DozeClock › Naps › 45 minutes

Is a 45-minute nap good? What happens when you wake up

Updated October 3, 2026 · Sources: NASA 1995 · Brooks & Lack 2006 · Tassi & Muzet 2000 · NINDS

Short answer

45 min

reaches deep sleep (N3) likely · grogginess on waking: moderate to high. Set the alarm for 60 minutes after you lie down to allow for falling asleep.

Time to set aside60 min15 min to fall asleep + 45 min asleep
Keep it before2:45 pmfor a 10:45 pm bedtime (8-hour gap)

General information from population studies (NIH, CDC, NSF, AASM). It is not medical advice and does not replace a clinician who knows you.

Lie down for 45 minutes and you will usually get as far as deep sleep (N3) likely. Waking from slow-wave sleep is the main cause of post-nap grogginess; sleep inertia can last from a few minutes to over 30 minutes. Grogginess afterwards: moderate to high.

Nap length versus grogginess — 45 minutes highlighted
10 mingrogginess: minimal20 mingrogginess: low26 mingrogginess: low to moderate30 mingrogginess: moderate45 mingrogginess: moderate to high60 mingrogginess: high90 mingrogginess: low

Sleep inertia ratings from Brooks & Lack 2006, Tassi & Muzet 2000, Rosekind 1995 · as of October 3, 2026

Why 45 minutes behaves this way

At this length you are likely inside deep sleep when the alarm goes, so plan for 10–30 minutes of sleep inertia before you are sharp — not a good choice before driving or a meeting. If you have the time, a full 90 minutes lands you in light sleep or REM instead.

Every nap length

NapReachesGrogginessSet aside
10 minlight sleep (N1-N2)minimal25 min
20 minlight sleep (N2)low35 min
26 minlight sleep, occasionally early deep sleeplow to moderate41 min
30 minoften enters deep sleep (N3)moderate45 min
45 mindeep sleep (N3) likelymoderate to high60 min
60 mindeep sleep (N3)high75 min
90 mincomplete cycle including REMlow (waking near the end of a cycle)105 min

15 minutes added for sleep onset · sources above · as of October 3, 2026

A person asleep under a blanket, face not visible
Photo by Annie Spratt on Unsplash

Related pages

26-minute nap26 min30-minute nap30 min60-minute nap60 min90-minute nap90 min Nap calculatorany start time and length Tonight's bedtimeby wake-up time

Sources

  1. A brief afternoon nap following nocturnal sleep restriction: which nap duration is most recuperative? — Sleep 29(6):831-840, 2006 (Brooks A., Lack L.)
  2. Alertness Management: Strategic Naps in Operational Settings — NASA Technical Memorandum 108839 (Rosekind M.R. et al.), 1995; also J Sleep Res 4(S2):62-66
  3. Sleep inertia — Sleep Medicine Reviews 4(4):341-353, 2000 (Tassi P., Muzet A.)
  4. Brain Basics: Understanding Sleep — NINDS (NIH)

General information from population studies (NIH, CDC, NSF, AASM). It is not medical advice and does not replace a clinician who knows you.