The next time your boss or co-worker finds you napping in your cubicle, be sure to refer them to a 2021 article in the journal Nature Communications titled “Genetic Determinants of Daytime Napping and Effects on Cardiometabolic Health.”
As you casually massage out the imprint your wrists left on your forehead, remind them that for you, napping is not due to indifference or sloth (though honestly, both may be warranted), but rather due to various genetic factors that are just now coming to light. Go ahead, directly quote the co-lead author of the Nature Communications article, Hassan Dashti: “…daytime napping is biologically driven and not just an environmental or behavioral choice.”
If that thoughtful and detailed explanation is met by the sound of crickets, it’s still possible that their quiet skepticism will lead one of them to actually read the article. If they do, here’s what they’ll find.
Dashti and his colleagues combed through two large genetic databases (in total, nearly a million people of European ancestry) and found 123 specific gene variations associated with nappers. Not surprisingly, these genetic variants seemed to sit close to or within gene regions that have previously been linked to sleep, including areas that are important in wakefulness.
Their data suggested two main reasons why some people might be nap-prone. Either they nap to make up a sleep deficit brought on by waking up too early or by poor-quality disrupted sleep, or because their own, personal sleep recipe simply calls for more sleep. In other words, they nap because something is wrong, or because napping feels right.
In Dashti’s study, 38% of participants reported sometimes napping, and 5% reported always napping — numbers that roughly square with U.S. surveys showing a third of adults (more often men than women) will take a nap on any given day. Those numbers tell us who is napping, but they don’t tell us how long they are napping, and nap length is important.
What happens during a nap?
You can think of a nap as a truncated version of a full night’s sleep, which works like a dishwasher: The sleeping brain goes through a series of wash and rinse cycles every evening.
Specifically, the brain progresses from light sleep phases called stage 1 and stage 2 sleep, into deep, more refreshing stage 3 sleep, and finally into the dream-producing rapid eye movement (REM) stage 4 sleep. This cycle is repeated a number of times every night, but stage lengths vary. Early in the evening there is more deep sleep, and later in the evening and early morning there is more REM sleep.
How long should a nap be?
It’s generally agreed that a nap of roughly 20 minutes is optimal. That’ll get you into stage 2 light sleep. Longer naps allow one to slide into stage 3 deep sleep, which, yes, is a very physiologically restorative sleep, but if you wake up suddenly in the middle of it, you will not feel restored: You will feel a bit hung over and “worse for wear.” Most of us have experienced this somewhat perplexing phenomenon. “Should have gone with the coffee,” we think to ourselves.
Longer naps of 60 to 90 minutes can avert this “sleepus interrupticus” hangover feel of a mid-range nap, but they should generally be avoided — unless one is looking to pay back a clear sleep deficit, say, from a late night at work, or a red-eye flight. Otherwise, a longer nap runs the risk of messing with that night’s sleep. This is also why experts don’t recommend taking a nap after 2 p.m.
Are naps good for you?
One of the benefits of napping can be a pause that refreshes, and there is plenty of scientific evidence to substantiate what nappers feel: mentally sharper, more energetic, i.e., caffeinated without the caffeine. (One study noted improved “frustration tolerance,” which we can all use more of in a world full of COMPLETE IDIOTS!!)
Obviously, if you are napping a lot to make up for consistently poor nighttime sleep, naps are only a temporizing measure, not a real solution. People with insomnia know they are having poor sleep because they are awake to know it. But those folks who sleep poorly due to the all-too-common obstructive sleep apnea are often unaware of the issue. Yes, they sleep through the night, but their breathing problems repeatedly startle the brain out of any restorative sleep.
Are meditation and napping the same thing?
I dabble in naps, and also in meditation, and to be honest, sometimes the one becomes the other. I wondered if science could tell me if napping and meditation were different versions of the same thing. The answer is hobbled by the fact that meditation comes in a myriad of styles and practices, and also by the fact that it doesn’t have the kind of profit margins that encourage deeply funded research.
The answer, I think, is that there are clear brain wave changes seen during meditation, but they don’t seem to approximate those seen in sleep. Squiggly brain waves aside, perhaps the best explanation is both obvious and rather pedestrian. Meditation is a conscious act, a quiet focusing, whereas sleep is an unconscious act. We “fall” asleep.
Sweet dreams.
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