# Understanding Your CPAP Data Report > Usage hours, leak, AHI and pressure tell different stories. Here is how to read your CPAP data before your next appointment. Canonical: https://findsleepdoctors.com/articles/understanding-your-cpap-data-report Last updated: 2026-10-30 Learn what usage, leak, AHI and pressure mean on a CPAP data report, how apps differ from SD card data, and what to ask your clinician. Updated 2026-10-26 · 7 min read · Sleep Doctor Near Me editorial. **Quick answer:** A CPAP report has two jobs: showing whether you used the machine and showing whether it controlled your breathing. Usage hours answer the first. Leak, residual AHI, pressure and flow limitation answer the second. The app's summary is a starting point; the SD card or clinician download gives the detail needed to solve problems. ## Compliance and efficacy are different Compliance means you used the machine. Efficacy means the machine was doing its job while you used it. A report can show excellent compliance and poor efficacy, or the reverse. Paying attention to only one half is how people end up with a perfect score and persistent fatigue. Insurance and public funding often focus on compliance. Your clinician should focus on both. ## Usage hours Most reports show average hours per night and the percentage of nights the machine was used. A common insurance threshold is at least four hours per night on 70% of nights, but that is a funding rule, not a treatment goal. Seven or more hours on most nights is a better target for most adults. Look at the distribution, not just the average. Four hours every night and eight hours twice a week can produce a similar average with very different biology. ## Leak Every mask has a designed vent flow. "Leak" usually means unintentional leak above that baseline. A high leak can dry your eyes, disturb sleep, reduce the accuracy of event detection and make the machine work harder to maintain pressure. Common causes include a mask that is too loose or too tight, a worn cushion, mouth leak, sleeping position, or a hose pulled tight. The leak graph is more useful than a single average. A spike at 3 a.m. every night suggests a positional or mouth-leak pattern. ## Residual AHI The residual AHI is the number of apneas and hypopneas the machine detected per hour while you used it. Under 5 is the usual target, but the number is calculated over mask-on time, not total sleep time. If you wore the mask for four hours, the AHI reflects those four hours. The machine's event detection is not as precise as a sleep study. It can miss hypopneas and respiratory effort-related arousals. A low residual AHI is reassuring, not a guarantee of perfect sleep. ## Pressure and flow limitation An auto-adjusting machine reports a median, 90th or 95th percentile pressure, and sometimes a maximum. A pressure that sits at the top of the range every night may mean the range is too low or the mask is leaking. A pressure that swings widely may mean the settings need review. Flow limitation is a subtler signal: the airway is narrowing but not closing enough to score an event. If flow limitation is high and you still feel tired, ask about it. Our article on [still feeling tired on CPAP](https://findsleepdoctors.com/articles/still-tired-on-cpap) covers the possibilities. ## Central events Some reports separate obstructive and central apneas. Central events can appear when treatment starts, especially at higher pressure, or in people with heart failure or neurological conditions. A new cluster of central events deserves clinical review. Do not change the pressure yourself to chase the number. ## Where to get the data - **Machine app:** convenient, but often limited to usage, leak and AHI. - **SD card:** the full data, including flow waveforms and pressure traces. You can review it with software such as OSCAR or SleepHQ. - **Clinician download:** the clinic can print or share a detailed report. - **Supplier portal:** some suppliers provide a dashboard, but the detail varies. If your machine only uploads to the cloud, ask the clinic or supplier for the detailed report. The data is yours. ## What to bring to your appointment Bring a 30-day or 90-day report, not a single night. One bad night is noise; a month of leak at the top of the chart is a pattern. Include the SD card if you have one. Write down what changed: a new mask, a cold, weight change, travel, or a pressure adjustment. Do not change settings before the appointment to make the data look better. The clinician needs the real picture. ## Questions to ask 1. Is my usage adequate, and is it consistent? 2. Is my leak within the mask's expected range? 3. What is my residual AHI, and is it calculated over the time I actually slept? 4. Is there flow limitation or a pressure pattern you are concerned about? 5. Are there central events or arrhythmias on the data? 6. Should we change the mask, the pressure range or the follow-up plan? Our guide to [getting started with CPAP](https://findsleepdoctors.com/articles/cpap-therapy-getting-started) covers the first months, and our [sleep doctor directory](https://findsleepdoctors.com/sleep-doctor-near-me) can help you find a clinic that reviews data properly. ## Frequently Asked Questions ### What is a good CPAP report? A good report shows consistent use of seven or more hours on most nights, leak within the mask's expected range, a residual AHI under 5, and no concerning central events or pressure patterns. Symptoms and how you feel matter too. ### Why is my AHI low on CPAP but I still feel tired? The machine's AHI is an average over mask-on time and may miss subtle events. Leak, short sleep, insomnia, medication effects, thyroid disease, iron deficiency and other conditions can also cause fatigue. Ask for a detailed data review. ### What does a leak rate of 24 L/min mean? It depends on the mask and the machine's expected vent flow. Some masks allow higher intentional leak than others. Ask your clinician whether your leak is within the mask's stated range and look at the leak graph over time. ### Can I read my own CPAP data? Yes. Many machines store detailed data on an SD card, and software such as OSCAR or SleepHQ can display it. Reading it is useful for spotting trends, but do not change pressure settings without clinical advice. ### How often should CPAP data be reviewed? Usually at the first follow-up after starting, then at least annually if stable. Review sooner if symptoms change, leak increases, or you have a new medical condition. Some clinics review data remotely between visits. ### Does insurance check my CPAP data? In the US, Medicare and many insurers require documented adherence for continued coverage. Other countries may not require it for funding, but clinics still monitor treatment. Ask your supplier and clinic what is reported. *This article is general information, not medical advice. It does not replace an assessment by a qualified clinician who can review your history, medications and test results.* ## Related guides in this series - [Sleep Doctors in Edina, Minnesota: How to Find the Right Specialist](https://findsleepdoctors.com/articles/sleep-doctors-edina-mn-us) — Edina, Minnesota lists 8 sleep providers and centers in the Find Sleep Doctors directory. This guide explains how to compare them, what to expect, and how to prepare before booking. - [Sleep Doctors in Helena, Montana: How to Find the Right Specialist](https://findsleepdoctors.com/articles/sleep-doctors-helena-mt-us) — A directory guide to 8 listed sleep providers and centers in Helena, Montana, with contact details and practical booking questions. - [Sleep Doctors in Burnsville, Minnesota: How to Find the Right Specialist](https://findsleepdoctors.com/articles/sleep-doctors-burnsville-mn-us) — This guide lists eight sleep providers and centers in Burnsville, Minnesota, with addresses and phone numbers from the Find Sleep Doctors directory. It also explains how to compare options, plan a visit, and prepare questions for a sleep medicine appointment. ## Ready to find a sleep doctor near you? Browse sleep medicine doctors across six countries, organized by region and city, and reach out directly — all in one free, verified directory. See [all countries and cities](https://findsleepdoctors.com/sleep-doctor-near-me). This medical guide reflects generally accepted clinical guidance for sleep disorders. It is informational and not a substitute for personalised medical advice — consult a qualified sleep specialist or your GP. ## Related - [All sleep health guides](https://findsleepdoctors.com/articles) - [Home](https://findsleepdoctors.com/) - [Country and city index](https://findsleepdoctors.com/sleep-doctor-near-me)