Does Series 12 have a bigger battery than Series 11?

Everyday battery life is unchanged at 24 hours. Low Power Mode rises to 38 hours. The outdoor workout figure rises to 10 hours from 8, and a 15-minute charge now delivers 12 hours of use, up from 8 hours on Series 11.

What is the Health Sensing System?

The Health Sensing System is a redesigned optical and electrical heart sensor on Series 12 that measures heart rate every five seconds throughout the day, rather than at intervals. It also measures HRV up to 24 times more often than Series 11 and provides two HRV variants: Recovery HRV and overall HRV.

What is the Readiness app?

Readiness analyses recent activity, training load, vitals and sleep to produce a daily 0–10 score with a recommendation: Recover, Pace Yourself, Ready, or Go For It. It updates throughout the day and requires Apple Watch Series 12 or Ultra 4.

Series 11 Archives -

Apple Watch Insider News

Apple Watch Series 12 vs Series 11: Full Comparison

9 September 2026

the5krunner

4 Comments

Apple Watch Series 12 vs Series 11 compared: every spec that's changed, plus battery life, health…