To nap or not to nap? That is the question. Although it’s probably not a question that kept Shakespeare awake at night, or – more relevantly – during the day. But it’s one many of us ask, particularly those of an age where circumstances allow for an afternoon snooze.
If your answer to the rather Shakespearean question above is ‘yes’, the next logical question is probably, ‘For how long?’ Old William might have asked it with a more Elizabethan turn of phrase: ‘Perchance a few moments? Perchance an hour?’
In the four centuries since the bard pondered sleep through his works (and he often did), science has made great strides. And those strides have produced a greater understanding of sleep and sleep cycles.
Understanding these cycles can help us make an educated decision on our nap length, should we choose to take one.
Nap time
While most probably think of an afternoon nap as something different to night-time sleep, the physiological process is the same. An afternoon nap is simply a small slice of the seven or eight hours sleep we have each night. The duration of a nap is the defining factor in whether it’s doing any good, though.
It all boils down to four distinct phases that make up each cycle of sleep. The full cycle for most humans is somewhere between 90 and 120 minutes. That cycle has a dream ending – literally – as it takes in the fourth phase of the cycle, REM sleep.
If you get to that stage in a nap, chances are you’re doing yourself good. But the three phases before that will determine how you feel after your nap. These are known as non-rapid eye movement sleep, generally referred to as N1, N2 and N3. Not so much Shakespearean as Bananas in Pyjamas-ish.
If you have a 20-minute nap, what many would call a ‘power nap’, you’ll likely go through the N1 and N2 phases. N1 usually lasts less than 10 minutes and doesn’t really bestow any benefits or do any harm. It’s a phase during which it takes very little to wake you up.
Moving into N2, your body will drop in temperature and your muscles will relax. At this stage your brain will fire off short bursts of neuronal activity. This is a good thing, because it helps make and maintain connections. In turn this has been shown to improve alertness, memory processing, mood and even physical performance.
The only real downside to waking from N2 sleep is you’ll feel better, but only for two or three hours. Overall, an N2 nap (10 to 25 minutes) is good for most of us.
The dreaded N3
Learning about the N3 phase of sleep takes me back to my early parenting days. Many over-50s like me will remember the afternoon nap of your baby or toddler as a godsend. Up to 40 minutes without having to give them your full attention. I would often use this break to have a nap of my own.
But what I remember vividly is the period immediately after the nap was over. My oldest son in particular was ‘Mr Grumpy’ in the 30 to 60 minutes post-nap. Actually that doesn’t quite capture his level of grumpiness. ‘King Grumpy’ is better.
Thanks to learning the science behind N3, at least now I know why he was so grumpy. N3, or slow-wave sleep, is considered a more restorative phase of sleep where the body starts to repair and regrow.
Waking up during the N3 stage does confer some health benefits, but these come at a cost. That cost takes the form of what’s called ‘sleep inertia’. Lasting from 30 to 60 minutes, the sleep inertia phase entails a period of grogginess and in some cases (to which I can attest) grumpiness.
But, if you can get through that cognitive dip phase “you’ll see the benefit of the nap”. So says Dr Jen Walsh, director of the Centre for Sleep Science at the University of Western Australia.
The verdict on naps
One or two studies have linked naps longer than 30 minutes with higher weight, blood pressure and cardiovascular risk. But the studies themselves have cited other lifestyle factors at play that possibly have a stronger causal relationship.
Overall, the scientific points to naps being generally beneficial – or at least not detrimental – to health. But this conclusion comes with a couple of riders. Firstly, it assumes you are regularly getting a good, healthy sleep at night.
Secondly, it assumes you a having a single daily nap. Taking lots of little naps during the day may signal of an underlying health problem. If this describes you, a visit to your GP might be a good idea.
In general, though, if you enjoy an afternoon nap and it helps you through each day, embrace it like Shakespeare did in Henry IV, Part 2, as “nature’s soft nurse”.
Do you like an afternoon nap? Does the length of your naps make a difference to your wellbeing? Let us know via the comments section below.
Also read: How apps and influencers are changing the way we sleep, for better or worse
