Book by a top neurologist reveals the surprising power of the nap

How to supercharge your day in just 10 minutes! Boost immunity. Beat stress. Even lose weight. A life-changing book by a top neurologist reveals the surprising power of the nap

  • One in five people in the UK claim to have trouble falling asleep every night 
  • Brice Faraut is a neuroscientist at the Sleep Centre at Hotel Dieu Hospital in Paris
  • Reveals how to harness the power of the daytime doze in extract from new book 

Want a New Year’s Resolution that not only helps you lose weight but improves your mood, combats stress and boosts your immune system including, it’s been proven, the efficacy of vaccines? Then pledge to take a daytime snooze.

Sleep deprivation in the UK has long been running at epidemic rates, with one in five having trouble falling asleep every night and a shocking two thirds of midlife women, aged 45-54, reporting disrupted sleep at least once a month.

But there’s a simple solution. It’s backed by dozens of scientific studies, and yet it’s still treated, perplexingly, as a bit of a joke. Known across the Mediterranean as a siesta, the daytime nap is a wonderfully protective night-time in miniature for repairing, soothing, healing and boosting — in as little as ten minutes.

As a neuroscientist at the Sleep Centre at Hotel Dieu Hospital in Paris, I’ve long studied the disastrous, even life-threatening consequences of poor sleep. And the nap, it seems to me, is a hugely under-estimated means of reversing some of the worst effects.

Brice Faraut, who is a neuroscientist at the Sleep Centre at Hotel Dieu Hospital in Paris, reveals how to harness the power of the daytime doze in an extract from his new book (pictured)

My new book shows you how to harness the power of the day-time doze, and how different kinds of naps have different benefits — whether taken in the morning or afternoon, whether for 90 minutes or just ten, whether you want to boost creativity or improve your memory.

Read on to discover why a siesta solves so many of our problems — and learn how to kick-start that napping habit . . .


What law decrees that nature should suddenly nod off when the sun goes down? It’s all down to the body’s master clock — or central pacemaker — comprised of two sets of 10,000 neurons within the brain, each the size of a pinhead.

Its job is to control a great many biological rhythms that synchronise body functions over each 24-hour period, rhythms that include, not only alternation between sleep–wake cycles, but also body temperature, the release of hormones, respiratory and heart rates, blood pressure and so on, without which we wouldn’t be alive. It’s this clock that makes us want to fall asleep and wake up at set times, and though the average cycle runs at 24 hours and 12 minutes, we’re not all the same.

If you have a speedy clock, you’re likely to be an early bird, and if your clock tends to take its time, you’re more likely to be a night owl. This is called your chronotype and it has an impact, as we shall see, on the ideal timing of a nap.


Brice said naps is one of the most effective things we can do to offset the gradual decline of sleep as we get older (file image)

Even a good night’s sleep is not a uniform whole: on the contrary, it’s broken up into a series of four to six cycles interspersed with imperceptible awakenings that are almost never remembered (provided they don’t exceed a few minutes’ duration).

In each of these cycles, three types of sleep follow one after another continuously: light slow-wave sleep (SWS), which boosts energy; deep slow-wave sleep, the most restorative and healing kind; and REM sleep, which plays an important role in the consolidation of memory and in relieving anxiety. You spend on average 40–50 per cent of your time in light sleep, 20–25 per cent in deep sleep, 20–25 per cent in REM sleep, and 5–10 per cent awake.

As we get older, I’m afraid to say our sleep undergoes a gradual decline, becoming lighter and more unstable, interspersed with more and longer awakenings. As a result, we often fail to feel fully refreshed and restored in the morning.

Deep slow-wave sleep, the most healing kind, in which the body’s inner medical team really goes to work on repairs, gradually diminishes around the age of 40 and becomes increasingly rare after 70. Taking naps is one of the most effective things we can do to offset the deleterious effects of this loss of deep sleep.


Studies have found the risk of becoming obese was twice as high for those who slept for five hours or less at night (file image)

It doesn’t take much sleep deprivation to alter the way we eat and to pile on the pounds as a result.

Prolonged sleep deprivation tends to disrupt production of the appetite-suppressing hormone leptin, which increases our hunger and can lead to weight gain.

When University of Colorado researchers restricted the sleep of volunteers to five hours a night for five consecutive nights, they put on an average of 1.8lb in five days.

Another Spanish study found the risk of becoming obese was twice as high for those who slept for five hours or less at night compared to those who slept for seven to eight hours, but, crucially, it was one third lower for those who took a half hour daily siesta, no matter how long they slept at night. Napping is one way to dial down our hunger — and keep our weight down, too.


People imagine a nap during the day will make it harder to get to sleep at night. But the exact opposite is true. A short nap of about 20 minutes will improve your mood and — if taken at least six hours before bedtime — your propensity to fall asleep and stay asleep at night.


Brice said the more accustomed you are to naps, the easier and more effective it will be (file image) 

Although sorely tempted, many don’t bother napping because they can’t nod off fast enough or feel as though they always wake up groggy or think there’s just no point dozing for five, ten, 15, or 20 minutes.

But they’re wrong: the power of the siesta lies in its capacity to produce certain effects of a night-time sleep in record time. And the more accustomed you are, the easier and more effective it will be.

A nap doesn’t have to be long to be useful. Depending on what your goals are and how much time you have at your disposal, you can adjust the duration and benefit from both light and deep slow-wave sleep.

You can also vary the timing depending on your chronotype, or to allow for missed sleep, or even target a particular stage of sleep.

Brice said the same nap at the same hour will be richer in REM sleep than in deep SWS for night owls (file image)

With early risers, for example, an early-afternoon nap exceeding 30 minutes will be richer in restorative deep slow-wave sleep than in REM sleep. (The earlier your night sleep ends, the greater your sleep pressure in the early afternoon and, in turn, the more deep SWS you’re likely to get in a nap of more than half an hour.)

For night owls, the same nap at the same hour will be richer in REM sleep than in deep SWS. For a more restorative sleep at a cellular level, owls have to put their nap off till as late as possible in the afternoon, though making sure to leave an interval of at least six hours between the end of the nap and bedtime.


You’re at work and you want to nap, but don’t want to experience ‘sleep inertia’ that comes after deep slow-wave sleep. The key here is to avoid deep SWS altogether, which is a cinch — you just have to take short naps of light sleep only.

But how to wake up on your own after 10 or 15 minutes before you enter deep SWS?

Brice said drinking a fully-caffeinated cup just before closing your eyes has the effect of improving cognitive performance and subjective alertness (file image)

You can set an alarm or you could take a ‘coffee nap’, which is when you drink a fully-caffeinated cup just before closing your eyes. Since it takes about 20 minutes for caffeine to kick in, the coffee will dispel sleep inertia after a nap of 20 minutes or more. Combining caffeine and a nap has the effect of improving cognitive performance and subjective alertness more than either practice does by itself.


We’ve heard an awful lot about vaccines, antibodies and killer T cells in recent months. A lack of sleep can seriously weaken the response of them to viruses.

After vaccinating two groups of people against hepatitis A, a team at the University of Lubeck found that a single night of sleep deprivation after the injection had the effect of halving the production of antibodies against the disease four weeks later.

The message is clear — for the best immune response to a virus, get all the sleep you can, and naps are a great boost.

So what’s your perfect siesta? 



  • You’re guaranteed to feel refreshed. Ideal before a meeting or appointment.
  • Highly effective in combating drowsiness and stimulating cognitive performance for a short while (two hours).


  • In cases of considerable sleep debt and chronic fatigue, it won’t suffice to brace you for an extended period of wakefulness.



  • The easiest to practise on a daily basis and stimulates alertness for more than two hours.
  • Alleviates pain, stress, boosts immunity and cuts risk of cardiovascular events.


  • May cause grogginess and effects don’t kick in until 20–30 minutes post-nap.
  • Takes at least 30–40 minutes all-in (allowing for the time it takes to fall asleep).



Improves alertness and cognitive performance for five hours.

Helps consolidate memory and boost creativity and immunity.


  • Sleep inertia after wake-up.
  • In those 60 and above, long naps may conflict with sleep–wake rhythms and could be associated with cognitive decline and increased cardiovascular risk.

Adapted by Alison Roberts from Saved By The Siesta by Brice Faraut (£14.99, Scribe) ©Brice Faraut 2021. To order a copy for £13.49 go to or call 020 3176 2937. Free UK delivery on orders over £20. Offer price valid until 24/01/2022.

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