Most people on CPAP therapy get a summary from their sleep clinic every six to twelve months. That summary usually looks something like: “Your AHI is 3.2. Therapy is effective.” And if that's all you hear, you nod along and go home.
The problem? A lot can happen between visits. Your weight changes. You switch sleep positions. Your mask degrades or your pressures drift. That time between clinic check-ins is where understanding your own CPAP data becomes genuinely useful — not to diagnose yourself, but to have a better conversation with your care team when you do see them.
Learning how to analyze your CPAP data at home puts you in a position to be a more informed participant in your own care.
Medical disclaimer: This article is for informational purposes only. AirwayLab is a data exploration tool, not a clinical decision support system. Nothing in this article constitutes medical advice. Your healthcare provider can interpret your data in the context of your individual health situation.
What “Analyzing Your CPAP Data” Actually Means
Analyzing your CPAP data means exploring patterns in the numbers your machine records every night: how often breathing events occur, how much air is leaking from your mask, whether your pressure is staying within expected ranges, and whether there are signs of flow limitation or respiratory effort-related arousals (RERAs).
What it doesn't mean is drawing clinical conclusions on your own. The data tells you whatyour machine recorded. It can't tell you whether therapy is appropriate for your specific health situation, whether your pressure settings are suited to you, or whether any changes you notice are medically significant. That interpretation belongs to your care team.
With that framing in place, here are the metrics worth paying attention to.
AHI (Apnea-Hypopnea Index)
AHI is the average number of apneas and hypopneas per hour. What's more useful than any single reading is trend over time — is your AHI stable, or is it gradually drifting? Your clinician can place these patterns in clinical context.
Leak Rate
CPAP machines need a sealed mask to deliver effective therapy. Some leak is normal (particularly with intentional exhaust vents), but large or unintentional leaks may mean your device is not delivering the full set pressure. Your machine records this, and it's worth knowing your baseline.
Flow Limitation
Flow limitation describes partial airway obstruction — your airway isn't fully collapsed (which would be a scored apnea), but it's not fully open either. Flow limitation doesn't always trigger a scored event, which is why it can go unnoticed in a headline AHI figure despite potentially contributing to disrupted sleep. Looking at flow limitation patterns is one area where home analysis adds context beyond a single nightly number.
RERAs (Respiratory Effort-Related Arousals)
RERAs are brief arousals caused by increased respiratory effort, often associated with upper airway resistance. They don't necessarily appear in standard AHI calculations depending on how your machine scores them. Some devices and analysis tools surface these separately — if you're waking frequently but your AHI looks unremarkable, your clinician may consider RERAs alongside AHI when reviewing your data.
How AirwayLab Analyzes Your CPAP Data
AirwayLab is a client-side data exploration tool. That means when you load your SD card data, it is processed entirely within your browser — your data never leaves your device, never touches a server, and never gets stored anywhere outside your own machine.
This isn't just a privacy stance (though it is that). It's also a transparency stance: AirwayLab is open-source under GPL-3.0, which means you — or anyone you trust — can read the exact code that runs on your data. Verifiable, not just claimed.
The tool is designed to complement tools like OSCAR, not to replace them. If you're already using OSCAR and want a second perspective on your data, or you're new to reviewing your therapy data and want somewhere accessible to start, AirwayLab is built to be usable without a technical background.
The free tier is complete. Core analysis features are free and always will be.
How to Analyze Your CPAP Data with AirwayLab: A Walkthrough
Step 1 — Export your data from your CPAP device
Most modern CPAP and BiPAP devices (ResMed AirSense, Philips DreamStation, and others) record detailed session data to an SD card. You'll need to remove the SD card from your device and read it with your computer, or use a USB card reader. If you've never exported your data before, our How to Export CPAP Data guide walks through the process device by device.
Step 2 — Load your data into AirwayLab
Go to AirwayLab's analysis page and use the file picker to select your SD card data folder. The tool reads the raw machine data directly in your browser. Nothing is uploaded — all processing is local.
Step 3 — Explore the dashboard
Once your data is loaded, you'll see a summary of recent sessions. From there you can browse AHI trends across days, weeks, and months; inspect nightly leak rate patterns; look at flow limitation signals; and view pressure data for APAP or BiPAP users.
Step 4 — Focus on trends, not individual nights
One night of elevated AHI isn't necessarily meaningful — disrupted sleep, a new position, a loose mask. Patterns across time are what matter. Use the date range selectors to compare weeks or months, and look for consistent changes rather than one-off readings. The How to Read CPAP Data article is a useful companion for understanding what the numbers mean.
A Note on Mask Fit and Leaks
If your leak rate is consistently elevated, it's worth doing a mask fit check before assuming a pressure or therapy issue. High leak rates can be associated with headgear fit, cushion wear, or mask positioning. Our CPAP Leak Rate Guide covers what's typical, what's not, and what to check first.
Medical disclaimer
This article is for informational purposes only. AirwayLab is a data exploration tool, not a clinical decision support system. Nothing in this article constitutes medical advice. Your healthcare provider can interpret your data in the context of your individual health situation.
Frequently Asked Questions
Is exploring my own CPAP data safe?
Exploring your therapy data is informational — it is not a substitute for clinical review. Use what you find to prepare better questions for your care team, not to make independent therapy decisions.
Do I need a specific CPAP device to use AirwayLab?
AirwayLab supports data from most common CPAP and BiPAP devices that record detailed data to SD card, including ResMed and some Philips models. Check the supported devices page for the current list.
Does my data get uploaded anywhere?
No. AirwayLab processes your data entirely in your browser. Nothing is transmitted, stored, or shared. Your data stays on your device.
What's the difference between AHI and RERA index?
AHI counts apneas and hypopneas per hour. The RERA index counts respiratory effort-related arousals separately. Some devices score these differently, and your clinician may consider both when evaluating therapy patterns.
I'm already using OSCAR — why would I also use AirwayLab?
OSCAR is excellent and AirwayLab is not trying to replace it. Some users find AirwayLab's interface easier to start with, or use it alongside OSCAR for a different view of the same data. Both are free, both are open-source.
Should I change my settings based on what I find?
Pressure settings are managed by your healthcare provider based on your clinical needs. Your clinician can interpret these patterns in clinical context.
Analyse Your CPAP Data with AirwayLab
Browser-based, free, and open-source. Your data never leaves your device.