The afternoon 'activity' that boosts energy

By Jeremy Fuchs
Published October 6, 2020

Key Takeaways

Napping is just happy hour for lazy people, right? Maybe not. Turns out that a quick midday snooze might be the most productive way to spend part of your afternoon.

A growing pool of evidence suggests that napping for a short period of time can be beneficial to both physical and mental performance. That’s why the US Army, for the first time ever, is encouraging soldiers to take naps, as noted in its new physical fitness training manual. “Soldiers can use short, infrequent naps to restore wakefulness and promote performance,” according to the manual. “When routinely available sleep time is difficult to predict, Soldiers might take the longest nap possible as frequently as time is available.”

You may not be gearing up for battle, but if you’re looking to gain an edge for your next intense workout, or to improve mental performance before a high-stakes surgery, lying down might be the best way to get a leg up.

Sound sleep, sound body

In sports, the pregame nap is nothing new—professional athletes in the NBA and NHL swear by the tradition. Even if they’re unaware of the science behind the process, there’s no mistaking the benefits—a quick nap pays dividends come game time, especially if you’re looking to recapture the benefits of last night’s poor sleep.

These benefits were illustrated in a study published in Medicine & Science in Sports & Exercise, which examined 13 elite-level karate athletes. After randomization for either a 30-minute nap or no nap, as well as for a typical sleep night or a partially deprived one, athletes completed karate-specific tasks. Scientists measured their capabilities by reaction times and their ability to complete squat and countermovement jumps. The study found that, when partially sleep deprived, athletes who took a nap were able to restore alertness. The naps prevented any reduction in performance, too.

Naps also appear to restore physical performance. A study in Chronobiology International measured soldiers’ performance on several exercises before and after sustained operations. The study included 61 cadets, half of whom napped for 30 minutes before exercise, and half who didn’t. The two groups completed 2 minutes of lunges and a 3,000-meter timed run. Following these military activities, those who didn’t take a nap saw their total lunge repetitions decrease by 2.3%, while those who napped saw a 7.1% increase in the number of lunges. In the 3,000-meter run, those who didn’t nap saw a 2.3% decrease in performance, while those who napped saw no statistically significant difference in performance.

It’s not entirely clear how nap length correlates with performance improvement. But it appears that any nap between 25 and 45 minutes is better than no nap at all. For example, in a study in Frontiers in Physiology, 17 fit men took a nap for 25 minutes, 35 minutes, or 45 minutes, or none at all, before engaging in a 5 m shuttle run. For those who napped, the average best distance increased, as much as 9% for those who napped for 45 minutes. Those who didn’t nap or napped for just 25 minutes had significantly higher rates of perceived exertion than those who napped for 35 minutes or more. Despite the underwhelming results of 25-minute naps, researchers concluded that athletes would benefit from a minimum 25-minute nap before exertion.

Even though there’s plenty of research to support the hypothesis that naps improve physical performance, caution is needed. There’s still a lot we don’t know, including the ideal nap length, the best time of day for a nap, when to nap in relation to desired time of peak performance, and much more. Plus, the evidence isn’t overwhelming and some studies suggest napping might even have undesirable effects on physical performance.

For example, a study in the International Journal of Sports Physiology and Performance monitored adolescent student track athletes, 12 of whom were shooters and 12 of whom were sprinters. The study found that naps had no effect on shooting function, while average sprint times actually increased, which researchers contributed to sleep inertia. What’s more, some research has found that frequent napping is associated with negative outcomes, including hypertension and diabetes, especially in older populations.

When it comes to studying sleep, there are tons of variables at play that make it difficult to prove that naps produce better exercise. Still, according to a growing pool of data, catching some quick Z’s before a workout appears to improve physical performance and stamina.

Sleep well, think well

What about cognition? Can napping have the same effect on our mental performance as it does on physical exertion?

Yes, similar benefits appear to be at play, according to the evidence.

A study in the Journal of American Geriatrics followed 22 men and women, between the ages of 50 to 83, who took either 45-minute or 2-hour naps. Regardless of napping time, participants increased their nighttime REM sleep—a period that experts believe is key for memory consolidation—and improved their performance on cognitive assessment tests.

That cognitive improvement is why people in high-pressure jobs with high cognitive loads—just like those who work physically demanding jobs—tout naps as a restorative tactic to improve performance at work. A NASA study that looked at pilots on long flights found that 26-minute naps improve alertness by 54% and performance by 34%. “Naps can maintain or improve subsequent performance, physiological and subjective alertness, and mood,” one of the study’s authors told The Guardian.

A review in Sleep Medicine concluded that, in young people, a midday nap minimizes sleepiness, enhances executive function, and facilitates memory consolidation and emotional processing. “In young, healthy populations who are in need of emotional or cognitive intervention, napping could be prescribed,” the authors wrote.

However, that same study found that those benefits do not necessarily extend to the older population, in which frequent napping was linked with cognitive decline. Because of these outcomes, more data are needed, so it’s probably premature to “prescribe” naps as a health enhancer for the older population.

Nappers of the world, rejoice

It may be time to shed ourselves of the association between napping and laziness. Evidence suggests that napping can provide profound physical and cognitive benefits, as has been demonstrated in studies of athletes and those in high-stress jobs.

But, until more studies monitor the long-term effects of regular napping, as well as its effects on older populations, there’s no guarantee that a nap is a silver bullet for better health.

That said, if you slept poorly last night or need a little boost this afternoon, a short siesta could be the best way to escape the mid-day blues.

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