What Is Obstructive Sleep Apnoea (OSA)?

Obstructive sleep apnoea (OSA) is a medical condition caused by the repetitive collapse of the upper airway during sleep. Obstructive sleep apnoea is the most common sleep-related breathing disorder. It causes you to repeatedly stop and start breathing while you sleep.

OSA occurs when the muscles supporting the soft tissues in your throat, such as your tongue and soft palate intermittently relax. This causes your airway to narrow or even close, momentarily cutting off your breathing.

Commonly, air should flow smoothly from the mouth and nose into the lungs at all times, even during sleep.

Periods, when breathing cessation occurs completely, are called apnoea or apneic episodes. In OSA, the normal flow of air is repeatedly stopped multiple times throughout the night.

OSA is very common among males, but it can affect anyone, including children. The incidence of OSA increases following menopause, where incident levels are similar in men and postmenopausal women.

Loud snoring is often associated with OSA, especially if the snoring is interrupted by periods of silence. Snoring is caused by airflow confined through the narrowed airway space.

It is important to take note that snoring doesn’t necessarily mean something potentially serious, and not everyone who snores has OSA.

Untreated OSA can lead to serious health issues such as:

  • Hypertension
  • Cardiovascular illness
  • Stroke
  • Diabetes
  • Atrial fibrillation 
  • Pulmonary hypertension

Diagnosing and subsequent treatment are essential to preventing complications from OSA.

What are the symptoms of obstructive sleep apnea?

The majority of individuals with OSA complain of daytime somnolence/ sleepiness. OSA results in episodes of decreased oxygen supply to the brain and other parts of the body, the sleep quality is poor. This results in daytime drowsiness and a lack of clarity in the morning.

Common symptoms are:

  • Loud snoring
  • Gasping
  • Choking
  • Snorting
  • Interruptions in breathing while sleeping

People with OSA may also experience the following symptoms:

  • Morning headaches
  • l Feeling disgruntled or grumpy
  • l Forgetfulness
  • l Drowsiness
  • l Repetitive awakenings throughout the night
  • l worsening depression
  • l poor job and school performance
  • l loss of interest in sex

Daytime somnolence puts people with sleep apnoea at risk for motor vehicle crashes and industrial accidents. They also become hazardous to other people. Treatment can help to completely relieve daytime somnolence

What factors and conditions cause obstructive sleep apnea?

  • Obesity hypoventilation syndrome, a breathing disorder in people with obesity
  • Endocrine conditions, such as hypothyroidism, acromegaly, and polycystic ovary syndrome, which may affect your breathing when you’re asleep
  • Chronic lung diseases, such as asthma, chronic obstructive pulmonary disease (COPD), and pulmonary fibrosis
  • Neuromuscular conditions, such as a stroke, can interfere with brain signals to your chest muscles and airway
  • Heart or kidney failure, which may cause fluid to build up in your neck and obstruct the upper airway
  • Pregnancy

What are the risk factors for OSA?

The risk for OSA increases if you have physical features that narrow your upper airway. Risk factors of OSA include:

  • Obesity
  • Large tonsils
  • Men with a collar size of 17 inches or more
  • Women with a collar size of 16 inches or more
  • A large tongue, which can block the airway
  • Retrognathia, which is when your lower jaw is shorter than your upper jaw
  • A narrow palate or airway that collapses more easily
  • Family history of OSA

How is obstructive sleep apnea diagnosed?

A diagnosis of sleep apnea begins with a complete history and physical examination. A history of daytime sleepiness and snoring are important clues.

Your doctor will examine your head and neck to identify any physical features that are associated with sleep apnea.

Your doctor may ask you about daytime drowsiness, sleep habits, and quality of sleep.

The following tests may be performed to diagnose OSA.

Polysomnography (PSG)

During polysomnography, you sleep overnight in a hospital or sleep center while connected to a variety of monitoring devices that record physiologic variables.

Patterns of physiologic abnormalities during sleep may indicate sleep-disordered breathing as well as many other sleep disorders.

While you sleep, the PSG will measure the activity of different organ systems associated with sleep. It may include:

EEG (electroencephalogram) and EOM (electrooculogram)

During an EEG, electrodes are attached to your scalp that will monitor brain waves before, during, and after sleep. The EOM records eye movement.

Brain waves and eye movements tell doctors about the timing of the different phases of sleep. The two broad phases of sleep are non-REM (non-rapid eye movement) and REM (rapid eye movement).

Decreased muscle tone and paralysis occur during REM sleep.

EMG (electromyography)

The EMG electrodes pick up the electrical activity generated during muscle movements. Muscle relaxation should occur during sleep. The EMG picks up when your muscles relax and move while you’re sleeping.

ECG (electrocardiogram)

A single lead ECG records the electrical signals from your heart during the sleep study to monitor your heart rate and rhythm.

Pulse oximetry

A pulse oximeter is clipped onto a thin area of your body that has good blood flow, such as a fingertip or earlobe.

The pulse oximeter is used to measure the oxygen saturation level of your blood. This level may decrease during episodes of apnea.


The main objective for the treatment of OSA is to make sure airflow isn’t obstructed during sleep. Treatment methods include the following:

Weight loss

Weight management therapy and exercise are usually recommended for people with OSA who also have obesity. Weight loss does not lead to  complete remission but it helps  decrease severity of OSA.

Losing weight, if your doctor has recommended it, could also reduce blood pressure, improve your quality of life, and decrease daytime sleepiness.

Continuous positive airway pressure (CPAP)

Continuous positive airway pressure (CPAP) therapy is the first line of treatment for OSA. It is administered through a face mask worn at night.

The face mask gently delivers positive airflow to keep the airways open at night. The positive airflow props the airways open.

CPAP is a highly effective treatment for OSA.

For people with mild or moderate OSA who don’t benefit from CPAP therapy, an oral appliance is a reasonable alternative to positive airway pressure.

Bilevel positive airway pressure (BPAP)

Bilevel positive airway pressure (BPAP) machines are sometimes used for the treatment of OSA if CPAP therapy is not effective.

BPAP machines, sometimes called BiPAP machines, have settings that deliver two pressures in response to your breathing: inhaled pressure and exhaled pressure. This means the pressure changes during inhaling versus exhaling.

Sleeping on your side

Since sleeping on your back (supine position) can make OSA worse for some people, positional therapy is used to help you learn to sleep on your side.

Take home message

Excessive daytime drowsiness and somnolence can be symptoms of OSA, which in the long term if not treated, may cause a myriad of other health issues. Speak to your doctor if you are experiencing similar symptoms and they would be able to help you create a treatment plan that combines lifestyle changes and other therapies

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