The Strategic Nap Guardrails
Use short, early naps without weakening nighttime sleep
- Difficulty
- Starter
- Time to result
- ~days to results
- Steps
- 5
- Confidence
- 99%
Walker rejects the idea that a nap is useless unless it reaches REM sleep. He says different sleep stages can provide different benefits and cites studies reporting alertness, reaction-time, learning, memory, emotional, cardiovascular, and blood-pressure effects from naps of varying lengths. His practical guardrails are narrower: keep a routine nap to about 20 minutes, avoid late-afternoon or evening naps, and do not nap when struggling to sleep at night. The mechanism involves both sleep inertia and sleep pressure. Longer naps can enter deeper non-REM sleep and leave a person groggy when abruptly awakened, while any nap releases some of the adenosine-linked sleepiness accumulated during wakefulness. This is general guidance from the episode, not medical treatment.
Origin
Extracted from The Diary of a CEO. Matthew Walker explains the rule while correcting Steven Bartlett's belief that only naps long enough to reach deep or REM sleep are useful.
Core principles
- 01A nap can help without completing a full sleep cycle
- 02Short naps reduce the risk of waking from deep sleep
- 03Late naps can reduce nighttime sleep pressure
- 04People struggling with nighttime sleep should protect accumulated sleepiness
How to run it
- 1
Check Nighttime Sleep
First decide whether you already struggle to fall asleep or stay asleep at night. If so, Walker's recommendation is not to nap during the day.
Pro tip Treat nighttime sleep as the priority outcome, not the nap itself.
Watch out Persistent sleep difficulty warrants appropriately qualified professional advice.
- 2
Choose an Early Window
Schedule the nap before roughly 2 or 3 p.m. Walker compares later napping to snacking before a meal because it reduces the accumulated appetite for sleep.
Pro tip Place the nap near the early-afternoon dip rather than the evening.
- 3
Cap the Routine Nap
Set the nap for about 20 minutes or less. Walker says this can provide benefits while reducing the likelihood of waking from deep non-REM sleep.
Pro tip A short nap can still be useful even without a full 90-minute sleep cycle.
Watch out The transcript does not promise the same response for every person.
- 4
Plan for Inertia
If you deliberately nap for 40 to 60 minutes, expect that an alarm may wake you from deep sleep. Leave time for the resulting grogginess to clear before safety-critical or demanding activity.
Pro tip Use the short format when you need to be functional immediately afterward.
Watch out Walker says sleep inertia can last close to an hour.
- 5
Review the Night
Observe whether the nap changes the following night's sleep onset or quality. Shorten, move, or remove it if nighttime sleep becomes harder.
Pro tip Judge the nap by the full day-and-night pattern rather than the immediate boost alone.
In the wild
Walker describes NASA research using naps of roughly 20 minutes to an hour for astronauts and ground staff. He reports improvements in task productivity and general alertness, and says the results helped create a NASA nap culture.
→ Napping was treated as a performance intervention rather than misconduct at work.
Illustrative example: a person who sleeps well at night takes a 20-minute nap at 1:30 p.m., leaves time to wake fully, and checks whether bedtime remains unaffected. If sleep onset worsens, they remove the nap.
→ The nap is retained only if it helps the day without harming the night.
Common mistakes
Chasing a Full Sleep Cycle
Walker says a nap does not need to reach REM sleep or complete a 90-minute cycle to provide some benefits.
Waking from Deep Sleep Unprepared
A 40-to-60-minute nap can end in deep sleep and produce substantial sleep inertia.
Napping Through Insomnia
Walker says daytime naps release accumulated sleep pressure and can make nighttime sleep harder for someone already struggling.
Is it for you?
Best for
It is best for people who sleep adequately at night and want a brief early-afternoon alertness reset.
Not ideal for
It is not ideal for people with insomnia or persistent nighttime sleep difficulty, whom Walker advises not to nap.
From the transcript
“keep it to 20 minutes”
“if you are suffering from insomnia don't nap during the day”
“try not to nap after about 3 P.M in the afternoon”
From the episode
Matthew Walker: The World’s No.1 Sleep Expert (The 6 Sleep Hacks You NEED!)