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

iOS 18

iOS 18.4 Coming Next Week With These New Features for Your iPhone

Friday February 14, 2025 6:18 am PST by
The first iOS 18.4 beta for iPhones should be just around the corner, and the update is expected to include many new features and changes. Bloomberg's Mark Gurman expects the iOS 18.4 beta to be released by next week. Below, we outline what to expect from iOS 18.4 so far. Apple Intelligence for Siri Siri is expected to get several enhancements powered by Apple Intelligence on iOS...
iPhone SE 4 Thumb 1

'New' iPhone SE Product Listing Appears on French Website

Wednesday February 12, 2025 6:49 am PST by
As the wait continues for Apple's long-rumored, fourth-generation iPhone SE, French electronics retailer Boulanger has prematurely published a product listing for a "new" model of the iPhone SE. The placeholder page says the device is "coming soon," but it offers no further information, and the price shown is obviously not real. The listing was spotted by a reader of the French technology...
apple launch feb 2025 alt

What to Expect From the 'Apple Launch' Next Week

Thursday February 13, 2025 11:48 am PST by
Apple has yet to announce any new devices this year, but that could change starting next week. Apple CEO Tim Cook today said to "get ready" for a "launch" on Wednesday, February 19. "Get ready to meet the newest member of the family," said Cook, in a social media post. The post includes an #AppleLaunch hashtag, along with a short video featuring an animated Apple logo inside of a circle....
apple launch feb 2025

Tim Cook Teases an 'Apple Launch' Next Wednesday

Thursday February 13, 2025 8:07 am PST by
In a social media post today, Apple CEO Tim Cook teased an upcoming "launch" of some kind scheduled for Wednesday, February 19. "Get ready to meet the newest member of the family," he said, with an #AppleLaunch hashtag. The post includes a short video with an animated Apple logo inside a circle. Cook did not provide an exact time for the launch, or share any other specific details, so...
iPhone 17 Pro Render Front Page Tech

iPhone 17 Pro With All-New Camera Bar Design Allegedly Revealed

Thursday February 13, 2025 5:49 pm PST by
Apple's next-generation iPhone 17 Pro will feature three rear cameras arranged in a familiar triangular layout, but the cameras will be housed in an all-new rectangular camera bar with rounded corners, according to YouTube channel Front Page Tech. iPhone 17 Pro camera design render created by Asher for Front Page Tech In a video uploaded today, Front Page Tech host Jon Prosser said the camera ...
M4 Mac mini Apple Video

Apple's Refurbished Mac Mini Pricing Has a Problem

Thursday February 13, 2025 6:20 am PST by
Apple this week began selling refurbished Mac mini models with the M4 chip for the first time, but this has led to a pricing conundrum. In the United States, Apple is offering a refurbished Mac mini with the base M4 chip, 256GB of storage, 16GB of RAM, and Gigabit Ethernet for $509, down from $599 new. This is the standard 15% discount that Apple offers on refurbished Macs. The issue is...
M4 mini Glowing Blue

Apple Begins Selling Refurbished M4 Macs

Wednesday February 12, 2025 11:35 am PST by
Apple today added MacBook Pro and Mac mini models with M4 series chips to its certified refurbished store in the United States, Canada, the United Kingdom, and Ireland for the first time since the computers were introduced in October 2024. Some refurbished MacBook Pro models with M4 chips are also available in Belgium, Germany, the Netherlands, Spain, and select other European countries. ...
iPhone 16 Apple Store

iPhone 17 in New Sizes This Year: What to Know

Thursday February 13, 2025 2:45 am PST by
Last year, Apple tweaked iPhone 16 Pro screen sizes to make them bigger than 2023's iPhone 15 Pro models, and this year we are also expecting a change in the size of the displays in the iPhone 17 lineup. Here's what we know. Standard iPhone 17 Apple could introduce a new display size for the standard iPhone 17 model in 2025. The iPhone 17 could measure in at 6.3 inches, up from 6.1 inches,...
Apple Ad on X

Apple Resumes Advertising on X

Wednesday February 12, 2025 2:18 pm PST by
Apple this month started advertising on X for the first time in more than a year. The company had stopped advertising on the social media platform in November 2023 following controversial remarks made by its owner Elon Musk. For example, the @Apple account is running an ad promoting Safari's privacy features. The ad was spotted by MacRumors contributor Aaron Perris. The @AppleTV account has a...

Top Rated Comments

iLoveDeveloping Avatar
65 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
65 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
65 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
65 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
65 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
65 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)