What Is Obstructive Sleep Apnea (OSA)?
Obstructive sleep apnea (OSA) is a sleep disorder characterised by repeated partial or complete upper airway obstruction during sleep. In adults, these breathing interruptions last for 10 seconds or more and can occur multiple times an hour. OSA can lower blood oxygen levels. Your brain briefly wakes you to reopen the airway. You may not remember these awakenings, but this sleep fragmentation reduces sleep quality.
A community study estimated that about 1 in 3 adults in Singapore had moderate to severe sleep-disordered breathing. OSA can affect people who are not overweight; jaw shape and a narrowed airway also contribute to risk.
If you or your partner notice loud snoring with pauses, gasping or choking, or if you have excessive daytime sleepiness, seek assessment promptly. There is no single cure for obstructive sleep apnea. Treatment can control symptoms, but ongoing care is often needed.
Different Types of Sleep Apnea
Sleep apnea can result from a blocked airway, reduced signals from the brain or breathing changes that emerge during treatment:
Obstructive Sleep Apnea (OSA)
This is the most common type of sleep apnea, in which the muscles at the back of the throat relax too much and block the upper airway. Symptoms include loud snoring, gasping for air during sleep and daytime sleepiness.
Central Sleep Apnea (CSA)
Central sleep apnea occurs when the brain does not send consistent signals to the muscles that control breathing. It may be associated with heart failure, stroke or certain medicines.
Complex Sleep Apnea (CompSA)
Complex sleep apnea, also called treatment-emergent central sleep apnea, describes central breathing pauses that appear or persist after OSA treatment. Follow-up determines whether they settle or need a change in therapy.
At Barrie Tan ENT Head & Neck Surgery, we assess whether your breathing pauses are obstructive and determine the appropriate care. Central or complex sleep apnea may also need assessment by a sleep physician.
What Are The Common Symptoms of OSA?
Common obstructive sleep apnea symptoms include breathing pauses noticed by another person and the following:
Gasping or Choking During Sleep
Waking up suddenly and gasping for air because of a blocked airway.
Restless Sleep
Frequent tossing and turning, and a feeling of non-restorative sleep
Sudden Awakenings
Frequent awakenings due to breathing difficulties
Morning Headaches
Headaches upon waking, which can have several causes
Excessive Daytime Sleepiness
Persistent fatigue and daytime sleepiness. You may fall asleep unintentionally.
Difficulty Concentrating
Problems with focus, memory and cognitive function due to poor sleep quality
Irritability and Mood Changes
Increased irritability, mood swings and even symptoms of depression or anxiety
Loud Snoring
Snoring is common, but not everyone who snores has obstructive sleep apnea.
Decreased Libido
Reduced interest in sexual activities due to fatigue and hormonal imbalances
Dry Mouth or Sore Throat Upon Waking
Resulting from mouth-breathing during sleep
Night Urination & Sweats
Frequent night urination (nocturia) and night sweats are also common and may indicate OSA in adults who wake repeatedly
Daytime Sleepiness
Excessive daytime sleepiness that affects driving or work performance should be reviewed early
Risks & Complications of OSA
Untreated obstructive sleep apnea is associated with health problems beyond sleep disruption and snoring, including:
Coronary Artery Disease
Increased risk of heart disease due to prolonged periods of low oxygen levels during sleep
Complications with Surgery
Increased risk of breathing complications during and after anaesthesia. Tell your surgical team if you have OSA.
Type 2 Diabetes
Higher likelihood of developing insulin resistance and type 2 diabetes
High Blood Pressure
Frequent episodes of low oxygen may lead to high blood pressure
Heart Attacks
Increased risk of myocardial infarction due to chronic stress on the cardiovascular system
Depression
Mood disturbances and depressive symptoms due to poor sleep quality and chronic fatigue
Daytime Fatigue
Persistent tiredness and lack of energy due to sleep-disordered breathing, impacting one’s health, daily functioning and quality of life
Stroke
Increased risk of stroke due to fluctuations in blood pressure and oxygen levels
Heart Failure
OSA can worsen existing heart conditions and contribute to heart failure
Liver Problems
Potential for liver dysfunction and fatty liver disease
Arrhythmias
Increased risk of abnormal heart rhythms, including atrial fibrillation
What Are The Causes of OSA?
Obstructive sleep apnea occurs when relaxed throat muscles allow the upper airway to narrow or collapse during sleep. Pregnancy, hypothyroidism and diabetes are also associated with OSA. Other risk factors include:
Weight and Obesity
Excess weight, particularly around the neck, can compress the airway and increase the risk of airway collapse during sleep. Abdominal fat is also a risk factor.
Obstructed Airway Passages
Structural abnormalities or blockages involving the nose, tongue or soft palate can cause upper airway obstruction.
Swollen Tonsils or Adenoids
Enlarged tonsils can block the airway, especially in children.
Swollen Adenoids
Similar to swollen tonsils, enlarged adenoids can also block airflow and contribute to OSA.
Nasal Obstruction
Chronic congestion or a deviated septum can restrict nasal airflow.
Weak Airway Muscle Tone
Reduced upper airway muscle tone can allow soft tissues to collapse inward during sleep.
Receding Jaw
A smaller or receding jaw can narrow the airway and increase the risk of obstruction.
Alcohol Use & Smoking
Alcohol relaxes upper airway muscles, while smoking can cause inflammation and fluid retention in the upper airway.
Sedatives Use
Sedating medicines, including benzodiazepines and opioids, can worsen sleep-disordered breathing. Ask your prescriber to review them.
Genetics
Inherited anatomy and muscle control patterns cluster in families, making family history a risk factor for OSA.
Age, Male Sex and Post-Menopausal Women
As you age and hormones change, your airway becomes more collapsible, so the risk is higher in men and postmenopausal women.
Chronic Nasal Congestion
Persistent nasal blockage promotes mouth breathing and negative airway pressure, increasing the likelihood of airway collapse.
Specific Craniofacial Features
A small lower jaw, high-arched palate or narrow nasal passages reduce airway space and predispose to obstruction.
How Is OSA Diagnosed?
An overnight sleep study confirms an obstructive sleep apnea diagnosis and measures severity. Assessment also includes your symptoms, medical history and physical findings:
Medical History Review
A detailed review of the patient’s medical history, including sleep habits, daytime symptoms and lifestyle factors, can provide important clues for diagnosis.
Physical Examination
The ENT doctor examines the nose, throat, neck and mouth for enlarged tissues or other narrowing. A flexible nasal endoscope may help assess the upper airway.
Home Sleep Study (HST)
Home sleep apnea testing uses portable equipment to record airflow, breathing effort, oxygen levels and heart rate. Home testing can be more convenient and less costly than a sleep lab study. It may suit adults with suspected moderate to severe OSA who have no significant complicating medical conditions. Some validated devices instead combine peripheral arterial tone measurement with oxygen and movement monitoring.
Polysomnography (PSG)
Polysomnography (PSG) is an overnight sleep lab study. It records brain activity, eye movements, heart rate, nasal and oral airflow, breathing effort and oxygen levels, helping distinguish OSA from other sleep disorders.
Oximetry
Overnight oximetry measures oxygen saturation continuously during sleep to detect drops that suggest apnea episodes. Oximetry alone cannot confirm or rule out OSA.
How We Choose The Test
STOP-BANG screens for OSA risk. The Epworth Sleepiness Scale assesses daytime sleepiness. Neither questionnaire can diagnose OSA. PSG is recommended when a home test is negative, unclear or incomplete, or when significant heart or lung disease, suspected central apnea, or severe insomnia makes home testing unsuitable. Home testing needs medical oversight and interpretation by a sleep medicine specialist. Arrange follow-up to review your results, including the Apnea-Hypopnea Index (AHI) and Oxygen Desaturation Index (ODI).
OSA Treatment Options
Obstructive sleep apnea treatment depends on severity, symptoms, airway anatomy and other health conditions. Continuous positive airway pressure (CPAP) is usually the first treatment offered for moderate to severe OSA. Your preferences and ability to use treatment consistently also matter:
Lifestyle Weight Management
Weight loss can reduce obstructive sleep apnea severity if you are overweight or have obesity. For adults with obesity, medication-assisted weight loss may be considered after medical assessment. Lifestyle changes, including exercise, limiting alcohol before bedtime, positional strategies, and myofunctional therapy (mouth and throat exercises), may support care. These measures do not replace prescribed OSA treatment and should not be used without reassessment. Maintaining a healthy weight after weight loss may help sustain improvement.
Positional Therapy
Sleeping on your back can worsen OSA. Positional therapy uses positioning devices or other measures to encourage side sleeping when your sleep study shows that obstruction occurs mainly while you lie on your back.
Customised Oral Devices and Appliances
Custom-made, adjustable oral appliances called mandibular advancement devices reposition the lower jaw to help keep the upper airway open. They may suit mild to moderate obstructive sleep apnea, or patients who cannot tolerate CPAP therapy or prefer an alternative. Dental partners fit and adjust oral appliances, with a repeat sleep study to confirm benefit and reviews for jaw or bite changes.
Nasal Decongestants
Nasal treatment can relieve congestion and improve CPAP comfort, but does not treat throat collapse on its own. Use decongestant sprays only short-term, because prolonged use can worsen blockage. Allergic rhinitis may need nasal steroid sprays instead.
Continuous Positive Airway Pressure (CPAP) Therapy
CPAP therapy delivers pressurised air through a nasal, nasal-pillow or full-face mask to keep the airway open during sleep. It is a first-line treatment for moderate to severe OSA and may also help mild OSA with troublesome symptoms. Use it whenever you sleep, including naps. Consistent use can take practice. If CPAP treatment is uncomfortable, seek review before stopping. We help adjust mask fit, leaks, humidification and pressure settings.
Surgery
If non-surgical options do not work or CPAP cannot be tolerated, surgical treatment may be considered according to the site of upper airway collapse. Options include uvulopalatopharyngoplasty (UPPP), tonsillectomy or adenoid removal, and maxillomandibular advancement (MMA).
UPPP removes or reshapes soft tissues around the soft palate. Drug-induced sleep endoscopy may help locate the collapse before surgery. Selected patients may also be assessed for an implanted hypoglossal nerve stimulator, which helps move the tongue forward during sleep.
Septoplasty or turbinoplasty may improve nasal breathing and CPAP tolerance, but usually does not cure obstructive sleep apnea alone. Surgery has risks and may leave residual OSA, so follow-up and sometimes repeat sleep testing are needed.
Children and OSA
In children, enlarged tonsils and adenoids commonly cause OSA. Paediatric obstructive sleep apnea can affect behaviour, school performance and growth. Assessment may include a sleep study, followed by discussion of treatment such as adenotonsillectomy when appropriate. Children’s test results and treatment needs differ from adults’.
Prevention and Daily Living
Proper sleep hygiene includes a regular sleep schedule. Maintain a healthy weight, avoid alcohol close to bedtime and treat nasal allergies promptly. Discuss sedative use with your prescriber rather than stopping medicines yourself. Regular reviews help maintain benefits and identify changes in symptoms or weight.
FAQs about OSA
What happens if sleep apnea is left untreated?
Untreated OSA is associated with serious health problems such as high blood pressure, heart disease, stroke, Type 2 diabetes and cognitive decline. It can also cause chronic fatigue, poor work performance and a higher risk of motor vehicle accidents.
Are there different severities of sleep apnea?
Yes. In adults, obstructive sleep apnea is classified as mild, moderate or severe using the Apnea-Hypopnea Index (AHI). It counts complete breathing pauses (apneas) and partial reductions (hypopneas) per hour of sleep:
- Mild obstructive sleep apnea: 5 to 14 events per hour
- Moderate obstructive sleep apnea: 15 to 29 events per hour
- Severe obstructive sleep apnea: 30 or more events per hour
When should I see an OSA specialist in Singapore?
See an obstructive sleep apnea specialist if you have loud snoring, gasp or choke at night, have daytime sleepiness despite a full night’s sleep, or have morning headaches and poor focus. If your partner notices you stop breathing during sleep, book an appointment soon.
How does an OSA clinic in Singapore do sleep tests?
In Singapore, doctors diagnose obstructive sleep apnea using a home sleep test (HST) or a sleep lab study (polysomnography). Your doctor will recommend the best option based on your symptoms. Results are usually ready in a few days.
Is OSA surgery covered by insurance or Medisave in Singapore?
MediSave may cover eligible surgical procedures, subject to withdrawal limits. Insurance cover depends on your policy and approval requirements. Before deciding on surgery, ask the clinic and your insurer to confirm eligibility, the expected costs and any amount you would need to pay yourself.
What should I expect during my first visit to an OSA clinic?
During your first visit, your doctor will review your overall health, sleep symptoms, prior treatments and any dental or jaw-related issues. An upper airway examination helps identify possible obstruction. Bring any previous sleep study, your medicine list and a CPAP usage report, if available, so the findings can guide your plan.
Is there a difference between CPAP and APAP, and which is right for me?
Yes. Continuous positive airway pressure (CPAP) delivers one fixed pressure to keep the airway open, while APAP adjusts pressure within a set range based on your breathing. APAP is helpful if pressure varies through the night or with position changes. CPAP is often preferred when a single therapeutic pressure is known or when medical conditions make stable settings safer. We will help you trial the mode that gives you the best control with the least effort.
Why do I wake up to urinate at night, and is it related to OSA?
Frequent night urination, called nocturia, is common in OSA. Repeated breathing pauses can trigger hormonal changes that increase urine production and fragmented sleep, making you more aware of bladder signals. Because nocturia can also be related to prostate issues, diabetes or evening fluid intake, we will review the whole picture and advise accordingly.
Can OSA trigger heart rhythm problems like atrial fibrillation?
OSA is associated with atrial fibrillation. Treating OSA improves night-time breathing, but does not replace treatment for a heart rhythm disorder. If you have palpitations or a known rhythm problem, tell us. We will coordinate with your cardiologist and align sleep and heart treatment plans.
How soon should I follow up after starting CPAP or an oral device?
Early follow-up helps you adjust to CPAP therapy or oral appliances. We usually review you at 2 to 4 weeks to fine-tune mask fit, humidification and pressure settings, then again around 3 months to confirm stable improvement. After that, we’ll check every 6 to 12 months, or sooner if sleepiness returns. For oral appliances, expect dentist-led titration over several visits and a repeat sleep study once the device is set. Bring your CPAP machine or oral appliance to appointments so we can review usage and make precise adjustments.
