A steady flow of air
A CPAP machine produces a flow of air and sends it through tubing to a mask.
CPAP Support Guide
Understanding your CPAP treatment
CPAP can take a little getting used to. This guide explains what the machine does, the parts you use, the main mask types and what you can try when something is not feeling right.
💙 Simple explanations • Practical tips • Patient-friendly
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What is CPAP?
CPAP stands for Continuous Positive Airway Pressure.
Keeps the airway open
The pressure helps prevent the upper airway from narrowing or closing during sleep.
Used while sleeping
For obstructive sleep apnoea, CPAP is normally worn whenever you sleep, including naps where advised by your clinical team.
How does CPAP work?
Think of the system as a simple path from the machine to your airway.
1
Machine
The machine generates the airflow at the pressure or pressure range prescribed for you.
2
Tubing
The tubing carries the airflow from the machine towards the mask. Some systems use heated tubing.
3
Mask
The mask delivers the airflow to your nose, or to your nose and mouth, helping keep the airway open.
What happens in your body during sleep apnoea?
Understanding the physiology can make CPAP feel much less mysterious. In obstructive sleep apnoea (OSA), the airway becomes narrow or closes during sleep. Your brain then reacts and breathing starts again.
A simplified diagram of what happens to the upper airway during normal sleep, obstructive sleep apnoea and CPAP treatment.
1
You fall asleep
The muscles that help hold the throat open naturally relax during sleep. For most people, the airway remains open.
2
The airway narrows
In OSA, the relaxed tissues of the upper airway can narrow or collapse. Airflow becomes restricted or stops.
3
Your body reacts
Oxygen can fall and carbon dioxide can rise. The brain briefly increases the drive to breathe and may cause a brief arousal, often without you remembering it.
4
CPAP prevents the collapse
CPAP provides positive pressure through the mask. This acts like an air splint, helping keep the upper airway open while you sleep.
The important idea: CPAP is not forcing you to breathe. It provides pressure that supports the airway so air can move in and out more normally during sleep.
Sleep apnoea: a few useful facts
These numbers are here to give you context. They are population-level figures, not a prediction about any one person.
2–3×
More common in men
Population studies generally find OSA is around two to three times more common in men than women. The difference becomes smaller after menopause.
40+
Risk increases with age
Age is an important risk factor. The HSE notes that OSA is more common over 40, although it can occur at any age.
5+
Apnoeas/hypopnoeas per hour
An AHI of 5 or more events per hour is commonly used to define OSA on a sleep study, with symptoms and the clinical picture also considered.
30+
Events per hour
For adults, an AHI over 30 is generally classed as severe OSA. A sleep service interprets the result alongside your symptoms and other findings.
Remember: being male, getting older or having a larger neck can increase risk, but OSA can affect women and people of any body size. Menopause, family history, nasal congestion, alcohol, smoking and other factors can also contribute.
Different CPAP machines
There are several types of positive airway pressure devices. Your sleep service will choose the type that is appropriate for you.
Common device types you may hear about
CPAP
Provides a fixed pressure that stays at the set level.
APAP / Auto-CPAP
Can adjust pressure within a prescribed range as your needs change during sleep.
Travel CPAP
A compact device designed to make taking treatment away from home easier.
Bilevel PAP
Uses different pressures for breathing in and breathing out and is used for selected patients and conditions.
The machines shown are illustrative examples rather than recommendations. Exact features vary by manufacturer and model.
CPAP components
Knowing the names of the parts makes it easier to explain a problem when you contact your sleep service or equipment provider.
Machine
Creates and controls the airflow.
Humidifier & water chamber
Adds moisture to the airflow on systems fitted with humidification.
Tubing
Carries air from the machine to the mask. It may be standard or heated.
Mask connector / swivel
Connects the tubing to the mask and allows movement.
Filters
Help keep dust and particles out of the airflow. Follow your manufacturer's replacement guidance.
Power supply
Provides electrical power to the machine.
Which mask do I need?
The right mask depends on comfort, breathing pattern, mouth opening and other individual factors. A good seal is important, but the mask should not be painfully tight.
Full Face Mask (FFM)
Covers the nose and mouth. It may be useful when treatment needs to be delivered through both or when mouth breathing is a significant issue.
Nasal Mask
Sits over the nose. It is a common option for people who are comfortable breathing through the nose during sleep.
Nasal Pillows
Uses small cushions at the nostrils. It has less material over the face and can suit some people who prefer a minimal design.
Hybrid / Under-nose
Combines features from different designs and can sit under the nose while also providing mouth coverage in some models.
CPAP troubleshooting
Common problems are often fixable with a mask adjustment, a different mask, humidification or help from your sleep team.
“My mask is leaking.”
Check the fit first. Re-seat the mask while lying in your normal sleeping position and adjust the straps gently. If tightening makes it worse, the mask may be the wrong size or shape. Your sleep team or equipment provider can check the fit and consider another mask.
“My mouth or nose is very dry.”
Dryness is common. Check whether heated humidification is available on your system and make sure the mask is sealing correctly. A blocked nose or mouth breathing can contribute to dryness. Speak with your clinical team if this is persistent.
“The air feels too strong.”
Do not change prescribed pressure settings yourself. Use any comfort features already enabled for you, such as ramp or pressure-relief features, and contact your sleep service if the pressure remains difficult to tolerate.
“There is water in the tubing.”
This is often called rainout. It can happen when warm, humid air cools inside the tubing. A heated tube, adjusting humidification or keeping the tubing warmer may help. Follow your machine manufacturer's guidance.
“My skin or nose is getting sore.”
The mask may need refitting. Avoid simply tightening it further. A different size or mask style, or a suitable mask liner/pad, may reduce pressure on the skin. Contact the sleep team if there is persistent soreness or broken skin.
“I keep taking the mask off during the night.”
This can happen while you are getting used to treatment. Check comfort, leaks, nasal blockage and pressure. A gradual routine can help, but persistent problems are worth discussing with your sleep team rather than stopping treatment without advice.
“The machine is noisy.”
Check the obvious causes first: make sure the machine is on a stable surface, the tubing is connected correctly and the mask is fitted properly. New or unusual noises from the machine itself should be discussed with the equipment provider.
Tips for getting used to CPAP
- Use your treatment consistently as advised by your sleep team.
- Practise wearing the mask while awake for short periods if you are finding it unfamiliar.
- Make one change at a time so you can tell what actually helps.
- Keep your equipment clean and follow the manufacturer's cleaning and replacement instructions.
When to ask for help
Contact your sleep service or CPAP provider if you are struggling with comfort, repeated leaks, persistent dryness, equipment problems or if you are unsure whether your treatment is working as expected.
Do not change your prescribed treatment settings yourself unless your clinical team has advised you to do so.
Information sources:
HSE Ireland – Obstructive sleep apnoea treatment ·
HSE Ireland – Causes and risk factors ·
NHLBI – Causes and risk factors ·
NHLBI – CPAP ·
NHS – Sleep apnoea ·
ResMed – CPAP devices ·
ResMed – CPAP mask types.
This page is for general education and does not replace advice from your GP, sleep clinic or equipment provider. Machine and mask features vary by manufacturer and model.