The coffee nap: caffeine, then a 20-minute nap
Updated October 27, 2026 · Sources listed below
A coffee nap sounds like a contradiction, but it works: drink a coffee, then nap for up to 20 minutes. Caffeine takes roughly 20 minutes to kick in, so it starts working just as you wake up, and the short nap keeps you out of deep sleep.
What the research shows
- Sleepy drivers: in a driving-simulator study, about 150 mg of caffeine taken right before a nap of 15 minutes or less reduced sleepiness and driving incidents more than either the nap or the caffeine alone.[1]
- After a 20-minute nap: caffeine taken before the nap was more effective at clearing post-nap sleepiness than bright light or washing your face.[2]
The combination works because the two fix different problems. The nap reduces sleep pressure; the caffeine covers the groggy minutes after waking (sleep inertia).[3]
How to take a coffee nap
- Drink a coffee quickly, about one to two cups (roughly 150 to 200 mg of caffeine, the range used in the studies).[1][2] An espresso or iced coffee is easier to finish fast than a hot mug.
- Lie down straight away. Don't wait for the caffeine to build.
- Sleep for up to 20 minutes, and have an alarm ring about 20 to 25 minutes after you drank the coffee, whether or not you fell asleep. Even light dozing helps.
- Get up and get light. The caffeine is starting to work; give it a few more minutes before anything that needs you sharp.
Who it suits, and who should skip it
- Good fit: drivers at a rest stop, shift workers before or during a night shift, anyone who needs to be sharp right after the nap.
- Skip it late in the day if caffeine keeps you up at night, if you're sensitive to caffeine, or if your doctor has told you to limit it.
- Not a substitute for sleep. If you're drowsy behind the wheel, a coffee nap at a safe stop is a short-term fix, not permission to keep driving for hours.
Frequently asked questions
Does a coffee nap really work?
Studies say yes. Caffeine taken right before a short nap reduced sleepiness more than the nap or caffeine alone in sleepy drivers, and it beat bright light and face washing for clearing grogginess after a 20-minute nap.
How long should a coffee nap be?
Up to 20 minutes. Caffeine takes roughly 20 minutes to kick in, and staying under 20 minutes of sleep keeps you out of deep sleep.
How much coffee for a coffee nap?
The studies used about 150 to 200 mg of caffeine, roughly one to two cups of brewed coffee. Drink it quickly, then lie down right away.
Sources
- Reyner & Horne, Psychophysiology (1997): caffeine combined with a short nap in sleepy drivers
- Hayashi, Masuda & Hori, Clinical Neurophysiology (2003): caffeine, bright light and face washing after a short daytime nap
- Hilditch & McHill, Nature and Science of Sleep (2019): sleep inertia, current insights
This guide is general information, not medical advice. Power Napper is not a medical device.