Central vs Obstructive Sleep Apnoea: What's the Difference?

Sleep apnoea isn't a single condition. There are two distinct types, and knowing which one might apply to you helps make sense of your symptoms and what to do about them.

The short answer

Obstructive sleep apnoea (OSA) happens when the soft tissue at the back of your throat collapses or narrows during sleep, physically blocking your airway even though your brain is still sending the signal to breathe. Central sleep apnoea (CSA) is different: the airway stays open, but your brain temporarily stops sending the signal to breathe at all. It's a communication problem rather than a blockage problem.

OSA is by far the more common of the two, and it's what most people mean when they talk about sleep apnoea. CSA is rarer and tends to be linked to other underlying health conditions. For a broader introduction to the condition itself, our guide on what sleep apnoea is, its symptoms, causes and treatment is a good starting point.

What causes each type

Obstructive sleep apnoea

OSA is a mechanical issue. During sleep, the muscles in your throat relax, as they normally do. In OSA, this relaxation allows soft tissue, your tongue, or your tonsils to sag back and partially or fully block the airway. Common contributing factors include:

• Being overweight, particularly with extra tissue around the neck
• A naturally narrow airway or the shape of your jaw
• Large tonsils or adenoids, especially in children
• Alcohol or sedative use before bed, which relaxes the throat muscles further
• Sleeping on your back, which allows the tongue to fall backward more easily

Central sleep apnoea

CSA arises from a fault in the signalling between your brain and the muscles that control breathing. It's less about anatomy and more about the body's regulation of breathing itself. It's often associated with:

• Heart conditions, particularly heart failure
• Stroke or other neurological conditions
• Use of certain opioid medications
• High altitude, though this is usually temporary
• Some cases occurring alongside OSA, known as mixed or complex sleep apnoea

How the symptoms differ

Both types share a core feature: repeated pauses in breathing during sleep that disrupt rest and lower oxygen levels. But there are some differences worth noting.

OSA is very often accompanied by loud, persistent snoring, followed by snorting or gasping as breathing restarts. Bed partners frequently notice this before the person with OSA does. CSA, by contrast, doesn't usually cause loud snoring, since there's no physical obstruction creating the noise. Instead, someone with CSA might simply stop breathing quietly for a period, then resume, sometimes with a shortness-of-breath sensation or a brief awakening.

Both types can lead to broken, unrefreshing sleep and daytime exhaustion, morning headaches, and difficulty concentrating. Because the daytime effects overlap so much, it's genuinely difficult to tell the two apart from symptoms alone. Our detailed page on night and daytime warning signs of sleep apnoea covers what to look and listen for in more depth.

Why the distinction matters

Getting the right diagnosis matters because the two conditions are treated quite differently. Treatments aimed at reducing airway obstruction, such as certain oral devices or positional changes, won't help if the root cause is a breathing signal problem rather than a blocked airway. Equally, CSA often points to an underlying condition, commonly heart-related, that needs its own attention alongside any breathing support.

This is one of the main reasons a proper sleep study is so valuable. A sleep study doesn't just count how often breathing pauses occur, it also looks at the pattern of chest and abdominal movement during those pauses. In OSA, your chest and abdomen keep trying to move as you attempt to breathe against the blockage. In CSA, that effort simply stops, because the brain isn't sending the instruction in the first place. This distinction is usually clear on the recordings, even though it isn't obvious to the person experiencing it.

How treatment approaches differ

Treating OSA

Because OSA is a structural problem, treatment focuses on keeping the airway open. Options typically include:

• Continuous positive airway pressure (CPAP), which uses gentle air pressure to hold the airway open
• Mandibular advancement devices, which reposition the jaw slightly forward
• Weight management, where relevant, to reduce pressure on the airway
• Positional therapy, to reduce time spent sleeping on the back

Treating CSA

CSA treatment tends to focus first on any underlying cause, such as managing heart failure or reviewing medications that might be contributing. Specialist forms of positive airway pressure therapy, adapted for CSA specifically, may also be used, but these are typically prescribed and monitored closely by a specialist rather than a general CPAP setup.

In both cases, ongoing management is a long-term commitment rather than a quick fix. Our guide to living with sleep apnoea and managing daily life and treatment has practical advice for adjusting to therapy and keeping symptoms under control day to day.

When to see a GP

You don't need to work out which type of sleep apnoea you might have before seeking help, that's what a proper assessment is for. But it's worth speaking to a GP promptly if you or your partner notice:

• Loud, frequent snoring, particularly with gasping or choking sounds
• Witnessed pauses in breathing during sleep
• Persistent daytime exhaustion, even after what feels like a full night's sleep
• Waking with headaches or a dry mouth most mornings

These are worth checking regardless of which type turns out to be involved, since both forms of sleep apnoea can affect your health and safety if left unmanaged, particularly around concentration and driving.

A practical next step

If any of this sounds familiar, the sensible move is a conversation with your GP, who can arrange a sleep study to establish exactly what's happening during your sleep. For a fuller picture of the condition as a whole, our sleep apnoea hub brings together our full range of guides in one place.