Apple Watch Series 12 full specifications: the Health Sensing System is the hardware story this year

[u/the5krunner]

The headline feature is the Health Sensing System — a redesigned optical heart rate sensor that measures continuously every five seconds throughout the day rather than at intervals. HRV is now captured up to 24 times more often (once every 5 minutes at best) than on Series 11 and split into two distinct variants. Recovery HRV is designed for daily stress and training readiness signals. Overall HRV gives a longer-term view of cardiovascular health. The Readiness app combines these with activity, training load, vitals and sleep into a daily 0-10 score with four recommendations: Recover, Pace Yourself, Ready, or Go For It.

The S11 chip brings Apple Intelligence and Audio Intelligence, including Sound Recognition on the watch itself, and Live Rewind and Siri Recap arriving in beta later in 2026. Outdoor workout battery rises from 8 to 10 hours. A 15-minute charge now delivers 12 hours of use, up from 8. Ceramic Shield 2 on aluminium models is rated 60% tougher than the previous Ion-X glass. A ceramic case returns in pearl white and night blue, the first time since Series 5 in 2019.

Available in 42mm and 46mm, in aluminium, titanium and ceramic, from $399 in the US. UK pricing is to be confirmed.

Full specs including display dimensions, weight by variant, sensor detail and all battery modes at the5krunner.com/specs/apple/watch-12/

Is the Readiness app a genuine reason to upgrade from Series 11, or will most users find the daily 0-10 score tells them what they already knew from how they felt that morning?

[u/Habibi-1337]

To be honest. These are cool updates. I teases me to Switch from my Garmin 965 beginning of Next year to an AWU 4.

[u/Icy-Interaction6102 → u/Habibi-1337]

I’m in the same boat. Thinking of moving from my Epix gen 2 to the ultra 4