SOUND

ASLEEP

THE EXPERT GUIDE
TO SLEEPING WELL

CHRIS IDZIKOWSKI

For Hilary
xx

Dr Chris Idzikowski, BSc, PhD, FBPsS, is Director of the Sleep Assessment and Advisory Service and the Edinburgh Sleep Centre. A leading expert on sleep and its disorders, he has served as Chairman of the British Sleep Society and has been a long-term council member of the Royal Society of Medicine’s Sleep Medicine Section. Dr Idzikowski has also sat on the boards of the European Sleep Research Society and the US Sleep Medicine Foundation. He is the author of five books, including Learn to Sleep Well (Watkins).

FOREWORD

I’ve often been asked why I became interested in sleep. After all, for most people sleep is something they barely think about – it comes as a surprise that anyone should devote their working life to understanding it. The short answer is that I don’t really remember. I certainly didn’t wake up one day and have an extraordinary interest in why I had slept the previous eight, nine, ten hours. I do know, though, that my Latin teacher, my wife, and my late friend and mentor Emeritus Professor Ian Oswald all had something to do with it. Their teaching methods, frank criticism of my work and fascinating insights into the human brain have all inspired me.

Looking after your sleep – and doing it in a way that isn’t harmful (by not using sleeping pills or alcohol, for example) is fundamental to your well-being. This book brings together the essence of everything I’ve learned about sleep in a way that I hope is practical and accessible. My aim has been to give you not only information about the nature of sleep, but also guidance on actions you can take at home to improve your sleep quality. I haven’t shied away from the importance of conventional medicine in the treatment of sleep disorders (I’m a scientist, after all), but I hope you’ll see that there are lots of ways in which you can enjoy better-quality sleep through simple changes to your lifestyle and by performing simple tasks that promote sleep.

It’s important that you work through the book from the beginning. In Chapters 1 and 2, I’ve offered an understanding of what sleep is and what it does (as far as we know). Information and simple measures will help you to make your own assessments of how well you sleep at the moment and how sleepy you are during the day. By going back to these early assessments when you’ve read later parts of the book, you can gain a good measure of your progress as you start to implement my techniques and tips for sleep improvement.

Arguably, the critical chapter in the book is Chapter 3 – the chapter on sleep hygiene. A safe building is constructed on deep and solid foundations. Sleep hygiene is the foundation of refreshing sleep. You cannot improve your sleep – at any level – without making good sleep hygiene your priority.

In Chapters 4 and 5, I’ve looked at some of the specific challenges that we face for our sleep quality at particular times or stages in our lives, as well as in particular circumstances.

If you think you have a sleep disorder, Chapter 6 aims to give practical advice on treatment – I’ve covered major disorders, as well as some of the more unusual ones. If you have an insomnia, I hope to enable you to make informed choices about your treatment, both at home and with the help of a sleep centre or a doctor.

Finally, in Chapter 7, I’ve provided a summary of conventional and complementary therapies that are often used to help people overcome sleep problems. Taking a scientific view of what’s available, I hope I’ve offered robust information and advice so that you can choose remedies and therapies that will have actual beneficial effects on your sleep improvement, if you need them.

Overall, I hope this book enables you to better understand the unique nature of your sleep so that you can put in place strategies that work for you. Your physical, emotional and mental well-being rely upon sleeping soundly. I wish you a peaceful night, every night.

Chris Idzikowski, January 2013

CONTENTS

Author’s acknowledgments

Foreword

Chapter 1: Sleep – an introduction

What is sleep? • What is tiredness? • What is dreaming? • How much sleep do you need? • You and your sleepiness

Chapter 2: The science of sleep

Scientists of sleep • Rhythms of the day and night • The brainwave revolution • Cycles and stages of sleep • The science of dreaming • The genetics of sleep • A memory for sleep • Your body during sleep

Chapter 3: Sleep hygiene – the deep sleep cleanse

The sleep hygiene review • Your sleeping space • Temperature control • Into the darkness • Noise and sleep • Making your bed • Rituals for sleep • The lifestyle factor

Chapter 4: Sleep, ageing and gender

Sleeping babies, rested children • Teens to twenties • Sleep and older age • Sleeping beauty, sleeping lion

Chapter 5: Good sleep guides for workers, parents, dreamers and more

A worker’s guide to good sleep • A shift worker’s guide to good sleep • A driver’s guide to good sleep • A flyer’s guide to good sleep • An athlete’s guide to good sleep • A performer’s guide to good sleep • A student’s guide to good sleep • A parents’ guide to good sleep • A dreamer’s guide to good sleep • A problem-solver’s guide to good sleep

Chapter 6: Sleep disorders – step by step

Sleep disorders classified • Insomnia: an overview • Adjustment insomnia • Psychophysiological insomnia • Other forms of insomnia • Narcolepsy • Parasomnias • Circadian rhythm sleep disorders • Sleep-related breathing disorders • Restless leg syndrome • Isolated symptoms, normal variants and unresolved issues • Nightmares • Mental disorder insomnia

Chapter 7: Pills, potions and therapies

Conventional medicine • Sleep centres • Complementary medicine • Gadgets, gizmos and the World Wide Web

Conclusion

Resources

AUTHOR’S ACKNOWLEDGMENTS

I’d like to acknowledge simply everyone I’ve worked with – friends, colleagues, staff, collaborators, students and so on have all contributed to my thinking – but especially my long-suffering editor Judy Barratt and publisher Bob Saxton.

CHAPTER 1

SLEEP – AN INTRODUCTION

We know that in the Paleolithic era early man slept on beds of straw, grass, brushwood and pelt. From observing the actions of chimpanzees, we know that our animal ancestors are to this day particular about their sleep. Chimpanzees build nests in trees to keep themselves safe from predators. These nests consist of a mattress lined with soft leaves and twigs. Across time and species, it seems that we don’t just need sleep, we need good-quality sleep in comfort and safety.

In this chapter I’ll try to answer some fundamental questions about sleep. What is it? What is it for? What are its features? Sometimes the answers are straightforward; often they involve the complex interplay of science, history and educated guesswork. Sleep remains something of a fascinating conundrum, but one that is essential to our existence.

WHAT IS SLEEP?

How would you describe sleep? Is it a period of complete shut-down? Is it total rest? Is it unconsciousness? In fact, sleep is none of these things. Although many people describe sleep as the body’s opportunity for stopping, in truth it is one of the most active periods of the day (or, rather, night) for our brain. There is no “shutting down” – two regions of the brain communicate and co-operate to create the state of sleep. In other words, sleep is an active process, not a passive one (and in the morning, the same two regions of the brain work together to create wakefulness). Some scientists think that we burn fewer than a hundred calories less during sleep than we would if we were awake but resting. This undermines the next hypothesis, that sleep is rest: sleep does involve physical rest, but we can rest nearly as effectively without actually sleeping. We aren’t unconscious during sleep, because a persistent or loud noise or other physical disturbance will wake us.

One of the most precise ways to describe sleep is to think of it as a temporary severance between the outside world and our perception or experience thereof. At the precise moment of sleep, connections between our brain and our senses virtually cease to function. During sleep we can’t really hear, taste, smell, feel touch, or see (except in our dreams). Another feature of sleep is that we can be woken from it (it is a reversible state). During dreaming sleep our limbs are immobilized in order that we can’t “act out” our dreams.

In physiological terms, sleep is a period of distinct cycles and stages. An adult with healthy sleep each night goes through four or five sleep cycles (see pp.20–21), each demarcated by an unnoticed moment of wakefulness. Every one of those sleep cycles is itself made up of five stages of sleep – until recently thought of as drowsiness, light sleep, two periods of deep sleep and REM (or dreaming) sleep (these stages have now been reclassified; see p.19). Sleep is triggered when two particular regions of our brain communicate with one another. We’ll go into which later, but the process is rather like two conductors trying to conduct a single orchestra to play the perfect tune. When they succeed and the instruments play in harmony, we fall asleep easily. As long as no one steps out of time or tune, we stay asleep. When the instruments are out of kilter, our sleep may not be restful. When this problem persists, we say we have a sleep disorder.

WHAT IS TIREDNESS?

Tiredness comes in many guises. The most common form of tiredness is the form we should all feel at the end of the waking day – a general fatigue that puts us in mind that it’s time to go to bed. This is a perfectly normal part of daily life. In itself, it may come as a feeling of mental tiredness (a long day at the office, which makes you feel sleepy), or physical tiredness (an active day hiking, cycling or gardening or doing physical work) – neither of which is a problem, as long as you feel refreshed again after a rest or ideally a good night’s sleep.

However, prolonged tiredness or tiredness that prevents you from functioning normally during the day may be a symptom of illness, or even an illness in itself. According to the Royal College of Physicians, a staggering one in ten people in the UK report feeling “tired all the time” and the problem is especially acute among women. If you feel that there’s no relief from your feelings of tiredness, you need to investigate what this might mean. Have a look at the box on pages 6–7 and see if any of the prompts apply to you – and then take appropriate action, which of course begins with making sure that your sleep is as healthy and restorative as it can be.

WHAT IS DREAMING?

Austrian psychoanalyst Sigmund Freud (1856–1939) claimed that dreams were the mind’s way to release pent-up desires or forbidden thoughts. His contemporary the Swiss genius Carl Jung (1875–1961) believed they formed an expression of our “collective unconscious”. He described this as the pool of symbolic archetypes that is identical to all people in all cultures and is distinct from the “personal unconscious”, which is the mind’s mapping of our own unique experiences.

However, since Freud and Jung put forward their theories, sleep researchers have tried to explain dreaming in rather more scientific terms. Put together a simple electric circuit to light a bulb, but overload the power with too many batteries and the bulb will not light. Our minds are rather like that. During the day, the brain is bombarded with information – from our senses and our learning – for us to process and store. Overload the brain, and we might feel befuddled, exhausted or even unwell. In the 1990s sleep experts considered the possibility that our dreams crucially help the brain to make sense of the overload, sifting through and ordering all the millions of fragments of data we process every day – a sort of unravelling and filing of everything that’s on our mind so that the mind itself can work.

This certainly seems to be the case when we look at the physical evidence for dreaming. We think that dreams occur mainly during a specific phase of sleep, known as REM – or Rapid Eye Movement – so-called because the eyes flick back and forth beneath our eyelids as we sleep. More recent research into the nature of REM has suggested that far from being a “light-hearted” break in the serious business of deep sleep, this phase must be essential to our well-being. When human beings are deprived of REM sleep, the body compensates for that deprivation by having extended periods of REM as soon as it can. If REM didn’t matter, why would the body or brain try at the soonest opportunity to catch up on the deficit? We still don’t fully understand why REM is significant, nor what dreams do exactly, but we can conclude that both seem to be an essential function of a healthy mind.

The characteristics of dreams

There are innumerable ways in which we could describe our dreams, but to the scientific mind there are three main characteristics that are unique to dreaming. First, we’re in temporary paralysis during our dreams in order that we can’t act them out. Second, we rarely ever dream that we’re someone else, even if our dreams are fantastical. Finally, our dreams are fragmented, whereas life is continuous.

Then there’s the question of whether or not dreams have meaning. I think this is a matter that entirely depends upon your point of view. Since time immemorial there have been those – scientists such as Sigmund Freud among them – who have believed firmly that dreams unearth deep messages from our unconscious, helping us to make sense of past events or anxieties in our lives. I think that dreaming is a time when you become aware of how your brain is processing information. For example, teeth probably mean work to a dentist, but they may symbolize death to someone looking to interpret their dreams by traditional associations. So, do your dreams have meaning? Yes, if you believe they do.

HOW MUCH SLEEP DO YOU NEED?

Is there such a thing as the “right” amount of sleep? What’s normal, and what signifies that we have a problem? As with so much about sleep research, the answers are not easy to give. What’s normal, acceptable and restorative for you might for me seem excessive or too little.

Age, genetics, health, the season, and the amount of racked-up sleep debt all help determine the number of hours of sleep each of us needs. And because no two of us are the same, nor are our sleep needs.

In 2009 a company in Massachusetts launched the Zeo (see box, p.202), a personalized sleep monitor that tells you how much light, deep and dreaming sleep you’ve had each night. For sleep researchers the Zeo is invaluable because it’s enabled us to see what an “average” night’s sleep is like over a large cross-section of the population (albeit people willing and able to buy the gadget, which at the time of publication is available for between $100 and $200). The readings from almost ten thousand Zeo participants tell us that the average American sleeps 6.8 hours a night, with six percent clocking up fewer than six hours of sleep a night and 12 percent having eight hours or more.

So, does that mean that around seven hours sleep a night is what we should aim for? Perhaps. In order to provide guidelines, experts have agreed that healthy adults need between seven and nine hours sleep. Teenagers need one to two hours more a night; and newborns under two months old should sleep between 12 and 18 hours in every 24. The sleep needs of people aged 65 and over naturally decrease, although there is much speculation as to why, including the consideration that certain medications may disrupt sleep.

As ever, this information is relevant only in light of your uniqueness. Although seven hours might suit your partner, you might need closer to nine. In this book, I’ve assumed that you’re aiming to sleep for eight hours a night, but do adjust my advice in light of your own needs.

YOU AND YOUR SLEEPINESS

Sleepiness is a basic “physiological needs” state. You might compare it to feeling hungry or thirsty. In a different way to hunger and thirst, though, the less good-quality sleep you have, the greater your sleepiness, not only when you’re about to go to bed, but at other times, too.

How sleepy you feel over the course of the day will depend upon all sorts of factors, including your general health, your age and what’s going on around you. If you’re stimulated and distracted, it can (up to a point) be quite easy to cast aside sleepiness and work through it. If you’re bored or doing something monotonous, sleepiness is harder to ignore. The elderly often feel sleepy between two and three o’clock in the afternoon, our “natural” siesta; while young adults, commuting from work on their way home, often report feeling sleepy as they drive.

In this respect, sleepiness is dangerous – but not only for your safety while driving a car. It can also affect your critical thinking and memory.

There are three main factors that affect daytime sleepiness:

•The duration of your nighttime sleep (how long you’ve slept during the night).

•The quality of your nighttime sleep (how well you’ve slept).

•The circadian time (the time of day).

Measuring sleepiness

In 1990, Dr Murray Johns, the founder of the Sleep Disorders Unit at Epworth Hospital in Melbourne, Australia, devised the “Epworth Sleepiness Scale” (ESS) in order to assess the daytime situations in which clients at his sleep clinic were most likely to feel an overwhelming desire to nod off. He asked his clients to score eight potentially sleep-inducing scenarios on a rising scale of zero to three – with zero indicating that the client wouldn’t feel sleepy in that situation and three indicating that the client would almost certainly nod off.

The scenarios Dr Johns gave were: sitting reading; watching TV; sitting inactive in a public place; being a passenger in a car for an hour without a break; lying down to rest in the afternoon; sitting talking; sitting quietly after an alcohol-free lunch; and driving, but being stopped for a few minutes in traffic. If his patients scored nine or more, he took that to be a good indicator that they might in fact have a sleep disorder. He assessed that healthy sleepers scored around five.

Measuring fatigue

If the ESS measures general levels of sleepiness, the Fatigue Severity Scale (FSS), developed by Dr Lauren Krupp of New York State University, estimates levels of weariness. Initially created to assess fatigue in patients with multiple sclerosis and the auto-immune condition lupus, the scale is now used to assess likelihood of a sleep disorder. Patients are asked to rate statements relating to how fatigued they feel in certain situations. For example, on a rising scale of one to seven for each, do you feel that fatigue interferes with: your family and work time? Your sustained physical functioning? Your general functioning? And your ability to carry out your responsibilities? Similarly, is fatigue brought on by exercise? Does it affect your levels of motivation? And does it force you to shorten periods of activity? Totting up your score for each, a total of twenty or more suggests you need to take action.

There are lots of online resources that enable you to take the ESS or the FSS, or tests like them. Or, alternatively you can simply score your responses to the scenarios as I’ve given them here. Over the course of this book, I’ll show you ways in which you can considerably improve those scores, which itself means that you’ll have improved the quality of your sleep.

CHAPTER 2

THE SCIENCE OF SLEEP

Sleep has fascinated thinkers and philosophers since ancient times. However, the science of sleep – the analytical measurement of this crucial physical state – is still in its relative infancy. In fact, in terms of modern research, sleep science has been around for only about fifty years (that’s not to say that others, centuries before, hadn’t tried to explain sleep). In this chapter I introduce you to some of the most influential sleep researchers past and present and highlight the contributions they’ve made to our understanding of sleep. Then I delve deeper into the science of sleep – from what happens to the brain and body as we sleep, to the cycles of sleep and the nature of dreaming.

SCIENTISTS OF SLEEP

Around 350BCE the Greek philosopher Aristotle recorded his thoughts on the nature of sleep and sleeplessness. He concluded, for example, that “sleep is, in a certain way, an inhibition of function, or, as it were, a tie, imposed on sense-perception, while its loosening or remission constitutes being awake.” By looking at humans and animals, Aristotle realized that when we sleep our acknowledgment of the senses ceases to function and in this way at least sleep is different from wakefulness.

However, it wasn’t until almost two millennia later that scientific investigations into the nature of the brain, as well as into the nature of sleep, made discoveries that now influence the way we think about sleep and wakefulness. In 1842, Edward Binns published The Anatomy of Sleep, the content of which is elucidated by its subtitle, “The art of procuring sound and refreshing slumber at will.” Binns mooted that sleep was an active process over which we have some control, rather than a passive one resulting merely as a consequence of tiredness. He believed that human beings could exert influence over sleep by removing all stimulation.

After Richard Caton, a British scientist working in the late 19th century, had attached electrodes to the scalps of animals, establishing that there was electrical activity in the brain, others were able to make great advances in sleep research. In the 1920s the German psychiatrist Hans Berger became the first to reveal that the human brain operated on a number of different electrical frequencies, which he recorded, calling the readings electroencephalograms (EEGs). Crucially for sleep science, he demonstrated that the brainwaves active in the human brain during sleep were different from those associated with wakefulness, although it was several years before anyone believed him.

Around the same time that Berger was making EEGs in Germany, Professor Nathaniel Kleitman, a Russian-born American psychologist, regarded by many as the founder of modern sleep research, was conducting experiments on himself and others to find more evidence for the nature of sleep. He spent periods of time underground, living in Mammoth Cave, Kentucky, to establish what happened to the body when it was forced to exist in perpetual darkness. He found that the body works on a circadian rhythm – a 24-hour cycle – which remains more or less constant whatever the light conditions of our environment.

However, Kleitman’s ambitions went beyond wanting to establish that our body doesn’t need light and dark in order to follow its natural rhythms. He wanted to challenge what had become the accepted wisdom that sleep was a single, linear state of rest. He proved instead that, as in fact Aristotle had believed centuries before him, sleep was the obverse side of the same coin as wakefulness – that the two were both mutually exclusive and interdependent; that they complemented one another. The result was perhaps his most famous publication, a book called Sleep and Wakefulness, which he published in 1939.

Kleitman, who lectured at the University of Chicago until he was over 100 years old, had two students who helped to put sleep medicine firmly on the clinical map. The first, Eugene Aserinsky, with Kleitman, established that REM sleep existed and that it had a connection with dreaming. However, it was another student, William Dement, who examined the connection in detail, firmly concluding that dreaming happens during REM sleep and publishing his findings in 1958.

Back in Europe, Michel Jouvet, a French neurologist and academic, dug deep into Dement’s discoveries about the links between dreaming and REM sleep. He went one step further, establishing through a series of experiments on cats that many muscles of the body go into a state of paralysis during REM sleep in order that we can’t act out our dreams. He called REM sleep a “paradoxical” stage of sleep in which the body goes into a strange, independent state of alertness.

From the 1960s onward, sleep research became more accepted as a branch of medicine, especially following French neurologist Henri Gastaut’s identification of sleep apnoea (see pp.171–4). We still have much to learn, but the work of these scientists makes the job of understanding sleep and treating its problems that much better informed.

RHYTHMS OF THE DAY AND NIGHT

Almost every living thing – including plants and animals and every individual cell in the body – has a 24-hour rhythm that sees it go through periods of activity and inactivity, fast metabolism and slow metabolism, growth and maintenance. We don’t know for certain why this internal 24-hour rhythm has evolved, but presumably it’s because that’s the daily cycle of the Earth as it turns on its axis while orbiting the Sun. We do know that humans have a specific bundle of between forty and eighty thousand brain cells that act as this internal metronome – it’s call the suprachiasmatic nucleus and is located in the hypothalamus at the base of the brain.

Rhythms that are attuned to the earthly 24-hour cycle of day and night are called circadian rhythms (from the Latin circa, meaning “about”, and dies, meaning “day”). Our sleep–wake cycle isn’t the only circadian rhythm we have – our oxygen consumption, urine output, muscle strength and, crucially for sleep, body temperature are just some of the other human functions that operate on a 24-hour clock. Think about your own performance over the course of a day. Perhaps you feel more mentally alert in the morning, and more physically able later. Interestingly, many World Records are set when athletes compete in the evening, when physical strength peaks.

In order to be classed as a circadian or biological rhythm, a cycle needs to persist even without external triggers. Nathanial Kleitman proved that the sleep–wake cycle was inbuilt when he spent three months underground without any natural light (see p.13). However, it’s important that the rhythms are able to be reset (they are what is known as “entrainable”) by exposure to external stimuli, such as light and heat – and this is how we cope with, for example, time zones. Finally, the rhythms must repeat once every 24 hours and they must retain their pattern of repetition regardless of the outside temperature.

The biological clock needs to synchronize with day and night. Anything that helps it get in step is called a zeitgeber and the most important zeitgeber we have is light. It’s probably for this reason that the suprachiasmatic nucleus sits over the optic nerve, through which the retina of the eye transmits the transitions from light to dark and back again, to the brain. White light is a combination of all the colours of the spectrum. Scientists have discovered that, when it hits the back of the eye, the blue light part of the spectrum strongly activates its own branch of the optic nerve, straight to the suprachiasmatic nucleus. It bypasses the area of the brain that slowly perceives dawning light, and triggers the brain to begin dealing with light information, and set up its rhythms accordingly, before you actually perceive the light itself.

THE BRAINWAVE REVOLUTION

Hans Berger established the existence of brainwaves in the 1920s. He attached electrodes to his subjects’ heads (see p.13) and called the recordings electroencephalograms (EEGs). He realized that there was more than one type of brainwave present in the human brain, which led to his identifying and naming “alpha waves” (also known as Berger’s waves). Alpha waves are oscillations in the electrical activity of the brain that vary at a rate of between 8 and 12 cycles per second (known as Hertz, or Hz), and Berger noticed that this happens when we’re awake, but resting with our eyes closed. He then immediately went on to identify “beta waves” – oscillations of between 12 and 30Hz – which he said occur when we’re actively thinking or concentrating.

Since Berger made his discoveries, there has been a brainwave revolution. Berger’s revelations were spot on, but they were only the tip of the iceberg. Below is a description of each brainwave type, from the fastest to the slowest, as we understand them.

Beta waves

Among the most frantic brainwaves are beta waves – the more intense our active thought processes, confusion, concentration or stress, the faster the beta-wave oscillations. Beta waves characterize wakefulness and are rarely present during sleep.

Alpha waves

Far from there being only one type of alpha wave, scientists now believe that there are in fact at least three types. The first, as Berger identified, occurs when we’re in a state of calm rest, but not asleep or even tired. The second occurs during REM sleep, when alpha waves are emitted from a different part of the brain to those of wakefulness. No one understands fully yet why alpha waves occur during REM sleep, although presumably this has something to do with the fact that REM sleep is usually when we’re dreaming. The third type of alpha wave is known as the alpha-delta and it occurs when we’re in non-dreaming sleep when there should be no alpha waves at all – it’s just that they “intrude” on the delta waves of sleep (see below). Alpha-delta intrusion is associated generally with sleep disorders, and one study published in 2011 has suggested that it may be particularly prevalent in people who suffer from depression (see pp.185–7).

Theta waves

Slow theta waves occur at 4 to 7Hz and indicate a deep state of relaxation, such as you might experience during meditation. They also occur as we drift off to sleep, becoming interspersed among the alpha waves that we experience as we close our eyes and relax. During this brief period between sleep and wakefulness, you might experience strange sensations and hallucinogenic-type visions that characterize a state known as “hypnogogia” (see box, p.21).

Delta waves

The slowest brainwaves that we know about are called delta waves, and it’s these brainwaves that characterize deep sleep (although very adept yogis might be able to experience them during meditation, too).