Of all the functions that the Apple Watch can do, the measurement of oxygen in the blood is one of the most curious. Although, this function is not intended for medical purposes, but as one more indicator of our physical well-being. But if you have heard of this Apple Watch function, you are also interested in knowing which Apple Watch models incorporate this utility. We are also going to review which versions of iOS we will need for this function.
How the Apple Watch measures blood oxygen
Although measuring oxygen in the blood seems, at first glance, something sophisticated and strange, the truth is that it is less complicated than we think. Apple Watches that have this capability have two elements: one in the hardware, and another in the software. The physical element that allows the watch to measure blood is one of the heart rate sensors, It is capable of emitting infrared light. That light shoots into the veins of the wrist, where we have to wear the Apple Watch. When the infrared light has bounced back to the watch, the piece of software is an algorithm that allows the watch to interpret the blood level based on what it “saw.”
The Apple Watch, however, needs a little more software to be able to indicate this data to us. Thanks to the Blood Oxygen application, we will have the interface through which we can obtain this indicator. The procedure to measure blood oxygen is as simple as opening the application, turning our wrist up, putting the Apple Watch on top of our wrist and touching the Start button on the Apple Watch. The reading lasts 15 secondsand when it’s done, we receive the results.
But, beyond this function, if you are buying an Apple Watch for the first time and want to measure your blood oxygen, not all watch models are compatible with this function, since they do not even have the Oxygen application in blood nor with cardiac sensors that also emit infrared light. The Apple Watches that incorporate this function are:
- Apple WatchSeries 6
- Apple WatchSeries 7
- Apple WatchSeries 8
- Apple Watch Ultra
On these models, if we want to use the Blood Oxygen app, Apple suggests an iPhone compatible with the latest version of iOS, since the Apple Watch also needs the latest version of watchOS for this app to work properly. We are currently running iOS 16 and watchOS 9. The iPhone 8 (and 8 Plus) with iOS 16 is compatible with watchOS 9. And although it may seem counter-intuitive, Apple’s website explains that this function is compatible if we have an iPhone 6S since it has iOS version 15.7.2, and the blood oxygen measurement application has been present since watchOS 7. So in the event that we have a somewhat older iPhone, such as an iPhone 7 and an Apple Watch with watchOS 7 or 8, even if we don’t update to the latest versions available, we can use the app.