Quick take
Oxygen reports are trend reports. Terms like ODI and time below threshold need context before they mean anything clinically.
Consumer oxygen reports often look authoritative because they include charts and percentages. The hard part is knowing which numbers are clinically meaningful and which might be sensor artifact.
Glossary table
| Term | Plain meaning | What can distort it |
|---|---|---|
| SpO2 | Estimated blood oxygen saturation from a pulse oximeter. | Cold hands, motion, sensor fit, nail polish, skin factors. |
| ODI | Oxygen desaturation index, usually drops per hour by a set threshold. | Different devices may use different drop definitions. |
| Basal SpO2 | Typical baseline level during the recorded period. | Bad baseline if the sensor was unstable. |
| Time below 90% | Share or minutes under a threshold. | Loose sensor can create false low time. |
| Artifact | Data that reflects measurement error more than physiology. | Motion, poor contact, low perfusion. |
How to read a report responsibly
- Check wear time and signal quality first.
- Look for repeated patterns, not one isolated dip.
- Compare the graph with symptoms or awakenings.
- Share the full report with a clinician if readings are concerning.
Sources and further reading
Related NightlyVitals pages
Frequently asked questions
Is time below 90% always dangerous?
It can be clinically important, but interpretation depends on your health, altitude, device quality, and symptoms. Discuss repeated lows with a clinician.
Can a loose ring sensor create false drops?
Yes. Poor contact and motion can create artifacts that look like oxygen drops.