By John Lauritsen

MINNEAPOLIS (WCCO) — You hear it all the time: You need 8 hours of sleep to be fully rested.

But do some people need more than others? And can some actually get by on less?

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“For most adults, 7 hours would be a minimum they should be getting,” said Dr. Timothy Morgenthaler.

He’s with the Mayo Clinic and he’s also the president of the American Academy of Sleep Medicine.

“We know that most adults need between 7 and 9 hours of sleep nightly,” Morgenthaler said.

He says that’s the range, there’s no magic number we should be aiming for.

Factors such as health, weight and our individual make-up determine if we can get by on 7 hours or slumber on to 9.

“And when we sacrifice on sleep, low levels of sleep are associated with increased diseases,” Morgenthaler said.

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While we hear a lot about people getting by on just a few hours of sleep, Morgenthaler believes that in a lot of cases getting less than 7 hours over a period of time can set you up for serious health problems.

“Significant diseases, like cardiovascular disease, mortality, diabetic diseases, things like that,” he said. “So we really want to make certain that people are getting enough sleep, high quality sleep.”

It’s about both quantity and quality of sleep.

Newborns need more than 12 hours a day. Children into their teenage years need 10 to 12 hours of sleep.

It’s not until we turn 22 — that’s the watermark age — that we can get by on 7 to 9 hours.

Why 22? Morgenthaler said it’s just our biology.

He advises avoiding alcohol, nictotine and caffeine before bed, and even using iPads.

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He also advises finding a safe, dark, quiet, and comfortable place to sleep.

John Lauritsen