Guide · Naps

Napping before a night shift

Last reviewed · Every claim links to its source

The short answer

Yes, nap before a night shift, above all before the first one. NIOSH calls this a prophylactic nap: in the studies it describes, naps of 1.5 to 3 hours in the afternoon or evening before a night shift improved alertness later that night. Wake with enough time for the grogginess to pass before you drive.

This guide follows NIOSH’s training for nurses on napping, which summarises the studies, and the shift-work sleep guidelines an expert panel agreed in 2023.

Why a nap before nights works

The longer you have been awake, the more pressure builds for sleep, and the easier it is to fall asleep and the deeper you sleep.2 A long nap before a night shift reaches the deeper stages of sleep and can reduce that build-up, which may soften the drop in alertness during the night.1

The first night is where it matters most. If you got up at 7 a.m. and work 7 p.m. to 7 a.m., you have been awake for 24 hours by the end of the shift. In a classic study, after 24 hours awake people did about as badly on a coordination test as at a blood alcohol level of 0.10%.8

What the studies found

NIOSH summarises several studies of naps before night work:1

  • Nurses and nursing aides who napped for 1.5 hours, from 3:30 to 5 p.m., felt significantly more alert during the second half of their first night shift than those who did not.
  • A 2.5-hour nap from 7:30 to 10 p.m. before a simulated night shift improved alertness compared with no nap.
  • A 3-hour nap from 2 to 5 p.m. led to higher alertness on a later night shift than no nap.
  • A 2.5-hour nap before the shift combined with caffeine at the start of it had positive effects on alertness.

How to nap before a night shift

  1. Before your first night, take a long nap

    The naps in those studies ran from 1.5 to 3 hours.1 The 2023 guidelines agree that longer naps, of about 90 minutes, can help pay down a sleep debt.4

  2. Pick the afternoon if you can

    If you normally sleep at night, NIOSH notes that the afternoon, around 2 to 4 p.m., is one of the easier times to fall asleep, and that it is harder in the late morning and in the one to three hours before your usual bedtime.2 An evening nap can work too, as the 7:30 p.m. study shows.1

  3. Before later nights, top up

    Once you are sleeping in the mornings, a shorter nap before you leave makes up what the day sleep missed. The guidelines suggest 7 to 9 hours of sleep in every 24, and they count a main sleep plus shorter ones.4

  4. If time is short, nap for 15 to 20 minutes

    Short naps of 15 to 20 minutes can boost alertness and performance, the guidelines say; under 15 minutes may be too short to help, and over 20 brings more risk of waking groggy.4 NIOSH adds that waking after about 20 or about 90 minutes may leave you less groggy than waking in between.3

  5. Make the room dark, quiet and cool

    The guidelines suggest a quiet, dark and cool place for a nap, the same as for your main sleep.4 Set an alarm you trust to wake you.

  6. Leave time to wake up before you drive

    End the nap with enough time to get ready and travel. Grogginess on waking is covered below, and the guidelines suggest avoiding driving while it lasts.4

Grogginess after a nap

Sleep inertia is the temporary disorientation and dip in performance or mood after waking.5 The guidelines say it usually lasts 15 to 30 minutes but can last up to two hours.4 It is worse when you wake from deep sleep, which NIOSH says you reach about an hour into sleeping, and when you are already short of sleep.3 NIOSH also notes that caffeine on waking, or just before a short nap, can reduce it.5

Naps on the night shift itself

Where your workplace allows it, a nap on the shift can help too. NIOSH says a 30-minute nap can help you feel more alert on an 8-hour night shift, and that a longer nap may be more useful on a shift of 12 hours or more; it also reports that a 2 to 3 hour nap during 12 to 16 hour night shifts was shown to maintain alertness.6 NIOSH is frank that longer naps are hard to arrange in many US hospitals.6

If you are very sleepy at the end of the shift, NIOSH suggests not driving: get a lift, take a taxi or public transport, or take some caffeine and then a short nap before you set off.7

When not to take a long nap

On your first day off, a long nap late in the day can make the first ordinary night harder. The guidelines advise avoiding longer naps in the four to six hours before your main sleep.4 Switching from nights back to days covers that day.

This is general information, not medical advice.

If you are very sleepy at work or on the road even after napping, you often cannot sleep when you have the chance, or your sleep is affecting your health, talk to your doctor.

Questions nurses ask

How long should a nap before a night shift be?

Before the first night, a long one: the studies NIOSH describes used naps of 1.5 to 3 hours.1 Before later nights, when you have already slept that morning, a shorter top-up works. A 15 to 20 minute nap can boost alertness when that is all the time you have.4

What time should I nap before my first night shift?

In the afternoon or early evening, ending with enough time to wake up properly and get to work. NIOSH notes that the afternoon, around 2 to 4 p.m., is one of the easier times to fall asleep for someone who normally sleeps at night.2

Is it worth napping during a night shift?

Where your workplace allows it, yes. NIOSH says a 30-minute nap can help on an 8-hour night shift and that a longer nap may be more useful on a shift of 12 hours or more, though such naps are hard to arrange in many US hospitals.6

Why do I feel worse after a nap?

That is sleep inertia, the grogginess after waking. It usually passes within about 15 to 30 minutes but can last up to two hours,4 and it is worse when you wake from deep sleep or are short of sleep.3 Avoid driving until it has passed.

From your roster

How Post Nights plans this from your roster

Post Nights reads the shifts you actually work and places the nap for you:

  • before the first night, when you have been up since the morning, and before each night after it;
  • longer before a single night on its own than before a night in a block;
  • ending in time to get ready and travel, from the commute you give it;
  • with Premium, a short nap on your break, where your workplace allows it, with a wake-up that rings through silent mode like your alarm.

The times come from a published model of the body clock, accurate to about an hour in laboratory studies that measured the light people saw. Yours is estimated from your roster, which is less precise, so every time in the app is a window rather than a minute.

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More guides

GuideHow to sleep after a night shiftSeven steps for the day sleep between nights. GuideSwitching from nights back to daysThe day after your last night, step by step.

Sources

  1. NIOSH. Training for Nurses on Shift Work and Long Work Hours (DHHS (NIOSH) Publication 2015-115), module 7, “Napping, an important fatigue countermeasure: before nights”. archive.cdc.gov
  2. NIOSH. Same training, module 7, “Nap times”. archive.cdc.gov
  3. NIOSH. Same training, module 7, “Nap duration”. archive.cdc.gov
  4. Shriane AE, Rigney G, Ferguson SA, Bin YS, Vincent GE. Healthy sleep practices for shift workers: consensus sleep hygiene guidelines using a Delphi methodology. Sleep 2023;46(12):zsad182. Guidelines 2, 6 and 7. doi.org/10.1093/sleep/zsad182 (free full text: PMC10710992)
  5. NIOSH. Same training, module 7, “Sleep inertia”. archive.cdc.gov
  6. NIOSH. Same training, module 7, “Naps at work (continued)”. archive.cdc.gov
  7. NIOSH. Same training, module 9, “Light (continued)”, on the drive home. archive.cdc.gov
  8. Dawson D, Reid K. Fatigue, alcohol and performance impairment. Nature 1997;388:235. doi.org/10.1038/40775