Blood oxygen levels between 95 and 100% are considered healthy; blood oxygen levels below 80% may lead to compromised heart and brain functionality. Risk of respiratory or cardiac arrest is common after continued low blood oxygen saturation.

To that end, Apple is developing a new health notification based on the vital measurement. When Apple Watch detects low blood oxygen saturation below a certain threshold, a notification will trigger alerting the user similar to current heart rate notifications.

Oxygen saturation

It’s unclear at this point what hardware and software will be required for blood oxygen detection and notifications.

It’s possible future Apple Watch Series 6 hardware will be required for the new health feature. It could also come to all or newer Apple Watch models with  watchOS 7 in the fall.

The original Apple Watch hardware is believed to be capable of measuring blood oxygen levels through the built-in heart rate monitor. Apple upgraded the heart rate monitor with Apple Watch Series 4, adding electrocardiogram features, but Apple Watch hasn’t offered blood oxygen measurement features yet.

Dedicated fingertip pulse oximeters are bulky and not on your wrist

The feature is one that competitors have already tackled, including Fitbit which is being acquired by Google, although Apple could potentially offer a more sophisticated version using the same FDA approval method as its ECG function.

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ECG upgrade

Speaking of the ECG feature, Apple is working on removing a current shortcoming of the current electrocardiogram function. Apple Watch Series 4 and 5 currently result in inconclusive ECG readings with heart rates between 100 and 120 beats per minute.

A future update, either in software or hardware, will remove that limitation with an upgraded version of the ECG app. Apple is also developing built-in sleep tracking features for a future Sleep app.