10 Fascinating Things That Happen While You’re Sleeping
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John Steinbeck once noted that “it is a common experience that a problem difficult at night is resolved in the morning after the committee of sleep has worked on it.” When my head hits the pillow and I can’t seem to turn off my thoughts, I like to picture the committee gathering in a miniature boardroom in my brain. I imagine tiny committee members heatedly arguing over my dilemmas while I snooze. What a relief to leave the toughest calls up to somebody else.
Whether you’ve imagined it or not, you’ve probably benefited from such a committee’s hard work. While we doze, our brains and bodies aren’t slacking off, they’re at work, repairing us after the day’s battles and refueling us for tomorrow’s slog—in more ways than you likely realize. (Want to pick up some healthier habits? Sign up to get healthy living tips delivered straight to your inbox!)
There’s probably no teeny boardroom. But here’s what’s actually going on while you’re conked out:
- You aren’t sleeping deeply most of the time.
Not all sleep was created equal: When you first drift off, you get only very light sleep, then progress deeper and deeper into dreamland. The sleep cycle starts in what’s called non–rapid eye movement or NREM stage 1 (the kind of sleep you might nab if you were the type to doze off during your college lectures; you know who you are). Then you move into a deeper NREM 2 and then to the deepest, NREM 3, also called slow-wave sleep. Finally, you land in rapid eye movement, or REM, sleep, the wild part of the ride when most of our dreams occur. The whole shebang usually takes somewhere between 90 and 120 minutes, so on a typical night you’ll cycle through four or five times, waking up for just a sec (even if you don’t realize you’re awake) after REM sleep before starting over in stage 1. (Tired all the time? Sleep has nothing to do with these 7 reasons.)
As the night goes on, you spend less time in that deliciously deep stage 3 and more time in REM sleep, which explains why your alarm so often wakes you up in the middle of a totally bizarre dream, says Sigrid C. Veasey, MD, a neuroscientist and a professor of medicine at the University of Pennsylvania’s Center for Sleep and Circadian Neurobiology. But we don’t really know why REM periods get longer in the wee hours, says Daniel A. Barone, MD, an assistant professor of neurology at the Weill Cornell Medical College’s Center for Sleep Medicine. One theory, he says, is that REM sleep may somehow prepare you to get your butt out of bed.