The Return of Blood Oxygen for Apple Watch
Apple (MacRumors, Hacker News):
Apple will introduce a redesigned Blood Oxygen feature for some Apple Watch Series 9, Series 10, and Apple Watch Ultra 2 users through an iPhone and Apple Watch software update coming later today.
[…]
This update was enabled by a recent U.S. Customs ruling.
To get around the ban, blood oxygen data collected on the Watch will now be measured and calculated on the iPhone that it’s paired to. While users won’t be able to view the data on their wrist, they’ll be able to view it in the iPhone’s Health app under the Respiratory section.
If Apple was violating the patents before, I don’t see how using the same sensors but moving the calculation to a different device should make it not a violation. But that determination seems to be ongoing; what’s changed is the interim import ban.
I may be speculating, (I doubt it) but it sounds like a friends in high places who like gifts moment to me.
Previously:
- Apple Announces American Manufacturing Program
- Apple Watch Sales Paused Over Masimo Patent
- Masimo v. Apple
Update (2025-08-15): John Gruber (Mastodon):
Also important, and not clear at all from Apple’s initial announcement this morning: After the iOS 18.6.1 and WatchOS 11.6.1 software updates, the iPhone and Apple Watch need to download an over-the-air asset to enable the redesigned Blood Oxygen feature. This apparently may take up to 24 hours. Until this asset download happens, the Blood Oxygen app on your Apple Watch will still say “The Blood Oxygen app is no longer available”. To jump-start the download, users can open the Health app on their iPhone, and the ECG app on their Apple Watch.
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The two patents […] are set to expire in August 2028, and I suspect this patent suit has been a last-ditch attempt to monetize them before they expire by extorting a settlement from Apple.
He doesn’t question whether the change is actually working around the patent and thinks Masimo is a patent troll. I’m not sure it’s that simple. Masimo is a real company with real products. It seems like Apple was predatory and that the clock is going to run out before Masimo can enforce its rights. I’m generally skeptical of software patents, but the fact that Apple had to go to such lengths to recreate the technology suggests that these weren’t junk patents.
I still haven’t seen a full explanation of exactly why it was updated to work this way. The assumption is that it’s to work around the patents, but the patents still seem to cover this same method. The ruling has been mentioned, but I’m not sure what about the ruling changes things in this way.
I’ve often wondered about the difference in Apple’s treatment of the blood oxygen and temperature sensors. By default, you don’t get an actual temperature reading; instead you get a variation from your “baseline” temperature. And Apple is careful to call it “Wrist Temperature” instead of just “Temperature,” presumably because it doesn’t want you comparing it with the value you’d get from an under-the-tongue thermometer or the thermometer used at your doctor’s office.
You can get the actual temperature readings from your watch by digging a little into the Health app. My temperature readings are generally a few degrees lower than my normal temperature measured by normal means.
By contrast, Apple will happily show you your blood oxygen reading[…]
A 2023 meta analysis of Apple Watch blood oxygen saturation studies in the medical journal Cureus found Apple’s device roughly comparable to medical-grade pulse oximeters, with occasional outlier results. The authors also said more analysis needs to be done to assess whether skin color affects measurement accuracy – a concern subsequently echoed by the FDA.
The authors also questioned whether providing blood oxygen measurements to inform wellness decisions is of any value. It is unclear, they said, whether an Apple Watch customer with an underlying condition will be motivated to seek medical attention based on a data display before being alerted by physical symptoms like shortness of breath.
“For the vast majority of individuals using the watch as a wellness tracker, it will likely not provide a meaningful benefit in terms of health guidance and might even cause psychological distress to those who worry about outliers that the watch occasionally produces,” the authors observed.
Update (2025-08-21): Tim Hardwick:
Medical technology company Masimo on Wednesday filed a lawsuit against U.S. Customs and Border Protection in which it challenged the agency’s decision to allow Apple to restore blood oxygen monitoring to its Apple Watch models (via Bloomberg Law).
In a complaint filed Wednesday in the US District Court for the District of Columbia, Masimo said that Customs acted unlawfully when it ruled on August 1 that Apple can import watches with pulse oximetry technology – a reversal of the agency’s decision from last year – without notifying Masimo. Masimo said it only discovered the ruling on August 14, when Apple publicly announced it would be reintroducing the pulse oximetry functionality through a software update.
Update (2025-09-04): John Gruber (Mastodon):
The CBP’s investigation centered around whether the Masimo patents were “limiting” — which seems to mean a device that does all these things: the sensors, the computation of results, and the display of results. Masimo argued that the patents weren’t limiting, and apparently made no argument for how the import ban on Apple Watches should stand if the patents were found by CBP to be limiting. The CBP asked the International Trade Commission — the outfit that instituted the import ban — whether they considered the Masimo patents to be limiting, and the ITC responded yes, they did, that that was the entire basis of the import ban.
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But the CBP ruling’s timeline makes clear that much of the investigation took place during the Biden administration in 2024. It reads to me like that same decision would have been made, at the same time, if Kamala Harris had won last year’s election.
While your post focuses on Masimo’s insinuation that the ITC behaved corruptly, after reading the complaint its clear that their actual legal argument is a pure process one. I don’t know the administrative legal requirements but if Masimo had a right to participate in that review process and wasn’t then the ruling might be held invalid.
Maybe the ruling makes legal sense, but this whole situation doesn’t make practical sense to me. It seems clear that computing and displaying the results on the same device as the sensors was not really the novel part of Masimo’s work. Otherwise, it would have been much easier for Apple to implement its own version.
The patent does specifically talk about having the display on a separate device (a mobile phone), but does that not matter because this particular idea was not included in the section with the numbered claims? If so, perhaps the takeaway is that the patent was drafted poorly.
But, just as a matter of common sense, why should splitting the device into two pieces made it not infringe? For example, it is not legal to import an illegal weapon by shipping the components separately and then assembling it yourself.
One could make the argument that what Masimo invented shouldn’t be patentable. But, assuming for the sake of argument that the patents are good, what’s the point of having them if they don’t actually offer protection from workarounds like this? It seems like the result of the patents is that Masimo doesn’t get exclusivity or licensing fees and Apple Watch customers end up with a slightly worse product. How is this helping anyone?
