The topic of “power naps” has received a lot of media coverage, and it’s been the subject of much scientific investigation over the past few decades. Do naps really have the benefits they’re purported to have? Professor Vishton assesses the evidence.
Edited by Kate Findley and proofread by Angela Shoemaker, The Great Courses Daily
The Sleep Cycles
Before exploring power naps, it’s important to understand that getting deep, restful sleep—specifically, REM sleep, or dream state—is critical for optimal brain functioning. With this in mind, it cannot be argued that we need eight hours of sleep. A trip through the five stages of a standard sleep cycle takes about 90 minutes.
If you sleep for approximately eight hours, you’ll go through about five of these sleep cycles, each of which culminate in REM sleep. The cycles are all similar, but not exactly the same. Every additional sleep cycle you complete has more and more dreaming.
Your first REM cycle of the night might last only 30 seconds—maybe a minute. The second cycle will tend to be twice as long; the third even longer.
The vast majority of this important brain process takes place in the last two sleep cycles of an eight-hour sleep session. If you reduce your sleep by a couple of hours a night—for example, you sleep six hours instead of eight—you might feel that you’ve still gotten a good night’s sleep.
In terms of total hours, that’s somewhat accurate. You’ve only missed out on about 25% of your sleep time. However, in terms of REM sleep time, you may have cut your night down by 40%.
Napping and REM Sleep
This is why eight hours per night is so important for your brain. With this in mind, Professor Vishton recommends that you don’t take naps, as napping can interfere with your ability to get REM sleep.
If you nap for 90 minutes, you’ll get a full sleep cycle in, including a brief bit of REM sleep. However, if that nap reduces the amount of sleep that you can get the following night, you will greatly reduce the total amount of REM sleep—again, by as much as 40 percent if you lose up to two hours.
What about power naps, though? If you feel tired in the middle of the day, the modern workplace tends to frown on napping. Many people just push through that tired feeling and reach for a cup of coffee or an energy drink.
An alternative that’s been suggested by many people is that we should just let people take a brief nap. Most companies would prefer to not pay their employees for sleeping on the job, but perhaps if you let people sleep for 20 minutes, you could get more productive work out of them throughout the rest of the day.
That sounds better than having a groggy employee doing mediocre work and perhaps even doing some bad work that’ll need to be undone in the future. Google and a few other companies have gone so far as to install napping pods at various locations around their campus.
Pros of Power Naps
That’s the idea, but is there science to support it? The good news for power nappers is that a 20–60 minute nap—less than a full cycle, without REM sleep—does boost cognitive function. Data indicates that these short naps lead to faster reaction times, better working memory, and better problem-solving abilities.
The bad news for power nappers is that essentially all these studies have been done with participants who were sleep-deprived. When experimenters conduct studies of power napping, a standard procedure is to start by asking participants to reduce their nightly sleep by about an hour-and-a-half or two hours for at least one night before they participate in a power nap experiment.
In some highly cited studies on this topic, participants have been prevented from sleeping for over 24 hours prior to participating. If you’re sleep-deprived, a power nap will help you, but it is a quick fix for a habit that is likely causing damage in the long run. If you’re not sleep-deprived, then you probably won’t nap when you’re given the opportunity.
According to Professor Vishton, you’ll receive more benefits from getting a full eight hours of sleep. Rather than trying to repair the damage caused from sleep deprivation by taking a power nap, he recommends that you try his challenge instead: Get eight hours of sleep a night for two weeks.
“If you decide that it’s not worth it, you can always go back to the shorter sleep times that you’re using now,” Professor Vishton said.
This article was edited by Kate Findley, Writer for The Great Courses Daily, and proofread by Angela Shoemaker, Proofreader and Copy Editor for The Great Courses Daily.
Peter M. Vishton is Associate Professor of Psychology at William & Mary. He earned his PhD in Psychology and Cognitive Science from Cornell University. Before joining the faculty of William & Mary, he taught at Northwestern University and served as the program director for developmental and learning sciences at the National Science Foundation.