A doctor has revealed the scientific reasons behind the ‘terrifying‘ sleep paralysis condition – and how to avoid it.

Good Morning Britain star and GP Dr Amir Khan took on the nightmarish subject in a recent Tiktok videowhere he explained that sleep paralysis is when our muscles are ‘temporarily switched off’ and our body is unable to move.

Sleep paralysis is an unusual condition where one wakes up in the night, unable to move, while experiencing a wide range of bizarre and terrifying hallucinations.

People recount feeling bound by an unexplainable force as they are awake and cognizant, but are unable to move any part of their body.

Addressing these fears, the TV personality asked: ‘Have you ever woken up in the middle of the night and felt like you couldn’t move your body? It’s scary right. Well that’s called sleep paralysis.’

Dr Khan then explained the reasons why it occurred as well as the science behind it.

‘It happens when your brain wakes up before your body does… during REM (rapid eye movement) sleep – that’s the bit where you dream and your muscles are temporarily switched off – so you don’t act out your dreams’.

He then went into the exact ‘scary’ and powerless moment many have recalled feeling during the dead of night.

‘If you wake up while that’s still happening you (will) feel paralyzed’, he stated.

The doctor listed other symptoms that are sometimes present during sleep paralysis, including pressure or pain on the chest, and vivid hallucinations of shapes, shadows or even human figures in the room.

‘That’s because your brain is still half in dream mode (and) half awake,’ he added.

Though Dr Khan admitted the experience can be ‘terrifying’, he also said it was pretty much ‘harmless’ and advised viewers not to worry.

He said that sleep paralysis only lasts a few seconds, and at max a couple of minutes before passing.

‘It’s always best to remember, I know it’s frightening and it feels scary, but it is nothing dangerous’ he further explained.

‘So if it happens to you don’t panic. Your body is just catching up with your brain.’

For those who are curious to know why sleep paralysis happens, the doctor said it was linked to poor sleep, stress or irregular sleep schedules.

And to counter these issues he provided a helpful set of advice.

‘So the best thing to do is to stick to regular sleep schedules, reduce stress and look after your sleep hygiene,’ concluded Dr Khan.

People were quick to share their own experiences of sleep paralysis in the comments of the video, which racked up nearly 300,000 views on TikTok.

One person said: ‘Yes! Scary as hell! Felt like being held down.’

Another said: ‘I try screaming but I can’t wake up making weird noises.’

Others shared: ‘So scary! Felt almost like a supernatural experience. Even when I fully came around I was left scared and heart pounding’;

‘I used to see a black large figure like a man scary as hell’;

‘The presence I feel in the room is so horrible, and I can’t move or talk’;

‘Anyone else experience swallowing problems during an episode? I’m convinced I can’t breathe when it happens.’

Some sufferers of the condition also report a feeling of pressure on the chest and can experience hallucinations, including terrifying figures.

Descriptions of the condition can be found in folklore dating back hundred of years when it was given names such as ‘old hag’ — due to the idea that a witch-like ghoul was sitting on the chest of the sufferer.

Modern science can’t explain why it occurs, however it is known to be more prevalent in those who suffer insomnia, post-traumatic stress disorder and anxiety.

People who experience sleep paralysis or hallucinations just before they nod off are more likely to suffer from depressiona 2018 research study revealed.

Lead author Professor Michael Grandner, from the University of Arizona, said: ‘The degree to which people reported these (paralysis and hallucinations) symptoms predicted (the) severity of (their) depression symptoms.

‘(Paralysis and hallucinations) are often thought to be relatively harmless and quite rare. But they can be very distressing to those who experience them’.

The researchers analysed 189 student athletes.

The study’s participants completed a survey that asked them to rate statements such as ‘when I am first awakening, I feel like I can’t move’ and ‘when falling asleep or waking up, I experience scary, dream-like images’ with ‘never’, ‘rarely’ or ‘often’.

Their mental health was assessed via the Centers for Epidemiological Studies Depression Scale.

Results further suggested 18 percent of the participants experience sleep paralysis occasionally, while seven percent do so at least once a week.

Some 24 percent have sleep hallucinations now and then, while 11 percent do so every seven days.

Study author Serena Liu added: ‘The fact that (sleep paralysis and sleep hallucinations) are so common among student athletes suggests that this is a group with some significant sleep problems that should be evaluated and dealt with’.