Apple announced Apple Watch Series 12 and Ultra 4 with a new Health Sensing System and S11 chip. Both watches now take heart rate every five seconds all day, measure HRV up to 24 times more often, and add a daily Readiness score; later this year the Health app gets a Health Age number and Quest Diagnostics labs that can be booked from the phone.
The case design does not change. What Apple did bring back is ceramic, last seen on Apple Watch Series 5 seven years ago, now in pearl white and night blue. AppleInsider notes Series 2, 3, and 5 had ceramic cases; the last two-color ceramic run was even longer ago. Both watches are up for pre-order and arrive in stores Friday, September 18, with Series 12 from $399 and Ultra 4 from $799.
Continuous heart rate and HRV
Apple says Series 12 and Ultra 4 now take heart rate every five seconds, all day, using larger green LEDs on a new optical and electrical sensor stack. It also claims the highest heart-rate accuracy of any wearable in its own study of more than 1,000 people — an Apple-run comparison, not an independent lab. Garmin already does continuous, passive heart-rate monitoring across all of its latest watches.
Heart rate variability (HRV) measurements are more frequent, too. Apple now measures variability up to 24 times more often, as often as every five minutes, and splits it into two numbers: Recovery HRV for daily stress and recovery, and overall HRV for longer-term cardiovascular health. Overnight Vitals now includes Recovery HRV against a personal baseline, and a new daytime vitals view lets you toggle night and day. Garmin has had HRV Status, overnight HRV, and Body Battery on that same recovery axis for a long time; Apple is now collecting the raw signal at a similar cadence.
Readiness
Readiness is a new watch app. It folds recent activity, training load, vitals, and sleep score into a single 0–10 number and a recommendation: Recover, Pace Yourself, Ready, or Go For It. The score updates through the day after a hard workout or a shift in daytime vitals, and it shows which inputs are driving it. Apple says the algorithm comes from the Apple Heart and Movement Study. Garmin Training Readiness already does a similar go / no-go read from sleep, HRV, recovery time, and acute load; WHOOP Recovery and Oura Readiness sit in the same category.
Health Age, Quest labs, and the WHOOP / Oura camp
Later this year, a redesigned Health app adds an Insights tab and a Longevity tab. Health Age uses Apple Watch data — VO2 max, resting heart rate, sleep, HRV — to show how those metrics track against your actual age, and you can fold in lab values such as A1c and LDL. Users in the U.S. can schedule and buy a 50-plus biomarker panel for $119 at about 2,000 Quest Diagnostics sites, directly from the Health app. The app also offers on-device movement evaluations for flexibility, strength, balance, and VO2 max using the iPhone camera and watch heart rate; Apple says it doesn’t store video.
WHOOP and Oura already sell a biological-age score plus a path into real bloodwork. WHOOP Age and WHOOP’s clinical/blood offerings, and Oura’s readiness plus age-style scores and lab partnerships, treat the wearable as only half the picture. Apple is now putting that same stack on a watch a few hundred million people already wear.
While Garmin does have a fitness age metric (derived from VO2 Max), it doesn’t explain how each component affects your age or offer tools to change the trend. Garmin also does not integrate with any labs at this time. It did just launch a screenless, no-subscription-required CIRQA Smart Band aimed at WHOOP for $199.99 with no subscription, and it is planning a smart ring. Apple’s readiness, age, and Quest labs on Series 12 and Ultra 4 will certainly put pressure on Garmin to enhance its health and longevity features.
Battery is still the gap
Series 12 is still a one-day watch: Apple quotes up to 24 hours of everyday use, up to 10 hours for an outdoor workout (25 percent more than Series 11), and a 15-minute charge for up to 12 hours. The Ultra 4 offers more than two days, up to 50 hours every day, up to 84 hours in Low Power Mode, up to 25 hours of full GPS and heart-rate outdoor tracking, and up to 45 hours in Max Extended Workout for a 100-mile effort with GPS still once a second.
Whil these improvements will certainly be appreciated by users and athletes alike, It still is far from Garmin watches’ multi-day battery. Anyone who charges once a week, or who wants multi-band GPS without thinking about a charger at mile 60, is still looking at Garmin for that part.
Ultra 4
The Ultra 4 has the same Health Sensing System and S11 chip, in natural or black titanium, with the longer battery and what Apple calls the most accurate on-device GPS in a sports watch — an Apple comparison against dual-frequency sports watches. Satellite SOS and its additional “action” button remain from the prior generation. The visible refresh includes new Trail, Alpine, and translucent Ocean bands. It starts at the same $799 as its predecessor.
S11, Audio Intelligence, and Siri AI
In addition to the health and wellness additions above, Series 12 and Ultra 4 also bring Audio Intelligence and a new Siri, both tied to the S11 chip. Apple calls S11 its most powerful wearable chip; it is what keeps five-second heart rate and the denser HRV sampling from flattening the battery, and it is required for Audio Intelligence.
Audio Intelligence is a new feature to the latest Apple Watch models only. It uses Sound Recognition to listen for things like sirens, alarms, doorbells, or a baby crying, and can ping the wrist even if the iPhone is not nearby. Live Rewind is a double-press of the Digital Crown that turns the last 15 seconds of a conversation into a text snippet, so you can catch something you missed. Siri Recap, if you turn it on, writes a short title and key points after a conversation — a summary, not a transcript — in a new Siri app. Shazam can also name a song on the Smart Stack without you asking. Apple says raw audio is processed in a hardware-isolated Secure Exclave and is not stored or available to apps, the user, or Apple. Live Rewind and Recap arrive in beta later this year, English first, initially excludes the EU, and users need a recent iPhone.
watchOS 27, which lands Monday, September 14 on Apple Watch Series 9 and later, SE 3, and Ultra 2 and later, also brings Siri AI (a more conversational Siri that can use personal context and general knowledge on the wrist), a single-hand tap to open a Smart Stack widget, Workout Buddy when the iPhone is not nearby, and perimenopause and menopause support in Cycle Tracking.
Series 12 comes in 42mm and 46mm sizes, made of aluminum, titanium, or ceramic, starting at $399, and the Ultra 4 starts at $799. Pre-order at Apple.
