What Is Sleep Apnea?
Sleep apnea is a sleep disorder in which breathing repeatedly stops or becomes shallow during sleep. It can happen when the upper airway narrows or closes, or when the brain does not send steady signals to the breathing muscles. These episodes can interrupt sleep and lower blood oxygen levels.
You may snore loudly, wake gasping, or feel tired despite a full night’s sleep. A partner may notice breathing pauses you don’t remember. Not everyone with sleep apnea snores, and snoring alone does not confirm the diagnosis.
A sleep study can establish whether you have sleep apnea and identify its type and severity. Treatment aims to improve breathing and support restful sleep, reduce daytime symptoms and manage associated health risks.
Different Types of Sleep Apnea
Obstructive sleep apnea (OSA): The most common type. The upper airway repeatedly narrows or closes during sleep, despite continued breathing effort.
Central sleep apnea (CSA): Breathing pauses occur because signals from the brain to the breathing muscles are disrupted, rather than because the airway is blocked.
Complex sleep apnea (CompSA): Also called treatment-emergent central sleep apnea. Central breathing pauses appear or persist during OSA treatment, commonly after starting CPAP. Follow-up determines whether you need continued treatment or an adjustment. Mixed sleep apnea combines central and obstructive components within the same breathing pause. It is distinct from complex sleep apnea.
What Are Common Sleep Apnea Symptoms?
Common symptoms of sleep apnea include:
- Daytime brain fog, low energy, irritability
- Excessive daytime sleepiness
- Unrefreshing or restless sleep
- Frequent loud snoring or breathing pauses noticed by someone else
- Waking short of breath or choking; a dry mouth or sore throat on waking
- Repeated awakenings and sleep disruption
- Morning headaches
- Night sweats
- Mood changes (including anxiety or depression)
- Sexual dysfunction or reduced libido
- Insomnia-like sleep patterns
If you fall asleep while driving or struggle to stay awake during safety-critical tasks, stop driving or operating machinery and seek prompt medical assessment.
What Are the Possible Causes of Sleep Apnea?
This sleep disorder stems from a mix of anatomical, airway inflammatory, and physiological issues, not a single cause.
Obstructive sleep apnea occurs when the upper airway narrows or collapses during sleep. Relaxed throat muscles, excess tissue or a narrow jaw can reduce the space available for breathing. Excess weight can contribute, but obstructive sleep apnea also occurs in people who are not overweight.
Common risk factors for obstructive sleep apnea include:
- Chronic nasal congestion, allergic rhinitis, sinus inflammation, nasal obstruction, or a deviated septum that can worsen nasal breathing and contribute to sleep-disordered breathing
- Enlarged tonsils and adenoids, especially in children
- Jaw and facial structure that contributes to upper airway obstruction
- Alcohol near bedtime, sedatives, sleeping pills, and smoking, which can worsen airway collapsibility and irritation and reduce upper airway muscle tone
- Family history and increasing age. Men have a higher risk, and women’s risk rises after menopause
Central sleep apnea is less common. It may be associated with heart failure, stroke, opioid medicines or high altitude. Identifying the cause helps guide treatment.
Risks & Complications of Sleep Apnea
Repeated sleep disruption and oxygen drops in untreated sleep apnea can affect alertness and blood pressure and are linked to cardiovascular disease and other serious health complications. The risks depend on the type and severity of sleep apnea and any other medical conditions.
Obstructive sleep apnea is associated with high blood pressure, abnormal heart rhythms such as atrial fibrillation, heart disease, heart failure, stroke, insulin resistance, type 2 diabetes and fatty liver disease, including nonalcoholic fatty liver disease. These are associated conditions and complications, not symptoms everyone develops. Treatment may improve blood pressure and daytime function, but cannot guarantee reversal of established heart disease.
Safety and healthcare implications also matter. Excessive daytime sleepiness increases the risk of road and workplace accidents. Undiagnosed sleep apnea can increase anaesthetic and post-operative risk, so it matters before surgery or sedation. A sleep medicine consultation is recommended.
When to See a Sleep Apnea Specialist
See a sleep apnea specialist if chronic snoring is accompanied by breathing pauses, choking or excessive daytime sleepiness. Your GP can also assess your symptoms and arrange a referral. A sleep specialist assessment helps determine the right sleep test.
An ENT specialist assesses nasal and throat obstruction, including enlarged tonsils or a narrow upper airway. Suspected central sleep apnea or complex medical conditions may also need a sleep medicine physician, respiratory physician, cardiologist or neurologist. Seek assessment if a partner notices breathing pauses or you have hard-to-control high blood pressure, and tell your surgical team if you suspect sleep apnea before an operation.
Seek emergency care immediately for symptoms suggesting a heart attack, stroke, heart failure, or severe breathing difficulty, as these are emergencies separate from sleep apnea.
How Is Sleep Apnea Diagnosed
Doctors diagnose sleep apnea through a clinical assessment and an appropriate sleep study. The test records breathing interruptions and blood oxygen levels during sleep to identify abnormal breathing patterns, including obstructive or central events.
Initial Assessment
Diagnosis involves a medical history review and a physical examination of the nose, mouth, neck and throat. Bring details of your sleep pattern, daytime sleepiness, risk factors, medicines and any breathing pauses noticed by a partner. Blood or thyroid tests may investigate other causes of fatigue; they do not confirm or exclude sleep apnea.
Sleep Studies (Polysomnography)
An attended overnight sleep study, called polysomnography (PSG), records brain waves, sleep stages, nasal and oral airflow, breathing effort, heart rhythm, oxygen levels and limb movements. It is usually performed in a sleep laboratory. This more detailed test is preferred when central sleep apnea or another sleep disorder is suspected, or when significant heart, lung or neurological conditions make home testing unsuitable.
A home sleep test, also called a home sleep apnea test (HSAT), may suit adults with suspected moderate to severe obstructive sleep apnea and no significant complicating medical conditions. It usually measures airflow, breathing effort, oxygen levels and heart rate, but most devices do not record brain waves or sleep stages. If sleep apnea is still suspected, a negative, unclear, or technically inadequate home sleep test may require laboratory polysomnography.
A split-night study combines diagnostic monitoring with continuous positive airway pressure adjustment later that night, when enough evidence of obstructive sleep apnea is recorded early in the study. It is not suitable for everyone.
Determining Your Sleep Apnea Severity (AHI Score)
The apnea-hypopnoea index (AHI) counts breathing pauses and partial reductions in breathing per hour of sleep. In adults, obstructive sleep apnea is classified as:
- Mild: 5 to fewer than 15
- Moderate: 15 to fewer than 30
- Severe: 30 or more
Your clinician also considers oxygen levels, symptoms and other conditions. Home tests may report a respiratory event index (REI), which can underestimate severity. Children use different criteria.
Sleep Apnea Treatments
Sleep apnea treatment depends on the type, severity, symptoms and your medical history. For obstructive sleep apnea, options include lifestyle changes, positive airway pressure, oral appliances and selected surgery. Central sleep apnea treatment addresses the underlying cause and may require different breathing support under specialist supervision.
No single sleep apnea treatment suits everyone. Mild sleep apnea with few symptoms may be managed differently from severe sleep apnea or obstructive sleep apnea causing marked sleepiness. Treatment decisions should consider what you can use consistently and how you will check its effectiveness.
Non-Surgical Management and Lifestyle Changes
Lifestyle changes may include weight loss if you are overweight, regular exercise, limiting evening alcohol and side sleeping when obstructive sleep apnea is worse on your back. Review sedating medicines with your prescriber rather than stopping them yourself.
Addressing nasal allergies or obstruction can improve comfort and tolerance of CPAP therapy. A regular sleep schedule and management of conditions such as hypertension and diabetes support overall care. These measures do not replace prescribed treatment for moderate or severe OSA.
CPAP and Related PAP Devices
Continuous positive airway pressure (CPAP) uses a sleep apnea machine to deliver pressurised air through a mask, keeping the upper airway open while you sleep. It is commonly recommended for moderate to severe obstructive sleep apnea and may also help mild obstructive sleep apnea with symptoms.
Using CPAP therapy consistently can be challenging. Successful use relies on practical details: the correct mask (nasal, oral, nasal pillows, or full-face), heated humidification, ramp settings, leak management, and desensitisation (e.g., wearing the mask before sleep). Some patients use Automatic Positive Airway Pressure (APAP), which automatically adjusts positive airway pressure.
Follow-up reviews symptoms, mask comfort, air leaks and device data to check that treatment is working. If central breathing pauses emerge during CPAP treatment, a specialist should review them for possible complex sleep apnea before changing the device or pressure settings. Adaptive servo-ventilation (ASV) adjusts pressure breath by breath for selected people with central sleep apnea. Suitability requires specialist assessment, particularly if you have heart failure.
Oral Appliances and Sleep Apnea without CPAP
A custom-fitted mandibular advancement device (MAD) holds the lower jaw forward to keep the airway open. It may suit selected people with mild to moderate obstructive sleep apnea, or those who cannot tolerate CPAP. A dentist fits and adjusts the device and monitors jaw discomfort or bite changes. Follow-up sleep testing checks whether it controls the apnea.
Other Non-Surgical Therapies Used in Selected Cases
Researchers have studied non-invasive tongue-muscle stimulation for chronic snoring and mild obstructive sleep apnea. This differs from implanted hypoglossal nerve stimulation. Suitability, evidence and local availability need assessment, and it should not replace prescribed treatment for moderate or severe OSA.
Targeted ENT Procedures and Sleep Apnea Surgery
Surgical treatment may be considered for selected people with obstructive sleep apnea when an identifiable obstruction can be treated, or CPAP is not tolerated despite support. ENT assessment evaluates the nose, palate, tonsils and tongue base. Drug-induced sleep endoscopy (DISE) may help identify where the airway collapses when planning treatment. These procedures do not treat central sleep apnea.
Options include:
- Nasal surgery, such as septoplasty or turbinate reduction, may improve nasal airflow and CPAP tolerance. It does not reliably resolve OSA on its own.
- Tonsillectomy removes enlarged tonsils that contribute to airway obstruction in selected adults and children.
- Palate surgery, such as uvulopalatopharyngoplasty (UPPP), may enlarge or stabilise the airway in selected people with obstruction at the soft palate or uvula.
- Jaw surgery, such as maxillomandibular advancement (MMA), moves the upper and lower jaws forward in selected patients with jaw-driven airway narrowing.
- Hypoglossal nerve stimulation for certain patients with moderate to severe obstructive sleep apnea who cannot tolerate CPAP therapy.
Surgery does not guarantee that sleep apnea will resolve. Some people still need continuous positive airway pressure or another treatment afterwards. Follow-up assessment and, where indicated, repeat sleep testing help establish the result.
Treatment Risks and Recovery
Treatments are generally safe, but involve trade-offs between benefit, comfort, and risk as part of your treatment plan.
Continuous positive airway pressure side effects (dryness, mask leak, nasal congestion) are usually manageable with mask changes, humidification, and adjustments. Oral appliances may cause jaw soreness or bite changes, which you should monitor.
Surgery carries risks like bleeding, infection, sore throat, and pain, with recovery varying by procedure. A crucial safety measure is perioperative planning: if you have sleep apnea, inform your surgeon and anaesthetist beforehand, and you might need to bring your CPAP to the hospital for restful sleep and a safer recovery.
Paediatric Sleep Apnea
Enlarged tonsils and adenoids are common causes of paediatric obstructive sleep apnea, which can affect behaviour, learning and growth. Estimates suggest that up to 5% of children have obstructive sleep apnea.
Daytime symptoms may include hyperactivity, irritability, or poor concentration, not just daytime sleepiness. Common symptoms include persistent snoring, restless sleep, mouth breathing, bedwetting, or unusual sleep positions.
Assessment may involve an ENT examination and a paediatric sleep study. Tonsillectomy and adenoidectomy may improve breathing when enlarged tonsils and adenoids cause obstruction. Some children have persistent obstructive sleep apnea after surgery and need further assessment or treatment.
How Can Barrie Tan ENT Help with Sleep Apnea in Singapore
Dr Barrie Tan is an ENT specialist at Gleneagles Hospital, Singapore. The assessment focuses on your symptoms, sleep-study findings, and any nasal or throat obstruction. The clinic offers sleep study services and home sleep apnea testing for suitable patients, with guidance on CPAP and discussion of surgery when appropriate.
Treatment for obstructive sleep apnea matches airway findings and sleep-study results. Dental referral may be appropriate for an oral appliance. If central sleep apnea or another medical cause is suspected, your treatment plan may involve a sleep specialist and other doctors.
Contact Barrie Tan ENT Head and Neck Surgery to discuss whether a sleep apnea assessment is appropriate for your symptoms.
FAQs about Sleep Apnea
How do I know if I have sleep apnea?
If you have loud snoring, wake up choking or gasping, feel unrefreshed, or have daytime sleepiness, you may have sleep apnea. The only way to confirm it is a sleep study, either at home or in a sleep lab, guided by your symptoms and medical history.
What are the ways to cure sleep apnea?
No single cure fits everyone. For some patients, obstructive sleep apnea may improve with weight loss or surgery when anatomy is the main contributor, while others need long-term CPAP or an oral device.
Can heart damage from sleep apnea be reversed?
Treating sleep apnea may improve blood pressure and reduce strain on the heart, but it does not reliably reverse established heart damage. Established heart disease still needs cardiology care, but sleep treatment can help reduce risk.
Is sleep apnea genetic?
Sleep apnea can run in families because airway anatomy, jaw structure, and body weight patterns can be inherited. However, lifestyle factors and treatable nasal or throat issues still matter.
Can stress cause sleep apnea?
Stress can worsen sleep quality, increase insomnia, and make fatigue feel more severe, but it usually does not create true obstructive apneas on its own.
Can sleep apnea cause dizziness?
Dizziness has many possible causes and is not a reliable sign of sleep apnea. If it persists or recurs, seek an assessment rather than assuming it is due to disturbed sleep.
Does sleep apnea go away?
Obstructive sleep apnea may improve after substantial weight loss or treatment of an anatomical obstruction, such as enlarged tonsils and adenoids in a child. Many adults need ongoing management. Reduced snoring does not prove that apnea has resolved; seek reassessment before stopping prescribed treatment.
