Only about a third of American adults nap, according to a 2009 Pew Research Center study -- mostly men over age 50. Women nap less than men, although they suffer more daytime sleepiness, in part because of their roles as caregivers to the young and old. Home health aides -- a largely female occupation -- topped 2012's most sleep-deprived jobs, in a list issued by Sleepy's, a mattress company, which used U.S. Centers for Disease Control and Prevention data. (Next came lawyers, police officers, doctors and paramedics, social workers, and computer programmers.)
"Do the best you can," says Karl Doghramji, director of the Jefferson Sleep Disorders Center at Jefferson University Hospital in Philadelphia. "If you're sleepy and you need to nap, taking one that's less than optimal is better than no nap at all."
But to get the most from your rest, try these nap tactics:
Customize your start and stop times.
There's no one-size-fits-all ideal nap. For most people, there's a window of opportunity around 1 p.m. to 2 p.m., when humans experience a dip in their circadian rhythm, says Doghramji, causing energy to flag. This roughly corresponds to a dip in the body's internal clock 12 hours earlier, or between midnight and dawn, when we sleep most deeply. Almost everyone experiences this post-lunch dip -- regardless of what they ate at midday.
The ideal nap length to reduce sleepiness and improve general thinking skills (like boosting alertness), with the fewest side effects, is ten minutes, according to a 2006 Australian study in the journal Sleep. In these so-called "power naps," you wake up before transitioning to deep sleep. A five-minute nap, in contrast, gave little benefit.
But longer naps can work, too. "A 30- to 45-minute nap hits the magic number for most sleep-deprived people," Doghramji says.
Consider what your brain might need from sleep. Thirty-minute naps tend to bring on a deeper sleep state that's good for remembering things, research has shown -- smart for students studying, for example -- but can be harder to snap out of. A really long shut-eye -- 90 minutes or so -- is thought to boost creative thinking because you rotate through an entire sleep cycle. Ninety-minute naps have also been found to enhance calm.
Factor in how well you're sleeping at night. To figure a good nap length for yourself, experiment. "Start with a half-hour nap -- that's the amount many studies of shift workers are based on," Doghramji says. "If it helps, stick to it or even try expanding the nap. But if it disrupts your night sleep, cut back." If you have trouble with sleeplessness at night, limit naps to no more than ten minutes. Or avoid napping altogether, Doghramji says. Daytime sleep will further interfere with your already-impaired ability to fall asleep and stay asleep at bedtime.
Don't start too late. Unless you're working a night shift or partying late, you don't want to nap after 3 p.m., suggests the National Sleep Foundation, or you may pay for it with troubled night sleep.
Set an alarm to wake you up. Use your mobile phone alarm. Or consider one of the many sleep-tracking gadgets, like Sleeptracker, a watch containing a tiny motion sensor that reads when you're sleeping restlessly, which can signal a shift to a lighter sleep phase. The idea is that this awakens you at an optimal time, when you're less apt to be groggy.
Drink some coffee first.
Caffeine is a stimulant that helps you stay awake -- which is why many people lean on coffee and energy drinks to plough through a busy day. Unfortunately, caffeine is less effective at keeping you awake than a good old nap, research shows.
There is a way to use caffeine to enhance the benefit of napping, however. Because caffeine takes about 15 to 30 minutes to have an effect after it's swallowed, some sleep experts suggest drinking a cup of coffee or another caffeinated beverage right before you nap. That way, when you awaken in 10 or 15 minutes, the caffeine will kick in and give you an energy jolt on top of the restorative effects of sleep.
Use a "caffeine nap" on long drives, too. This finding is based on British comparative research that found the caffeine-plus-nap combo was more effective for helping sleepy drivers than either using caffeine alone, cold air, the radio, getting more nighttime sleep, taking a placebo, or using rest alone. The National Sleep Foundation recommends that sleepy drivers pull over in a safe spot, drink a caffeinated drink, and sleep for 20 minutes or so before driving again.
Quit caffeine for the rest of the day. Continuing to guzzle black coffee and power drinks will only interfere with night sleep.
More secrets to great naps
Figure out your best nap triggers.
The most reliable way to train yourself to nod off is to make napping a regular habit: same time, same place every day.
Sleep triggers -- the atmosphere and other prompts you create for sleep -- can also help you fall asleep faster. But your nap triggers shouldn't be the same ones you use at bedtime, because you don't want to lull your body into hours of uninterrupted slumber.
It's best to skip the pj's, for example. And although darkness helps with nighttime sleeping, there's no need to obsess over eyeshades and blackout curtains to block out daylight. A small 2011 study at the University of California, San Diego, found that light had no effect on the ability of subjects to fall asleep or stay asleep during afternoon naps.
Try a hammock or a rocking chair. A rocking motion really does lull most people to sleep faster, found a 2011 study of brain waves in sleeping adults, reported in the journal Cell Biology. The rocking nappers tested also fell into a deeper sleep.
Offload your worries. Sleep-medicine specialists often recommend that insomniacs write in a diary or write lists of their stressors before they go to bed at night. Instead of keeping such concerns top of mind, the act of putting them on paper seems to put them aside. The same idea can work at naptime.
Keep your cool. People sleep better when it's colder. Try adding a sweater or snuggling under a warm blanket in a room with the thermostat set low.
Try an app to help you nap. Download the mindless sounds of water, waves, birds, crickets, white noise, or other soothing sounds on your iPod or mobile phone. Some nappers swear by a hypnosis track. Sleep tracker apps can help you record total zzz's.
Get over the embarrassment and guilt.
One surprising impediment to napping: people's hang-ups about taking them. After all, we don't live in a siesta culture. "At work, napping is considered a weakness, and people are embarrassed to take them," says Doghramji. Even people who work from home, like caregivers, are reluctant to "sleep when the baby (or Grandpa) sleeps" because napping is so deeply associated with sloth.
Remind yourself of the health benefits. Napping not only gives energy to the sleep-deprived, it's been shown to boost memory, productivity, creativity, and mood. An afternoon nap can lower blood pressure and is even associated with reduced risk of death from coronary heart disease, researchers reported in the Archives of Internal Medicine in 2007. Not bad results from a 10-, 20- or 30-minute investment.
Tell yourself you're in good (and trendy) company. A 2011 human resource study found that 6 percent of workplaces -- including Google -- had nap rooms, a slow but steady increase over the previous year. Another poll by the National Sleep Foundation found that 34 percent of those surveyed said their employers allow them to nap at work. New guidelines even recommend napping for medical residents, a population that was once encouraged to work nonstop marathon hours.
Remember that napping is portable. Can't get to your cozy bed? You can nap anywhere, even sitting up. If your company isn't among the cutting edge with "energy pods" (like Google) or "quiet rooms" (like Nike), try lying down on your office or conference room floor with your feet against the door. Or bring a yoga mat you can set down in a break room -- or go to your car during lunch to nap for 15 minutes after you eat.
Give yourself time to snap out of it.
If you nap longer than ten minutes, you'll probably suffer from something called "sleep inertia," that groggy, sluggish feeling that persists right after you wake up. It can make you feel more tired than before the nap, which puts many people off the very idea of napping, though it's a temporary sensation. Studies of shift workers and pilots (known to catnap while waiting in long takeoff lines) have found that when you hustle and go immediately after sleep, you're more apt to make mistakes and function more poorly, Doghramji says.
Transition back to focused work. Don't schedule an important meeting, task, or conversation for the first ten minutes or so after a nap.
Nap for shorter or longer periods if the grogginess bothers you. In general, beyond 10 minutes, the longer the nap, the more likely you are to be affected by sleep inertia. Exception: a full-blown 100-minute nap. That's long enough to go through the entire sleep cycle.