By Kim Glovas

PHILADELPHIA (CBS) — Teenagers are prolific texters. But now’s there’s evidence that they are even doing it in their sleep.

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It’s called sleep texting.

“It’s just what you’d think it is, it’s texting while asleep,” says Elizabeth Dowdell, nursing professor at Villanova University, “It’s exactly what is sounds like, or really more between that, you know, that area between being asleep and being awake.”

“The phone will beep, they’ll answer the text,” Dowdell says. “They’ll either respond in words or gibberish. (It) can even be inappropriate. Ex-girlfriends contacting ex-boyfriends, saying ‘I miss you. I want to see you.’ The thing that happens, though, is that when they wake up, there’s no memory.”

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Dowdell says teens should get eight, nine or ten hours of sleep a night.

“Overplugged and overextended teens and young adults tend to get less than that,” she says, “so this interrupts what could be a good night’s sleep, because they’re an hour-and-a-half or two hours into their sleep cycle, and they’re answering texts or the machines are beeping at them.”

Dowdell says sleep interruption can lead to obesity, depression, failing grades and more.

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She says the answer is a technology-free bedroom, or, at the very least, putting the phone on the other side of the room, and turning off the ringer.