Ultrahuman Ring Air Blood Oxygen (SpO2) Not Measuring — What It Means & How to Fix It

What Does This Error Mean?

Ultrahuman Ring Air SpO2 is measured during sleep only, and only when the ring fits snugly. Enable SpO2 monitoring in the app, ensure a proper fit, and wear the ring every night for readings to appear.

Affected Models

Ultrahuman Ring Air
Ultrahuman Ring Air Raw
Ultrahuman Ring Air Aster

Common Causes

SpO2 monitoring not enabled in the Ultrahuman app
Ring too loose — sensor cannot maintain contact during sleep
Ring not worn during sleep
Cold sleeping environment causing vasoconstriction
Nail polish or dark pigmentation on the finger near the sensor

How to Fix It

Enable SpO2 monitoring in the Ultrahuman app: go to Profile > Ring Settings > Blood Oxygen and toggle it on.

SpO2 monitoring is off by default to conserve battery. It must be manually enabled before the ring measures blood oxygen during sleep.
Confirm you wear the ring every night on your index or middle finger.

SpO2 is measured only during sleep. There is no daytime SpO2 reading from Ultrahuman Ring Air. The ring must be worn during the night for this data to appear.
Ensure the ring is snug — it should not rotate on your finger.

SpO2 measurement uses red and infrared light that must pass through your finger. Any gap between ring and skin prevents accurate measurement. Use the Ultrahuman sizing guide if unsure.
Remove nail polish from the ring finger.

Dark nail polish absorbs the infrared and red wavelengths the SpO2 sensor uses, producing unreliable or missing readings.
Check the app the morning after a full night of wear — SpO2 data appears after the morning sync.

SpO2 data is transferred during your first sync of the morning. Open the Ultrahuman app after waking and allow it to sync before expecting SpO2 data to appear.

When to Call a Professional

If you consistently see SpO2 readings below 90% and have symptoms such as breathlessness, chronic fatigue, or morning headaches, see a doctor. These may indicate sleep apnea or a respiratory condition requiring clinical evaluation.

Frequently Asked Questions

What is a healthy SpO2 reading from Ultrahuman Ring Air?

A healthy blood oxygen reading is 95–100%. Readings of 90–94% are considered low, and below 90% is a concern that warrants medical evaluation. Note that consumer ring sensors are less precise than medical-grade pulse oximeters.

Can Ultrahuman Ring Air detect sleep apnea through SpO2 dips?

Ultrahuman Ring Air can detect SpO2 dips during sleep that may be consistent with breathing events, but it cannot diagnose sleep apnea. If you see frequent drops below 90% in your SpO2 overnight graph, mention this to your doctor — they can order a proper sleep study.