Is an afternoon nap actually healthy? The 10–20 minute rule that could boost your alertness

There is something deeply familiar about the urge to sleep after lunch. In many Indian homes, an afternoon nap or siesta has traditionally been part of the daily routine. In modern work culture, however, napping is sometimes viewed as laziness or a sign of poor sleep.

The science tells a more nuanced story: a short, well-timed nap can be useful, but napping is not a necessity for everyone, and longer or frequent naps may sometimes signal an underlying problem.

What exactly is a nap?

A nap is a short period of sleep taken during the daytime, usually outside the main nighttime sleep period. People nap for different reasons: to recover from inadequate sleep, improve alertness before an anticipated period of wakefulness, or simply because they enjoy it.

Our biology partly explains the afternoon slump. Even after a good night's sleep, the circadian clock produces a natural dip in alertness in the early-to-mid afternoon. This is why you may feel sleepy around lunchtime or shortly afterwards, not necessarily because your lunch was too heavy.

When is the best time to nap?

For most adults, early afternoon, roughly between 1 and 3 PM, is a sensible window. It coincides with the natural circadian dip in alertness and is less likely than a late-afternoon nap to interfere with nighttime sleep. The exact timing is individual. Someone who works night shifts or has an unusual sleep schedule will have a different optimal nap time.

How long should you nap?

For everyday use, 10–20 minutes is a good target. This is often called a 'power nap', a brief nap intended to improve alertness and performance without allowing the sleeper to enter deeper stages of sleep.

Research shows that short daytime naps can improve alertness, reaction time, memory and aspects of cognitive performance. But there is an important caveat: the shorter the nap, the lower the likelihood of waking from deep sleep and experiencing significant sleep inertia.

What is sleep inertia?

Ever woken up from an afternoon sleep feeling worse than before you slept?

That groggy, disoriented, temporarily less-alert state is called sleep inertia. It can impair reaction time and cognitive performance immediately after waking. It is generally more likely after longer naps, particularly when they contain more slow-wave sleep.

Therefore, if you have an important meeting, operate machinery or need to make critical decisions immediately afterwards, give yourself some time to become fully alert.

Are longer naps bad?

Not necessarily. A 30–90-minute nap can sometimes be useful, particularly in people who are sleep-deprived, shift workers and athletes. Longer naps may provide additional recovery and can benefit some aspects of memory and physical performance.

The trade-off is that they increase the possibility of sleep inertia and, particularly when taken late in the day, may make it harder to fall asleep at night.

A 90-minute nap can also contain a substantial portion of a sleep cycle, including REM sleep, but it is not something most healthy adults need routinely.

What about long-term health?

Short naps appear useful for immediate alertness, mood and cognitive performance. However, observational studies have repeatedly found associations between frequent or prolonged daytime napping and obesity, diabetes, cardiovascular disease and mortality.

Does this mean long naps cause these diseases?

Not necessarily. Long naps may partly be a marker of an underlying problem, such as poor nighttime sleep, sleep apnoea, depression, chronic illness, medication effects or insufficient sleep. A 2024 meta-analysis involving more than 1.8 million people found associations between habitual napping and several adverse health outcomes, but observational studies cannot establish causation.

Thus, a long nap should not automatically be labelled unhealthy, but a sudden increase in the need for daytime sleep deserves attention.

Does everyone need a nap?

No. If you sleep adequately at night, remain alert and function well during the day, there is no medical requirement to take an afternoon nap. Someone who routinely needs a two-hour nap every afternoon despite getting adequate nighttime sleep should ask why rather than simply assuming that more daytime sleep is healthier.

Is siesta cultural or genetic?

There is certainly a cultural component. Siesta traditions are particularly prominent in parts of southern Europe, Latin America and some Asian and Middle Eastern populations. Social schedules, climate, meal patterns and work practices can all influence napping habits.

But biology also matters. Twin research suggests that genetic factors contribute substantially to individual differences in the tendency to take a siesta, although environment and lifestyle remain important. So, the afternoon nap is neither purely cultural nor purely genetic.

The practical prescription

For most healthy adults: If you feel sleepy in the afternoon → try a 10–20-minute nap, preferably around 1–3 pm. Set an alarm. Wake up, get some light and movement, and allow a few minutes for alertness to return. And remember the most important rule: A nap should supplement good nighttime sleep, not substitute for it.

A short afternoon nap may be one of the simplest ways to refresh the brain and body. But if you regularly need long naps to get through the day, the better question may be: “Why am I so sleepy?”

The opinions expressed in this article are those of the author and do not purport to reflect the opinions or views of THE WEEK.