Apple recently announced some big changes to the Health app, as well as new sensors in the upcoming Apple Watch Series 12 and Ultra 4. The company bundled these and other health-related announcements together, but that doesn't mean you need an Apple Watch 12 to take advantage of all the new features. Here's the breakdown of which Apple Watches will get the new features—and which ones don't need an Apple Watch at all.
Readiness and more accurate heart rate require the Apple Watch Series 12 or Ultra 4You'll need the new Series 12 or the Ultra 4 to get Apple's new heart rate sensor—the one it's billing as the most accurate in any wearable. (Huge if true.) These two watches also have the new S11 processing chip. The sensor and the chip are required for what Apple is calling its "health sensing system," which gives you more frequent heart rate and HRV readings throughout the day. According to Apple, the new systems measure heart rate every five seconds instead of every five minutes, and HRV every five minutes instead of every few hours. Overnight vitals will now include a Recovery HRV score that's compared to your baseline (so you know when your body is under more or less stress than usual). The Readiness score seems to rely on these readings, so you'll need one of the new watches to get that score.
