Why a Coffee Power Nap Works

Drink Coffee Before a Nap To Feel More Rested

If you drink coffee before a 20 minute power nap, you'll be more refreshed and awake than if you took a nap and then drank coffee.  Glow Images, Inc, Getty Images

By Anne Marie Helmenstine, Ph.D.

You're tired, but you don't have time to really sleep. Rather than taking a power nap or grabbing a cup of coffee, try taking a coffee power nap. Here's what a coffee power nap is and why it actually leaves you feeling more refreshed and awake than either a power nap or a cup of coffee or even a nap followed by coffee.

What Is a Coffee Power Nap?

A power nap is a short nap (15-20 minutes) that takes you into stage 2 sleep. It's just long enough to stave off some of the worst effects of sleep deprivation or exhaustion, but not so long that it drags you into slow wave sleep (SLS) or deep sleep, which would leave you feeling groggy if you ended it too soon (sleep inertia). Research has shown that even a 6-10 minute nap helps improve concentration, alertness, motor performance, and learning, while a 30 minute nap confers the benefits of a full sleep cycle, markedly reducing fatigue and reversing much of the physiological damage of sleep deprivation.

A coffee power nap or caffeine power nap is when you drink coffee or a caffeinated beverage right before settling down for your nap.

How a Coffee Power Nap Works

The short explanation is that it takes about 20 minutes for caffeine to jolt your system and 45 minutes before it reaches maximum effect. So, the caffeine doesn't keep you from falling asleep, but it's there to boost your performance the minute you wake up.

Here's the longer explanation: When you drink coffee or tea or your favorite energy drink, the caffeine is absorbed into your blood stream through the walls of the small intestine. From there, the molecule travels to your brain, binding to the receptors that would accept adenosine, a molecule that accumulates when you are tired and causes you to feel sleepy. So, about 20 minutes after taking it, caffeine helps you feel more awake because additional adensoine can't find a binding location. When you sleep, even if it's just a quick nap, your body naturally clears the adenosine from the neural receptors. This is why you feel more awake after a nap.
When you drink coffee and take a nap, the sleep clears the adenosine so you wake up feeling refreshed, and then the caffeine kicks in and blocks the receptors so you won't get tired again as quickly. Plus, caffeine boosts your metabolism and gives you all those other great stimulant side effects. It's a win-win situation.

How Do We Know It Works?

Scientists can't get into your brain to see the neural receptors and measure binding rates, but the effects of the coffee power naps have been observed. One study conducted by scientists at Loughborough University in the UK found that tired study participants made fewer mistakes in a driving simulator following a 15-minute coffee power nap. They got the benefits of the nap even if they reported having trouble falling asleep. Japanese researchers found test subjects performed better on memory tests and felt more rested following caffeine naps. The Japanese study also indicated exposure to bright light following a nap or washing your face could help wake you up.

Of course, I advise you to conduct your own experiment to test out the coffee nap for yourself!

How To Take a Coffee Nap

1. Drink coffee or tea containing 100-200 mg of caffeine. Don't add sugar or milk. If you choose an energy drink, go sugar-free or else the surge in blood glucose levels may keep you from falling asleep. Alternatively, you could take a caffeine pill.
2. Set your alarm for 20 minutes. Don't go past 30 minutes because the coffee nap works best if you're awake when the caffeine hits your system.
3. Relax. Sleep. Enjoy. It helps to wear an eye mask or turn out the lights. It's okay if you can't fall all the way asleep. Research indicates even deep relaxation, such as meditation, makes a big difference.
4. Wake up feeling refreshed!