CPAP vs APAP: What’s the Difference?

If you’ve been diagnosed with obstructive sleep apnoea or are looking into treatment options, you may have come across the terms CPAP and APAP.

While both machines are designed to help keep your airway open while you sleep, they work in slightly different ways. Understanding the difference between CPAP and APAP can help you have a more informed conversation with your healthcare professional or sleep specialist about which type of therapy may be suitable for you.

In this guide, we’ll explain what CPAP and APAP machines are, how they work, the key differences between them, and some of the factors that may influence which option is right for you.

What is CPAP?

CPAP stands for Continuous Positive Airway Pressure.

A CPAP machine delivers a continuous stream of pressurised air through a mask while you sleep. This pressure helps prevent the upper airway from narrowing or collapsing, which can cause the pauses in breathing associated with obstructive sleep apnoea.

A typical CPAP system consists of:

A CPAP machine
A mask
Air tubing
An air filter
A humidifier, depending on the machine and your needs

The CPAP machine is generally set to deliver a specific pressure throughout the night.

For example, if your prescribed pressure is 10 cmH₂O, the machine will generally aim to provide that pressure while you sleep.

The pressure setting is determined as part of your sleep assessment and treatment plan. Your healthcare professional or sleep specialist can advise on the appropriate settings for your individual circumstances.

What is APAP?

APAP stands for Automatic Positive Airway Pressure, sometimes referred to as Auto CPAP.

Like a CPAP machine, an APAP machine uses pressurised air to help keep your airway open. The main difference is that an APAP machine can automatically adjust the pressure within a prescribed minimum and maxium range in response to changes in your breathing rather then CPAP which is set to a set pressure.

For example, an APAP might be set to operate between 6 and 14 cmH₂O.

If the machine detects that you require more pressure, it can increase the pressure. If less pressure is required, it can reduce the pressure within the prescribed range.

This means that instead of providing one fixed pressure throughout the night, an APAP machine can respond to changes in your breathing patterns.

CPAP vs APAP: What’s the main difference?

The simplest way to understand the difference is:

CPAP = one prescribed pressure

APAP = automatically adjusts pressure within a prescribed range

Both therapies are designed to treat obstructive sleep apnoea by helping to maintain an open airway during sleep.

The key difference is how the machine delivers that pressure.

Feature	CPAP	APAP
Full name	Continuous Positive Airway Pressure	Automatic Positive Airway Pressure
Pressure delivery	Generally fixed pressure	Automatically adjusts within a prescribed range
Responds to changes during the night	Limited	Yes
Can be suitable for obstructive sleep apnoea	Yes	Yes
Requires a mask	Yes	Yes
Can use humidification	Yes	Yes, depending on machine
Pressure settings	Usually one prescribed pressure	Minimum and maximum pressure range

How does an APAP machine know when to change pressure?

This is one of the biggest differences between APAP and traditional fixed-pressure CPAP.

Throughout the night, your breathing can change for a number of reasons. Your sleeping position, nasal congestion, alcohol consumption, sleep stage and other factors can influence your airway and breathing.

An APAP machine monitors aspects of your breathing and can respond to certain changes by adjusting the pressure within the range that has been prescribed.

For example, you may require less pressure while sleeping on your side but more pressure when sleeping on your back.

An APAP machine may adjust accordingly.

However, it is important to understand that an APAP machine isn’t simply choosing whatever pressure it wants. The machine operates within its programmed pressure range, and those settings should be determined by your doctor.

Is APAP better than CPAP?

Not necessarily.

There isn’t one machine that is automatically better for everyone.

Both CPAP and APAP can be effective treatments for obstructive sleep apnoea, and the most appropriate option depends on your individual circumstances.

Some people do very well with a fixed CPAP pressure, while others may benefit from the ability of an APAP machine to adjust pressure during the night.

Your sleep study results, prescribed treatment, symptoms, breathing patterns, comfort and other health factors may all be relevant when deciding which therapy is appropriate.

The goal isn’t necessarily to find the most advanced machine. The goal is to find a therapy that is effective, comfortable and sustainable for you.

Potential benefits of CPAP

One advantage of fixed pressure CPAP is its simplicity.

Because the machine is generally delivering a consistent pressure, some users may find the therapy predictable and straightforward.

Potential benefits can include:

Consistent pressure

The machine delivers the prescribed pressure rather than continually adjusting within a range.

Straightforward therapy

For some people, a fixed pressure is all that is needed to effectively manage their obstructive sleep apnoea.

Established treatment

CPAP has been used for many years and is a well established treatment for obstructive sleep apnoea.

Can be highly effective when correctly prescribed

When the appropriate pressure has been determined and the machine is used consistently, CPAP can be an effective treatment for many people with obstructive sleep apnoea.

Potential benefits of APAP

One of the main attractions of APAP is its ability to adjust pressure as your breathing changes.

Potential benefits can include:

Automatic pressure adjustments

The machine can adjust pressure within the prescribed range in response to detected breathing changes.

Adapts throughout the night

Your pressure requirements may not be exactly the same throughout every night—or even during different stages of the same night.

May provide lower pressure when appropriate

Because the machine can adjust pressure within its prescribed range, it may not need to remain at the maximum pressure throughout the night.

Can be useful when pressure requirements vary

Some people experience changes in their pressure needs depending on factors such as sleeping position or other circumstances.

Again, APAP isn’t automatically the better choice. The suitability of APAP depends on the individual and their prescribed therapy.

Does APAP feel different from CPAP?

It can.

Some people notice very little difference between CPAP and APAP, while others may notice changes in pressure during the night.

With CPAP, the pressure is generally consistent.

With APAP, you may experience the pressure increasing or decreasing as the machine responds to changes in your breathing.

Whether this feels more comfortable depends on the individual.

Comfort can also be affected by factors other than the machine itself, including:

Mask fit
Mask type
Pressure settings
Humidification
Sleeping position
Nasal congestion
Mouth breathing
Air leaks
Personal preference

If you’re finding your therapy uncomfortable, it doesn’t necessarily mean that you need a different machine. Sometimes a mask adjustment, different mask style, humidification or other changes can make a significant difference. You can speak to one of our friendly educators if you have any concerns.

What about APAP and pressure settings?

This is an important point.

APAP machines typically operate between a minimum and maximum pressure. These settings should not simply be chosen based on guesswork.

Your prescribed pressure range should be determined by your healthcare professional or sleep specialist based on your individual treatment requirements.

If you already use an APAP machine and you’re experiencing discomfort, excessive leaks, difficulty sleeping or other problems, speak with your doctor or CPAP educator before changing your pressure settings yourself.

CPAP, APAP and the importance of your mask

Regardless of whether you use CPAP or APAP, your mask plays a major role in successful therapy.

A machine can be working correctly, but if your mask doesn’t fit properly, you may experience air leaks, discomfort or difficulty maintaining your therapy.

There are several common types of CPAP masks, including:

Nasal masks

These cover the nose and are a popular option for many users.

Nasal pillows

These sit at or around the nostrils and are generally smaller and less intrusive than traditional nasal masks.

Full-face masks

These cover both the nose and mouth and can be useful for people who breathe through their mouth during sleep or have been advised to use this type of mask.

There isn’t one mask that is best for everyone.

Your sleeping position, breathing habits, facial shape, comfort preferences and other factors can all influence which mask may suit you.

What if I’m struggling with my CPAP or APAP?

If you’ve recently started therapy, it’s completely understandable that it may take some time to adjust.

Some people adapt quickly, while others need to make adjustments to their mask, humidification or routine before therapy becomes comfortable.

Common issues include:

Feeling uncomfortable wearing the mask
Air leaks
Dry mouth
Dry or blocked nose
Feeling claustrophobic
Difficulty falling asleep with the mask
Waking during the night
Pressure discomfort
Removing the mask during sleep

Don’t assume that you simply have to put up with these problems.

A CPAP professional or healthcare provider may be able to help identify the cause and find a more comfortable solution.

Can I switch from CPAP to APAP?

In some circumstances, a person may be suitable for a different type of PAP therapy.

However, changing machines or pressure settings should be discussed with your healthcare professional or sleep specialist.

Your treatment needs are individual, and switching from CPAP to APAP isn’t necessarily the right solution for every problem.

If you’re experiencing difficulties with your current therapy, it’s worth having the issue assessed rather than simply stopping treatment.

Which one should you choose: CPAP or APAP?

There is no universal answer.

The right choice depends on your individual diagnosis, treatment requirements, pressure needs, comfort and advice from your healthcare professional.

As a general guide:

CPAP may be suitable when:
A consistent, fixed pressure effectively manages your obstructive sleep apnoea and you are comfortable using that therapy.

APAP may be suitable when:
Your prescribed therapy calls for pressure adjustments within a specific range, or your pressure requirements vary during sleep.

The important thing is to focus on effective treatment and long-term compliance, rather than simply choosing the machine with the most features.

Frequently Asked Questions

Is APAP the same as CPAP?

No. Both use positive airway pressure to help keep the airway open, but traditional CPAP generally delivers a fixed pressure, while APAP automatically adjusts pressure within a prescribed range.

Is APAP more comfortable than CPAP?

It can be for some people, but not necessarily for everyone. Comfort depends on many factors, including the machine, pressure settings, mask, humidification and individual preferences.

Can I use the same mask with CPAP and APAP?

Generally, CPAP masks can be used with both CPAP and APAP machines because the mask connects to the machine through standard CPAP tubing. However, always check compatibility with your specific equipment.

Does APAP treat sleep apnoea?

APAP is used to treat obstructive sleep apnoea by providing positive airway pressure to help prevent the upper airway from collapsing during sleep.

Should I change my CPAP pressure myself?

You should not change your prescribed pressure settings without discussing it with your doctor. If your therapy isn’t comfortable or effective, seek advice so the cause can be properly assessed.

How do I know whether CPAP or APAP is right for me?

The best option depends on your individual circumstances and treatment requirements. Your sleep specialist or healthcare professional can help determine which therapy is appropriate.

The Bottom Line

CPAP and APAP both have the same overall goal: to provide positive airway pressure to help keep your airway open while you sleep.

The main difference is how they deliver that pressure.

CPAP generally provides a consistent, fixed pressure, while APAP automatically adjusts pressure within a prescribed range in response to changes in your breathing.

Neither option is automatically better for everyone. The most appropriate therapy depends on your individual needs, diagnosis and treatment plan.

If you’re having difficulty with your current CPAP or APAP therapy, don’t give up. Issues such as mask leaks, discomfort, dryness or difficulty adapting can often be addressed with the right support.

Need help finding the right CPAP equipment or making your current therapy more comfortable? Contact our team for advice on masks, machines and CPAP accessories on 0431300890 or email us on [email protected]

This article is intended for general information only and should not replace advice from your doctor, sleep specialist or other qualified healthcare professional. Always follow your prescribed treatment plan and speak with your doctor before making changes to your therapy or pressure settings

CPAP vs APAP: What’s the Difference?