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Sleep and Health


By the time Australians reach the average life expectancy of around 80 years, they will have spent approximately 28 years asleep
. Good sleep is essential for general health and wellbeing, but unfortunately, many Australians sleep poorly, too little or (in some cases) too much, and can suffer mental and physical health problems as a consequence. In this article, we look at what is known about sleep, its intersections with physical and mental health, and how we can all improve the quality and quantity of our sleep.


What is sleep health?

Although it is common knowledge and clinically certain that good sleep is essential to health, the term ‘sleep health’ is infrequently used and rarely defined. Health care tends to focus on the definition, identification and treatment of sleep problems rather than sleep health.

In the journal Sleep (2014), Daniel Buysse proposed the following definition of sleep health:

Sleep health is a multidimensional pattern of sleep-wakefulness, adapted to individual, social, and environmental demands, that promotes physical and mental well-being. Good sleep health is characterised by subjective satisfaction, appropriate timing, adequate duration, high efficiency, and sustained alertness during waking hours.

Buysse’s definition recognises that ‘sleep health is best understood in the context of individual, social, and environmental demands, i.e., that good sleep health may not look the same in every situation or every individual’.

Most people sleep between seven and nine hours each night. Fewer than seven hours of total sleep per day is generally considered to be insufficient.

Sleep occurs in cycles of about 90 minutes: each cycle consists of quiet sleep, a period of deeper sleep and then dreaming sleep. These components of sleep are all vital to feeling refreshed.
Everyone wakes during the night (as many as 10–12 times), but for very short periods, so they aren’t remembered. As people get older, their sleeping patterns become increasingly broken in nature, and daytime naps become important components of their total sleep time.

The epidemiology of sleep problems

Sleep problems are highly prevalent in the general community. The 2016 Sleep Health Survey of Australian Adults found that between 33 per cent and 45 per cent of Australian adults get sleep of inadequate duration or quality. Sleep apnoea (a disorder in which breathing is repetitively interrupted during sleep, due to collapse of the upper airway) affects an estimated 8 per cent, insomnia 20 per cent and restless legs syndrome 18 per cent of adults.

Snoring occurs when air does not flow smoothly through the air passages, or when the soft tissue in the throat vibrates during sleep. Frequent, loud snoring is reported by 24 per cent of men and 17 per cent of women. Seventy per cent of frequent, loud snorers report daytime impairment or other sleep-related symptoms. Other common sleep disturbances include hypersomnia (excessive daytime sleepiness), circadian rhythm disturbance, and disorders related to poor sleep hygiene (habits that prevent a good night’s sleep).

The indirect financial costs associated with sleep disorders and the conditions attributable to them were estimated at $4.3 billion in 2010. This included $3.1 billion for lost workforce productivity, and costs associated with motor vehicle and workplace accidents of $646 million. Sleep apnoea accounted for 62 per cent of the total cost ($2.6 billion) and insomnia 36 per cent ($1.5 billion). Sleep disorders were responsible for direct costs to the hospital system of $96.2 million, of which 73 per cent was due to sleep apnoea and 7 per cent to insomnia.

Sleep and physical health

The brain’s circadian system regulates the timing of sleep. Peaks and troughs in biological activity and inactivity are known as circadian rhythms. Misalignment between the circadian system and the external environment causes sleep to occur outside societal norms and can lead to sleep disorders.

Sleeping less than six or seven hours on average per night has been shown to increase the risk of obesity, type 2 diabetes and heart disease. People who sleep less than eight hours per day on average have higher body mass index, and can experience undesirable changes in levels of leptin and ghrelin (the hormones that control appetite); in addition, when sleep-deprived, people tend to gravitate towards eating comfort foods that are high in fat and sugar.

Short sleep reduces natural immune function, increasing the risk of infections and possibly cancer, and is associated with reduced life expectancy. Data from three large cross-sectional studies revealed that sleeping five hours or less per night increased all-cause mortality risk by about 15 per cent.

Sleep disruption and altered sleep patterns also threaten health and impair normal functioning. About 1.5 million Australians are shift workers who are at heightened risk of circadian rhythm misalignment, inadequate and poor-quality sleep, and sleep disorders such as sleep apnoea, insomnia and cardiometabolic diseases.

Between 32 per cent and 36 per cent of shift workers fall asleep at work at least once a week, and the risk of experiencing an occupational accident is at least 60 per cent higher for non-day shift workers than day-shift workers. Parents of newborns have been shown to experience sleep disturbance comparable to that of people working permanent night or rotating shifts.

Sleep and mental health

Sleeping problems, such as difficulty falling asleep, not getting enough sleep or having regularly disrupted sleep patterns, are associated with anxiety and depression. The association works both ways: people who are anxious and/or depressed are more likely to have sleep problems than people without these conditions.

Large, prospective community samples provide solid evidence for the bidirectional relationship between insomnia and depression. Jansson-Frojmark and Lindblom’s study of 3000 Swedish residents (Journal of Psychosomatic Research, 2008) showed high anxiety and depression at baseline predicted insomnia, while untreated insomnia at baseline predicted depression and anxiety at the one-year follow-up. In the United Kingdom, a prospective study of 2363 adults found depression at baseline predicted insomnia at follow-up (Morphy and colleagues, Sleep, 2007). In Siversten and colleagues’ study of 24 715 Norwegians (Psychosomatic Medicine, 2012), strong longitudinal and bidirectional associations between insomnia and depression were found over measurements taken 11 years apart.

Ageing and sleep

Older people naturally produce less melatonin (a sleep-promoting hormone) than younger people, so they tend to find falling asleep more difficult. However, many other factors can interfere with an older person’s sleep, including symptoms of menopause, such as hot flushes; the need to urinate during the night; and medical problems such as arthritis, osteoporosis, Parkinson’s disease, indigestion, heart disease, sleep apnoea and lung diseases such as asthma and chronic obstructive pulmonary disease (COPD). The drugs used to treat these conditions may also interfere with sleep.

The incidence of dementia increases rapidly with age. Up to half of people with dementia have abnormal sleep patterns; they are often sleepy during the day and find it difficult to sleep at night. They may also experience a reduction in sleep quality, including less deep, restful sleep and a lighter sleep overall.

Management of insomnia

Charles and colleagues (Australian Family Physician, 2009) found that in 95 per cent of cases, Australian general practitioners managed their patients’ insomnia with medication. Eighty per cent of medications prescribed were benzodiazepine derivatives, 15 per cent were benzodiazepine-related drugs and the remaining medications were antidepressants. Management of insomnia with medication can be effective in the short term, but has the negative consequences of dependence and can be ineffective over the longer term.

To date, cognitive behavioural therapy (CBT) targeting maladaptive sleep behaviours and thoughts has been shown to be the most effective objectively measured treatment for insomnia. CBT can be an effective treatment in older age groups and depressed individuals, producing outstanding improvements in total sleep time, sleep efficiency and waking frequency that are maintained at long-term follow-up.

Britt Klein, Brooke Andrews, Janet Haynes and Sue Lauder of Australia’s Federation University have developed a six-module mobile and web-based biopsychosocial and cognitive behavioural intervention program for insomnia. The program, iSleepWell, includes a monitoring system that can help users to track their progress as they work though the program.

Achieving better sleep hygiene

Sleep hygiene means having good sleeping habits; things you can do to give yourself the best chance of regular, refreshing sleep. The following tips for improving sleep through simple behavioural change are from Sleep Disorders Australia’s sleep hygiene fact sheet.

DO

DON’T

Go to bed at the same time each day.

The body has a natural clock, which will make you sleepy when you’re ready for bed. Try not to ignore this. Going to bed too early may also result in disturbed sleep.

Exercise just before going to bed.

Exercising immediately before bed stimulates the body and may make it difficult to fall asleep. Take your exercise earlier in the day, preferably before dinner time.

Get up from bed at the same time each day.

Getting up at the same time helps to keep your body clock synchronised with the diurnal cycle. If you can stick to a regular waking and sleeping time, your body will become accustomed to it. Avoid the temptation to try to make up for a poor night’s sleep by sleeping in. However, this doesn’t mean that you should be obsessive about it, an occasional night out or sleep in is not going to hurt in the long run.

Engage in stimulating activity just before bed.

Playing a competitive game, watching an exciting program on television or a movie, or having an important family discussion stimulates your mind and thoughts will overflow to the bedroom. Worrying about or planning the next day’s activities may be a natural thing to do, but try to avoid it.

Get regular exercise each day.

There is good evidence that regular exercise improves restful sleep. Ideally, this should be taken before dinner or in the morning.

Drink caffeine-containing drinks in the evening.

Coffee and tea are the obvious caffeine-containing drinks but colas and many other soft drinks also contain caffeine. Read the labels. A glass of warm milk can work well. If frequent trips to the toilet are a problem during the night, try not to drink too much before bedtime and make sure you go to bed with an empty bladder.

Try to spend some time outdoors during the day or in natural light.

Light helps the body to produce melatonin, which promotes sleep. Exposure to sunlight early in the day is particularly helpful if you have trouble getting to sleep.

Make the bedroom as restful as possible.

Keep the temperature low, noises and outside light to a minimum, and leave distracting things such as beeping watches and clocks outside.

Use your bed only for sleep and sex.

Some people use the bed as a lounge room – studying, watching television, playing computer games and so on. Avoid this: make sure that the bed is associated with sleeping. The brain makes connections between places (the bedroom) and events (sleeping) that need reinforcement. Make sure the bed is for sleeping and that sleeping happens in the bed.

Take medications as directed.

Prescription medications may cause you to be alert or sleepy, and the instructions that come with them should be followed. Try to take your medication around the same time each day.

Be comfortable and relaxed.

If you are cold in bed, warm the room or wear warm pyjamas. Warm hands and feet are particularly important. If you have uncomfortable pillows, mattress or bedclothes, change them. You will spend the next seven to nine hours in bed and you want to be comfortable. A warm bath about an hour before bedtime causes the body’s temperature to rise and then fall, which may promote sleep.

Understand your sleep needs.

Most people need between seven and nine hours’ sleep each day, but this includes naps and time spent dozing in front of the television. Be realistic in your expectations of your sleep needs.

 

 

  • About the author: Campbell Aitken
  • Dr Campbell Aitken is a freelance editor and a senior research fellow at the Burnet Institute.

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