Apple Watch Blood Oxygen Monitoring Feature Found in iOS 14 Code

Apple is working on a new Apple Watch feature that detects blood oxygen levels, according to newly discovered code snippets in iOS 14 (via 9to5Mac).

applewatchheartratesensor
Blood oxygen saturation naturally fluctuates throughout the day, but large variations can be linked to health issues. For example, 95-100 percent oxygen in the blood is considered normal, but a drop below that percentage could be a sign of a serious respiratory or cardiac problem.

At the center of Apple's new feature is a new health notification based on blood oxygen levels – when Apple Watch blood oxygen saturation drops below a certain threshold, the wearer is alerted, just like existing heart rate notifications.

Apple holds patents for blood oxygen monitoring, and early prototypes of the first Apple Watch featured sensors that measured blood oxygen monitoring among other biometrics, but many of these functions never made it into the final product because of consistency issues.

When the original ‌Apple Watch‌ was released back in 2015, iFixit actually discovered that Apple's heart sensors have the capability to monitor blood oxygen levels, but Apple has never activated it.

It remains to be seen whether the latest incarnation of the feature will rely on new hardware in the Apple Watch Series 6 or if it will come as a software update as part of watchOS 7, both of which are expected to arrive this year. Rumors persist that sleep tracking will also be included in the next Apple Watch model.

Other smartwatch and fitness tracker makers including Google-owned Fitbit already offer blood oxygen monitoring features in some of their devices, so Apple is playing catch-up in this regard, but that could mean the company has a more advanced implementation of the feature in the works.

Related Roundup: Apple Watch 10
Buyer's Guide: Apple Watch (Neutral)
Related Forum: iOS 14

Popular Stories

iPhone 17 Pro 3 4ths Perspective Aluminum Camera Module 1

iPhone 17 Pro Launching Later This Year With These 12 New Features

Sunday April 13, 2025 7:52 am PDT by
While the iPhone 17 Pro and iPhone 17 Pro Max are not expected to launch until September, there are already plenty of rumors about the devices. Below, we recap key changes rumored for the iPhone 17 Pro models as of April 2025: Aluminum frame: iPhone 17 Pro models are rumored to have an aluminum frame, whereas the iPhone 15 Pro and iPhone 16 Pro models have a titanium frame, and the iPhone ...
Apple 2025 Thumb 1

10 Products Still Coming From Apple in 2025

Friday April 11, 2025 4:14 pm PDT by
Apple may have updated several iPads and Macs late last year and early this year, but there are still multiple new devices that we're looking forward to seeing in 2025. Most will come in September or October, but there could be a few surprises before then. We've rounded up a list of everything that we're still waiting to see from Apple in 2025. iPhone 17, 17 Air, and 17 Pro - We get...
Foldable iPhone 2023 Feature Homescreen

Foldable iPhone Resolutions Leak With Under-Screen Camera Tipped

Monday April 14, 2025 3:12 am PDT by
Apple's upcoming foldable iPhone (or "iPhone Fold") will feature two screens as part of its book-style design, and a Chinese leaker claims to know the resolutions for both of them. According to the Weibo-based account Digital Chat Station, the inner display, which is approximately 7.76 inches, will use a 2,713 x 1,920 resolution and feature "under-screen camera technology." Meanwhile, the...
iPad Pro iPadOS

iPadOS 19 Will Be 'More Like macOS' in Three Ways

Sunday April 13, 2025 6:43 am PDT by
A common complaint about the iPad Pro is that the iPadOS software platform fails to fully take advantage of the device's powerful hardware. That could soon change. Bloomberg's Mark Gurman today said that iPadOS 19 will be "more like macOS." Gurman said that iPadOS 19 will be "more like a Mac" in three ways:Improved productivity Improved multitasking Improved app window management...
M6 MacBook Pro Feature 1

Waiting for the Perfect MacBook Pro? 2026 Might Be the Year

Thursday April 10, 2025 4:19 am PDT by
Apple in October 2024 overhauled its 14-inch and 16-inch MacBook Pro models, adding M4, M4 Pro, and M4 Max chips, Thunderbolt 5 ports on higher-end models, display changes, and more. That's quite a lot of updates in one go, but if you think this means a further major refresh for the MacBook Pro is now several years away, think again. Bloomberg's Mark Gurman has said he expects only a small...
Apple Vision Pro with battery Feature Blue Magenta

Vision Pro 2 Rumored to Have Two Key Advantages Over Current Model

Sunday April 13, 2025 7:15 am PDT by
Apple is working on a new version of the Vision Pro with two key advantages over the current model, according to Bloomberg's Mark Gurman. Specifically, in his Power On newsletter today, Gurman said Apple is developing a new headset that is both lighter and less expensive than the current Vision Pro, which starts at $3,499 in the U.S. and weighs up to 1.5 pounds. Gurman said Apple is also...
maxresdefault

The MacRumors Show: New iOS 19, iPhone 17, and Apple Watch Ultra 3 Leaks

Friday April 11, 2025 7:13 am PDT by
On this week's episode of The MacRumors Show, we catch up on the latest iOS 19 and watchOS 12 rumors, upcoming devices, and more. Subscribe to The MacRumors Show YouTube channel for more videos Detailed new renders from leaker Jon Prosser claim to provide the best look yet at the complete redesign rumored to arrive in iOS 19, showing more rounded elements, lighting effects, translucency, and...
top stories 2025 04 12

Top Stories: iOS 19 and iPhone 17 Pro Rumors, Siri Revamp Turmoil, and More

Saturday April 12, 2025 6:00 am PDT by
It was a big week for leaks and rumors in the Apple world, with fresh claims about iOS 19, the iPhone 17 Pro, and even the 20th anniversary iPhone coming a couple of years from now. Sources also spilled the tea on the inner turmoil at Apple around the Apple Intelligence-driven Siri revamp that has seen significant delays, so read on below for all the details on these stories and more! iOS ...
iPhone 16e Feature

iPhones, Macs, and Other Apple Devices Exempted From Trump Tariffs

Saturday April 12, 2025 9:44 am PDT by
Apple and other electronics manufacturers have received a break from Trump's reciprocal tariffs, with the U.S. Customs and Border Protection agency sharing a long list of products excluded from the levies last night. iPhones, Macs, iPads, Apple Watch, and other Apple devices will not be subject to the 125 percent tariffs that have been put in place on imported Chinese goods, nor will Apple...

Top Rated Comments

iLoveDeveloping Avatar
67 months ago

It's quite illogical and stupid to wear a watch or iWatch for analyzing sleep behavior.
Are you serious??? Really? ? Tons of people want this! This is one of the reasons I have used Fitbit for years and still haven’t gone to Apple Watch! If they implemented this, I’d buy it right away!!
Score: 12 Votes (Like | Disagree)
nitramluap Avatar
67 months ago

It can be added to a Series 5 with an OS update. Apple Watches have had the hardware to measure it for years. The problem is accuracy. If Google/Fitbit are now doing it, it looks like accuracy is reliable enough now that Apple is willing to implement it.
Actually, this is false.

In order to measure SpO2 you require a red & infrared LED array - not green & infrared. Green LEDs are very good at detecting a pulsatile flow of a red substance (ie. Blood) even in tricky situations where there is lots of movement; red, not so much. This is why most fitness trackers use green LEDs for pulse rate detection during workouts.

A pulse oximeter needs a red & infrared LED due to the unique characteristics of the difference between the absorption spectra of oxygenated haemoglobin & deoxygenated haemoglobin at very specific light frequencies - which just happen to be red (660nm) & infrared (940nm).

Unless the old hardware has a dormant red LED which I’m pretty sure it doesn’t, this will require new hardware. But I would also question the need for it for the general public, unless it is coupled with sleep monitoring.

Disclosure: I’m an Anaesthesiologist (and an Apple Developer ;)).
Score: 8 Votes (Like | Disagree)
PickUrPoison Avatar
67 months ago

Not to say it's a bad thing, but wearing a smartwatch or iWatch isn't an intuitive approach for sleep analysis.
Are you sure? I’ve heard it’s quite illogical and stupid...
Score: 7 Votes (Like | Disagree)
m.x Avatar
67 months ago
While I hope this feature will be available for Series 4 watches, the more interesting part of this article is that 9to5mac got their hands on a part of iOS14. Is there more to come?
Score: 7 Votes (Like | Disagree)
shinkansenwarrior Avatar
67 months ago
Sp02 monitoring is the one thing that I felt was missing to make the iWatch a complete product IMO.
Let's hope this feature becomes available and I hope it can measure blood/oxygen levels accurately.
I am looking forward to seeing this.
Score: 7 Votes (Like | Disagree)
nexu Avatar
67 months ago

Not necessarily. The feature may require a new sensor or other hardware in the upcoming Series 6.
Knowing Apple, they’ll make it series 6 exclusive even if it’s technically possible on series 5
Score: 6 Votes (Like | Disagree)