Apple Reintroduces Blood Oxygen Monitoring to Apple Watch Models in the USA Amid Ongoing Patent Dispute

Apple has confirmed that yesterday, August 14, it is reintroducing the blood oxygen (SpO2) feature in the USA via a software update. This follows a disruptive and protracted legal battle on patent infringement with Masimo over its pulse-oximetry technology. The key change Apple has made is a technical one that shifts the processing of the measured data to your iPhone.

Details on the Redesigned Feature

Much of the world has remained largely oblivious to this issue, which only affects US owners of Apple Watch Series 9, Series 10, and Ultra 2, ie those bought after January 17, 2024. Those US owners who want the feature back require updating their iPhone to iOS 18.6.1 and Apple Watch to watchOS 11.6.1.

Despite not initially being made available on watchOS 26 (currently in beta), it will inevitably appear in the live software in September or even an earlier beta before then, although Apple has not stated that.

Key Technical Change

US customs have approved (14-Aug-2025) the key technical change, which sees Apple moving the measurement, calculation and display of blood oxygen from the Watch to the iPhone, although the Watch still collects the raw data. Previously, the SpO2 information was available directly on the Watch.

Background of the Dispute and Timeline

The timeline of the case specifics dates back over a decade, although the meat of the legal case only surfaced and developed over the last five years

2013–2014: Apple hires key Masimo/Cercacor personnel (e.g., Marcelo Lamego, Michael O’Reilly), underpinning Masimo’s trade-secret claims.
January 9, 2020: Masimo and Cercacor sue Apple in US District Court (Central California) for patent infringement and trade-secret theft related to Apple Watch health-monitoring tech.
June 30, 2021: Masimo files an ITC complaint alleging infringement of five patents and seeking an import ban on pulse-oximetry-equipped Apple Watches.
May 1–2, 2023: California trade-secrets trial ends in a mistrial; Masimo plans a retrial, but none has occurred as of 15 August 2025.
October 26, 2023: ITC issues limited exclusion order for patent infringement, banning US imports effective December 26, 2023 (targeting Series 9, 10 and Ultra 2).
Apple pauses sales from December 21–24.
December 27, 2023: Federal Circuit grants temporary stay; lifted in January 2024, reinstating ban on January 17, 2024. Apple disables SpO2 on new US units to resume sales. (More: the5krunner)
October 2024: Delaware jury rules Masimo smartwatches infringe two Apple design patents, awarding $250 nominal damages. Although this doesn’t resolve the core dispute, some see it validating Masimo’s patents.
July 7, 2025: Oral arguments in the Federal Circuit for Apple’s ITC appeal (case: Apple Inc. v. ITC).
August 14, 2025: US Customs approves Apple’s software redesign, enabling SpO2 restoration via update.
– Add that the ban only affects US-purchased units post-January 17, 2024; pre-ban or non-US units retain original feature.

Ongoing

The case is not over. As you can see from the timeline above, the ITC ruling is still under appeal, and no final decision has been made. There could be a potential retrial this year or later.

The key date of January 17, 2024, remains; US purchases of affected models could experience further changes after that date. Early models and those bought internationally remain unaffected.

Apple has a solution it thinks is legally valid. Any new Watch models will likely use the same solution, and future rulings or changes will likely impact them in the USA.

How Apple Utilises SpO2 Data for Wellness Insights

Q: Is SpO2 data important?

A: For most of us, in most situations… “Not so much”.

Apple uses SpO2 data, measured via red/infrared light sensors, for general wellness, not medical diagnosis. The data is subsequently integrated into features like the Vitals app (watchOS 11).

Blood Oxygen is a key ‘vital sign‘ when taken by a medical professional in a medical setting. Low SpO2 (below 88%) may indicate serious conditions like hypoxemia.

Lower Blood Oxygen affects humans at higher altitudes. For some athletes (climbers), it can be a critical raw metric to be aware of because of the potentially fatal conditions it indicates.

However, for most of us, those factors are unimportant, and we benefit from how SpO2 can be used to interpret less serious conditions and track patterns for lifestyle changes.

Apple and its wearable competitors commonly measure and use SpO2 data during sleep to spot trends and oxygen desaturation events. This data can identify potential respiratory issues like sleep apnea. The same data then flag up Sleep Apnea Notifications (watchOS 11 or later) to prompt medical evaluation.

Vital Signs

That aside, Apple includes SpO2 in its Vitals app (watchOS 11), alongside heart rate, respiratory rate, wrist temperature, and sleep duration.

To a degree, it is used to assess respiratory function, as low SpO2may indicate hypoxemia or illnesses. Combined with HRV data, this offers holistic cardiovascular/respiratory views of our physiologies. However, although these wearable technologies have been validated to some degree, they remain susceptible to the vagaries of how we wear and use the watches. For example, data is measured when your body is still and is impacted by the tightness with which it is worn.

Take Out

Apple has strategically positioned its Watch for the future because of its ability to underpin an understanding of health and wellness. SpO2 is one of the key ‘vitals’ that Apple must include in its suite of metrics. Hence, the company has to have a long-term, viable solution for capturing and using this data – thus the company’s willingness to invest in lengthy legal proceedings.

Many industry commentators, including myself, imagined a new sensor or sensing method to get around the patent, perhaps hoping that the urgency of sorting out SpO2 capture would lead the company to bring forward any plans for its next generation of sensor. Instead, the company has changed the method it uses to determine SpO2.

The story is still not over, and there could be future twists and turns, perhaps even further problems for Apple in the USA with this technology. Today’s developments indicate that the writing is on the wall for a relatively prompt resolution that will not derail Apple’s plans.

Sources and Further Resources

With 20 years of testing Garmin wearables and competing in triathlons at an international age-group level, I provide expert insights into fitness tech, helping athletes and casual users make informed choices.

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