Saved by the Siesta: fight tiredness and boost your health by unlocking the science of napping

Saved by the Siesta

Brice Faraut is a neuroscientist specialising in the effects of restricting sleep, leading to new discoveries on the effects of sleep deprivation and people’s capacity to recover from it. He is the author of numerous scientific publications.

Scribe Publications

18–20 Edward St, Brunswick, Victoria 3056, Australia

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First published in French as Sauvés par la sieste by Actes Sud 2019

Published in English by Scribe 2021

Text copyright © Actes Sud, 2019

English language translation copyright © Eric Rosencrantz 2021

All rights reserved. Without limiting the rights under copyright reserved above, no part of this publication may be reproduced, stored in or introduced into a retrieval system, or transmitted, in any form or by any means (electronic, mechanical, photocopying, recording or otherwise) without the prior written permission of the publishers of this book.

The moral rights of the authors and translator have been asserted.

Scribe acknowledges Australia’s First Nations peoples as the traditional owners and custodians of this country, and we pay our respects to their elders, past and present.

978 1 925849 71 4 (Australian edition)

978 1 912854 72 1 (UK edition)

978 1 950354 57 3 (US edition)

978 1 925938 41 8 (ebook)

Catalogue records for this book are available from the National Library of Australia and the British Library.

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For my children, and for Fanny

Sachons dormir, nous saurons veiller.

By learning how to sleep,

we shall learn how to wake.

Alain (Émile-Auguste Chartier, 1868–1951)

Contents

Introduction

Part I Portrait of the Sleeper

1. The Ins and Outs of Sleep

2. Healing Sleep

Part II A World of Sleep Debt

3. The Sandman’s Debtors

4. How Deep in Debt Are We?

Part III The Siesta, or: The Force Awakens

5. Pocket Medicine

6. The Art of the Siesta

7. A Therapeutic Stroll

Conclusion

The Call of the Siesta: The Napper’s Cheat Sheet

Acknowledgements

Bibliography

Notes

Introduction

Nowadays, instead of giving sleep its rightful place in our lives, we sacrifice it on the altar of work or subdue it with drugs, or at least food supplements. In my own country of France, sleeping pills are regularly taken by 6–7 per cent of the adult population and psychotropic drugs by 18 per cent, while we consume 1.4 million packs of supplements containing melatonin every year. ¹ Millions of people grapple daily with a lack of sleep that saps their energy, undermines their health, and can even prove life-threatening. And yet there’s a simple solution to the problem: get some sleep. Which, in our hyperactive society, often means take a nap. So how come doctors never prescribe this particular ‘drug’? Why is this ancestral remedy so sorely underrated in our society?

It is, to be sure, a trending topic: the media increasingly relay the latest scientific findings on the benefits of the power nap, entrepreneurs tout its positive effects on productivity, and people look wistful at the very thought of it. Yet napping has hardly caught on. We’re still liable to harbour doubts about the seriousness of daily practitioners of the afternoon snooze. We can’t help suspecting it’s a drag on productivity — even though 50–70 per cent of the nation’s workforce complain about not getting enough sleep. Should we feel guilty about seeking to remedy an evil that’s wearing us down? Who says we’re allowed to sleep seven or eight hours a night — but not a few extra minutes every day? The answer is at least as old as the industrial world: despite the curative virtues of taking a snooze, many people still think it’s a bit too easy, and a bit lazy, to give in to the temptation. On the contrary, however, there is wisdom in napping. In fact, it is of pressing importance to give the nap its due, to acknowledge its therapeutic benefits, and to reinstate it as a daily routine on a par with our regular meals, our daily grind, and our nightly repose. May this book serve to convince you of that.

And after all, the habit of napping isn’t entirely alien to you: you did it every day, albeit sometimes reluctantly, for the first few years of your life. Yet while you may have renewed a nodding acquaintance with the occasional catnap on weekends or holidays, you’ve likely never dared to ‘take it to next level’. But it’s an ally for your daily life, and its aid is most effective when routinely enlisted. It’s not just there to fill idle hours on lazy days of leisure, but to help your body and mind feel and function a little better every day, and to protect them from the chronic sleep debt from which all, or nearly all, of us suffer. And some more than others. For though sleep belongs to everyone, not everyone gets their fair share. Many in the world’s labour force have to work nights, shifts, weekends, overtime. The bite that takes out of their nightly rest, estimated at an average of an hour and half per night for 20 per cent of the population, exacerbates the daily travails of the workaday world. So it’s high time our leaders, in business and government, acknowledge and address the problem. Sleep is not lost money or time. Just as you can’t have light without dark, life wouldn’t be possible without sleep. (Isn’t it said that we spend a third of our lives sleeping? If only that were true …)

Everyone knows that sleep is ‘refreshing’ and ‘restorative’, but that’s an understatement. Do you have any idea what’s going on in your slumbering body? The function of sleep is not only to rest your muscles and reinvigorate you. It also enables growth, slows down the ageing process, consolidates useful information and disposes of useless clutter in your memory, synthesises the proteins necessary for the upkeep and regeneration of your cells, eliminates toxins, reorganises neural connections, boosts your immune system, fuels creativity, maintains wellbeing, and preserves your equilibrium. This is why it’s so important to protect your nightly rest from everything in our ultra-connected day and age that might adversely affect it — especially the blue light of electronic devices — combined, whenever possible, with its natural daytime counterpart, its de facto scale model: a restorative nap. Chronic sleep deprivation takes a toll on our mental health, which is no surprise: losing our sleep is losing part of our selves. To remedy the situation, some take sleeping pills or antidepressants, but at the risk of meddling with the architecture of sleep, altering its primary functions and causing irreversible long-term damage.

Studies conducted all over the world — including the research my colleagues and I coordinate at the Hôtel-Dieu Hospital in Paris on the functions of sleep, and especially on the nap — show that napping is a highly adjustable all-purpose remedy for sleep deficit, a ‘medicine’ for the future, many of whose virtues are now known to us. We’ve come a long way since the firmly held Age of Enlightenment notions that sleep involves a ‘compression of the brain’, that snoring is ‘the sign of deep sleep’, and that ‘only illness and extreme heat can induce men to take a nap’. ² Science has progressed, and in recent years a considerable number of studies have shown how napping can not only cure extreme fatigue, but also combat drowsiness, pain, gloominess, immunological fragility, stress, hypertension, obesity, and cardiovascular disease. How many of us would simply live better, and longer, if we paid more attention to the benefits of sleeping better, or more, and above all more frequently?

At least one great man is said to have set an example for us: a certain Leonardo da Vinci, who treated himself to a good 15-to-20-minute snooze every four hours. He apparently grasped, long before his contemporaries (as in so many other domains), that sleeping and snoozing are conducive to genius. Even if this is just another legend, it is not without solid foundation: napping does indeed have the effect of a marvellous magic potion on human physiology. To reap the rewards of this practice, however, we need to know the finer points: the right sleeping positions, the times of day conducive to falling asleep, the most effective durations, the stages of sleep that boost alertness, cognitive performance, memory, and creativity, and tips on how to fall asleep quickly and wake up without feeling drowsy.

No one has ever survived prolonged total sleep deprivation, and the most tenacious (or craziest) of them all, the legendary Randy Gardner, only held out for 264 hours, or 11 days. The experiment took place in the United States back in 1964 and was never repeated. The 17-year-old volunteer guinea pig reportedly suffered moodiness and coordination problems after three days without sleep, and hallucinations by the end of the fifth day. His memory was malfunctioning by the seventh day, and he was seized with paranoia on the tenth day. On the last day, he was dazed, his face drained of all expression, and he asked to stop the experiment: he no longer understood what it was about. ³

Five years earlier, likewise in the US, a disc jockey by the name of Peter Tripp survived 201 hours without sleep in a ‘wakeathon’ to raise funds for the March of Dimes charity. He, too, started hallucinating after four days: the controls on his mixing desk morphed into columns of swarming insects, and the physician tasked with helping him overcome his anxieties became an executioner hell-bent on burning him at the stake. ⁴ Since then, other experiments, better prepared and less stressful, have borne out the biological utility of sleep. Most of them are carried out in the laboratory and controlled by sophisticated equipment that uses electrodes to measure the activity of the subject’s brain, muscles, and eyes, as well as blood and saliva samples to monitor the ever-fluctuating composition of body fluids. The lay reader is likely to be as surprised as many a scientist at how wonderfully active our slumbers are despite their apparent serenity.

But let’s begin at the beginning. Before delving into the sleeper’s inner world, let’s attempt a rough portrait of the sleeper to see how we sleep, how much sleep we need, and what our nocturnal habits and rhythms are. This will give us a better understanding of the tremendous machinery that sleep sets in motion inside the body and brain. These tools will give us a better understanding of the benefits of napping, its techniques and therapeutic potential, and why it’s a real public-health issue in our modern-day, sleep-deprived world.

Part I

Portrait of the Sleeper

1

The Ins and Outs of Sleep

All sleepers look a bit alike, and yet we’d be hard put to find any two people who sleep the same way. Naturally, we often see them lying on their backs, bellies, or sides, lips parted, eyes gently shut, faces softened or sullen. Sometimes their arms move about and they seem surprised by their body’s caprices. They smile in their dreams, frown in their nightmares, and eventually stretch their limbs with obvious relish. But however similar they may be, no two sleepers have the same way of beginning their nightly repose and dividing it up, making it last, interrupting it, and emerging from their slumbers sated and reinvigorated the next morning. This is because, for one thing, sleep needs differ according to numerous criteria, not the least of which is age. Our sleeping habits are also partly determined by our genetic heritage. Nevertheless, in the east and west, north and south, whether the days are longer or shorter, whether the sun sets early or late or shines nonstop, a day lasts only 24 hours.

The human clock, our inner sun

AN OBSESSION WITH RHYTHM

Since the dawn of time, the fall of night has inexorably summoned the animate world to sleep. But what law decrees that nature, animal and vegetable alike, should suddenly nod off when the sun goes down? It is because of a marvel of miniaturisation, at least in the mammalian brain, that enables the body to measure time. The body’s ‘master clock’ — or ‘central pacemaker’, as it’s also called — comprises two sets of 10,000 neurons, each the size of a pinhead, which scientists have unflinchingly dubbed the ‘suprachiasmatic nuclei’ of the brain’s hypothalamus. ¹ Its job is to control a great many biological rhythms that synchronise body functions over each 24-hour period — hence the term ‘circadian’ (from the Latin circa, ‘approximately’; and diem, ‘day’). Those rhythms include not only alternation between sleep–wake cycles, but also our body temperature, the release of hormones, our respiratory and heart rates, blood pressure, digestive functions, and all our nutrient and energy metabolism, without which we wouldn’t be alive. ² Even our physical and intellectual performance depends on this inner ticking, which has recently been shown to play a crucial role in cell division and the repair of our DNA as well. ³ Even in our earliest infancy, this biological clock puts a stop to our wriggling and cooing in the cradle every four hours and makes us drop off again. And when we grow up, it makes our eyelids grow heavy at just about the same time just about every day, and makes us wish — without admitting it to a soul — we could simply lay our head down on the desk in front of us for a little snooze.

The circadian rhythms of several body functions controlled by our biological clock.

TO EACH OUR OWN TEMPO

Even if it seems to be directly synchronised with daylight, our biological clock is autonomous. Put a Mimosa pudica (aka ‘sensitive’ or ‘sleepy’ plant) in an opaque box and its leaves will reopen at dawn all the same, and every bit as proudly as outside in a garden. ⁴ Hole up for several months in a flat without any light and your biological clock will set your daily pace all the same — according to your particular