Napping is having a moment. Starting a few years ago, industries looking to boost the creative productivity of their workers — in Silicon Valley and beyond — caught wind of research showing that a short afternoon nap can refresh the body and recharge the mind in ways similar to nighttime sleep.
Sara Mednick is an associate professor of psychology at the University of California, Irvine and author of the book "Take a Nap! Change Your Life." The book is based on more than 15 years of research into the cognitive and physical benefits of napping, including significantly improved performance on tests ranging from visual perception to creativity.
Napping is not for everybody (or every business), says Mednick, but here's what she and other sleep researchers have learned about the neuroscience of naps and the recipe for the most effective workday siesta.
Timing is Everything
Assuming you have a forward-thinking boss who watches a lot of TED Talks about the connection between sleep and success, you still have to figure out when exactly to take that office snooze and for how long.
"The rule of thumb is that six to eight hours after waking up in the morning is a good nap time," says Mednick, which for most office workers falls somewhere between 1 p.m. and 3 p.m.
And the length of the nap? Most sleep experts, including the National Sleep Foundation, recommend a nap of 20 to 30 minutes. Napping longer than that, they say, is more likely to leave you groggy, a condition called "sleep inertia."
But Mednick's research has revealed that longer naps, in some cases, can bring unique cognitive benefits associated with different parts of the natural sleep cycle.
Longer Naps for Boosted Creativity
"We find that there are really specific sleep stages that support different kinds of performance benefits from creativity to heightening our perception to just having better all around memory," Mednick says. "There's a lot of evidence to show that the brain is definitely processing our prior experiences and helping to form new ideas as well."
In a 2002 study, Mednick found that when people took a 60-minute nap, they significantly outperformed those who took 30-minute naps on a visual perception test administered at different points throughout the day. And the non-napping group wasn't even close.
But Mednick says that a 90-minute snooze may indeed be the "perfect nap."
"With a 90-minute nap, you're going to go through all the sleep stages and that's as good as a it gets," she says, citing a 2009 study showing that REM sleep — the deep dream-state only obtainable with at least a 90-minute nap — resulted in a significant improvement on creative problem-solving tests compared with non-REM naps.
Then again, what are the odds that even the grooviest boss is going to be all right with a 90-minute nap in the middle of the day? Mednick says that even a five-minute power nap will improve alertness and push the brain's reset button.
Honor the Nap
Nancy Rothstein is The Sleep Ambassador, a former risk management executive turned sleep evangelist who consults with corporations on smart sleep habits for healthier, happier and more productive workers. She calls it the ROI of a good night's sleep.
To be clear, Rothstein does not believe that naps are the answer to America's national health epidemic of sleep deprivation. In fact, she says that companies that install high-tech napping pods in their break rooms without providing sleep training along with them are "doing a disservice to their workers."
But Rothstein recognizes that harried, under-rested workers may need to take a midday nap from time to time. So if you're going to nap, she says, "you might as well do it right."
"Honor that time," Rothstein says. "Set the phone to silent. Choose a cool, dark and quiet place, or as cool, dark and quiet as you can get. If you work at home, don't nap in bed, because you want to associate your bed with nighttime sleep."
Rothstein strongly warns against taking a nap after 4 p.m., especially if you already suffer from insomnia and have a hard time falling asleep.
"That's not a good idea," says Rothstein. "You'd be better off sitting up, focusing on your breath and taking a 10-minute meditation break."
Nix the Coffee Nap
You've probably heard of the coffee nap, a legendary office worker trick credited to the Japanese in which you chug a cup of coffee or other caffeinated beverage immediately before taking a 20-minute power nap. The idea is that the caffeine will kick in right as you're waking up, giving you twice the bang for your napping buck.
Mednick doesn't recommend it, especially if your coffee nap happens in the early or mid-afternoon. In fact, she doesn't recommend drinking caffeine of any kind after 12 noon.
"Caffeine stays in your body four to six hours," Mednick says. "It's easy to imagine it might help you when you're waking up, but at the same time it might really hurt you trying to get to sleep at night. I would just count on the nap doing what it needs to do and you won't need the caffeine afterward."
Not Everyone is a Napper
If you're one of those people that wakes up groggy and disoriented no matter how short or long you nap, you're not alone. Mednick says that she has data under review that seem to show that roughly half of all people are not natural nappers.
"There's a specific, potentially genetic predisposition to be able to sleep in the middle of the day and wake up and feel refreshed and have your brain be able to recover from such a big change," says Mednick. "People who are not nappers, they actually do feel pretty crappy and don't always show the memory benefits. But there's not a lot of understanding right now about what makes a napper a napper."
It could be that some people are monophasic, meaning they benefit most from one long period of sleep, while others are biphasic, needing two bouts of sleep within a 24-hour cycle.
In Mednick's TEDx Talk, Give It Up for the Down State, she touts the cognitive and psychological benefits of all sorts of restful activities, not just naps.
If a nap leaves you in a lurch, stand up and go for a 20-minute walk instead. Listen to some music. Play the guitar. Play with your kids. Do anything that will unplug your brain from work and refresh you mentally and physically.