What Do the Readings Mean on My CPAP Machine?

November 24, 2020 | CPAP Tips & Tutorials |
Understanding CPAP readings can help improve therapy

If you are new to CPAP therapy, you may be overwhelmed by the various settings and numbers displayed on your CPAP machine. The readings on your CPAP machine reveal important information about your sleep health and the success of your therapy. In this guide, we will break down some of the key readings you should pay attention to, what those readings mean, and offer some best practices for remaining compliant with your CPAP therapy and improving your sleep health.

It is Important to Understand the Readings on a CPAP Machine

Continuous positive airway pressure, or CPAP, therapy treats sleep apnea by providing pressurized air to your airway to prevent it from collapsing during sleep. Remaining compliant with this therapy not only improves sleep quality but may help reduce the risk of other factors related to sleep apnea, such as cardiovascular disease, type 2 diabetes, stroke, and hypertension. In order to remain compliant, you must ensure that your equipment is functioning properly.

Each of the key readings we are going to look at examines your AHI score, the current air pressure setting, and mask leakage.

What are the Readings on A CPAP Machine?

Let’s take a closer look at these key readings to be aware of:

Apnea-Hypopnea Index (AHI)

AHI is the score given to determine the severity of your sleep apnea. The AHI number indicates how many apnea events (how many times you stop breathing) you have per hour.

  • An AHI reading under 5 is considered normal
  • A reading of 5-15 apnea events indicates mild sleep apnea
  • Readings of 15-30 are considered moderate sleep apnea
  • If your AHI is 30 or more, it is considered severe sleep apnea

The exact location of this number may vary depending on your machine, but your most recent AHI score can be found in your sleep reports. Some CPAP machines also store your sleep data wirelessly, allowing you to review it from your phone or computer. If your CPAP therapy is successful, the AHI number will drop to 5 or less.

Air Pressure (cmH2O)

Air pressure is determined by your sleep doctor based on the severity of your sleep apnea. It is measured in centimeters of water, or cmH2O, and is the main number that appears on screen when the machine is on. Too much or too little air pressure can cause side-effects, so this number should only be changed if approved by your doctor. 

Auto CPAP machines (sometimes referred to as APAP machines) will raise or lower the air pressure as needed throughout the night. For example, if an individual is a side sleeper but rolls to their back while sleeping, more air pressure may be required to keep their airway open. The auto CPAP will increase the air pressure to ensure the airway stays open. Other features, such as ramp, may also change your CPAP pressure as needed.

Mask Leakage

The final reading you should be aware of is the mask leak reading. CPAP masks are designed to move as you move, providing a comfortable fit without you feeling suffocated or claustrophobic. However, sometimes a CPAP mask may move too much causing air pressure to leak out from the side of the mask. This leakage is important because the more air that leaks out, the less air is available to keep your airway open. This means that therapy will not be as effective.

Nightly sleep reports can tell you how much mask leakage you experience each night. An average leak rate registers 20-24L/minute or less. This is because most masks have tiny venting holes to allow the CO2 that you exhale to escape the mask. Anything higher than this and it may be time to replace your CPAP mask. 

Best Practices for CPAP Use 

One of the simplest practices to ensure you are getting consistent and accurate therapy is to regularly clean & replace CPAP equipment as needed. CPAP masks can often attract dirt and oils from our skin, causing them to deteriorate and even tear over time. It is important to clean mask cushions with soap and water regularly and replace them approximately every three months. If you use a humidifier with your CPAP to prevent nasal dryness, it is important to disinfect that to prevent the build-up of germs and mold that can make you sick.

Another key practice for effective CPAP therapy is consistency. New users tend to get frustrated if CPAP does not work immediately. Give it time and wait before making adjustments. It can take a few nights before acclimating to your settings.

If, over time, your sleep apnea symptoms do not improve, despite maintained equipment and regular use of therapy, you may need to consult your doctor. Either your current sleep settings need to change, or other lifestyle changes need to be taken into consideration, such as cessation of drinking or smoking, weight loss, etc.

If you need help understanding your CPAP machine readings, or are interested in learning more about the wide array of products we have to offer, contact our knowledgeable customer care team questions@thecpapshop.com or give us a call at 866-414-9700

Chris Vasta


Chris Vasta

Over a 10+ year career at PHH Mortgage managing a $100 million portfolio, Chris Vasta learned the ins and outs of the business world. He learned how to establish business relationships, lead a multi-prong team, and implement strategies for long-term growth. In 2007, Vasta used that experience to transition his role into president of The CPAP Shop. Over his tenure, Vasta has been involved in everything from website design to warehouse layout. His hands-on approach with customers has evolved into an in-depth understanding of the challenges of beginning and adhering to sleep therapy. He often provides his insights on product…

10 Comments Leave new

  • KEN

    My air pressure is set at 5 and 15. What is that actually mean and what is it doing.

    • Chris Vasta

      Hi Ken, air pressure is determined by your sleep doctor based on the severity of your sleep apnea. It is measured in centimeters of water, or cmH2O, and is the main number that appears on screen when the machine is on. Air pressure delivers airs through a user’s nose and/or mouth through a mask to help ensure their airways stay open through the night. The higher the air pressure setting, the more air a user needs during the night. Feel free to reach out to our knowledgeable team at 866-414-9700 to learn more.

  • Pat

    Dream station has quite working-reading message-111716-12933 service required-what to do

  • Jim Sensenbach

    MyAir seems to lag behind a day when reporting my AirSense readings. Note that I woke up one hour ago so that will change. Also I take naps so important information is how sessions are assigned to a day and when that is done.

  • Brenda Mcgowen

    What does it means when wearing you capa machine. And it’s only reading at 46% after 6 nights of wearing it with no changes

    • Chris Vasta

      The machine can detect when your mask is not getting a good seal or when the mask has become dislodged. It may also be that you do not currently have a good mask fit.

  • Leroy Kramvik

    Yesterday I had the pressure on my CPAP machine increased from 10 to 11. The nurse at the clinic made the adjustment. This morning I was unable to check the AHI reading as it failed to be displayed on the CPAP machine. The nurse must have made an error when adjusting my machine. Can I correct this at home?

    • Andrew Rivenbark

      Leroy, feel free to contact our customer care team at 866-414-9700. One of our reps should be able to help walk you through the process of accessing your AHI report.

    • ralwoe

      You can change the pressure or other settings by pressing the home button and menu knob simultaneously for at least 5 seconds. This allows you to get into the clinical settings menu. Use the menu knob to select. Always good idea to make notes of the current settings as a reference, before changing anything.

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