Apple Watch Series 12 hands-on: New sensing system, health features and audio intelligence

The Apple Watch Series 12 features a re-engineered sensing system with a ring of 12 LEDs and extra photodiodes, improving skin contact and enabling higher-frequency heart-rate, VO2 max, and HRV measurements that generate a 0-10 Readiness score based on activity, sleep, and vitals. It adds an Audio Intelligence suite—including Siri Recap and Live Rewind—and a redesigned Health app that displays AI-generated summaries at the top, requiring a compatible iPhone for full functionality.