When people talk about grabbing a little extra sleep, they might say they're going to try to get 40 winks. But here's another important number regarding sleep: Eighteen minutes.
The New York Times reported last week about a new study showing that Americans now are getting 18 minutes more sleep on an average weeknight than they were in 2003. (The number on weekends, when millions of sleep-deprived Americans try to catch up by sleeping in, also rose, but by only about 11 minutes; that's partially because we tend to sleep longer on weekends in the first place.)
Now, you might be thinking: "Eighteen minutes? What's the big deal? There are drum solos in popular music that last about that long."
Well, for the medical experts who study sleep, this new study from the University of Pennsylvania (published last month in the journal Sleep) is a big deal. It's one of the first signs that many Americans finally are waking up (sorry) to the fact that they've shortchanged their sleep.
"I think it's important to see the trend moving in the right direction," said Dr. Mark Reploeg, the medical director of the Samaritan Sleep Medicine Program, which is supported by The Corvallis Clinic’s Sleep Medicine Department.
On average, the Times noted, Americans get more than eight hours of sleep on weeknights and somewhat more on weekends.
But that's just the average: Sleep length among Americans varies widely. The federal Centers for Disease Control and Prevention report that more than a third of adults get insufficient sleep, defined as less than seven hours.
And although we don't yet fully understand exactly why we need sleep, a number of studies have pointed out the risks of not getting enough: Poor sleep has been linked to weight gain and an increased risk of Type 2 diabetes and heart disease. Law enforcement officials frequently talk about the risks posed by drowsy drivers. The list of potential risks goes on and on.
Reploeg said our national obsession with burning the candle at both ends, the idea that we need to squeeze out every ounce of possible productivity out of every minute, has played a big role in creating a nation with more than 100 million sleep-deprived people.
"Sleep is sort of the last thing that gets factored into the equation" of our busy schedules, he said.
So the study is good news. It could be that at least some Americans are starting to pay attention to their bedtime routines.
In particular, the study found that Americans are making more time for sleep by cutting down on the amount of time they spend watching TV and reading right before going to bed.
That jibes with the advice that sleep experts like Reploeg have been doling out for years: Try to sleep in a cool and dark room. Try to keep noise to a minimum. Try to stick to a routine, which includes consistent times for going to bed and for waking up; keep to that schedule even on weekends, he said.
In addition, experts for years have urged people to limit their screen time before bedtime. In particular, Reploeg noted, be careful about devices such as smartphones, tablets and computers, which tend to emit blue-wavelength light. The brain interprets light at that wavelength as a signal to wake up, he said.
The implication in the study — that Americans finally are getting the idea about healthful sleep habits — jibes with what Reploeg said he's seeing these days in his practice. Increasingly, he said, the patients he's seeing in the sleep clinic already have gone through those first steps. As a result, he and his colleagues can immediately move on from those basics and begin evaluating what deeper issues might be at work in those patients. "That's where our expertise comes into play," he said.
Reploeg trained as a neurologist. As he worked through his rotations, he found himself increasingly drawn to the subject of sleep, in part because he sensed that it was an area on the cusp of major research breakthroughs.
And some of those breakthroughs have occurred, he said. But part of the appeal of studying sleep is that it's still a subject swaddled in considerable mystery; for such a common experience, "we still don't have all the basic answers," he said.
For example: It's still not completely clear why we need to sleep in the first place. Part of the reason may be housekeeping: Researchers have found that during sleep, the space between brain cells gets bigger, allowing the brain to flush out toxins.
Reploeg puts it another way: Sleep, he said, "is a way to clean house. It's a way to recover from the wear and tear of the day."
And it may be that Americans are finally coming to understand all of that, he said: "People are prioritizing sleep."