If you've recently been diagnosed with sleep apnoea, it's natural to want to understand why it's happening. This guide walks through the common causes and risk factors in plain language. It's general information to help you feel more informed, not a diagnosis. Your GP or a sleep clinician is the right person to confirm your type of sleep apnoea and guide treatment, and our clinical partner CLM Sleep offers sleep studies if you need testing.
The two main causes at a glance
| Type | What's behind it | Typical sign |
|---|---|---|
| Obstructive (OSA) | Soft tissue relaxes and blocks the airway during sleep | Loud snoring, gasping or choking |
| Central (CSA) | The brain briefly stops signalling the body to breathe | Often little or no snoring |
| Complex / mixed | Features of both OSA and CSA | OSA symptoms that persist after the blockage is treated |
What causes obstructive sleep apnoea (OSA)?
OSA is the most common type. When you fall asleep, the muscles in your throat and tongue relax. In some people, that soft tissue falls back far enough to narrow or block the airway, so breathing is briefly interrupted and oxygen levels dip. After a short pause, your brain rouses you just enough to take a breath, often with a snort or gasp. This can repeat many times a night, frequently without you noticing.
Common risk factors for OSA
- Sleeping on your back: gravity allows the relaxed tongue and soft palate to fall back and narrow the airway.
- Carrying extra weight: additional tissue around the neck and throat can crowd the airway during sleep.
- Larger tonsils or adenoids: these can physically restrict airflow, a common factor in children.
- Nasal congestion: hay fever, colds, sinus issues and a blocked nose make airflow harder.
- Alcohol and sedatives: these relax the throat muscles further, which can worsen obstruction.
- Anatomy: a naturally narrow airway, a low-hanging uvula or jaw shape can play a role.
Having a risk factor doesn't mean you'll develop sleep apnoea, and not everyone with OSA fits this list. A sleep study is the way to know for certain.
What causes central sleep apnoea (CSA)?
With central sleep apnoea, the airway is open, but the brain doesn't send the usual signal to breathe. Breathing pauses for several seconds, and during that time the body makes no effort to draw a breath. People with CSA often don't snore. Recognised contributors include:
- Heart conditions: reduced heart function, such as heart failure, can disrupt normal breathing patterns.
- High altitude: lower oxygen levels can trigger central pauses in breathing.
- Some prescription medicines: certain opioid painkillers can affect the brain's breathing control.
- Neurological conditions: stroke or damage affecting the brainstem can interfere with breathing signals.
What is complex (mixed) sleep apnoea?
Complex sleep apnoea shows features of both OSA and CSA. It's sometimes identified when someone with obstructive apnoea continues to have breathing pauses even after the physical blockage is managed with CPAP, suggesting the brain's signalling is also involved. It can be more involved to treat, and your clinician may adjust your therapy or device settings to suit. This is very much a conversation to have with your sleep specialist.
How is the cause confirmed?
Because the three types have different causes and treatments, getting the right diagnosis matters. Diagnosis usually involves:
- A review of your symptoms and history with a GP or sleep clinician, including any risk factors.
- A sleep study (polysomnography), either in a sleep lab or as a home test, which records airflow, breathing, oxygen levels and other measures while you sleep.
If you think you may have sleep apnoea but haven't been tested, our partner CLM Sleep can arrange a sleep study, or you can read more in our FAQ.
How treatment relates to the cause
Treatment is matched to the type and severity of apnoea, and your clinician will guide what's right for you. Common approaches include:
- Lifestyle changes: side-sleeping, weight management and limiting alcohol before bed can help with milder OSA.
- CPAP therapy: a machine delivers a steady stream of air through a mask to hold the airway open, the most common treatment for OSA.
- Auto-adjusting (APAP) and bilevel devices: these vary the pressure to suit your needs and are sometimes used for central or more complex cases on clinical advice.
- Other options: dental devices, and in some cases surgery, may be considered, decided with your clinician.
If CPAP has been recommended for you, the CDW team can help you choose genuine, Australian-supplied equipment and find a mask that fits comfortably. We're an authorised dealer of TGA-regulated devices from ResMed, Fisher & Paykel, Philips Respironics and Löwenstein, with up to 50% off RRP, free shipping over $200 and a real consultant to talk to. Browse CPAP machines, auto-adjusting CPAP machines and CPAP masks, or use our mask finder to narrow the choices. Prefer to chat in person? Visit our Elizabeth store in South Australia.
This page is general information and is not medical advice or a diagnosis. Sleep apnoea is a medical condition that should be assessed by a qualified health professional. Please speak to your GP or a sleep clinician about your symptoms and treatment, and never change prescribed therapy without their guidance.
