Sleepwalking and sleep talking: what they are and what to do

What is sleepwalking?

Sleepwalking means getting up and moving around while still asleep. It comes out of deep non-REM sleep, usually in the first part of the night, and each episode tends to last a few minutes. The person's eyes are open but glassy, and they may wander the house, open doors, use the bathroom in the wrong place, or go through everyday motions like getting dressed or moving things around.

During an episode they respond little or not at all, and if you speak to them they may answer in short, muddled phrases. The next day they don't remember what they did. Sleepwalking belongs to the same family as night terrors: in both, part of the brain switches on while another part stays asleep. If your nights also bring screaming and sudden fright, our guide to night terrors explains what to do.

What is sleep talking?

Sleep talking, which doctors call somniloquy, is saying words, mumbling, laughing or speaking in full sentences without being aware of it. Unlike sleepwalking, it can happen both in REM sleep, when dreams are most vivid, and in non-REM sleep. Most of the time it lasts a few seconds, and the talker neither notices nor remembers it.

A team led by the neurologist Isabelle Arnulf in Paris recorded and analyzed hundreds of episodes from adults in a sleep lab and published the results in 2017. The single most common word was “no,” and a share of what people said was negative or profane; even so, nearly everything that could be made out was grammatically correct. Keep in mind that most of those volunteers had a sleep disorder, so the findings don't necessarily describe everyone who talks in their sleep.

Who sleepwalks or talks in their sleep?

Sleep talking is very common. In a survey of 1,000 adults in Norway, two out of three said they'd done it at some point, and about one in six in the previous three months. It's more frequent in childhood and tends to run in families.

Sleepwalking is less common, though more so than many people assume. A 2016 review pooling data from roughly 100,000 people estimated that about 7 percent of people sleepwalk at some point in life, with 5 percent of children and 1.5 percent of adults doing so in the past year. The authors note that the studies varied a lot. Most children who sleepwalk stop by their teens without treatment, and having relatives who sleepwalk makes it more likely.

What makes episodes more likely

Sleepwalking and sleep talking show up more when sleep is disrupted. The UK's National Health Service lists factors like these, worth reviewing if episodes become frequent:

• Too little sleep, or an irregular schedule.
• A fever or an illness.
• Stress and worry.
• Alcohol, especially in the evening.
• Some medications, including certain sleeping pills.
• Other sleep problems, such as sleep apnea or restless legs syndrome.

Is it dangerous to wake a sleepwalker?

The belief that you must never wake a sleepwalker, because they could have a heart attack, lose their mind or die of shock, is a myth. There's no evidence that waking them causes harm like that. What is true is that being woken abruptly can leave a sleepwalker deeply confused, frightened or angry, and in that state someone might shove or swing out without meaning to.

So the advice from sleep specialists isn't “never wake them” but “do it gently, and only if you need to.” Most of the time it's enough to steer them back to bed without waking them. And if they're in danger, say near the stairs, a window or the front door, letting them carry on is riskier than calmly waking them.

What to do when someone is sleepwalking

If you find someone walking in their sleep, the most useful thing is to guide rather than correct. These steps work for a child or an adult:

• Stay calm, and don't shout at them or shake them.
• Speak softly in simple words, like “let's go back to bed.”
• Take their arm or hand gently and lead them back to their own bed.
• If you do need to wake them, say their name from a little distance and give them time to get their bearings.
• Don't ask them to explain themselves, either then or the next morning; they don't know what they did.
• Note the time and anything unusual about the day; it helps you work out what sets episodes off.

Making the home safe for a sleepwalker

The main risk of sleepwalking is falls and bumps. Preparing the house is what protects a sleepwalker most, and the NHS suggests steps like these:

• Lock doors and windows, and keep the keys out of sight.
• Put a safety gate on the stairs if there are children.
• Clear the floor and the path to the bathroom, and leave a dim light on.
• Put away knives, tools and medications.
• Don't let a child who sleepwalks sleep on the top bunk.
• If there's a chance they'll leave the house, a door alarm or a bell on the door will alert you.

Sleep talking: what it does and doesn't reveal

Whatever someone says in their sleep isn't a confession or a hidden truth. Often it has no clear link to their life, and sometimes it doesn't even come from a dream. Treating it as a revelation, or quizzing the person while they talk, only leads to misunderstandings.

Sleep talking almost never needs treatment. If your partner's voice keeps waking you, earplugs or a soft background sound can help. It's worth bringing up with a doctor when it comes with shouting or flailing, heavy daytime sleepiness or loud snoring, since it can accompany other sleep problems.

REM sleep behavior disorder: a different thing

Not every nighttime movement is sleepwalking. In REM sleep behavior disorder, the person acts out what they're dreaming: they shout, kick, punch or leap out of bed. Normally, during REM sleep the muscles are held almost completely still so that we don't act out our dreams; in this disorder, that brake fails.

The differences from sleepwalking are clear. It usually begins after age fifty and is more common in men. It happens more in the second half of the night, when there's more REM sleep. If you wake the person, they usually remember a vivid dream, often of fending off an attack, and they rarely leave the room. It can be linked to some medications and, in some cases, it shows up years before neurological conditions such as Parkinson's disease. That doesn't mean those will follow, but it does make it worth seeing a sleep specialist, who will usually order an overnight sleep study.

When to see a doctor

Occasional sleepwalking in childhood usually needs no treatment. See your doctor or your child's pediatrician if you notice any of these signs:

• Injuries, near misses or attempts to leave the house.
• Frequent episodes that disrupt the sleeper's rest or the family's.
• Heavy daytime tiredness, loud snoring or pauses in breathing.
• Sleepwalking that starts in adulthood or after a new medication; don't stop any medication without talking to your doctor first.
• Sudden, forceful movements that seem to act out a dream, especially after age fifty.