Training You Can Do With Your Eyes Closed

"Napping is a huge, hidden opportunity for athletes to improve their performance without having to 'do' much", says Amy Bender, an adjunct assistant professor of kinesiology at the University of Calgary in Canada.

Part of the benefit of a proper nap is that it activates your parasympathetic nervous system (aka a "rest and digest" response), which brings your body back to homeostasis. It slows your heart rate, decreases blood pressure, relaxes your muscles and increases your energy storage, says Bender. It's only when all of those physiological changes reduce your body's stress that you're able to recover. Think of a nap like a system reboot: Powering down and switching off completely can reduce sluggishness when you power back up.

"Even a short nap can enhance alertness and reaction time", says Cheri Mah, MD, a physician scientist at the UCSF Human Performance Center and a Nike Performance Council member who specialises in sleep and performance in elite athletes. Naps can also lower your rate of perceived exertion (RPE, or how hard you feel like you're working) during a workout and improve your same-day endurance, research shows. Between the two, you may be more likely to max out during a HIIT workout or tack extra mileage onto a run.

Having a snoozing strategy that meets your particular needs is what can unlock these game-changing perks. Here's how to do a midday doze right.

If you're looking to perform your best during an afternoon or evening workout, try to get your nap in between 1 and 4 pm, says Bender. "That aligns with the natural circadian dip in alertness we all have in the afternoon, and it's not so close to bedtime that it's going to impact your ability to fall asleep at night".

How soon you're planning to work out afterwards also matters. Especially after naps lasting 90 minutes or more, you want to give yourself 95 to 155 minutes before you train, to shake off sleep inertia—that slow, heavy feeling you get right when you wake up—says Bender.

If you're taking a shorter nap, you might benefit from less lag time between sleeping and exercising. A study published in The Journal of Biological and Medical Rhythm suggests that a 25-minute nap that ends two to three hours before your session might be better for your performance than one that ends four hours before. The exact reasoning is TBD, but Bender thinks that a two- or three-hour window could be the right balance between sluggishness wearing off and alertness kicking in.

Yep, science shows that even 10 minutes can be restorative. In a study published in the journal Sleep, researchers found that a super-short nap after a night of poor shut-eye can immediately increase alertness and boost cognitive performance for up to three hours. Though the participants responded to a test battery, which included visual reaction time and cognitive tasks, better attentiveness and brain function may help you recall choreography or react faster to dynamic movements.

The National Sleep Foundation considers this the ideal length. It allows you to tap into benefits like improved alertness, enhanced task performance and confidence in said performance, stronger determination and an improved mood. That's probably why this sweet spot is commonly referred to as a "power nap".

A half-hour nap can help you overcome mental and physical declines in performance caused by either sleep loss or training fatigue in the afternoon, found research published in Medicine & Science in Sports & Exercise. Taking one before a workout or fitness event when you're feeling off can be a good idea, because you won't get into the deeper stages of sleep that make you feel groggy, says Bender.

In a study published in Frontiers in Physiology, researchers found that a 45-minute nap was the best for improving performance and reducing RPE scores during a 5-metre shuttle-run test. In this case, the deep sleep actually pays off: Stage 3 sleep, which you typically enter after 30-ish minutes, is crucial to recovering from the wear and tear of training.

The time to take a seriously long siesta is when you didn't get a solid night's sleep, says Bender. This longer nap should get you through a complete sleep cycle with time in light sleep and deep sleep, which is when human growth hormone is released to kick-start recovery, she explains. You'll also get some REM sleep, which research shows helps boost memory (key for learning a new exercise), and you'll still wake before entering a new cycle, when you're more likely to hit snooze. Pro tip: Set your alarm for slightly more than 90 minutes. This will give you time to fall asleep and make you more likely to wake up naturally before your alarm goes off.

There aren't any hard and fast rules on how often you should be catching midday Zs. Bender recommends athletes nap at least three times a week, or every other day. And the amount of time in each sleep stage is different when sleep is consolidated versus when it's broken up, says Dr Mah, so on days your body needs legit recovery, prioritise a solid eight at night instead.

The only thing you don't want to do? Depend on naps as a fix for consistently poor sleep. A nap should be one piece of your recovery toolbox—not a go-to in your first-aid kit.