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What Goes Wrong in Sleep? An Overview of Sleep Disorders

What Goes Wrong in Sleep? An Overview of Sleep Disorders

Written by Dr. Ruwanthi Jayasekara

Consultant Respiratory Physician (MBBS, MD Medicine, MRCP UK, ESRS/ Expert Somnologist)

Good sleep is essential for a good life, and we spend about one-third of our lives sleeping. Therefore, it is essential to be aware of disorders that can occur during sleep, how to identify them, and treatments are available for them.

What types of sleep disorders are there?

There are many types of sleep disorders but here are some of the most common ones: 

  • Insomnia (difficulty in falling asleep and/or staying asleep)
  • Sleep related breathing disorders (eg. Sleep apnoea)
  • Central disorders of hypersomnolence (conditions with excessive sleep)
  • Parasomnias (involves unusual and undesirable physical events or experiences that disrupt your sleep)
  • Sleep-related movement disorders 

Let’s take a deeper look into each of the above-mentioned sleep disorders including how each affects the patient and what they can do to prevent them.

types of sleep disorders


People with insomnia find it very difficult to fall asleep and/or sleep well at night despite having a suitable environment and time to sleep. This will result in an impairment in their daytime functioning. In some people, this can be short-term, such as in anticipation of a stressful event like facing an exam or starting a new job. In others, this goes on for many months and years, causing distress to the patient.

Patients with insomnia will be evaluated using 

  • Sleep diaries – These let you measure and record when the patient went to bed, when they woke up during the night and woke up in the morning
  • Actigraphy – It is a wearable sleep test that tracks the patient’s movements while they are sleeping to analyse when they’re asleep and awake
  • Polysomnography (sleep study) – It is a comprehensive test that records brain waves, oxygen level in blood, heart rate, breathing, leg movements, etc during the sleep study.

This condition’s management includes sleep hygiene measures, medication revision and cognitive behavioural therapy.

Sleep-related Breathing Disorders

These conditions are involved with abnormal and difficult respiration during sleep. While some of these sleep-related breathing disorders have low health impacts, others may have serious consequences due to their effects on the patient’s sleep and balance of oxygen and carbon dioxide in their blood.

There are a few types of sleep-related breathing disorders. They are 

  • Obstructive sleep apnoea 
  • Central sleep apnoea
  • Sleep-related hypoventilation disorders
  • Sleep-related hypoxemia

Some risk factors of obstructive sleep apnoea are 

  • Male sex
  • Ageing
  • Obesity
  • Smoking
  • Alcohol use 
  • Certain craniofacial features such as receding jaw or small chin
  • Patients or their bed partners complain of loud snoring
  • Fragmented sleep
  • Getting up frequently to go to the toilet
  • Feeling excessively sleepy in the daytime
  • Feeling irritable and moody in the daytime

Apnoeic Spells and its Treatments

Sometimes a spouse may notice that the patient stops breathing at night for prolonged periods. This phenomenon is known as an apnoeic spell. Patients are evaluated with sleep studies called ‘polysomnography’, tests that evaluate sleep in detail and diagnose the underlying sleep disorder. The first line treatment is CPAP therapy (a device that provides continuous positive airway pressure). Additionally, weight loss with exercise and a healthy diet are also substantial.

Central Disorders of Hypersomnolence

These are a rare group of sleep disorders where patients complain that they are always sleepy during the day and the night. Patients tend to fall asleep in the daytime even after adequate sleep. E.g. Narcolepsy. Some patients with excessive sleepiness may have an underlying undetected medical or psychiatric condition. 

Excessive sleep has a significant detrimental impact on the patient’s life. These patients must be evaluated with sleep studies and blood investigations before starting their treatment.

Circadian Rhythm Sleep-Wake Disorders

Circadian rhythm sleep-wake disorders are a group of disorders where the patient’s body’s clock, which helps to maintain a regular day and night pattern, is affected. 

There are several types of circadian rhythm sleep-wake disorders.

  • Delayed sleep-wake phase disorder

This is where the patient does not fall asleep until the morning and tends to wake up in the afternoon – the patient’s circadian clock is delayed compared to the average population. These patients may struggle to wake up on time for school and work. 

  • Advance sleep-wake phase disorder

On the other hand, this disorder tends to have an early sleep pattern and early rise pattern. There are various types of disorders. Shift workers also suffer from the detrimental effects of not sleeping on time and staying awake when they should be sleeping. 

  • Jet lag disorder 

This is another condition in which people suffer due to crossing time zones. Understanding these conditions is vital as many treatment modalities help reduce these problems.


Parasomnias are another set of sleep disorders involving a lot of sleep movement. In certain sleep stages, some people have confusional arousals, sleepwalking, sleep terrors, sleep-related eating, violent movements in sleep, acting out dreams, nightmares etc. Patients are evaluated with a sleep diary and polysomnography. These conditions must be identified and treated as many patients suffer from poor sleep and daytime dysfunction due to these issues.

Sleep-related Movement Disorders

Sleep-related movement disorders include restless leg syndrome and periodic limb movement disorder, where the patient has a lot of leg movement at night, leading to disturbed sleep.

How do you prevent sleep disorders from occurring in the first instance?

The baseline management of any sleep disorder is the maintenance of good sleep hygiene practices.

  • Maintain a regular sleeping and waking up time
  • Have regular meals
  • Avoid caffeinated drinks close to bedtime
  • Avoid smoking and alcohol
  • Keep your devices away at least one hour before bedtime

Despite these measures, if a patient feels that they have an issue with their sleep, it is best not to delay diagnosis, as sleep is essential for a healthy life. They can consult experienced sleep specialists via the oDoc app to have a comfortable and convenient consultation in just three taps within the comfort of their own home.

Dr Ruwanthi Jayasekara

SLMC 25147

Chest Physician


  1. How Is Actigraphy Used to Evaluate Sleep, Sleep Foundation (2022)
  2. Sleep-Related Breathing Disorders, Sleep Foundation (2022)

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Insomnia – Everything You Need To Know

Insomnia - Everything You Need To Know

female with insomnia struggling to sleep at night

People with Insomnia find it hard to fall asleep, stay asleep or even go back to sleep if woken up. Insomnia may cause someone to feel tired when woken up, drain their energy level, resulting in a low performance at work, mood swings and even some adverse health conditions such as diabetes, hypertension and weight gain.

The amount of sleep needed varies from person to person. However, an average person needs at least six to nine hours of sleep. Quality sleep plays a vital role in overall well-being. Not getting sufficient sleep regularly can significantly impact physical and mental health along with the quality of life. 

What are some insomnia symptoms?

Insomnia is defined as: 

  • Difficulty in falling asleep at night
  • Waking up in the middle of the night
  • Waking up too early

As a result, here are a few other symptoms related to the lack of sleep:

  • Feeling drained out/tired
  • Difficulty in focusing or paying attention 
  • Increase in carelessness
  • Feeling tired and lethargic during the day
  • Feeling anxious or depressed 

Insomnia can be both short-term and long-term. Short term insomnia tends to last for a few days or weeks and is often triggered by stress. Whereas long-term or chronic insomnia is when sleep difficulties occur at least three times a week for three months or longer.

What causes insomnia?

Insomnia may be the primary problem, or it may be associated with other health conditions. However, several things may contribute to insomnia, including environmental, physiological, and psychological factors.

Causes for chronic insomnia include:

  • Stress: Concerns regarding jobs, education, finance, family and health can affect the mind’s activity at night, making it difficult to fall asleep.
  • Schedule: Circadian rhythms are 24-hour cycles that are part of the body’s internal clock running in the background to carry out essential functions and processes. One of the most essential and well-known circadian rhythms is the sleep-wake cycle. When the sleep schedule is disrupted due to working/studying till late at night, travelling across multiple time zones, working a late or early shift, or frequently changing shifts, it makes it difficult to fall asleep.
  • Poor sleep habits: Eating, watching TV till late, using smartphones, playing video games before bed can interfere with the sleep cycle. Similarly, poor sleep habits include an irregular bedtime schedule, naps, an uncomfortable sleep environment, and using the bed for work, eating or watching TV.

Common causes of insomnia include:

  • Mental health: Trauma, anxiety, depression could affect the sleeping patterns, leading to insomnia.
  • Medication: Many prescribed drugs can interfere with sleep, especially severe illnesses.
  • Illnesses: Insomnia is influenced by medical conditions such as cancer, diabetes, asthma, Parkinson’s and heart diseases. 

Additionally, excessively drinking caffeine may also cause irregular sleeping habits, while nicotine in tobacco products is another stimulant that can interfere with sleep. On the other hand, alcohol may help fall asleep, but it prevents deeper stages of sleep and often causes awakening in the middle of the night.

What are the risk factors of insomnia?

Almost everyone has experienced a couple of sleepless nights. However, the risk of insomnia is more significant if someone falls into a specific demographic or experiences certain lifestyle factors:


  • Over the age of 60: Changes in sleep patterns and health.
  • Women: During the menstrual cycle and menopause, the hormonal shifts influence sleep patterns. Further, during menopause, night sweats and hot flashes often disrupt sleep. Insomnia is common during pregnancy, especially in the first and third trimesters.
  • Mental or physical health condition. 
  • Constant stress
  • Irregular schedule

How can insomnia be prevented?

Good sleep habits will help improve sleep and prevent insomnia. 

  • Consistent bedtime and wake up time
  • Stay active (regular physical activities)
  • Create a bedtime routine that will help get in the mood to sleep (Taking a warm bath, reading or listening to soft music.)
  • Avoid or minimise caffeine, alcohol, and prevent the use of nicotine.
  • Avoid large meals and beverages before bedtime.
  • Keep the bedroom dark, quiet and cool to make it comfortable.

Insomnia is not a nuisance or a small inconvenience but an actual sleep disorder that can significantly impact one’s physical, mental and emotional health. 

If you think you have insomnia, feel free to reach out to a healthcare professional via the oDoc app as soon as possible. They can assist you in exploring the possible causes and offer help with finding the best treatment for your needs.


  1. Insomnia, Cleveland clinic (2020)
  2. Insomnia, Mayo Clinic (2016)
  3. Everything you need to know about Insomnia, Healthline (2022)
  4. Circadian Rhythm, Sleep Foundation (2022)

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