Need to know
Napping is back in vogue
You’re back from lunch and ready to get back to work except… you feel sleepy. Should you force yourself to stay awake, or should you let yourself doze off? Would it help, or would it ruin your night’s sleep? We are sleep scientists and we’re going to walk you through the science of napping and how to nap in a way that is of maximal benefit.
Naps are short periods of sleep that occur outside a main nocturnal period. It is critical to distinguish these planned periods of daytime sleep from episodes of irresistible sleep that are not intended. The latter could signify significantly inadequate nighttime sleep, jetlag, a sleep disorder, or a neurological condition that requires medical attention.
Toddlers, young children, and younger adolescents nap regularly, but with brain maturation comes a reduced tendency to nap from mid-adolescence to midlife. Afternoon napping used to be a fixture in Mediterranean, Middle Eastern and East Asian societies, providing a respite from high outdoor temperatures and to accommodate for sleep patterns, such as waking up very early in the morning for prayers. However, with economic development, air-conditioning and the emergence of work schedules aligned to those in Western Europe and North America, the practice has declined in many countries where it was once common. In most Western societies, a nap would mean sleeping at the workplace, but this is often frowned upon and carries the connotation that one is not putting in effort or is being slovenly – for instance, in 2019 the US government formally banned any federal employees from napping at work.
There has been a recent rekindling of interest in napping – as reflected in a rise in research papers, media coverage and even companies offering at-work nap facilities. This has happened for at least two reasons. The first relates to many people’s impression that they are not obtaining adequate nocturnal sleep. This can cause them tiredness and a lack of motivation to work, particularly in the afternoon. For these people, a mid-afternoon nap can help boost cognitive function.
Consider our research with adolescents, who were allocated either five or six-and-a-half hours of sleep at night over successive nights. We found that a 60- or 90-minute nap restored their alertness and ability to pay attention almost to the level of control participants, who were averaging nine hours of sleep a night. Although we don’t recommend using napping as a daily remedy to compensate for lack of nocturnal sleep, our findings clearly suggest that napping is an effective countermeasure when applied sparingly.
A second reason for the new spate of interest in napping relates to people who obtain adequate or near-adequate sleep at night, but who have become interested in using naps as a performance-optimisation tool. Their interest is justified by a recent research review showing that, even with adequate nighttime sleep, naps can boost productivity and learning.
For instance, one study compared people’s ability to memorise facts, depending on which of three conditions they were in: the first group had two learning episodes separated by a 60-minute nap; the second group had two learning episodes separated by a 60-minute break; and the third group continued cramming through the 60-minute break. You can imagine these as representing some of the ways students choose to spend their afternoons during a semester. All the groups were tested 30 minutes after the second learning session. At this point, both the cramming and the napping groups outperformed the group that simply took a break, but crucially only the napping group showed this memory advantage when tested again a week later. Such findings suggest that, instead of forcing oneself to continue learning without a break, taking a nap between learning sessions might result in greater productivity. Indeed, several companies are beginning to provide facilities for napping to achieve this.
Most research in this field has focused on using sleep to aid memory-consolidation after a period of learning – this is the process by which information is made more durable to forgetting and interference from similar material. However, naps can also benefit initial encoding of information. Our own work has demonstrated that naps prior to study can facilitate fact-learning and the building of new knowledge. Related research shows that naps are linked to subsequent increases in brain activation in the hippocampus, a structure crucial for supporting memory.
Naps: worth giving them a try
Despite all these reasons to nap, only about half of adults report regularly taking naps. While for some the barrier may be opportunity, for others it may be the feeling that they are incapable of napping. If you find yourself in this category, don’t brush off napping just yet. In this Guide, we will share advice on napping that will help you give it another go. In particular, we will address questions on timing and duration: how long to nap for, at what time of day, and we’ll give you evidence-based reasons for our recommendations.
Even if you feel confident about settling down for a nap, perhaps you’ve had the unpleasant experience where a nap has lasted too long, or you did it too late and it’s affected your nighttime sleep. Or perhaps you started a set task too soon after waking from your nap and were set back by ‘sleep inertia’ – the grogginess immediately after waking. This Guide is for you, too – in fact, it’s for anyone who has wondered about napping better, how napping can be beneficial, or for those who want to try napping for the first time.
What to do
Get comfortable and wind down
When the time you’ve planned to nap comes around, it’s quite likely that you will not be able to nap in the same environment as your nighttime sleep, and so you will have to make do with what is most comfortable wherever you are, as best you can. If you find them tolerable, use eye masks to block out light, and earplugs to mute audio distractions. Of course, you should mute your digital devices for the allocated time you plan to nap. In the same way you would prepare for sleep at night, it’s also a good idea to wind down by physically and mentally putting aside work and taking several minutes to quieten your mind. Do whatever works for you: listening to music, a boring online lecture, a story book. It doesn’t matter if you lie or sit – it’s certainly possible to nap while sitting, commuters do this on public transportation every day!
Use short naps as a daily booster
People use naps for different reasons, and how you go about napping depends in part on why you are napping. If we assume for a moment that you are wanting to nap to alleviate temporary sleepiness, improve alertness and/or feel more positive overall, then, as a general guide, we suggest aiming to nap for 10 to 30 minutes. You might wonder whether 10 minutes is worth it. In fact, on days following a regular night of sleep, studies show that even a short, 10-minute nap can be beneficial. In a recent experiment we performed with participants who adhered to their normal overnight sleep habits, we compared the effects of nap durations ranging from 10 to 60 minutes on their self-rating of sleepiness, alertness and positive mood. We found robust improvements on all these measures after all the nap lengths, even naps as short as 10 minutes.
Longer naps may be appropriate if you did not get enough nighttime sleep
When you’ve not been getting the amount of nighttime sleep you’re used to, it can affect your mental performance during the day. In this scenario, you can use a nap to give yourself a cognitive boost, bringing yourself back up to at least your baseline level of function. We’ve shown this in our own research, specifically by looking at what psychologists call ‘vigilance’, which is your ability to respond quickly to the unpredictable appearance of a target stimulus. Tests of vigilance have been used to determine fitness to work in airline pilots or professional drivers, and are also relevant for persons having to monitor computer screens or devices for infrequent but important signals.
In our studies, we restricted our participants’ nighttime sleep, to simulate a period of two school weeks of getting just five hours of sleep per night. We found that a 60-minute nap helped to reduce the progressive decline in our participants’ vigilance as their sleep restriction accumulated over successive nights. In the vigilance task we gave them, those participants who napped had about a quarter the number of lapses, compared with the control participants who stayed awake all through the afternoon.
Use naps to aid learning
Naps are not only effective for improving vigilance, but also for other facets of cognition relevant to learning. We recently summarised the findings from 60 experimental studies that investigated the benefits of naps ranging from 30 to 120 minutes on cognitive assessments of memory, vigilance and processing speed (how long it takes to complete a mental task). Our analyses showed that, across these different tests, naps had the strongest benefits for vigilance, followed by a particular type of memory – known in psychology as ‘declarative memory’ – that helps us learn and remember facts (as opposed to autobiographical memory, for instance, or procedural memory – which is memory for skills).
For declarative memory, there’s more evidence for the benefit of naps of 30 to 90 minutes, rather than shorter naps of around 10 minutes. Several experiments from our lab have shown that, compared with staying awake for the same period, naps ranging from 30 to 90 minutes boost the encoding of pictures and the learning of factual knowledge. This could be because napping restored the performance decline that would have occurred naturally with sustained effort had it not been for a nap. As shown by others too, the advantages conferred by napping are slightly greater for habitual nappers (people who nap at least once a week) compared with nonhabitual nappers, so it’s worth making napping a regular part of your routine if you want to use it as a way to aid your studies.
Find your own sweet spot for nap duration
How long you choose to nap for won’t depend only on why you’re napping, but also on how soon after waking you will need to begin work. Assuming you’re not severely sleep-deprived, a 30-minute nap will boost your alertness and mood while keeping sleep inertia minimal (remember, this is the grogginess you can experience for a short time after napping, which can temporarily cause a reduction in your cognitive performance).
Naps longer than 30 minutes have trade-offs – greater potential benefit balanced against sleep inertia. Compared with short naps, longer naps can result in greater sleep inertia upon waking that may take longer to dissipate. We recently tested this in our lab by comparing participants’ cognitive performance five minutes after they woke from naps ranging from 10 to 60 minutes in length. Compared with our participants’ baseline (normal) reaction times, we found that their reaction times were slowed following 30- to 60-minute naps, but not following a 10-minute nap. However, this was seen for only one out of several test measures, and was resolved within 30 minutes. Hence, sleep inertia seems to be minimal and short-lived, at least for naps not exceeding an hour.
Overall, our advice is that, if you simply desire a nap for a quick boost in alertness and to lift your mood, then a 30-minute nap might suit these purposes, and offers the best balance in terms of practicability and benefit. When setting aside time for a nap, remember that it may take around five to 10 minutes to fall asleep so, if you’re planning a 30-minute nap, allocate at least 40 minutes for the entire rest period.
Just as there are inter-individual differences in nocturnal sleep duration, the optimal nap duration differs from person to person, so experiment to find what’s best for you within our suggestions.
Time your nap wisely
When it comes to napping well, timing can be as important as duration. Sleepiness is affected by how long one has been awake and by the cyclical behaviour of the circadian clock. If you’ve slept well, a morning nap is unlikely and not advisable. This is because a good night’s sleep dissipates ‘sleep pressure’ from the previous day’s long stretch of wakefulness. If you do feel sleepy in the morning, this is probably because you haven’t had enough sleep overnight or because your circadian clock is disrupted, for example after a night shift or following travel across multiple time zones.
Catching a nap in the evening, around dinner time, will likely come much more naturally. It’s especially easy to nap in the evening if you’ve had a taxing workday that follows a night of inadequate sleep. Be mindful though that if you nap this late, it may make it harder to fall asleep at your usual bedtime by prematurely lowering the sleep pressure built up through the day. As such, if an evening nap is your only option, aim to keep it short (around 10 minutes). So, unless you are preparing to stay up late that night, the better option might be to avoid the nap altogether and go to bed earlier than usual.
If you have the freedom to choose, the most favourable time to take a nap is mid-afternoon. This will coincide with the mid-afternoon dip that occurs in most people’s circadian rhythm. Remember, even a brief nap of around 10 minutes can give you a perk-up. Contrary to advice from the World Economic Forum that an afternoon nap might interfere with your nocturnal sleep, our studies with adolescent participants found that a nap scheduled at 2pm with wake-up time around 3-3.30pm did not adversely lengthen the time taken to fall asleep at night.
What if you have tried napping but cannot?
If you’re someone who has tried to nap following our suggestions but still cannot, don’t worry. The propensity to nap appears to be determined by one’s genetic heritage, just as sleep duration is. A recent body of work shows that even closing your eyes for several minutes without actually sleeping can be restorative. It is not yet known why this is so, but a period of quiet rest where external stimulation is at a minimum may have beneficial properties, especially for consolidating information. So, regardless of whether you managed to fall asleep, the time set aside for quiet rest may still be worth it.
Key points – How to nap
- Napping is back in vogue. As a cultural practice, napping had been in decline, but individuals and organisations are increasingly aware of the growing research that shows the benefits of napping, both to compensate for inadequate nighttime sleep and for providing a cognitive boost.
- Naps: worth giving them a try. Many people who might benefit from napping haven’t tried it or feel they are incapable. If you find yourself in this category, don’t brush off napping just yet.
- Get comfortable and wind down. There are basic practicalities to consider such as eye masks and ear plugs, and you also need to get in the right frame of mind, just as you do at nighttime.
- Use short naps as a daily booster. If your main purpose is to use naps to alleviate sleepiness, improve your alertness and boost your mood, a quick, 10-minute nap should do the trick.
- Longer naps may be appropriate if you did not get enough nighttime sleep. If you haven’t been sleeping well at night, then you can use longer naps (around 60 minutes) to help compensate and protect your day-time mental function, though this shouldn’t be a long-term solution.
- Use naps to aid learning. There’s evidence that naps ranging from 30 to 90 minutes can be used to enhance learning – either prior to study, to enhance encoding of new material, or after studying, to boost the consolidation of your new memories.
- Find your own sweet spot for nap duration. When you’re choosing your nap time, it’s worth taking into account not only why you are doing it but also what you will be doing afterwards – especially so you avoid excess sleep inertia (grogginess) after a long nap.
- Time your nap wisely. Napping well isn’t only about your mindset and setting the appropriate duration, but also about choosing when to nap, especially to avoid compromising nighttime sleep. For most people, if you have the freedom to choose, the most favourable time to nap is mid-afternoon.
- Don’t worry if you seem unable to nap. A recent body of work shows that even closing your eyes for several minutes without actually sleeping can be restorative in itself.
Can naps ever be bad?
In adults, seven hours is increasingly regarded as a sweet spot for nocturnal sleep duration for the average person. Although the benefit of naps can be present regardless of whether people sleep less or more than seven hours the night before, achieving adequate nocturnal sleep should still be our goal. While having clear benefits to cognition and mood, naps do not fully compensate for inadequate nocturnal sleep and should not be thought of as a replacement for it.
You may have read reports of naps being associated with greater cognitive impairment in the elderly. This is more often found in persons who already have an underlying illness, or who fall asleep involuntarily and frequently. Falling asleep involuntarily in the day other than after being sleep-deprived is not normal and is not considered ‘napping’. It is a reflection of underlying illness, and you should seek medical attention if this occurs.
There are studies showing a link between habitual napping and hypertension. This does not mean that napping causes hypertension. Instead, a recent large-scale genetic study has found that the tendency to nap and an elevated risk of hypertension may be co-inherited. If you are already a habitual napper, stopping napping may not, therefore, reduce your risk of hypertension.
Links & books
We created the Need for Sleep website as part of our landmark series of studies in which we tracked teens and compared how different ‘doses’ of nighttime sleep and naps affected cognitive performance, learning and memory. The site contains accessible information on our findings.
In his post ‘Can Naps Make Up for Lost Sleep in Adolescent Learners?’ (2019) for the Neuroscience Community at Nature Portfolio, James Cousins explains the implications of research into the benefits of napping for adolescents, and looks to the future of the field.
In his article ‘Naps: A User’s Guide’ (2022) for BBC Science Focus magazine, the science writer Ian Taylor spoke to several experts to hear their tips.
In the episode ‘Synaptic Homeostasis of Sleep’ (2022) from the Sleep Science Podcast, the neuroscientist Chiara Cirelli talks about her hypothesis that sleep helps to downscale saturated synapses, so that capacity is restored after sleep and more learning can take place. This mechanism could help to explain the benefit of daytime naps for learning.
The book Take a Nap! Change Your Life (2006) by the neuroscientist Sara Mednick and her co-author Mark Ehrman provides an in-depth practical programme for incorporating napping into your life.