Sleep: The secret to sleeping well and waking refreshed

Slow-wave sleep lasts for roughly the first three hours of the night and it is very difficult to wake people up from it. People who are woken at this stage often act quite strangely, almost as if they are drunk.

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Ultradian rhythm

Scientists believe there may be a brain rhythm that is mainly revealed during sleep as a 90-minute REM cycle. As this lasts less than 24 hours it is known as an ‘ultradian rhythm’ (Ultra from the Latin for ‘beyond’). Dreams occur on a roughly 90-minute cycle.

At the deep-sleep stage, the EEG shows highamplitude slow waves. The mind begins to drift, thoughts are unfocused, and the brain becomes ‘dormant’. A person in this stage of sleep tends to stop moving and their postural muscles relax. Heart rate and breathing slows, the body temperature ‘thermostat’ in the hypothalamus is lowered and body temperature reduced. Kidney function decreases and less urine is produced.

Stage 5: Rapid Eye Movement (REM) sleep

Stage 5 sleep is commonly known as Rapid Eye Movement, or REM sleep, named after the darting eye movements that have been observed in people in this sleep stage. It appears after 80-90 minutes’ sleep in recurring phases known as an REM cycle. It initially lasts for about ten minutes, then increases in length, with the final one lasting for about an hour. In young adults, REM sleep can last for up to two hours in total.

For many sleep scientists, REM sleep is the most interesting and exciting of all sleep stages, for this is when dreaming occurs, and is when the brain is most active. In fact, curiously, EEGs taken at this time are more similar to those taken during wakefulness than at other sleep stages. The brain shows increased cerebral metabolism, cerebral blood flow, intracranial pressure and brain temperature, and many parts of the brain that control functions such as heart rate, blood pressure, breathing, body and brain temperature and sweating are less well regulated than at other times. Even sexual organs are aroused and men often have penile erections. In fact, there was a time when REM EEGs were used to determine whether men’s impotence was physical or psychological, though this has all changed in recent years with the introduction of Viagra.

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Are you a dreamer?

If you don’t think you dream, try setting your alarm clock at 15-20 minutes earlier than your usual morning wake-up time. This will almost certainly ensure that you will be awoken out of REM sleep. Go to bed preparing yourself to remember what is in your mind when you wake up. When the alarm goes off, think about what has been going through your mind.

REM sleep and dreaming

Scientists believe we dream during REM sleep, and that the dreams become more vivid as the sleep stage progresses. Most REM sleep occurs towards the end of the night and can sometimes reach its peak in the early morning, (which is why you can often remember dreams clearly just as you wake up). But the memory of the dream usually fades within minutes.

Sigmund Freud and dreams

Although he originally trained as a doctor, Sigmund Freud (1856-1939) is best known for his study of the mind, and is often referred to as the father of psychoanalysis. Freud believed that the mind consisted of three main elements: the ego (the conscious self), the superego (the mind’s moral guardian) and the id (psychic and unconscious mental energy), and that the demands of the id, left unchecked during sleep, were expressed in dreams.

In Freud’s psychodynamic theory, dreams symbolized unconscious thoughts and mental processes, and interpreting their meaning was a ‘royal road’ to understanding the subconscious mind. One of Freud’s contemporaries, Carl Jung (1865-1961), formulated the idea of the ‘collective unconscious’ (a reservoir of memories and experiences), his list of the many recurring themes in dreams including: water, being trapped, travelling, running, being chased, death, choking, falling, houses, flying, nudity, being late and sex.

Freud’s influence on psychiatric thought has now largely declined, but his book The Interpretation of Dreams (1900) remains one of the most significant works of the 20th century.

REM sleep has often been described as paradoxical because it has many contradictions. Although EEG readings show that the brain is so active at this time that it may be using even more energy than during wakefulness, the muscles, by contrast, are completely paralyzed, apart from rapid eye movements and the odd, involuntary twitching of fingers. Since vivid dreams also occur at this time, some people believe the muscle paralysis is there to stop the dreams from being physically acted out.

did you know?

During REM sleep your brain is as active as when you are awake.

Dreaming through the ages

Dreaming has intrigued and fascinated people for thousands of years before the works of Sigmund Freud, and many of the world’s greatest civilizations and religions have used dreams to guide their everyday lives. Let us look at some of the most famous examples below.

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An ancient Hindu tale that is still relevant today describes three states of mind: the state of wakefulness (vaiswanara), when a person perceives ‘what is presented to them by their senses’, the state of dreaming sleep (taijasa) ‘which can reflect in the mind what has happened in a person’s past’, and the state of dreamless sleep (prajna) when ‘the veil of unconsciousness envelops thought and knowledge, and the subtle impressions of the mind apparently vanish’.

The ancient Egyptians

By around 2000 bc, the ancient Egyptians were already transcribing their dreams on to papyrus. Egyptians believed that dreams brought messages from the gods and that dreaming was the best way of attaining divine revelation. They developed methods for inducing or incubating dreams, including building sanctuaries that had special beds for dreaming.

The ancient Greeks

Sanctuaries and shrines for promoting dreams were also adopted by the Greeks, who in addition had specific dream rituals. Those entering the Shrine of Apollo at Delphi were required to abstain from sex, or eating meat, fish and fowl two days before. Once in the shrine, they made an animal sacrifice to the god from whom they wanted to receive the dream and would then sleep on the skin of the sacrificed animal, sometimes near the statue of the appropriate deity. The Greek god Hypnos was thought to bring sleep to mortals and his son Morpheus was said to send warnings and prophecies to those sleeping in the temples.

The early Christians

The Judeo-Christian tradition also used dreams as a guide to waking behaviour, most notably in the story of Jacob’s dream of the ladder going up to heaven recounted in Genesis, which was seen as a turning point in his spiritual development. Various books from the Old Testament used dreams for guidance – it was assumed that the conventional way for God to communicate with his people was through dreams. Dreams were similarly used in the New Testament; for example, in stories of the Flight into Egypt and the dream of the Magi at the birth of Christ.

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Take it to the next level…

• Chronotherapy 180

• Circadian rhythm disorders 139

• Light 38

• Light therapy 178

• Melatonin supplements 178

• Seasonal Affective Disorder (SAD) 17

• The work of sleep clinics 168

Other sources

• For professional sleep research societies, visit www.wfsrs.org

• To read specialist journals on sleep, visit www.journalsleep.org

• For brain basics and disorders, go to www.ninds.nih.gov or www.websciences.org/s ltbr/

• For contemporary discussion and links on sleep, visit www.neuronic.com or read sleep blogs: scienceblogs.com/clock/

In the first century ad, Ignatius of Antioch dreamt of angels singing alternating chants and introduced this antiphonal singing in monastic communities as a consequence. (Ignatius could possibly be described as one of the early sleep researchers as he claimed that all people dreamt and that this could be observed by their movements when asleep!) And in the fourth century, Chrysostom declared that dreams were symbolic reflections of a spiritual world.

The early philosophers

The early philosophers had opposing views on dreams. Plato argued that there was a world beyond the physical one and that it was possible to communicate with it through dreams, while Aristotle argued that knowledge was gained through sense and reason and that there were no divine communication pathways of communication – dreams were just the remnants of an overly stimulating wakefulness. The debate still continues…

2 Why can’t we sleep?

Surveys show that 95 per cent of us will suffer from sleeping problems at some point in our lives, and insomnia is cited as one of the main reasons for visits to the doctor. But what is insomnia? And, more importantly, why do we get it? All too often the answer lies within. This chapter looks at the important roles that Nature, lifestyle and environment have to play.

All about insomnia

Studies show that 50 per cent of us have symptoms of insomnia at any given time. We often use the word ‘insomnia’ when we miss one night’s sleep. But what does insomnia really mean?

What is insomnia?

In normal usage ‘insomnia’ just means not being able to sleep. The inability to sleep can be caused by literally anything. Sometimes people talk about insomnia when they have not given themselves enough time to sleep, but when considered by a sleep disorder specialist, insomnia is often just regarded as a symptom and a cause is sought, e.g. depression (see page 156). Nowadays a sleep disorder specialist may regard insomnia as a disorder in its own right with very specific sleep-related causes (see pages 127-31). The changes in the usage of the word can cause confusion (particularly when surveys are conducted). An outdated classification simply described three types:

did you know?

• Insomnia is the most common mental health problem in the UK.

• One in ten people will suffer from chronic insomnia at some point in their lives.

• Transient insomnia – short-term sleeping problems (usually lasting only a few days). Often caused by one-off changes in your sleep cycle, such as long-distance travel and jet lag, or illness. This is by far the most common type, and accounts for about 75 per cent of all cases of insomnia.

• Short-term insomnia – sleeping problems caused by a more prolonged period of stress, due to, say, financial problems or marital break-up. This can last for weeks.

• Chronic insomnia – the often inevitable result of untreated short-term insomnia. It can last for months, and, in rare cases, years. It is a long-term problem that often recurs.

Sleeplessness and insomnia

It may be better to use two words: ‘sleeplessness’ for the times that sleep is impossible, but you know why; and ‘insomnia’ for the times that you do not know why you cannot sleep. Some reasons for sleeplessness include:

• lifestyle (work, shifts, caring for an invalid, children)

• poor sleeping environment (noise, uncomfortable mattress, etc.)

• stress (bereavement, divorce, etc.)

• a poor diet

• stimulants, medicines and drugs

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Using sleeping pills

Prescription of sleeping pills costs the UK about £22.4 million per year. About 15.5 million prescriptions are written. Taking sleeping pills has been shown to increase the risk of road accidents (last year there were 32,220 serious injuries and deaths on UK roads).

As a general rule, a good way to find out if you have true insomnia is to ask yourself if there is any obvious reason for your sleeping problems. If not, and you have had the problem for a few weeks, then you are likely to be suffering from the condition.

Diagnosing insomnia

Insomnia can develop from sleeplessness, and often patients will know when their sleep problems started but cannot understand why they have not gone away. Psychiatrists rarely diagnose insomnia but when they do the following conditions must be met:

• The time it takes to get to sleep must be more than 30 minutes. Total sleep time during the night is usually between three to six hours. The sleep may be unrefreshing.

• The problem must occur three or more nights a week.

• The insomnia causes major problems in daytime functioning (socially, at home, at work).

• It must have lasted for three months or longer.

• There are no environmental, lifestyle, medical or psychiatric causes for the problem.

The role of Nature

Understanding when our bodies are working against us can sometimes be half the battle when trying to understand why we can’t sleep. Here are some of the natural factors that can affect sleep.

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Women and sleeping

Polls carried out in the USA by the National Sleep Foundation found the following:

• Almost three out of four women get less than eight hours’ sleep a night.

• Sleep is disturbed for 2.5 days on average during the menstrual cycle.

• More women complain of sleep problems during menstruation (71 per cent) than during the week preceding menstruation (43 per cent).

• Sleep-disrupting conditions such as anxiety and depression are twice as likely to occur in women than in men.

Gender

It is a sad fact of life that you are more likely to have sleep problems if you are a woman. The reason for this is partly due to the female bodily cycles. Much of women’s lives is governed by the sex hormones oestrogen and progesterone, and hormonal fluctuations, as in the menstrual cycle, pregnancy and the menopause, can severely affect sleep either directly, or through their effects on anxiety and general mood. Pre-menstrual women commonly report sleeping difficulties in the week before their period starts, but even women who don’t suffer from pre-menstrual symptoms can still take longer to fall asleep, wake more often and feel less refreshed after sleep during the second phase of their cycles. Sleep disturbances also become more common during the menopause, when women report waking up more often at night and feeling more tired during the day.

Studies on the effects on sleep of Hormone Replacement Therapy (HRT) and oral contraceptives have shown that these hormones have direct effects on the brain. Oestrogen has widespread effects on mental performance, mood, movement coordination and pain. However, the monthly fluctuation of oestrogen and progesterone impacts on cognitive function, mood, appetite and temperature, as well as the sexual organs and breasts, making it more difficult to work out how they affect sleep directly.

There is evidence to suggest that women’s role in society may affect their sleep even more than hormonal changes. The added pressures many women face of juggling stressful jobs with their roles as mothers and wives can often pose an intolerable burden, exacerbated by the fact that many women ignore their fatigue.

Age

Ageing can greatly affect sleep, with the number of hours declining as you get older. While a young adult will sleep on average for 7-8 hours, by old age this will go down to about six. Quality of sleep is affected too. Stage 4 sleep is reduced, and the proportion of REM sleep, which makes up abut 50 per cent of baby sleep, will, in the latter stages of life, go down to 15-20 per cent. Although the cause may be inevitable, there are still steps you can take to improve the situation (see Chapter 4).

General constitution

Your sleep is more likely to be poor if your general health is poor, even if you are not suffering from a specifically sleep-related disorder (see Chapter 6). Conditions such as heart disease, general breathing problems and arthritis can make it difficult to get comfortable at night, and will almost certainly have an impact on your sleep. Consult your doctor if this becomes an issue. For many people emotional issues and character make-up may come into play.

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Adult sleep A recent US National Sleep Foundation survey looking at the relationship of sleep problems in adults aged between 55-84 found:

• Nearly one in four adults had at least four medical conditions.

• Depression, heart disease, pain and memory problems were most associated with insomnia.

• Ninety per cent of those that did not have any medical condition thought their sleep quality was good or excellent. This went down to 78 per cent if they had 1-3 medical conditions, and 59 per cent if they had four or more conditions.

• Obesity, arthritis, diabetes, lung disease, stroke and osteoporosis were more likely to be associated with other sleep problems (e.g. snoring, restless legs).

The role of diet

The role of food and drink in sleep is often overlooked but there is increasing evidence that healthy eating habits can have many beneficial effects. The first stage is to identify and eliminate the main sleep spoilers.

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UK safe limits for alcohol

• Men should drink no more than 21 units of alcohol per week (and no more than four units in any one day).

• Women should drink no more than 14 units of alcohol per week (and no more than three units in any one day).

• Pregnant women: if you have one or two drinks of alcohol (one or two units), once or twice a week, it is unlikely to harm your unborn baby. However, the exact safe limit is not known.

Alcohol

Drinking small amounts of alcohol (especially a glass of wine with meals) can be pleasurable, and its benefits well recognized. The problem comes when alcohol is drunk in large doses.

Drinking alcohol at night is commonly believed to be helpful for sleep. This is a myth. Drinking large doses may make you fall into a deep sleep straight away, but as soon as the immediate effects of the alcohol wear off (usually after 3-5 hours), you will wake up feeling exhausted, and your sleep is likely to be disrupted for the rest of the night. Drinking large amounts of alcohol can depress brain activity and induce unconsciousness. Breathing is also invariably impaired, leading to snoring. Alcohol also has a diuretic affect, which means that, depending on how much you’ve drunk, you could end up getting up to go the toilet several times during the night.

Caffeine

Caffeine is a very powerful stimulant that is known to cause the delay of sleep onset. Studies have shown that a dose equivalent to one cup of coffee taken at bedtime can both increase the time taken to fall asleep and decrease sleep quality, especially in non-REM deep sleep (see page 19). In a few individuals, a dose of coffee in the morning can also have an effect the following night, indicating that extremely low concentrations of caffeine can affect sleep. Like all stimulants, caffeine may make you feel increasingly alert during the day, but, as well as causing insomnia, prolonged, high-dose usage (more than six cups of coffee a day) can lead to the following nasty side-effects:

How much alcohol is in your drink?

Sample drink Quantity Alcohol by volume Units Can of lager 500ml 4.00% 2 Glass of cider 500ml 4.00% 2 Alcopop 400ml 5.00% 2 X-Strong lager 500ml 8.00% 4 Glass of wine 160ml 12.50% 2 Cocktail 125ml 40.00% 5 Shot of spirits 25ml 40.00% 1

Note: A unit is 10ml of alcohol, whether it is spirits, lager or wine.

• persistent anxiety

• an inability to concentrate

• increased muscle tension

• diuresis (increased urination)

• agitation, excitement and panic attacks (with high doses)

• vertigo, dizziness, tinnitus, convulsions

• increased body temperature

• confusion, disorientation, paranoia

• palpitations

• nausea

watch out!

A good night’s sleep does not result from high doses of alcohol. A night’s sleep deprivation will enhance the effects of alcohol and after five nights of partial sleep loss, three drinks will have the same effect on your body as six would on a regular night.

must know

Caffeine

• Caffeine is readily absorbed and peak concentrations occur 30-60 minutes in young adults after ingesting it. High doses slow the metabolism down and can remain in the brain for 9-15 hours.

• Percolated coffee usually contains more caffeine than instant. If the coffee grounds are boiled during preparation, as is common in Scandinavian countries, the caffeine content can be as high as 500mg per cup.