Napping's not such a no-no, after all -- but do it right
The nap has long been the troubled stepchild of the universally admired good night's sleep. At work, if you get caught napping, it could get you into trouble or, more mildly, sully your reputation for diligence.
In studies, naps have been linked to ill health, although usually as a consequence, not a cause. And in sleep recommendations, naps have taken a back seat - or been cast as a threat to nighttime sleep. On its Web site, the American Academy of Sleep Medicine tells people to "avoid taking naps if you can."
But lately, naps have been shedding some of their bad-for-you image. Researchers are finding benefits. A few employers have become accommodating of the quick snooze. And some research suggests that instead of fretting about napping more as we get older, we should plan on adding daytime sleep to our schedule as a way to make up for the normal, age-related decay in the quality of our nighttime sleep.
Naps, of course, can be an antidote to daytime sleepiness, and we get sleepy during the day for a wide variety of reasons. There is a biological clock located in a cluster of cells in the hypothalamus of the brain. Those cells orchestrate the circadian (that is, daily) ups and downs of many physiological processes (body temperature, blood pressure, secretion of digestive juices), including sleep and wakefulness.
As you might expect, the usual circadian pattern is wakefulness during the day followed by gradually increasing sleepiness in the evening, but it's also common to have a little "hump" of midafternoon sleepiness programmed into the circadian schedule. An afternoon nap is one way to accommodate that hump.
In 2008, British researchers reported results of a study that compared getting more nighttime sleep, taking a nap, and using caffeine as ways to cope with the afternoon hump. The nap was the most effective.
Another factor in daytime sleepiness is the number of hours you've been awake. After about 16 consecutive hours without sleep, most of us will start to feel tired. If you work a night shift, or have problems sleeping at night, your 16-hour allotment of wakefulness may begin - and end - earlier, which can set you up for grogginess in the late afternoon or early evening. A short nap won't completely reset the timer, but it can buy you some time before the grogginess sets in again.
A few tips:
• Keep it short. The 20- to 30-minute nap may be the ideal pick-me-up. Longer naps can lead to sleep inertia - the post-sleep grogginess that can be difficult to shake off.
• Find a dark, quiet, cool place. You don't want to waste a lot of time getting to sleep. Reducing light and noise helps most people nod off faster. Cool temperatures are helpful, too.
• Plan on it. Waiting till daytime sleepiness gets so bad that you have to take a nap can be uncomfortable and dangerous if, say, you're driving. A regular naptime may also help you get to sleep faster and wake up quicker.
• Time your caffeine. Caffeine takes some time to kick in. A small Japanese study published several years ago found that drinking a caffeinated beverage and then taking a short nap immediately afterward was the most restful combination because the sleep occurred just before the caffeine took effect.
Since 2000 or so, researchers at Harvard University and elsewhere have conducted dozens of experiments that have shown that sleep improves learning, memory, and creative thinking. Even catnaps of six minutes have been shown to make a difference in how well people retain information.
Robert Stickgold, a Harvard sleep researcher, says napping makes people more effective problem solvers. His research group has shown that taking a nap seems to help people separate important information from extraneous details. Stickgold says his and others' findings argue for employer policies that actively encourage napping, especially in today's knowledge-based economy. Some companies have set up nap rooms, and Google has "nap pods" that block out light and sound.
Understandably, employers are concerned about abuse: employees catching up on sleep they should be getting on their own time. But there may be a place for "strategic napping," especially among people who work a night shift. Results from a New Zealand study published in 2009 showed that air traffic controllers working the night shift scored better on tests of alertness and performance if they took advantage of a planned nap period of 40 minutes.