World Sleep Day: 18 March 2022
It’s fascinating the way that our perception of sleep changes throughout the lifespan. As children, when everything is new and bright and exciting, many of us would do anything we could to avoid sleeping. We’d stay up late whenever we could get away with it, get up at 6AM on a Saturday morning, and go to sleepovers at our friends’ houses where staying up the whole night was almost like a badge of honour. As adults, however, I know very few of us who wouldn’t welcome an extra hour or two of sleep at night – or a nice, relaxing nap just after lunch. But what are the actual benefits of napping? And what are the costs?
Benefits of Napping
There’s evidence to suggest that napping, in moderation, can have a range of cognitive benefits. If you’ve ever had to sit through a long and boring class, meeting or presentation after a bad night’s sleep, you know that sleep deprivation makes tasks such as learning, concentration, and forming memories far more difficult. Just like a snack can give us energy, a short nap can help satiate some our sleep drive, and lead to improved concentration, memory, and learning ability over the next few hours. It makes sense, really – our brain has priorities, and it’ll tend to prioritise our physical needs (food, sleep, safety, shelter) first and foremost. When we’re not getting enough of those needs, we find it really difficult to effectively concentrate on or engage with more complex pursuits, like work, social connections, or recreational activities. Napping can provide a short-term relief when we’re deficient in sleep, and in doing so can free up our brain to focus on what we want it to.
Risks of Napping
But as with anything in life, naps are a little more complex than just a miracle cure for flagging attention, and we have to consider the potential negative outcomes of such a process. Firstly, the timing of the nap matters – the later our naps occur in the day, the more they have the potential to produce delays in our sleep. Just like having a snack just before dinner can spoil our appetite, the closer we time our naps to our main night-time sleep, the less sleep drive we’ll have, and the harder it’ll be for us to get to sleep quickly and easily. That sleep delay we can experience from having late afternoon or evening naps can then lead to us having a poor night of sleep, for which we then might try to compensate through additional naps, causing a cycle of sleep delay. We often feel most inclined to take naps in the Post-Lunch Dip, a period between 12:30-14:00PM linked with decreased alertness, and generally aligned with hottest time of the day. Try to avoid naps after 3PM generally, and after 5PM especially. The closer the nap is to your bedtime, the more we want to avoid it.
Secondly, the timing matters. Longer naps are associated with more delays to our sleep, but they’re also associated with increased sleep inertia – that is, the feeling of grogginess you get when you first wake up. Naps over 30 minutes are associated with greater sleep inertia – we both feel more groggy initially, and any performance benefits from the nap are delayed. The ideal length of a nap is 10-20 minutes, which I’m sure sounds very short to most people! Anything beyond that, however, and we start to see serious sleep inertia – and being woken up out of the deep sleep that comes with longer naps can be a very disorienting experience.
Key Points:
Naps have the potential for both significant benefits and significant costs.
When you do nap, do so early in the day, and avoid naps in the late afternoon and beyond.
Try to keep naps short, generally 10-20 minutes.
If you find yourself routinely using naps to compensate for reduced sleep, especially when that reduced sleep is because of delays in your sleep at night, this is a cycle that can produce repeated sleep delays. Try to reduce or eliminate napping, or consult a GP or Mental health Professional for more detailed sleep interventions.
One final caveat – these recommendations concern someone engaged in a general, 9-5-ish job, or studying at high school/university, or just someone who keeps relatively standard daytime hours. If you’re doing shift work, take this with a grain of salt, as naps are often necessary to function with unpredictable work shifts. Take note that our sleep needs change significantly throughout the lifespan too, with younger children requiring more sleep, as well as longer and more frequent naps.
References
Farhadian, N., Khazaie, H., Nami, M., & Khazaie, S. (2021). The role of daytime napping in declarative memory performance: a systematic review. Sleep Medicine, 84, 134-141.
Lau, H., Tucker, M. A., & Fishbein, W. (2010). Daytime napping: Effects on human direct associative and relational memory. Neurobiology of Learning and Memory, 93(4), 554-560.
Tietzel, A. J., & Lack, L. C. (2001). The short-term benefits of brief and long naps following nocturnal sleep restriction. Sleep, 24, 293-200.