Napping
Short daytime sleep, and how its length and timing change whether it helps or hinders.
Last revised
Key takeaways
- Short nap for alertness: 10-20 minutes
- Length that commonly causes grogginess: 30-60 minutes
- Most useful single change: Keep naps to 10-20 minutes and set an alarm.
- Commonest mistake: Napping 30 to 60 minutes if you need to function immediately after.
- See a doctor if any of the signs under "When to get help" below apply to you.
Why it matters
Ten to twenty minutes improves alertness; thirty to sixty can leave you groggy, and late naps use up the sleep pressure you need that night.
The numbers, in one place
| Measure | Figure |
|---|---|
| Short nap for alertness | 10-20 minutes |
| Length that commonly causes grogginess | 30-60 minutes |
| Full sleep cycle | about 90 minutes |
| Best window | early afternoon, roughly 1 p.m. to 3 p.m. |
| Caffeine nap | coffee immediately before a 20-minute nap |
What helps
- Keep naps to 10-20 minutes and set an alarm
- Nap in the early afternoon rather than late
- Nap before a night shift or a long drive
- Treat a persistent need to nap as something to get checked
What to avoid
- Napping 30 to 60 minutes if you need to function immediately after
- Napping late in the day if you struggle to sleep at night
- Driving while fighting sleep; pull over somewhere safe and nap first
In depth
A nap can be a useful tool, but its effect depends on length and timing. Sleep progresses through stages: light sleep at first, then deeper slow-wave sleep, then lighter sleep and REM. A short nap of 10 to 20 minutes usually keeps you in light sleep, so you wake feeling refreshed. A nap of 30 to 60 minutes often ends during deep sleep, and waking from deep sleep causes sleep inertia, a groggy, disoriented feeling that can last a while.
Naps also use up sleep pressure, the drive to sleep that builds while you are awake. A short nap in the early afternoon uses only a little and rarely affects night sleep for most people. A long or late nap can reduce sleep pressure enough to make it harder to fall asleep at night. That is why napping is often discouraged for people with insomnia, even though it can be helpful for others.
The early-afternoon dip in alertness is a natural part of the body clock, and napping during it can improve alertness, mood and performance. Strategic naps are especially useful before night shifts or long drives. However, a persistent need to nap despite getting enough sleep at night is not normal and may point to a sleep disorder such as sleep apnea or narcolepsy, or to another health problem.
Signs and symptoms
- Feeling refreshed and more alert after a short nap
- Grogginess or disorientation after waking from a longer nap
- Difficulty falling asleep at night after a late or long nap
- Needing to nap daily despite enough sleep at night
- Falling asleep unintentionally during the day
- Vivid dreams at nap onset or during short naps
Causes and risk factors
- Short or poor-quality sleep the night before
- The natural afternoon dip in alertness
- Shift work or irregular schedules
- Sleep disorders such as sleep apnea or narcolepsy
- Medicines that cause drowsiness
- Illness, depression or other medical conditions
How it is checked
If you need to nap often or fall asleep unintentionally, your doctor will ask about your night sleep, daytime sleepiness and health. They may use the Epworth Sleepiness Scale, a questionnaire that rates how likely you are to fall asleep in everyday situations. A sleep diary can show whether you are getting enough sleep at night.
If a sleep disorder is suspected, your doctor may arrange an overnight sleep study. For suspected narcolepsy, this is often followed by a multiple sleep latency test, which measures how quickly you fall asleep during several scheduled daytime naps and whether you enter REM sleep quickly. Blood tests may check for anemia, thyroid problems or other causes of fatigue.
Related topics
- What the Guidance Really Says About Sleep and the Brain (Brain Health)
- What the Guidance Really Says About Shift Work and Health (Workplace Health)
- Teen Sleep: What Published Guidance Supports (Teen Health)
- What the Guidance Really Says About Sleep and Chronic Pain (Chronic Pain)
Where to go next
- Answers to the Common Questions on Napping
- The Short Guide to Napping
- Sleep: The Complete Guide
- The Body Clock: Sorting the Evidence From the Noise
- The Sleep Environment: What Published Guidance Supports
When to get help
See your doctor if you need to nap daily despite enough time in bed, if you fall asleep without meaning to, or if you have sudden muscle weakness with strong emotion, which can be a sign of narcolepsy. Do not drive while excessively sleepy, and call 911 for someone who cannot be woken or is breathing abnormally.
Where this comes from
- National Institute of Neurological Disorders and Stroke — Narcolepsy
- American Academy of Sleep Medicine — Healthy Sleep Habits
How this page was put together
Every figure, recommendation and warning above is taken from the guidance named in Where this comes from. Nothing on this page is inferred, summarized or generalized beyond what those bodies publish: where they give a number, it is their number, and where they are silent, so are we. Pages are rebuilt whenever the underlying record changes. Sign-off by a named clinician, where it has happened, is shown at the top of the page along with the date.
Medical disclaimer
This article is general information, not medical advice. It cannot account for your own history, medication or circumstances. Always speak to your doctor, pharmacist or another qualified health professional before making changes that affect your treatment, and never delay seeking medical advice because of something you have read here. In an emergency, call 911.