You spend a third of your lifetime asleep and good quality sleep is as vital for your health and well-being as eating and breathing. 1 Sleep restores your physical and mental energy and even helps you make sense of things by consolidating your memories and experiences. 1
Not getting good quality sleep can lead to many short- and long-term complications like daytime fatigue, poor concentration, decreased daytime performance and serious conditions like diabetes, hypertension, heart disease and depression. 1-3
So, what goes on behind closed eyes? How exactly does sleep work? Normal sleep is made up of two main phases; non-rapid eye movement (NREM) and rapid eye movement (REM) sleep. While you’re visiting Slumberland you pass through a 90-minute sleep cycle made up of mostly NREM sleep (containing both light and deep sleep phases) and some REM sleep (during which time your muscles are paralysed, and you experience dreams). 1,2
Typically you will have 5-6 of these sleep cycles in a night.
There’s a lot more to sleep than just closing your eyes and shutting yourself off from the world. Sleep is governed by a complicated process that is thought to entail two components: 2,4
- Homeostatic sleep need – this is the need to sleep that builds up the longer you stay awake.
- A circadian pacemaker – an internal “clock” that tells you when it’s time to sleep. This clock is regulated by melatonin, a hormone secreted by the brain during the night. The circadian clock is closely linked to other body rhythms such as temperature and blood pressure. 4
As you age, especially once you’re over 50, difficulty falling asleep, staying asleep and waking up much earlier are commonly experienced. 5 This is widely referred to as insomnia, and in older people, it can be caused by an age-related decrease in melatonin secretion. 4 Other causes of insomnia can include various types of illness, pain, learned behaviour, stress, anxiety or external factors like noise, cold temperatures, or bright lights. 3,6 Insomnia is not the only sleep disorder that affects people, though, and sleep disorders aren’t necessarily limited to older people. Here are just a few of the sleep disorders that can affect children, adults and the elderly alike:
Narcolepsy 1,6 is a rare condition that results in extreme sleepiness and irresistible sleep attacks during the day. It can cause serious problems for sufferers who can fall asleep at inopportune, or even dangerous times. People with narcolepsy may even fall asleep while in a business meeting or driving. They may also experience cataplexy, a sudden loss of muscle tone, which can lead to jaw drop, head droop, slurring and falling to the ground.
Obstructive sleep apnoea 1,6 is characterised by a blockage in the airway that causes loud snoring and pauses in breathing followed by a loud snort or choking sound as the airway unblocks. These sounds usually wake sufferers up and disturb their and their partner’s sleep. Obstructive sleep apnoea is more common in older and overweight people and smoking and alcohol increases the risk of developing it.
Restless leg syndrome, 6 as the name implies, is a disorder characterised by an almost irresistible urge to move the legs just as you’re falling asleep. This urge is brought on by unpleasant sensations in the legs that have been described as “creeping”, “crawling”, “prickling”, “itching”, or “tingling”. These sensations and leg movements usually interfere with sleep onset.
Night terrors,1,3,6 is a parasomnia (a disorder characterised by abnormal or unusual behaviour of the nervous system during sleep). It affects 30-40 % of children at least once in their lifetime. The child usually wakes up screaming or crying and is sweaty, flushed, terrified, unresponsive and if awakened is confused and disorientated. They usually don’t remember anything about the night terror in the morning.
Sleep walking, 1,6 like night terrors, also occurs during deep sleep and there’s no memory of it in the morning. It’s also more common in children than in adults. It can range from simple sitting up in bed to walking outside in an attempt to “escape”.
Jet lag 6 is an example of a sleep disorder relating to circadian rhythm disruption and follows rapid travel across multiple time zones, with symptoms lasting longer with eastward travel. These symptoms include insomnia, excessive sleepiness, decreased daytime function, dry and itching eyes, nausea, headaches, bloating and dizziness. People over the age of 50 are more likely to develop jet lag than those under 30. DM
For more information on sleep and sleep disorders visit www.sleepless.co.za and download your free sleep diary.
- Mental Health Foundation. Sleep Matters: The impact of sleep on health and wellbeing. Mental Health Awareness Week 2011. [Online] 2011 [cited 2020 Jul 14]. Available from: URL: http://www.mentalhealth.org.uk/content/assets/PDF/publications/MHF-Sleep-Report-2011.pdf?.
- Zisapel N. Sleep and sleep disturbances: biological basis and clinical implications. Cell Mol Life Sci 2007;64:1174-1186.
- Wilson SJ, Nutt DJ, Alford C, Argyropoulos SV, Baldwin DS, Bateson AN, et al. British Association for Psychopharmacology concensus statement on evidence-based treatment of insomnia, parasomnias and circadian rhythm disorders. J Psychopharmacol 2010;24(11):1577-1600.
- Zisapel N. Melatonin and Sleep. Open Neuroendocrinol J 2010;3:85-95.
- Weyerer S, Dilling H. Prevalence and Treatment of Insomnia in the Community: Results from the Upper Bavarian Field Study. Sleep 1991;14(5):392-398.
- American Academy of Sleep Medicine. The International classification of sleep disorders, revised: Diagnostic and coding manual. Chicago, Illinois: American Academy of Sleep Medicine, 2001. [Online] [cited 2020 Jul 14]. Available from: URL: https://vct.iums.ac.ir/uploads/icsd.pdf.
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