What do sleep talkers say? A new study may surprise you.
Sleep talking, also referred to as a "somniloquy," is a common parasomnia. Many of you are likely to have woken yourself up, suddenly aware that you are mumbling or shouting, or a partner may have told you a humorous tale about the weird words you muttered as you slept last night.
Sleep talking is estimated to affect around 5 percent of all adults, but many more of us may experience this complex behavior, particularly if we're stressed or sleep-deprived.
In fact, research has indicated that more than 66 percent of us have spoken during sleep at some point in our lives.
We know little about the brain mechanisms that provoke sleep talking but research has suggested that it arises as a part of rapid eye movement (REM) sleep behavior disorder, wherein the region of the brain that paralyzes speech and movements during sleep fails to function effectively.
The good news is that, by itself, sleep talking is largely harmless — though the person that has to listen to you jabbering while they're trying to get some shut-eye might disagree.
If you're anything like me, you're likely more concerned with what you say in your sleep, wondering if you blurted out something highly embarrassing.
Well, the new study — published in the journal Sleep — confirms your fears.
Swearing and negativity common
Conducted by Dr. Isabelle Arnulf, of the Sleep Disorders Unit at AP-HP, Pitié-Salpêtrière Hospital in Paris, France, the research reveals that sleep talk is brimming with negative and vulgar words that are often directed toward another person.
The team came to the new findings by studying 232 adults. Of these, 129 had REM sleep behavior disorder, 87 experienced sleepwalking, sleep terrors, or both, one adult had sleep apnea, and 15 adults had no sleep-related disorders.
Over 2 nights, the researchers used video polysomnography to record any speech episodes as the participants' slept. They monitored the frequency of speech episodes, the words that each adult said, and whether subjects spoke positively or negatively, as well as whether or not their words were aimed at others.
There were a total of 883 speech episodes among the participants, including 3,349 decipherable words.
The most common word spoken during speech episodes was "no," and this word appeared around four times more when the subjects were asleep than when they were awake.
But that isn't the worst part: the team found that nearly 10 percent of all the speech episodes contained swearing, with the "F word" appearing around 800 times more during slumber.
Swearing during sleep was more common in men than women, and men tend to sleep talk more in general.
We might swear, but our grammar's good
Talking to MNT, Dr. Arnulf said that the team wasn't too surprised by its results, pointing out that when people dream — which usually occurs during REM sleep — negative emotions are not uncommon.
She told us that "[...] people may act out — and speak loudly — only when they are extremely worried; the rest of their speeches remaining inner and silent."
"[S]leep talkers may face situations in dream[s] in which anybody would swear, had they happened awake — e.g., need to escape a danger, and shouting, or need to counter-fight, and insulting the aggressor," Dr. Arnulf added.
In essence, if you're dreaming about a stressful work situation or an argument with a partner, don't be surprised if a few expletives slip out of your mouth.
But, despite the words that we say in our sleep being far from ideal, we can be safe in the knowledge that our grammar doesn't suffer.
"What we now know," Dr. Arnulf told MNT, "is that sleep talking is very similar to talking awake, in terms of correct grammar, with subordinate sentences, and silence for other[s] to answer, as in awake turn of speech."
"The differences," she said, "are qualitative: nocturnal language is negative, tense, more vulgar, and addressed to somebody, not to oneself. It suggests that the brain uses the same networks as awake, and that sleep talking translates the concomitant dreaming activity, which is tense, too."
Next, the researchers plan to shed some light on the gestures that correspond with what sleep talkers say — something that Dr. Arnulf refers to as "co-sleep gestures."
"The persistence of co-speech gestures would suggest that the connection between frontal and temporal area is maintained during sleep," she told us.
So, if you want to know whether you pack a good punch in your sleep, watch this space.