It’s mid-afternoon and you’re struggling to stay awake. Which is better? Grabbing a cup coffee or taking a 20-minute power nap? Surprisingly, it’s doing both together.
Drinking a cup of coffee then taking a quick nap is called a “coffee nap,” and scientists have found it maximizes alertness.
The idea sounds counterintuitive. After all, doesn’t caffeine actually inhibit sleep? Yes – but not if you drink coffee immediately before napping then sleep 20 minutes or less. In that case, you actually take advantage of an odd fluke in the manner that both caffeine and sleep affect your brain.
After you drink a cup of coffee, the caffeine enters your bloodstream and flows into your brain. There, it enters receptors in your brain that are usually filled by adenosine, a similarly-shaped molecule that is the byproduct of brain activity. When enough adenosine accumulates, it makes you feel tired. Caffeine, on the other hand, blocks the receptors from accumulating adenosine.
The reason coffee naps work is it takes about 20 minutes for caffeine to enter the bloodstream and hit the brain’s receptors. When the caffeine arrives at the brain, it only hits some of the adenosine receptors. However, sleeping naturally clears the adenosine from those brain receptors.
So, if you can sleep for 20 minutes right after you drink a cup of coffee, you’re clearing out those adenosine receptors, then waking up right around the time the caffeine hits the brain.
Here are a few things to keep in mind when taking a coffee nap:
While researchers have not actually observed how a coffee nap impacts the brain, they have studied the effects of coffee naps.
For example, a few studies by researchers at the UK’s Loughborough University have found that sleep participants who took a 15-minute coffee nap performed better in a driving simulator than when they were given only coffee or only took a nap.
Another Japanese study determined that people who took a coffee nap did significantly better on a series of memory tests than those who only took a nap. This study found participants also did better with coffee naps than with naps plus washing their faces, or naps plus having bright light shined in their eyes, two other stimuli that have been proven to help sleepiness.
So the next time you feel yourself struggling to stay awake mid-afternoon, grab a quick cup of coffee then take a short rest. Studies show you’ll feel better and more alert in no time.