To nap, or not to nap. That is often the question when the mid-afternoon doldrums hit. Napping has several benefits including boosting memory, fighting fatigue, reducing stress, and empowering your immune system, but you have to make sure that you nap for the right length of time, otherwise you’ll feel more tired than you did when you started the nap. To help you understand what the optimal nap length is, we’ll explain how sleep works so you can harness the power of a nap.

How Sleep Works

Sleep is a fascinating biological need all of us have. More and more researchers have been studying why we sleep and have found that we need sleep for memory retention, physical recovery, learning, and so much more. They’ve also come to understand how sleep works, and it comes down to two things: sleep pressure and sleep stages.

Sleep Pressure

In his book, Why We Sleep, Matthew Walker explains that sleep pressure is a combination of three different things: circadian rhythm, adenosine, and melatonin. Our circadian rhythm is our internal clock that signals to the brain when it is time to be awake and when it is time to sleep. When our internal clock signals to the brain that it is time to wake up, adenosine slowly begins to accumulate in our brains throughout the day. Adenosine is a hormone that gradually tells our brain activity to slow down so we’re tired by the end of the day. It is at its lowest in the morning and highest at night right before you fall asleep. In addition to our circadian rhythms and adenosine, melatonin plays a huge role in sleep pressure. When your circadian rhythm recognizes that it’s getting dark, the hormone melatonin is released and signals to our brains that it's time to fall asleep. Between circadian rhythms, adenosine, and melatonin, we’re sure to feel sleepy at the end of the day—unless you’ve had caffeine in the afternoon, but that’s an entirely different conversation.

Sleep Stages

Once we fall asleep, our brain starts to go through different sleep phases, and each phase has a distinct purpose. When you first fall asleep, your brain enters light NREM—Non-REM—sleep. Your body then transitions into deep NREM sleep, which is critical to restorative sleep for your body and mind. Once your body has passed through deep NREM sleep, it goes back into light NREM sleep and then enters REM—rapid eye movement—sleep. REM sleep is essential for memory, learning, and creativity, and it is also the stage in which the most vivid dreams occur.  Your brain will cycle through these sleep stages anywhere between four to six times in one night, and each stage is essential to getting all the benefits sleep can provide.

Harnessing the Power of a Nap

You may be thinking, this information is all fine and dandy, but what about naps? Actually, sleep pressure and sleep stages have a lot to do with the optimal nap length, and here are a few nap tips that will explain why.

Nap Before 2:00 or 3:00 PM

Napping in the mid-afternoon is the best way to make sure your circadian rhythm stays on time. If you nap any later than that, you may disrupt your sleep at night, which is what you want to avoid.

Set Your Alarm for 20 Minutes

Setting an alarm and napping for 10-20 minutes allows you to get into the restorative stages of light NREM sleep. If you sleep longer than 20 minutes, say 30-40 minutes, your body will slip into deep NREM sleep, which will make you feel groggy when you wake up. Taking an even longer nap, such as a 90-minute nap, will make your body slip into REM sleep, so you’ll feel even more tired and have trouble sleeping at night.

Nap Sitting Up 

This one may sound a bit odd, but napping while sitting up is a great way to get just the right amount of sleep. If you nap while sitting up and hold a pencil in your hand with your palm up on the arm of a chair, the pencil will drop out of your hand when your body starts to relax into deep NREM sleep. When the pencil drops, it will make noise to wake you up and prevent you from sleeping too much. 

The next time you feel sleepy after lunch, remember that it’s perfectly acceptable to take a nap. Naps have huge health benefits, but make sure you only nap for about 10-20 minutes.

Learn More: 

Napping

Stages of Sleep

How Long Is an Ideal Nap?