Definition
Sleep can be defined from several perspectives, but it is primarily defined as a reversible, repetitive, and normally stationary state of immobility in which the ability to perceive and respond to the external environment is suspended. Sleep is driven by brain activity, but it is also deeply connected to physiological changes in other parts of the body.
Human sleep is divided into non-REM (non-rapid eye movement sleep) and REM (rapid eye movement sleep). A normal adult’s nightly sleep consists of four to six cycles. Sleep usually begins with non-REM sleep and progresses into deeper sleep. The first REM sleep occurs 80 to 100 minutes after sleep onset, followed by a cycle of about 90 minutes between non-REM and REM sleep.
Non-REM sleep can be classified into four stages based on the depth of desensitisation and brain waves. REM sleep accounts for 20 to 25 per cent of total sleep time. It is during REM sleep that people dream, and it is known that if you wake up during REM sleep, you will remember most of your dreams, but if you wake up after REM sleep has ended, you will remember very few.
Sleep disorders are very common, with approximately 20% of the population having experienced or suffering from them. Sleep disorders can lead to a number of personal and social problems, including learning disabilities, decreased performance, traffic accidents, safety accidents, mood disorders, social adjustment, marital dissatisfaction, and occupational accidents.
In addition, untreated sleep disorders can worsen or delay recovery from existing medical, neurological, and psychiatric conditions, and can lead to serious illnesses such as myocardial infarction and stroke. Most people with sleep problems have one or more of the following three symptoms
1) Insomnia
2) Strange movements, behaviours, or feelings during sleep
3) Daytime hypersomnia
There are many different types of sleep disorders. Often, two or more sleep disorders are present together.
Insomnia
Insomnia is the most common sleep disorder. About a third of the general population experiences recurrent insomnia, and 9% of people are bothered by insomnia on a daily basis. Insomnia that lasts less than a month is most often caused by stress, so if you can eliminate the stress, the symptoms will often improve naturally. Sleep hygiene, education, stress management, and short-term use of sleep promoters can help prevent the transition to chronic insomnia. There are also several medications that can unknowingly cause insomnia, so a careful review of the patient’s medications is necessary. The treatment of insomnia depends on the cause. If the insomnia is caused by a sleep disorder that has a secondary cause, the principle is to treat the underlying condition. In the case of insomnia caused by stress or idiopathic insomnia with no specific cause, non-drug treatments should be used first and sleeping pills should be used second. In particular, the following habits are called sleep hygiene, which should be adopted for a good night’s sleep.
1) Avoid napping.
2) Stay in bed for a consistent amount of time. For example, if you decide to sleep for eight hours, you should get up and leave the bed eight hours after you start lying down, regardless of whether you have slept or not.
3) Exercise regularly every day and finish your workout six hours before you go to bed.
4) Take a hot bath about two hours before bed.
5) Keep your wake-up time consistent, even on weekends and holidays. Don’t oversleep on the weekend because you were sleep deprived during the week.
6) Avoid substances that interfere with sleep, such as tobacco, coffee, tea, cola, and alcohol. Alcohol has a sleep-inducing effect, but it also prevents deep sleep, which means you’ll wake up more often in the second half of your sleep, which in turn affects your sleep.
7) Avoid looking at the clock when you wake up at night.
8) If you lie in bed and can’t fall asleep for more than 10 minutes, get up and do something simple to help you fall asleep. Reading a book is better than watching TV.
9) Use your bed only for sleeping and avoid lying in bed to do other things or think.
Sleep breathing disorders are caused by increased airway resistance during sleep and are classified as central sleep apnoea syndrome and obstructive sleep apnoea syndrome.
Of these, obstructive sleep apnoea syndrome is the most common, affecting 2-4% of middle-aged adults. Obstructive sleep apnoea syndrome is a condition in which breathing is temporarily reduced or interrupted during sleep due to a narrowing or blockage of the airway.
When a person falls asleep, the muscles of the throat relax, allowing the uvula and tongue to touch the larynx and block the airway, causing the throat and larynx to vibrate as air passes through, resulting in snoring. Each time you have a hypopnea or apnea, the oxygen level in your blood drops and you wake up, which in turn prevents you from getting a deep sleep.
This leads to poor sleep quality, daytime tiredness, and sleepiness. If you’re an obese person who usually snores loudly at night, and you notice a lot of daytime sleepiness and a headache when you wake up in the morning, you may have obstructive sleep apnoea.
Due to daytime sleepiness and cognitive decline, people with obstructive sleep apnoea have poor memory and concentration, which increases the risk of motor vehicle accidents and workplace accidents.
They also have a higher incidence of cardiac artery disease such as myocardial infarction and angina, stroke, pulmonary hypertension, and arrhythmias. This can be diagnosed by polysomnography and can be significantly improved by weight loss. In some cases, surgery such as uvulopalatopharyngoplasty (UPPP) can be performed.
Narcolepsy
Narcolepsy is a complex neurological disorder characterised by excessive daytime sleepiness. It is relatively rare and most often occurs between the ages of puberty and 30.
Common symptoms of narcolepsy include cataplexy, which is a sudden loss of strength in response to emotional stimuli such as laughing out loud or being angry; sleep paralysis, in which the head is awake but the body is unable to move; and hypnagogic hallucinations, in which dreams appear to come true when falling asleep or waking up.
A polysomnogram is essential to diagnose narcolepsy. Some wakefulness stimulants can be used to prevent daytime sleepiness.
Restless legs syndrome
Restless legs syndrome is characterised by the following four symptoms
1) An urge to move the legs, usually accompanied by an uncomfortable or unpleasant sensation in the legs.
2) The urge to move or unpleasant sensations start or worsen when you are not moving.
3) The urge to move or unpleasant sensations are partially or completely relieved by movement.
4) The urge to move or unpleasant sensations are worse in the evening or early night than during the day.
All patients with restless legs syndrome feel the urge to move their legs due to unpleasant sensations in the legs. Because of this, most of them have difficulty falling asleep and wake up frequently during the night.
In many cases, a primary cause of restless legs syndrome cannot be found, but secondary causes of restless legs syndrome include iron deficiency, Parkinson”s disease, uremia, pregnancy, peripheral neuropathy, hypothyroidism or hyperthyroidism, and rheumatoid arthritis.