Even on the best of days, life can be exhausting. If you find your energy flagging in the middle of the day, you might like to know that 34 percent of Americans nap. Napping is a healthy way to restore the deficits of sleep deprivation. Whether you bow down to the ritual of a mid-afternoon siesta or never stop to snooze, you may think twice about the power of napping after reading about these eight benefits—just in time for National Nappy Day.
1. Napping can boost your immune system.
Sleep deprivation—particularly repeated, chronic lack of sleep—takes a toll on your neuroendocrine and immune functions by increasing inflammatory molecules known as cytokines, as well as stress hormones like cortisol and norepinephrine. A 2015 study in the Journal of Clinical Endocrinology & Metabolism took 11 healthy young men and restricted them to a night of only two hours of sleep. Blood and urine tests measured higher cytokines and levels of norepinephrine in both groups after sleep deprivation. The following day, one group was given two half-hour naps, while the control group did not have any naps. Blood and urine samples of those who napped showed that their cytokines and norepinephrine levels had returned to normal, as though they had never lost a night of sleep.
2. A nap can improve night alertness.
For people who work at night, or through the night, several studies have shown that naps from between 30 minutes and four hours long that are taken in advance of the shift—what's known as a "prophylactic nap"—improve performance and alertness. These naps can also improve nighttime driving alertness on the way home from the shift. However, most of these studies also include the administration of caffeine, which likely contributed. Yet a 1995 study in Sleep, which compared naps and caffeine, found that "naps, in general, provided longer and less graded changes in performance, mood and alertness than did caffeine, which displayed peak effectiveness and loss of effect within about six hours."
3. Naps + caffeine are a one-two punch against sleepiness. Just ask a surgeon!
Surgeons must often perform continuous surgery for hours longer than the average person would ever have to persist at a task. A 1994 study in the journal Ergonomics found that naps were indeed effective at keeping surgeons who had to remain awake for 24 hours alert, but only when caffeine was administered, too. Neither naps or caffeine alone were sufficient.
4. Frequent naps can improve daytime alertness.
Daytime napping also appears to improve mental alertness and performance, according to a number of laboratory studies. However, researchers found that shorter naps were more effective than longer ones. The most effective time of them all was 10 minutes, which produced the best outcomes in all sleep measures including "subjective sleepiness, fatigue, vigor, and cognitive performance." A 30-minute nap could produce the same effects but brought about "a period of impaired alertness."
5. Naps can help you learn new skills.
If you want to get better at learning a new skill, you might want to take more frequent naps. A 2006 study in Biological Physiology broke participants into two groups: those who napped frequently and those who napped sporadically. Each group was given a nap before a reading task. Habitual nappers—people who reported napping frequently—did better on the reading and retention task. Researchers determined that the brains of habitual nappers consolidated motor learning better, which is part of the process of learning a new skill.
6. Napping can improve your physical stamina.
It turns out that napping is not only just good for mental processes, but has a positive impact on physical stamina and performance as well. A 2007 study in the Journal of Sports Sciences put 10 healthy men through a series of sprints before and after a 30-minute, post-lunch nap. Sprint times improved after the naps, suggesting to the researchers that a post-lunch nap "improves alertness and aspects of mental and physical performance following partial sleep loss." They suggest that napping may be an important part of the regimens of athletes who are undergoing restricted sleep during training or competition.
7. Want to improve your memory? Take a nap!
One of the many functions of regular nighttime sleep is to consolidate memory. A 2010 study in Neurobiology of Learning and Memory set out to see whether daytime naps also improve memory processes, particularly associative memory (the ability to make connections between unrelated objects). Thirty-one healthy participants were given a learning task at 12 p.m. to memorize two sets of face-object photograph pairs. The objects in each pair occurred in both sets but were paired with different faces. Participants were broken into two groups: those who had a 90-minute daytime nap or those who did not. At 4:30 p.m., participants who napped showed notably better retention of associative memory.
8. A 90-minute nap is as good as a full night's sleep for perceptual learning.
Previous research demonstrated that people perform better on a visual texture-distinguishing task after a night of sleep than they do immediately after learning it. A 2003 study in Nature Neuroscience found that people performed just as well on the test after a 60- to 90-minute nap as they did after a full night of slumber.
"What's amazing is that in a 90-minute nap, you can get the same [learning] benefits as an eight-hour sleep period," lead author Sarah Mednick said in an interview with the American Psychological Association. "The nap is having an additive benefit on top of a good night of sleep."
This article originally ran in 2017.