate fake memories from real ones. The prefrontal cortex, responsible for focus, starts to become very confused.

what should I study?
Staying up all night studying is counterproductive. Image via iStock.

You feel 'spacey' or dizzy

Feeling 'out of it' when you're tired is linked to your visual cortex. According to Attn, if you imagine your visual cortex as a boat, then "losing sleep is like cutting off the rope that ties the boat to the dock, leaving you drifting in the ocean."


You have difficulty speaking

Speaking of confusion, tiredness can interfere with our ability to articulate ourselves properly.

Sleep deprivation affects the temporal lobe, which controls language processing. So often we find ourselves slurring, or feeling as though a word is on the tip of our tongue, when we haven't had enough sleep.

You're not as funny

Being funny relies very much on a) finding the right words and b) being quick. If you're tired, your brain allows you to do neither of those things.

You lose the ability to swiftly switch between topics, make interesting connections, and think on your feet.

You might think of a funny joke, but by the time you do it's about 14 minutes too late.

Your appetite increases

If you've ever wondered why you seem to have more willpower in the morning as opposed to, say, just after dinner, here's your answer.

When you're tired, your cravings are significantly increased, and it will be far harder say to say 'no' to chocolate.

A study out of Uppsala University found that people feel hungrier and reach for larger portions when they've suffered a bad night of sleep.

You make bad decisions

Don't go trying to make a big decision after only a few hours of sleep. It WILL be the wrong one.

The aforementioned prefrontal cortex is also in charge of controlling impulses (another reason why you can't stop eating Tim Tams when you're tired...) and it gets lazy when it's not been properly rested.

Maybe don't jump onto The Iconic or... I don't know, buy a house when you're sleep deprived. (Post continues after gallery.)


According to the National Sleep Foundation, the average adult aged between 18 to 64 requires seven to nine hours sleep a night.

A bad night's sleep every now and then will not do irreparable damage, and is completely normal. But sleep deprivation over weeks, months or years can cause serious health conditions like heart disease, high blood pressure, stroke and diabetes.

So it might be time to make sleep a priority in 2017.