Apple has unveiled the Apple Watch Series 12, introducing a new Health Sensing System, more frequent heart-rate and heart-rate variability monitoring, a new daily “Readiness” score and a range of artificial intelligence-powered features.
The new smartwatch is powered by Apple’s S11 chip and watchOS 27, with the company positioning the Series 12 as a major upgrade in health, fitness, safety and intelligent assistance. Apple says the new health-sensing technology provides its most accurate heart-rate sensing in a wearable to date.
New health sensing system
The biggest change in the Apple Watch Series 12 is the introduction of the Health Sensing System, which combines new optical and electrical heart sensors with the S11 chip.
The system is designed to collect heart-rate information more frequently throughout the day. Apple Watch Series 12 measures heart rate every five seconds using larger, power-efficient green LEDs in its optical heart sensor.
Apple says a study involving more than 1,000 participants found that the new Apple Watch had the highest heart-rate accuracy among the wearable devices included in the comparison.
The more frequent measurements are also intended to improve the accuracy of activity and exercise tracking, while allowing users to see their heart rate in real time through the updated Heart Rate app and a new watch-face complication.
More frequent heart rate variability monitoring
Heart rate variability, or HRV, receives a substantial upgrade in the Series 12.
Apple Watch can now measure HRV up to 24 times more frequently than before, with readings available as often as every five minutes. The data is divided into two categories: Recovery HRV, which focuses on daily signals associated with stress and recovery, and overall HRV, which provides a broader view of cardiovascular and general health.
The updated Vitals app also incorporates Recovery HRV into overnight measurements and compares the information with the user’s personal baseline.
For the first time, Apple is adding a daytime Vitals view alongside the existing overnight information. This allows users to compare their health measurements throughout the day and potentially identify changes before they appear in overnight readings.
Readiness score offers a daily health assessment
Another major addition is Readiness, a new score intended to help users understand how prepared their bodies are for the day ahead.
The feature analyses recent physical activity, training load, health measurements and sleep data before producing a score from 0 to 10. It then provides one of four recommendations: Recover, Pace Yourself, Ready or Go For It.
The score is not fixed for the entire day. It can change as new information becomes available, including after a demanding workout or changes in daytime health measurements.
Apple says the Readiness algorithm was developed using data from its Apple Heart and Movement Study, with input from exercise scientists and physicians.
More accurate step and distance tracking
The Series 12 also brings changes to everyday activity tracking.
Apple has redesigned the watch’s pedometer model using new machine-learning algorithms. The company says this improves distance measurements during indoor walking and running workouts, while the S11 chip enables more accurate step counting throughout the day.
A new Steps complication allows users to see their step count directly on the watch face without opening a separate application.
Redesigned health app and health age
Apple is also redesigning the Health app on the iPhone to provide a broader view of a user’s long-term health.
The updated app will use Apple Intelligence to organise health information and provide more personalised insights. A new Insights tab will surface relevant health information, while a Longevity tab will analyse health data collected over time.
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The Longevity section will include a Health Age feature, which compares certain health measurements with the user’s actual age to show how those metrics are tracking over time.
Apple says the redesigned Health app is scheduled to arrive later in 2026, initially in U.S. English.
Apple intelligence comes to the watch
The Series 12 expands Apple’s use of artificial intelligence with new Audio Intelligence features.
One of these is Sound Recognition, which can alert users to important sounds such as sirens, alarms, doorbells and a crying baby. The feature is particularly aimed at helping people who are deaf or hard of hearing and can operate even when the user’s iPhone is not nearby.
Another feature, Live Rewind, allows users to retrieve the previous 15 seconds of a conversation. A double press of the Digital Crown displays the recent conversation as text, allowing users to review something they may have missed.
Siri Recap can generate a title and key points from a conversation, allowing users to review the information later. Apple has also integrated Shazam into the watch, enabling it to identify music playing nearby and display the song and artist. AApple
Apple says Live Rewind and Siri Recap are designed with privacy protections. Conversation snippets and summaries are end-to-end encrypted in the Siri app with iCloud syncing, and Apple says it cannot access the content.
Siri gets more intelligent
With watchOS 27, Apple Watch Series 12 gains a new version of Siri powered by Apple Intelligence.
The updated Siri can use personal context and broader knowledge to respond to users while they are on the move. Apple has also introduced a new Siri Modular watch face designed to make the assistant easier to access.
The AI features require a compatible Apple Intelligence-enabled device and may vary by language and region.
S11 chip powers the new features
At the heart of the Series 12 is Apple’s S11 chip, which the company describes as its most powerful wearable processor.
The chip plays a central role in the new health-sensing system and supports the higher-frequency heart-rate and HRV measurements. It also powers the machine-learning algorithms used for improved step tracking and enables the new Audio Intelligence capabilities.
The combination of the S11 processor and updated sensors allows the watch to perform more health and AI processing while remaining a compact wearable device.
Battery life and faster charging
Despite the additional sensing and processing capabilities, Apple Watch Series 12 retains up to 24 hours of everyday battery life.
Apple has increased battery performance during outdoor workouts, with the watch offering up to 10 hours of battery life during an outdoor workout — a 25 percent improvement over the previous model.
Charging has also been accelerated. Apple says 15 minutes of charging can provide up to 12 hours of additional battery life, representing a 50 percent improvement over the previous model’s equivalent charging performance.
Price and availability
Apple Watch Series 12 starts at $399 in the United States. Pre-orders opened on September 9, with retail availability scheduled to begin on September 18.
The company is also introducing new Apple Watch bands in a range of colours and designs. watchOS 27 will become available on September 14 for compatible Apple Watch models, although some features will require newer hardware or an Apple Intelligence-enabled device.
