Apple may soon add oxygen blood level monitoring to the Apple Watch. It is not yet clear if this feature will be available on all models or just the Apple Watch Series 6.

According to 9to5mac, code found in iOS 14 suggests that Apple is working on enhancements to watchOS that will continuously analyze oxygen levels in the bloodstream, as well as new improvements to the watch's electrocardiogram (ECG) feature.

This feature will work similarly to heart rate and ECG monitoring, alerting the user if the Apple Watch detects oxygen levels outside of a healthy range. Oxygen levels between 100 and 85% are considered normal. Below that level, the notification is triggered in the same way as a current arrhythmia or extreme heartbeat, which can damage the heart and affect brain function.

As iFixit discovered in a 2015 teardown, the Apple Watch is perfectly capable of measuring oxygen blood flow levels even when the function has never been activated. So, in theory, Apple could add oxygen monitoring to all Apple Watch models.

However, it is unlikely to happen, as Apple has a long story of adding additional features to its latest model devices, even though the older models have perfectly functional hardware. Google's latest Fitbit added blood oxygen monitoring to older models through a simple software update.

It is also possible that Cupertino will add a more accurate dedicated oximeter to the Apple Watch Series 6, justifying making it a new feature only for the 2020 model. In addition, it is reasonable to assume that a new dedicated oximeter comparable to current medical devices may also be required for FDA approval.

ECG functionality may be enhanced in the next watchOS update. Currently, the ECG feature on the Apple Watch Series 5 and Apple Watch Series 4 does not work well during exercise. ECG readings become unreliable when heartbeats exceed 100-120 beats per minute.

According to a code review by 9to5mac, this limitation will be resolved in the near future with new software or a new combination of hardware and software.

Whether it is the Apple Watch Series 6 or simply a software upgrade available for older models, Apple continues to make steady progress in turning its focus to human health.