Do Power Naps Actually Work? Here's What The Research Says

An increasing number of elite athletes are now prioritizing a midday nap, but does it really enhance their performance?

For most people, the word "nap" conjures images of drowsy toddlers and sleepy seniors.

It doesn't exactly evoke chiseled athletes at the apex of human performance. But the connotations of mid-day naps are changing quickly, as sports teams are leaving no stone unturned in their quest to gain an edge. Clemson football's new $1.5 million complex includes a nap room with eight bunk beds, and the Boston Red Sox recently installed a nap room at Fenway Park. International soccer powerhouse Real Madrid have 81 private bedrooms inside their team facility. Napping during the day has become second-nature for many NBA players, including LeBron James and Steph Curry, and Los Angeles Dodgers ace Clayton Kershaw always takes a brief nap three hours prior to first pitch.

We've long known that sleep has a robust connection to athletic performance, but how powerful can a power nap really be? STACK dove into the research to see just how beneficial a session of mid-day shuteye might be for an athlete.

Research on direct links between napping and athletic performance is surprisingly lacking. One of the few studies that fits into this category is a 2007 study that was published in the Journal of Sports Science. The study examined how a mid-day nap might affect a variety of mental and physical performance metrics after a night of partial sleep deprivation (in this case, participants slept for four hours—from 11:00 p.m. to 3:00 a.m.—the previous night). One group took a 30-minute nap commencing at 1:00 p.m. the following day, while a control group simply sat quietly during this time. The nap group experienced improvements in heart rate, alertness, sleepiness and both 2-meter and 20-meter sprint times. Mean reaction times and grip strength were not affected.

"These results indicate that a post-lunch nap improves alertness and aspects of mental and physical performance following partial sleep loss, and have implications for athletes with restricted sleep during training or before competition," the authors concluded. Obviously, improved sprint speed is a huge benefit for athletes. Improved alertness is another big plus. Though this study might not have found napping to improve reaction time, others have.

A 1995 study from NASA looked at how "strategic naps" might improve the performance of long-haul flight operations. The crew members were randomly divided into two groups. One was allowed a "40-minute nap opportunity" during flights while the other was not. The nap group participants slept for an average of nearly 26 minutes during each nap period. At the conclusion of the study, it was found that the nap group demonstrated a 16% improvement in median reaction times and a 34% improvement in performance lapses over the non-nap group. Improved reaction time has obvious benefits for any athlete, as does enhanced focus.

Napping can also help athletes get into a better head space before training, practice or competition. Researchers from the University of Michigan wanted to see how a midday nap might affect frustration and impulsive behavior. Adult participants—all of whom had a consistent sleep schedule for at least three days prior to the test—were given questionnaires that inquired about their sleepiness, mood and impulsivity. They were also given some cognitive tasks. After this initial testing, one group was assigned to take a 60-minute nap while the other had to watch a nature documentary. Afterwards, they completed the same questionnaire and tasks again. Not only did the nappers report feeling less impulsive, but they exhibited greater patience and commitment to solving the tasks than those who didn't nap. While participants might not have run a 40-Yard Dash or tested their Vertical Jump, this is still valuable insight for an athlete. Imagine the difference between showing up to practice disgruntled and with a short fuse or showing up focused and eager to compete. It's hard to quantify, but there's no doubt attitude can have a significant impact on your performance.

Naps have also been found to aid memory. You don't have to doze off for an extended period of time to experience this benefit, either—a 2008 study found that even a 6-minute nap was sufficient at improving memory. Improved memory offers numerous benefits for an athlete. It could be the difference between remembering the complicated play you installed three weeks ago or totally blanking and blowing your assignment.

A 2011 study in the journal SLEEP found that Stanford basketball players were able to dramatically improve their on-court performance simply by increasing their total amount of sleep time. While the study didn't look at naps exclusively, napping did play a key role in the participants' goal of sleep extension.

Per Standford Medicine:

The researchers asked the players to maintain their normal nighttime schedule (sleeping for six to nine hours) for two to four weeks and then aim to sleep 10 hours each night for the next five to seven weeks. During the study period, players abstained from drinking coffee and alcohol, and they were asked to take daytime naps when travel prohibited them from reaching the 10 hours of nighttime sleep.

While the athletes averaged about 8.45 hours of sleep per night during the sleep extension period (up from 6.66 hours of sleep per night at baseline), that still left them significantly short of their 10-hour goal. Therefore, we can conclude that frequent naps were utilized throughout the study period.

The results speak for themselves. At the end of the study, players ran 282-foot sprints (equivalent to running the full length of the court three times) at an average of 15.5 seconds. That was a significant improvement over the average 16.2 seconds they achieved before the sleep extension. But perhaps even more surprising was the dramatic increase in shooting accuracy. More sleep helped the players increase their free-throw percentage by an average of 9 percent and their 3-point percentage by an average of 9.2 percent. Reported fatigue levels also decreased, and players reported improved performance in practice and games.

A midday nap has been found to improve sprint speed, reaction time, alertness, sleepiness, patience, focus and memory. All of these things can help athletes raise their game in a multitude of ways. While more research needs to be done on the connection between napping and athletic performance, what's available is extremely encouraging. It's also important to remember that naps don't need to be exceedingly long to give you a boost. Napping for too long during the day can actually cause issues, as it may disrupt your nighttime sleep schedule or lead to prolonged sleep inertia (grogginess and and decreased cognitive function). The National Sleep Foundation says 20 minutes is all you need to receive improved alertness, enhanced performance and increased mood. They also warn against napping for 30 to 60 minutes, as that amount of napping allows you to only briefly hit the deeper stages of sleep, which can result in prolonged sleep inertia effects. If you're fortunate enough to find a 90-minute window to nap, and you know it won't negatively effect your nighttime sleep, go for it. The NSF says that should give your body time to go through one complete sleep cycle so you'll wake up feeling refreshed and re-energized.

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