The House of Wellness

You’re awake and aware, but you can’t move.

Maybe you spotted a dark figure in the room, felt a presence or a heavy weight on your chest. It’s the stuff of nightmares.

If this has happened to you, you’re not alone. And no, it’s not a ghost.

What you’re experiencing is likely sleep paralysis, a common yet unsettling phenomenon that is said to affect about one in three people at least once in their lives.

What is sleep paralysis?

Dr Therese Thornton, of Monash University Healthy Sleep Clinic, says sleep paralysis happens when you’re caught between sleep and wakefulness, especially during rapid eye movement (REM) sleep – the stage in which most dreams happen.

“It’s most common when you wake up, but it can also happen as you’re falling asleep,” Dr Thornton says.

“Your brain wakes up, but your body is still asleep, creating a disconnect.”

Normally, during REM sleep, your muscles are temporarily paralysed to prevent you from acting out your dreams, she explains, but if this paralysis lingers after you wake up, you’re left in a temporary state of immobility.

These episodes often come with vivid hallucinations and typically last anywhere from a few seconds to a few minutes, though most instances are over in just a few moments.

What causes sleep paralysis?

Sleep paralysis has been a recorded phenomenon for centuries, across all parts of the world, with an estimated prevalence rate of about 30 per cent.

“Some people may experience only one or two episodes of sleep paralysis in their lifetime, without any other neurological or psychological condition being present,” Dr Thornton says.

Sleep psychologist Dr Sara Winter says there are several factors that can contribute to sleep paralysis, including sleep deprivation, stress and certain medical conditions.

“It’s more common in people with central disorders of hypersomnolence, like narcolepsy,” Dr Winter explains.

“These conditions can lead to REM intruding on waking experiences.”

Other contributing factors include anxiety, irregular sleep patterns, and substance use.

What does sleep paralysis feel like?

While experiences vary, common sensations during sleep paralysis include a complete inability to move or speak, chest pressure and hallucinations.

“The hallucinations are part of that transitional state, and they can include visual or tactile sensations,” Dr Winter says.

“For some, they feel scaly or prickly sensations or pressure, which can be misinterpreted depending on the person’s frame of reference.”

Why does sleep paralysis feel so frightening?

One of the most distressing aspects of sleep paralysis is the intense fear or hallucinations often associated with it.

“Waking up unable to move activates the brain’s threat-response system, leading to a fight-or-flight reaction,” Dr Thornton explains.

“The low respiratory set point during REM sleep can make individuals feel like they’re suffocating, which only heightens the sense of danger.”

She adds that the hallucinations often fall into three categories:

• The incubus type, where individuals feel pressure on their chest or experience difficulty breathing

• The intruder type, which involves a sense of a shadowy, threatening presence nearby

• The vestibulomotor type, which includes sensations of floating or out-of-body experiences and is less often tied to fear.

“These experiences are vivid and influenced by cultural beliefs,” Dr Thornton says.

“In some cultures, they’re interpreted as demonic possession or alien abductions, which can perpetuate fear and anxiety, increasing the likelihood of future episodes.”

How to prevent sleep paralysis

Both experts agree that understanding the condition is key to reducing its frequency and the distress felt during an episode.

Dr Thornton says a good approach is to focus on good sleep hygiene: “Maintain a consistent sleep schedule, manage stress and avoid excessive alcohol or drug use.”

During an episode, Dr Thornton suggests relaxing and concentrating on moving a small body part such as a finger to break the paralysis.

When to seek help

Sleep paralysis is a way for your body to let you know that something is a little out of balance, and the experts say it’s a good reminder to stop and check in with yourself.

For example, are there factors in your life that could be better managed, such as insufficient sleep, alcohol or drug use, stress or anxiety?

If sleep paralysis is recurrent or highly distressing, Dr Thornton suggests seeking professional help.

“A sleep specialist can assess for underlying conditions and provide tailored strategies,” she notes.

This article originally appeared in print, and on The House of Wellness.