Have you ever answered the phone in the morning to discover it was actually your alarm clock going off, or had a conversation in the middle of the night and woken up the next day with no recollection of it? Researchers found many of us have had a similar experience in our lifetime.
The study, out Monday in the journal Neurology, says one in every seven people suffer from sleep "drunkenness" disorder, also called confusional arousal.
Confusional arousal is when a person wakes up and remains in a confused state for a certain period of time before either going back to sleep or fully waking up.
These episodes typically happen, according to the National Institutes of Health, when someone is awakened during non-rapid eye movement (REM) sleep, which is a deeper sleep period.
And they're usually triggered by a forced awakening, like an alarm or phone call.
The study authors had more than 19,000 adults fill out a survey about their sleeping habits.
They found 15.2% of the participants experienced one episode of confusional arousal during the past year. Maurice Ohayon, lead study author and a sleep expert at Stanford University, was surprised by the substantial percentage.
When he looked carefully, he says, he found over half of these participants have "confusional arousal one time or more a week, and that is considerable." What's even more interesting, says Ohayon, is how long confusional arousal seems to last.
While more than one third of the participants who experienced episodes once a week reported they lasted under 5 minutes, 32.3% of people said their episodes lasted between 5 and 15 minutes and 30% of people experienced episodes lasting 15 minutes or more.
If someone is experiencing these episodes, they need to let their doctors know, says Ohayon.
An episode can cause violent behavior during sleep, according to the study.
"You can hurt yourself physically, hurt someone (else).