Drinking coffee before a nap may seem counterintuitive.
However, many people endorse this habit as a way to boost energy levels.
This article provides a detailed look at the science behind coffee naps and whether they offer benefits.
What Is a Coffee Nap?
A coffee nap refers to drinking coffee before sleeping for a short period of time.
This is thought to boost energy levels because of its effect on adenosine, a chemical that promotes sleep (1).
When you feel tired, adenosine circulates through your body in high amounts. After you fall asleep, adenosine levels begin to drop.
Caffeine competes with adenosine for receptors in your brain. So while caffeine doesn’t decrease adenosine in your body as sleep does, it prevents this substance from being received by your brain. Therefore, you feel less drowsy (1, 2, 3).
Scientists suspect that drinking coffee before a nap may boost energy levels, as sleep helps your body get rid of adenosine. In turn, caffeine has to compete with less adenosine for the receptors in your brain (1).
In other words, sleep may enhance the effects of coffee by increasing the availability of receptors for caffeine in your brain. That’s why a coffee nap may increase energy levels more than just drinking coffee or sleeping.
You may think that drinking coffee would prevent you from napping, but keep in mind that it takes some time until your body feels the effects of caffeine.
A coffee nap entails drinking coffee before sleeping for a short period. It’s thought to boost energy levels by increasing your brain’s capacity to receive caffeine.
Timing Your Coffee Intake and Naps
Most experts propose that the best way to take a coffee nap is to consume caffeine right before falling asleep for approximately 15–20 minutes (4, 5).
This timing is suggested partially because it takes about that long to feel the effects of caffeine (5).
Moreover, you may fall into a type of deep sleep called slow-wave sleep if you sleep for a half-hour or more.
Waking up during slow-wave sleep can lead to sleep inertia, a state of drowsiness and disorientation. It’s thought that limiting coffee naps to less than 30 minutes may prevent this (6).
The time of day that someone takes a coffee nap may also be important.
One small study in 12 healthy adults found that participants who had 400 mg of caffeine — the equivalent of four cups of coffee — six, three or zero hours before bed all experienced disrupted sleep (7).
This research indicates that it may be best to take coffee naps more than six hours before bedtime.
Finally, the amount of caffeine consumed before a coffee nap appears to impact its effectiveness.
Most research suggests that 200 mg of caffeine — about two cups of coffee — is the approximate amount you need to feel more alert and energized upon waking (4, 5, 8).