Apple announced the Apple Watch Series 12 and Apple Watch Ultra 4 on Wednesday, with the biggest changes centered on a redesigned health sensing system and a new suite of audio and AI features powered by the S11 chip.
Rebuilt sensor hardware
Both models feature a redesigned rear sensor array with a larger electrode surface for better ECG readings.
The update arranges photodiodes in a ring pattern for more efficient light collection and uses larger green LEDs that improve heart rate accuracy while lowering power draw.
The company cited a study involving hundreds of participants across running, cycling, and HIIT workouts, using an ECG chest strap as the reference standard, to back its claim that Series 12 and Ultra 4 deliver the most accurate heart rate tracking of any wearable.
A new Readiness feature processes overnight sleep data, recent activity, and key vitals each morning to generate a daily score that guides users toward recovery, moderate effort, or harder training.
The updated Heart Rate app surfaces more frequent readings, and new watch face complications put the data closer to hand.
Health app overhaul
Apple is also redesigning the iOS Health app with Apple Intelligence built in. A new Health Age feature combines Apple Watch metrics such as VO2 max and sleep quality with blood test biomarkers to estimate how a user’s health indicators compare with their calendar age, then surfaces habits that influence that result.
A Longevity tab gathers sleep, movement, and heart health insights in one place.
Users can enter lab results manually or pull them from synced medical records. In the United States, Apple will offer a Quest Diagnostics blood panel covering more than 50 biomarkers for $119.
A new VO2 max test combines iPhone camera data with Apple Watch sensors to produce results after a short exercise sequence, without requiring a lab visit. The redesigned Health app arrives later this year.
Audio Intelligence and Live Rewind
On the audio side, a new Audio Intelligence system brings Sound Recognition to Apple Watch, using the device’s microphones to detect sounds like alarms, doorbells, and crying babies. Apple highlighted this as particularly useful for deaf or hard-of-hearing users.
A Live Rewind feature displays a rolling 15-second transcript of nearby speech, while a separate Siri Recap function generates titles, summaries, and key points from daily conversations.
Users can schedule Siri Recap or toggle it directly through Control Center. Apple confirms the audio features do not create or store recordings, relying on the S11 chip’s dedicated always-on processor to handle Audio Intelligence locally. Siri Recap launches in English beta later this year, with additional languages coming later.
Design and materials
Series 12 aluminum models gain Ceramic Shield displays, which Apple says are 60 percent tougher than the previous glass.
Color options include Space Gray, Black, Light Gold, and Dark Bronze aluminum, alongside polished titanium in Radiant Gold and Natural, and ceramic in Pearl White and Night Blue.
