Frequently Asked Questions
How long should I nap?
The ideal nap length depends on your goal. For a quick alertness boost, 20 minutes (a power nap) is optimal — you stay in light sleep and wake easily. If you need creativity and memory consolidation, 90 minutes lets you complete a full sleep cycle including REM. Avoid napping 30-60 minutes, as you'll likely wake from deep sleep feeling groggy. NASA research found that even a 26-minute nap improved pilot performance by 34% and alertness by 54%.
What is a coffee nap?
A coffee nap (also called a "nappuccino") involves drinking a cup of coffee immediately before a 20-minute nap. It works because caffeine takes approximately 20 minutes to be absorbed and reach your brain. While you nap, your brain naturally clears adenosine (the chemical that makes you sleepy). When you wake, the caffeine arrives to block adenosine receptors that are now empty. Multiple studies have shown that coffee naps reduce driving errors and improve cognitive performance more than either coffee or napping alone.
Why do I feel worse after napping?
Feeling worse after a nap is caused by sleep inertia — the groggy, disoriented state that occurs when you wake from deep sleep (Stage 3). This typically happens with naps lasting 30-60 minutes. Your brain has shifted into slow-wave sleep but hasn't completed the cycle. It can take 15-30 minutes for this fog to clear, and during that time your cognitive performance is actually worse than before the nap. To avoid this, keep naps to 20 minutes or extend to a full 90-minute cycle.
What is the best time to take a nap?
The best time to nap is during your post-lunch circadian dip, typically between 1:00 and 3:00 PM. During this window, your body temperature naturally drops and sleepiness increases regardless of whether you ate lunch. Napping during this window means you'll fall asleep faster and the nap won't interfere with nighttime sleep. Avoid napping after 4:00 PM — late naps can make it harder to fall asleep at bedtime and reduce the quality of your nighttime sleep.
Is napping bad for nighttime sleep?
Short naps (under 30 minutes) taken before 3:00 PM generally do not interfere with nighttime sleep for most people. However, long naps or naps taken late in the afternoon can reduce your "sleep drive" — the adenosine buildup that makes you feel sleepy at night. If you struggle with insomnia, it's best to avoid napping entirely or limit yourself to a 20-minute power nap early in the afternoon. For most healthy adults, a well-timed nap can actually improve overall 24-hour cognitive performance without harming nighttime sleep.
How long is a NASA nap?
The NASA nap is 26 minutes long. It comes from a 1995 NASA study (published by researchers Mark Rosekind et al.) conducted on long-haul pilots and astronauts. The study found that a planned 26-minute nap during flights improved pilot performance by 34% and physiological alertness by 54% compared to the no-nap control group. The 26-minute window keeps you in restorative Stage 2 sleep while accounting for a few minutes to fall asleep, avoiding the deep sleep that causes grogginess.