Apple has designed a new algorithm that Apple Watch uses to measure electrocardiogram (ECG) waves, according to developer documentation for the iOS 14.3 and watchOS 7.2 betas.
In the official documentation, a new "version 2 algorithm" declaration has been added. No other information is included.
The ECG feature includes irregular heart rhythm detection, which intermittently measures the user's heart rate in the background and sends a notification if it detects an anomaly it categorizes as atrial fibrillation, which can be a serious heart arrhythmia condition.
Based on beta code uncovered by MacRumors, it's likely that the new algorithm will allow the ECG app to check for atrial fibrillation (AFib) at higher heart rates - during exercise, for example.
iOS 14.3 will introduce support for Apple Fitness+, Apple's upcoming fitness service that will work with the Apple Watch, plus it brings a new Cardio Fitness feature that lets you know if your VO2Max levels are low. VO2Max is a useful measurement of overall fitness and heart health.
iOS 14.3 is set to be released on Monday, December 14, which is also the day that Apple Fitness+ is coming out.
On this week's episode of The MacRumors Show, we discuss Google's latest wave of announcements for Android and Gemini, the newly announced Fitbit Air, and Apple Watch Series 12 rumors.
Subscribe to The MacRumors Show YouTube channel for more videos
The centerpiece of Google's announcements this week was Gemini Intelligence, Google's new umbrella platform for AI across phones, watches, cars,...
Apple will unveil watchOS 27 during its WWDC 2026 keynote on Monday, June 8, and a handful of new features have been rumored already.
The first developer beta of watchOS 27 should be available immediately following the keynote, and a public beta typically follows in July. The update should be released to all users with a compatible Apple Watch model in September.
Below, we recap watchOS...
For many years now, it has been rumored that the Apple Watch will eventually gain non-invasive blood sugar monitoring capabilities, which would enable millions of people with diabetes to track their blood glucose levels without needing to prick their skin with a needle or wear a dedicated continuous glucose monitor.
According to Bloomberg's Mark Gurman, Apple recently shifted oversight of...
Wait what? The ECG only works when your finger is on the Digital Crown. It can’t work in the background.
The background irregular heart rhythm detection does not use the ECG but it is grouped with the ECG features (which is technically inaccurate but they are related features, just different technologies). It's been around as long as the ECG: "Using the optical heart sensor in Apple Watch Series 1 or later, the irregular rhythm notification feature will occasionally check the user’s heart rhythm in the background for signs of an irregular heart rhythm that appears to be AFib and alerts the user with a notification if an irregular rhythm is detected on five rhythm checks over a minimum of 65 minutes." (https://www.apple.com/newsroom/2018/12/ecg-app-and-irregular-heart-rhythm-notification-available-today-on-apple-watch/)
Still waiting for ECG in Japan! Any news about it?
Since ECG received final medical approval in Japan this September, I guess maybe iOS 14.3 will cover ECG functionality also Japan as well? *finger-crossed*
