Now with this responsive web design, you can easily change the text size to fit your eyesight needs.
If you browse on a desktop computer, a modern web browser will allow you to hold down the Ctrl key (Command key on a Macintosh) and press the + or - key to increase or decrease the text size, and 0 to go back to the default size.
On a smartphone or a tablet, you can simply pinch open on the screen to zoom in (i.e. to enlarge) and pinch close to zoom out (i.e. to reduce) everything.
You may also change the text size from the menu.
On the Page menu, select Zoom, then Larger.
Insomnia is a common problem in the society. A good sleep helps to restore our energy and cognitive function. Before proceeding to the definition of insomnia, let’s discuss the sleep cycle first:
Sleep can be divided into two phases: rapid eye movement sleep (REM Sleep) and non-rapid eye movement sleep (Non-REM Sleep). On the other hand, non-REM sleep can be divided into 4 Stages: Stage 1, Stage 2, Stage 3 and Stage 4. Stages 1 and 2 are called “light sleep” whereas Stages 3 and 4 are called “deep sleep”. For a normal general adult, REM sleep constitutes 20% to 25% of a sleep cycle whereas the remainder is the Non-REM sleep.
Sleep starts from light sleep of the non-REM sleep, then deep sleep of non-REM sleep, followed by REM sleep. This cycle of different phases of sleep is called a sleep cycle. A sleep cycle lasts from 90 to 120 minutes. Usually, a general adult has 4 to 6 sleep cycles per night.
The importance of sleep cannot be denied and every sleep stage has its own function. Non-REM sleep helps to repair the cells of our body and ensure that our body has enough rest in order to face the challenges in life the next day. On the other hand, REM sleep helps to process the information we learnt and helps to reinforce our memory and learning ability. Therefore, a good sleep can ensure that we are healthy both physically and psychologically in order to keep ourselves in an optimal function and to keep ourselves in good mood.
Insomnia is a type of sleep disorder. According to DSM-IV of the American Psychiatric Association, there are two major criteria in diagnosing sleep disorders: 1. Sleeping problems persist for more than 1 month; 2. Sleeping problems bring about anxiety, tiredness, and worries or resulted in deterioration of work function and role damage. On the other hand, ICD-10 of the World Health Organization defines insomnia as follows:
Different researchers and studies define insomnia in different ways. Insomnia can be broadly divided into 4 types:
The sufferer has difficulty in getting off to sleep while in bed and needs more than 30 minutes for sleep onset. The sufferer will become anxious, restless and worried. This is common in people having anxiety disorders.
The sufferer has intermittent, shallow sleep.
The sufferer still feels tired when wakes up, as if he/ she has not slept the previous night.
The sufferer wakes up 1 to 2 hours earlier than his/ her usual wake up time and could not fall asleep again. This phenomenon occurs for more than 3 nights per week and the sufferer feels tired, sleepy, moody, and irritable during daytime. This is common in people suffering from endogenous depression.
There are two major causes of insomnia: Primary insomnia and secondary insomnia. The causes of secondary insomnia include: mental and mood disorders, physical illnesses, substance abuse, and other sleep disorders. Research reveals that the prevalence of insomnia increases with age. For people aged 70 years or above, the rate of insomnia amounts to 35%. Insomnia is more prevalent in females than in males.
Occasional insomnia will not cause great harm to the body. However, if the insomnia persists, it can bring about adverse effects on the physical and psychological health of the sufferer. It can affect the quality of life, cognitive function, memory, and the work function of the sufferer and can impose substantial socioeconomic burden to the society.
Sleep hygiene can help to fight against insomnia:
If the above methods (sleep hygiene) cannot help you to have a good sleep, you may need to consult a doctor.
(Special thanks to Dr Bonnie Siu of Castle Peak Hospital for authoring this article)