Why do we talk in our sleep?

Woman in bed, being kept awake by her partner
(Image credit: Getty)

Strange though it may seem, talking in your sleep is a common phenomenon. So what causes this nocturnal chattering, is it linked to our dreams, and should we be concerned about it? We consulted a sleep expert to get the lowdown on sleep talking. 

If you think your sleep talking is related to a lack of sleep or poor quality sleep, check out our tips on what to do when you can't sleep or how to use the Navy SEAL Sleep Technique to fall asleep fast. Or for more weird nocturnal phenomena, explore if a full moon really affects sleep

What is sleep talking?

"Talking in your sleep is a common kind of parasomnia or abnormal sleep activity," explains Theresa Schnorbach, a psychologist and sleep scientist who's also the sleep advisor at Emma (the brand behind on of today's best mattressses). "Two out of every three people talk in their sleep at some stage in life, and it's particularly frequent among youngsters." Typically, it's harmless, although it can in some cases be a sign of a  more significant sleep disorder or health problem (we'll get into that later). 

Sleep talking can take place in any sleep stage; Theresa explains that typically it's easier to understand during early phases of sleep (for example, non-REM stages 1 and 2). If you're talking during later stages like non-REM stage 3 and REM sleep, it's more likely to just sound like moaning and groaning. 

What do people sleep talk about?

Sleep talk can range from odd words or rumblings and grumblings to full conversations that you can't recall, but how it relates to what's going on in the sleeper's brain is harder to pin down. "The origins of the content during periods of sleep talking have been the subject of conflicting research," says Theresa. "Speech may or may not be related to a person's life, recent events, or previous talks. Although some research suggests that it is sometimes linked to dreams, not all sleep talking appears to be tightly linked to dream activities.

Man asleep in bed, lying on his stomach

(Image credit: Getty)

Why do we sleep talk?

While there's more research required when it comes to figuring out the reason why people talk in their sleep, we currently think that it's generally caused by a lack of sleep, or disturbed sleep. That might be due to a disruptive sleep environment – for example if your room is too warm or cold, or there's too much ambient light creeping in – or caused by stress or alcohol. 

There can be other causes, though. "Sleep talking seems to be more common in those with underlying mental health conditions," explains Theresa. "It is thought to occur more frequently in those suffering from post-traumatic stress disorder (PTSD)."

What about shouting in your sleep? 

Most sleep talking is harmless, but shouting in your sleep might be related to another sleep disorder. "Sleep disorders such as REM sleep behaviour disorder (RBD) and sleep terrors lead some people to yell while sleeping. Sleep terrors, also known as night terrors, are characterised by terrifying screaming, writhing, and kicking," says Theresa. "It's difficult to wake someone who is suffering a sleep terror."

Is talking in your sleep harmful?

"Random isolated occurrences of sleep talking are rarely problematic," Theresa explains. However, if it's causing you distress, you might want to consult a professional for advice. "If your sleep talking starts suddenly as an adult or involves significant anxiety, screaming, or violent actions, you should visit your doctor or a sleep specialist," she continues. They will probably ask you how long you've been talking in your sleep, so speak to your bed partner, roommate or whoever beforehand so you have this information.

"Sleep talking can be diagnosed without the use of any testing. If you have symptoms of another sleep problem, your doctor may request testing such as a sleep study or sleep recording (polysomnogram)."

For more information and advice on how to improve your sleep habits, take a look at the Emma Up app.

Theresa Schnorbach headshot
Theresa Schnorbach

Theresa Schnorbach is a psychologist and sleep scientist, specialized in Clinical Psychology and Cognitive Neuropsychology. She has completed post-graduate training in Cognitive Behavioural Therapy for Insomnia (CBT-I) with the German Sleep Society (DGSM), endorsed by the European Research Society. She works as a sleep specialist for bed brand Emma.

Ruth Hamilton
Homes Editor, TechRadar

Ruth is currently Homes Editor on Tom's Guide's sister site TechRadar, where she reviews and writes about everything from air fryers to vacuum cleaners to coffee machines, as well as the latest smart home gadgets. Prior to making the shift to Homes, Ruth was Tom's Guide's Sleep Editor. A certified Sleep Science Coach, she has tested more mattresses than her small flat can handle and will talk at length about them to anyone who shows even a passing interest.

  • Andy77717
    admin said:
    Sleep expert explains the science of sleep talk, and whether it should be a cause for concern.

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