Apple just made a pretty bold claim: that Apple Watch Series 12 has the most accurate heart rate sensing of any wearable on the market. And for once, they have a study to back it up. Over 1,000 participants, diverse demographics, head-to-head against other leading wearables. Apple Watch came out on top. That’s not nothing.
What’s new in the hardware
The Series 12 and Ultra 4 both get a new Health Sensing System with upgraded optical and electrical heart sensors. Heart rate now measures every five seconds, all day, passively in the background. HRV tracking jumps to every five minutes, which is 24 times more frequent than before. Apple is also giving users two HRV readings: one for day-to-day stress and recovery, one for broader cardiovascular health trends. The Vitals app now covers both overnight and daytime readings, so you can catch shifts in your metrics before they snowball.
The readiness score
This is the feature that’ll actually change how people start their mornings. Apple Watch now gives you a daily 0-10 readiness score based on your activity, sleep, and vitals, then tells you plainly what to do: Recover, Pace Yourself, Ready, or Go For It. It updates throughout the day too. So if you crushed a hard workout at lunch, your score adjusts. Simple, useful, and built using data from the Apple Heart and Movement Study.
The Health app gets smarter
Apple announced a redesigned Health app powered by Apple Intelligence, coming later this year with iOS 27. There’s a new Insights tab that summarizes your heart, sleep, fitness, and readiness data throughout the day, plus a For You section with personalized tips. A new Longevity tab digs into long-term trends across heart health, sleep, mental wellbeing, and more.
- Heart rate measured every 5 seconds, all day
- HRV tracked up to every 5 minutes
- Daily readiness score with plain-language recommendations
- New Insights and Longevity tabs in the Health app
- All health data stays private and on-device
But here’s the real question: will people actually change their behavior based on a score? That’s always been the challenge with health wearables. The tech is getting genuinely impressive. Now Apple needs users to trust it enough to act on it.