PRODUCT

Put your oxygen on the same night as your therapy: CPAP SpO₂ overlay

Your CPAP machine counts events. It cannot tell you what they did to your oxygen. Pair a recording oximeter with Apnealytics and your overnight SpO₂ and pulse are drawn on the same time axis as your airflow, pressure and events, with ODI₃, ODI₄ and T90 worked out for you.

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Free on every plan · Web, iPhone, iPad, Android

Night detail in a browser frame with airflow, pressure, event strip, SpO2 and pulse traces sharing one crosshair, desaturations shaded, and tiles for SpO2 average, nightly low, ODI3, ODI4, T90 and pulse

What it is

The SpO₂ overlay reads the export from your pulse oximeter and lines it up with the night your machine recorded. It supports the Wellue O2Ring, the CMS50 family from Contec via CSV, ResMed's SAD.edf files, and any oximeter that exports EDF or CSV. It is the feature people ask for when they want to know whether a "Mild" AHI night still came with meaningful desaturations.

Event strip above an SpO2 trace with desaturations shaded coral and aligned with hypopnea and obstructive markers, pulse below, crosshair reading SpO2 and pulse; ODI3 / ODI4 / T90 tiles

How it works

Record
Wear your oximeter overnight as usual.
Export
Save the night as EDF or CSV from the oximeter's app or software.
Upload
Drop the file into Apnealytics on the web or import it from the companion app. It is matched to the therapy night by date and time.
Analyse
Apnealytics computes SpO₂ average, median and low, pulse, ODI₃, ODI₄ and T90 for the night.
Compare
Open the night to see oxygen beside events and pressure, and watch desaturation metrics in Trends over time.

What you'll see

Overlaid traces
SpO₂ and pulse drawn under your airflow, pressure, leak and event strips with a shared crosshair, so you can read "SpO₂ 88 percent, pulse 71, during this cluster of obstructive events" at a glance.
Desaturation analytics
ODI₃ — desaturations of at least 3 percent per hour. · ODI₄ — desaturations of at least 4 percent per hour, the threshold some insurers and labs use. · T90 — minutes and percentage of the night spent below 90 percent. · SpO₂ average, median and nightly low and pulse summaries.
Vitals alongside
If you also sync Apple Health or Health Connect, the daily SpO₂ average and low from your watch sit in the Vitals tiles. The oximeter overlay is the detailed, second-by-second view; the watch summary is the daily trend.
Trends for oxygen
ODI and T90 over 30D, 90D, 1Y or All, with the same change-point markers as the rest of Trends, so you can see whether a pressure change or new mask moved your oxygen as well as your AHI.

Real Vitals screen in a browser frame: blood oxygen, resting heart rate, HRV and sleep duration charts from Apple Health

Free vs Pro

Apple Health and Health Connect vitals, including daily SpO₂ average and low, are free. Oximeter file import, the per-night SpO₂ overlay and ODI₃ / ODI₄ / T90 analytics are Pro features, at $8.99 a month or $99.99 a year.

See pricing

FAQ

Questions people ask

Help center →

Which pulse oximeters work with Apnealytics?

The Wellue O2Ring, CMS50-family devices from Contec that export CSV, ResMed SAD.edf files, and any oximeter that exports EDF or CSV. You are not limited to a branded device; if your oximeter can save a standard file, Apnealytics can usually read it. See the oximeters page for details.

What is ODI and how is it different from AHI?

AHI counts breathing events per hour that your machine detects from airflow. ODI counts oxygen desaturations per hour from an oximeter, at a 3 percent (ODI₃) or 4 percent (ODI₄) drop. They often track each other but not always; some events do not desaturate, and some desaturations are not scored as events. Seeing both is the point.

What does T90 mean?

The time you spent with SpO₂ below 90 percent, shown as minutes and as a share of the night. It captures sustained low oxygen that a per-hour index can miss. What a given T90 means for you is a question for your clinician; Apnealytics reports it, it does not interpret it clinically.

Does my Apple Watch count as an oximeter here?

Partly. Apple Health and Health Connect give Apnealytics a daily SpO₂ average and low, shown in Vitals for free. They do not provide a continuous overnight trace, so the per-night overlay and ODI / T90 analytics need a recording oximeter's EDF or CSV export.

Will SpO₂ data appear in my doctor's report?

Yes. On Pro, the oximetry summary for the period, including ODI₃, ODI₄, T90 and nightly lows, is included in the PDF report alongside AHI, usage and leak.