15 weird and wonderful things that happen while you sleep

Ever jolted awake by what sounded like an explosion? Or wondered why you can’t sneeze while you’re asleep? From bizarre brain tricks to your body’s overnight repair jobs, sleep is far stranger (and far busier) than most of us realise.

Bang! You’re just drifting off when it happens. A deafening crash, or a door slamming, maybe a gunshot or even a cymbal crashing beside your head.

Your eyes fly open, your heart is racing… and the house is completely silent.

If this has happened to you, don’t worry, the name is much scarier than the condition. It’s called Exploding Head Syndrome, and despite sounding terrifying, it’s harmless. As odd as it sounds, it’s just one of the many strange discoveries scientists have made about what happens while we sleep.

Far from shutting down for the night, your body gets surprisingly busy and while you’re asleep, your brain cleans house, your heart gets a rest, your immune system prepares for tomorrow and your body quietly gets on with countless repair jobs.

Some of what happens overnight sounds almost unbelievable, and here are 15 of the strangest and most fascinating.

1. You might “hear” an explosion that never happened

Exploding Head Syndrome usually strikes as you’re falling asleep or just waking. People report hearing a loud bang, clap, crash or explosion that’s completely imaginary.

It’s startling, but it isn’t dangerous, and it doesn’t mean anything is wrong with your brain.

2. Your brain gives itself a nightly clean-up

Every day your brain produces waste products. During deep sleep, it flushes much of that away through a remarkable cleaning system scientists only fully recognised in the past decade.

Think of it as taking out the rubbish before morning.

3. Your memories are sorted overnight

Ever wondered why it’s easier to remember something after sleeping on it?

That’s because your brain spends the night deciding what to keep, what to strengthen and what can safely be forgotten.

4. Your heart finally gets a breather

While you’re asleep, your heart beats more slowly and your blood pressure drops, giving your heart and blood vessels a chance to recover after a busy day.

5. Your body starts the night shift

Sleep is prime time for repairs, as your muscles recover, skin renews itself, tiny injuries begin the process of healing, and cells are replaced.

Your body is quietly working overtime while you do absolutely nothing.

6. Your immune system gets ready for tomorrow’s germs

While you sleep, your body produces infection-fighting cells and proteins that help protect you against viruses and bacteria.

Miss out on enough sleep and your immune system doesn’t perform nearly as well.

7. Believe it or not, you can’t sneeze while you’re asleep

It’s weird, but it’s true.

The reflex that triggers a sneeze is effectively switched off during sleep. If something irritates your nose, you’re far more likely to wake up first.

8. Your body cools itself down

A drop in body temperature is one of the signals that helps you stay asleep.

That’s why a cool bedroom often makes for a much better night’s rest than one that’s too warm. Personally, my sleep patterns have improved dramatically since not having the heating on overnight.

9. Your hormones get a nightly reset

Many of the hormones that control hunger, stress, growth and metabolism are released or adjusted overnight.

Miss out on enough sleep and that balance can start to slip.

10. Your brain works through your emotions

There’s a reason problems often seem easier after a good night’s sleep.

During REM sleep, your brain processes emotional experiences, helping you make sense of the day and sometimes putting things into perspective.

11. You’re temporarily paralysed… but that’s a good thing

During dreaming, your brain temporarily switches off most muscle movement.

Without this built-in safety feature, we’d be far more likely to leap out of bed while dreaming we were running from a tiger, or trying to score the winning goal or try.

12. Part of your brain keeps watch in a strange bed

Ever notice the first night in a hotel is often your worst?

Scientists think one side of the brain stays slightly more alert in unfamiliar surroundings, just in case there’s something to worry about.

13. That falling feeling has a name

Just as you’re drifting off, your whole body suddenly jerks and you feel as though you’ve stepped off a cliff.

It’s called a hypnic jerk.

Nobody knows exactly why it happens, but almost everyone experiences it from time to time.

14. Sleeping on a problem really can work

We’ve all heard the advice to “sleep on it”.

Turns out there’s good science behind it. Your brain continues processing information overnight, which is why people sometimes wake with a fresh idea, or finally work out the answer to a problem that seemed impossible the night before.

15. Scientists still don’t know everything about sleep

For something we spend about a third of our lives doing, sleep remains surprisingly mysterious and researchers are still trying to understand exactly why we sleep and why it’s so essential.

One thing is certain: sleep isn’t wasted time. It may be one of the most important things we do for our long-term health.

The bottom line

Getting a good night’s sleep isn’t simply about waking up feeling refreshed.

Every night your body runs one of the most sophisticated maintenance programs imaginable: your brain clears away waste, your heart recovers, your immune system prepares for the next day and damaged tissues begin repairing themselves.

So if you’ve ever felt guilty about turning in early, don’t. Your body has the night shift covered, and it’s doing some of its best work while you’re fast asleep.

Also check out Sleep Struggles After 60: Here’s How To Fix It