Apple Watch Series 12 checks your heart rate 60 times more often and finally tells you when to take a rest day
The redesigned health sensor brings five-second heart-rate readings, more frequent HRV tracking and a new Readiness score
Apple has unveiled the Apple Watch Series 12, and while it looks similar to its predecessors – which was to be expected – there are some exciting updates for the fans of Apple's mainline wearable.
The biggest upgrade is the Health Sensing System, a redesigned sensor array shared with the Apple Watch Ultra 4 that Apple claims significantly increases the amount of heart-rate data the watch can collect throughout the day.
Background heart-rate readings are now taken every five seconds, including while you’re moving around, which Apple says is 60 times more frequent than before.
Heart-rate variability, or HRV, can meanwhile be sampled as often as every five minutes, 24 times more frequently than previously.
Apple has also redesigned the hardware sitting against your wrist, increasing the surface area of the electrodes to improve skin contact during ECG readings.
The photodiodes are now arranged in a ring to capture light more efficiently, using larger, more power-efficient green LEDs for optical heart-rate sensing.
Apple is making a fairly substantial claim about the results, too, saying the new system delivers the “most accurate heart rate sensing in a wearable.”
The company says it reached that conclusion after testing the Apple Watch head-to-head against other wearables, using an ECG chest strap as the reference while hundreds of participants ran, cycled and completed HIIT workouts.
It is an Apple study rather than an independent comparison, of course, so we'll see how the Series 12 performs against the latest Garmin, Coros and Polar watches in real-life tests.
Apple Watch finally gets Readiness
More frequent heart-rate and HRV measurements also feed into one of the most significant new fitness features Apple has introduced in years.
Readiness may already be familiar to Garmin, Oura, and Whoop users, but it's a brand-new addition to the Apple Watch.
Each morning, Apple Watch analyses your recent activity, sleep, and vital signs before producing a single score that indicates how much capacity your body has for exercise and everything else the day might throw at it.
Apple groups the results into straightforward recommendations, including Recover, Pace Yourself, Ready, and Go For It.
Apple says your Readiness can change throughout the day as new information comes in, and the result can be viewed either directly on Apple Watch or through the Fitness app on iPhone.
HRV is also being added to the Vitals app, where users will be able to see both overnight and daytime information.
Apple says this should make it easier to spot changes in your physiological state before they show up in your overnight metrics.
The Apple Watch Series 12 starts at $399, with pre-orders opening today ahead of availability from 18 September. Apple has not yet given UK, EU or AU pricing in the presentation.
