Skip to main content

Your Apple Watch’s SpO2 sensor might be a lot better than you thought

The Apple Watch’s SpO2 sensor that allows wearers to measure their blood oxygen levels was impressive when it first debuted, but it may be even more accurate than initially marketed.

According to a recent study, the Apple Watch’s blood oxygen reader is comparable to medical-grade pulse oximeters. Although Apple Watches shouldn’t be used in lieu of official medical devices, it’s nice to know that the readings they’re displaying are accurate enough to be reliable.

The case back differences between the Apple Watch SE 2 and Apple Watch Series 8.
Apple Watch SE 2 (left) and Apple Watch Series 8 (right) Andy Boxall/Digital Trends

First reported by 9to5Mac, the study was published this month in the Digital Health journal and sought to compare a “commercially available smartwatch” to a medical-grade pulse oximeter. The watch the study used was the Apple Watch Series 6, the first of Apple’s smartwatches to include an SpO2 sensor, which is over two years old at this point.

Recommended Videos

The results of the study showed that the Apple Watch “can reliably detect states of reduced blood oxygen saturation with SpO2 below 90% when compared to a medical-grade pulse oximeter.” To come to that conclusion, the study used 24 healthy participants, each one wearing an Apple Watch Series 6 on their wrist and clamped a Masimo Radical-7, a common pulse oximeter, on the middle finger of the same hand. The participants then did various breathing exercises to manipulate their blood oxygen levels to see how the Apple Watch performed when compared to the Masimo Radical-7. By the end of the tests, there were 642 blood oxygen readings to compare.

To reiterate: If you’re looking for a fully accurate blood oxygen level reading, it’s still best to use a proper medical device. But the results of the study show that Apple’s wearable tech is certainly moving in the proper direction for providing accurate medical information. In addition to the SpO2 sensor, Apple Watches provide alerts for irregular heartbeat rhythms that may suggest atrial fibrillation, medication intake reminders, and sleep tracking.

While Apple doesn’t claim that any of its devices can be used as concrete medical readers, the features that have been added to Apple Watches, in particular, are extraordinarily useful for those looking to monitor their bodily functions and have informed conversations with healthcare providers should they discover anything noteworthy.

Peter Hunt Szpytek
A podcast host and journalist, Peter covers mobile news with Digital Trends and gaming news, reviews, and guides for sites…
WatchOS 11 will change your Apple Watch more than you realize
The Apple Watch Series 9 with the Snoopy watch face.

Since its reveal at WWDC 2024 this June, I've been incredibly eager to try Apple's watchOS 11 update. What was initially expected to be a small, tepid update, watchOS 11 quickly proved to be much more exciting than we initially thought.

There are the big hallmark features, of course — specifically the ability to pause your activity goals, plus Apple's new Vitals app. But there are plenty of smaller features, too, and they're just as deserving of your attention.

Read more
Why you shouldn’t buy these 5 Apple Watch Series 9 alternatives
A person wearing the Apple Watch Series 9, showing the Snoopy watch face

Nike Globe watch face Andy Boxall / Digital Trends

Not only are there a lot of smartwatches and fitness bands to choose from these days, but the Apple Watch range itself is surprisingly extensive — especially considering it began life with only a single model available. Simply put, it remains the best smartwatch to get if you own an iPhone.

Read more
Why you shouldn’t buy a new Apple Watch right now
The curved screen on the Apple Watch Series 9.

It has been over six months since the Apple Watch Series 9 and Apple Watch Ultra 2 launched, and they are still considered two of the best smartwatches on the market. However, there are two significant reasons why you might not want to purchase either of these models.

Those reasons are the Apple Watch Series 8 and the first-generation Apple Watch Ultra. That's right — buying a 2022 Apple Watch over the newer models might be a better choice for you.
Why now's a great time to buy an old Apple Watch
The Apple Watch Series 9 (top) and Apple Watch Series 8 Andy Boxall / Digital Trends

Read more