Apple has announced a software update that will re-implement the ability to measure blood oxygen levels, also known as pulse oximetry, on recent US Apple Watch models. This feature was previously removed due to a patent dispute with California-based medical device maker Masimo.
According to Johns Hopkins, pulse oximetry can be helpful in assessing health conditions such as heart attacks and asthma. However, the Apple Watch’s pulse oximetry functions were not approved by the FDA and are intended for “wellness” data entertainment rather than medical diagnostics.
The feature will be available on iPhone with iOS 18.6.1 and watchOS 11.6.1 for certain US Apple Watch Series 9, Series 10, and Apple Watch Ultra 2 models purchased on or after January 18, 2024. The updated design change involves displaying blood oxygen measurement data on the iPhone rather than the Apple Watch.
A 2023 study found that Apple’s device was roughly comparable to medical-grade pulse oximeters, but highlighted the need for further analysis to assess skin color’s effect on measurement accuracy. Some experts questioned whether providing blood oxygen measurements would be of value in informing wellness decisions, citing concerns about potential psychological distress from outlier results.
Source: https://www.theregister.com/2025/08/14/apple_watch_revives_blood_oxygen