Apple is set to roll out a significant software update for its recent US Apple Watch models, reintroducing the ability to measure blood oxygen levels through a feature known as pulse oximetry. This capability is particularly valuable for individuals managing health conditions that can impact blood oxygen levels, such as various heart and lung diseases, including heart attacks and asthma, as noted by experts at Johns Hopkins.
During the COVID-19 pandemic, the demand for devices equipped with pulse oximetry surged, as many sought to monitor their health proactively. However, it is essential to note that, unlike the Apple Watch's EKG feature, the pulse oximetry function has not received approval from the US Food and Drug Administration (FDA). This means that while the feature can aid in wellness tracking, it is not designed for official medical diagnostics.
In January 2024, Apple was compelled to remove this feature after the International Trade Commission (ITC) ruled that its blood oxygen measurement technology infringed on patents held by the California-based medical device company Masimo. This ruling resulted in an import ban, restricting the sale of Apple Watches in the US with the pulse oximetry capability.
On Thursday, Apple announced a new software update that will bring a redesigned Blood Oxygen feature to select Apple Watch users, specifically those with Apple Watch Series 9, Series 10, and Apple Watch Ultra 2 models in the US. This update will be available through iOS 18.6.1 and watchOS 11.6.1. Importantly, Apple Watch models purchased before the deactivation of this feature, or those bought outside the US, will not be affected by the changes.
The redesigned feature will not display blood oxygen readings directly on the watch, as was previously the case. For Apple Watch models bought in the US on or after January 18, 2024, with part numbers ending in LW/A, the analysis of Blood Oxygen data will now occur on the paired iPhone, allowing users to view results in the iPhone's Health app. This functionality is part of the latest versions of iOS and watchOS.
A recent meta-analysis published in the medical journal Cureus evaluated the performance of the Apple Watch's blood oxygen saturation measurements, finding it comparable to medical-grade pulse oximeters, albeit with some occasional discrepancies. The researchers called for further investigation to determine whether skin color affects the accuracy of these readings—a concern that has also been echoed by the FDA.
The study raised questions about the practical value of providing blood oxygen measurements for wellness decisions. It remained uncertain whether an Apple Watch user with a pre-existing health condition would seek medical attention based on data displayed by the device before experiencing physical symptoms like shortness of breath.
For the majority of users utilizing the Apple Watch as a wellness tracker, the blood oxygen feature may not deliver significant health insights. Additionally, it could potentially lead to psychological distress for those who become anxious over occasional outlier readings. The typical range for oxygen saturation is between 95% and 100%, and given the variability in the studies reviewed, users may sometimes receive readings that fall outside this range, which should not necessarily cause alarm.
In summary, while Apple’s reintroduction of the blood oxygen measurement feature is a step forward for wellness tracking, users should remain informed about the limitations and intended use of this technology.
