Apple Watch Series 12 Marks a New Era in Wearable Technology

The Apple Watch Series 12 may not look drastically different at first glance, but it packs some significant upgrades that set the stage for exciting advancements in health and wearable technology. While it retains the familiar design, buttons, and sensor types of its predecessors, the real changes lie beneath the surface.

This year’s updates can be split into two main themes: catching up with the recent surge in AI health technology and leading the charge in AI wearables that provide insights based on your daily activities. Apple is stepping up its game in the wearable market, which has been quick to adopt AI for analyzing health data. At the same time, the Series 12 aims to redefine a market that has been somewhat niche and problematic. Regardless of the angle, AI is a key player in this evolution. While many of the concepts introduced with the Series 12 aren’t entirely new, they are being executed by a company with Apple’s vast reach and reputation.

After spending a week with the Series 12, I can’t claim to have experienced everything it has to offer, as several intriguing health and AI features won’t be available until later this year. However, the internal upgrades already provide meaningful enhancements. Here’s a look at the health features available at launch, along with a sneak peek at the innovative AI capabilities on the horizon.

**New Hardware**

Two major hardware updates distinguish the Series 12 (and the Ultra 4) from earlier models. The first is the new S11 chip, which includes a secure enclave for processing microphone data, alongside a faster CPU, GPU, and Neural Engine. Additionally, the health sensor array has been completely redesigned. While it doesn’t capture new types of data, it allows for more frequent, accurate, and energy-efficient health metric measurements. The electrodes for the EKG feature are now larger for better skin contact, the photodiodes have been optimized for improved light reflection capture, and the optical LEDs are bigger and consume less power.

These hardware enhancements enable a range of new software features, such as more frequent heart rate sampling, a new readiness score, and a suite of AI-driven ambient listening features dubbed Audio Intelligence.

The revamped sensors allow for continuous heart rate monitoring, a feature that was previously limited to sampling every five minutes when not in workout mode. Now, the Series 12 measures heart rate every five seconds, both at rest and during activities. While other wearables have offered this for some time, it’s a significant improvement for those needing to monitor their heart rate due to health conditions.

Apple has published a white paper comparing the accuracy of its continuous heart rate monitoring to that of a Polar H10 chest strap and other competitors across various workouts and rest periods. While I can’t replicate such a study, I did wear an H10 during two runs and a walk, and the Series 12 consistently stayed within five beats per minute of the H10. There was a slight delay compared to the chest strap, but it’s negligible in everyday use.

I’ll continue to test the Series 12 and Ultra 4 against other devices, but I’m confident that the Apple Watch is now on par with many popular wearables.

The S11 chip also noticeably improves Siri’s responsiveness on the Series 12 compared to my Ultra 3. While there may still be some latency as Siri processes requests, it’s less pronounced. My overall impression of Siri on the wrist remains unchanged from my watchOS 27 preview: this is Apple’s most capable smartwatch yet, and the addition of a pinch gesture for item selection enhances one-handed control.

I didn’t notice any negative impact on battery life from continuous heart rate tracking. Some may complain that the Series 12 doesn’t offer multi-day battery life and sticks to the 24-hour estimate of the Series 11. However, I believe that faster charging is a sufficient trade-off. In a 20-minute charging test, I went from 20% to 64% battery. Yes, this means daily charging in short bursts, but I’ve yet to experience the watch dying on me. I also think it’s important to give your wrist a break daily, and showering is a perfect time to go without the watch for 20 to 30 minutes.

**Are You Ready?**

All this new hardware sets the stage for a more comprehensive health tracking experience. That’s likely why a redesigned Health app is set to launch later this fall. From what I’ve seen in demos, it promises to be a significant overhaul, featuring AI-driven insights, a longevity tab with a Health Age score, VO2 max assessments using your phone’s camera, and even the option to order a blood panel through a service for $119. The revamped app is currently available in the latest iOS 27 developer beta, and I’ll share my early impressions soon. For now, I’ll focus on what’s available at launch.

The standout feature available today is Apple’s version of a readiness score, a concept popularized by other fitness trackers to gauge recovery from physical stress. Essentially, it indicates how “ready” you are to work out again.

Apple determines readiness through a combination of overnight, daytime, and weekly metrics, including activity levels, sleep scores, and overnight vitals like resting heart rate, respiratory rate, wrist temperature, and a new recovery heart rate variability (HRV) metric. While the Apple Watch has measured HRV for years, this new recovery HRV uses a different formula and benefits from the updated sensor array, allowing for more frequent measurements. Regular HRV provides a long-term view of stress and cardiovascular health, while recovery HRV focuses on daily, short-term strain.

Generating the readiness score takes about seven nights of sleep with at least four hours of rest. On the eighth day, you’ll wake up to a score ranging from 0 to 10. A score of 0 to 1 suggests recovery is needed, 2 to 4 means to “pace yourself,” 5 to 7 indicates you’re “ready,” and anything 8 and above signals it’s time to “go for it.” My week of sleep and accuracy testing resulted in a readiness score of 7.

I believe people generally know how they feel regarding workouts. This feature is particularly useful for athletes who may overtrain and need a reminder to take it easy. I appreciate that the score isn’t static; a good nap or an intense workout can influence your readiness throughout the day. For those familiar with Garmin devices, it’s akin to a blend of Body Battery (which tracks energy levels in real-time) and traditional readiness scores. Given the influx of new metrics from various wearable companies, I commend Apple for consolidating what could have been multiple data points into one.

After WWDC, I expressed relief that Apple wasn’t diving headfirst into AI health coaching features. I must slightly revise that stance, as Apple is clearly beginning to incorporate some AI health trends, albeit cautiously. It seems Apple is thoughtfully considering which trends to adopt and which to avoid, a wise long-term strategy. I’m still glad that Siri AI isn’t playing a more prominent role just yet.

**Audio Intelligence, Part One**

In addition to improved performance, the S11 chip introduces a surprising update: ambient listening. This capability powers Audio Intelligence, a suite of four features that transform the microphone into a potentially powerful AI tool.

The most eye-catching features are Live Rewind and Siri Recap. Live Rewind allows you to view a short transcript of the last 15 seconds, while Siri Recap provides a summary of your conversations throughout the day. Given the current public concerns about privacy and surveillance, these features have sparked considerable discussion online. However, I couldn’t test them as they won’t be available until a software update later this year.

What I could test were faster Shazam song identification and sound recognition for alerting you to urgent nearby noises. Both features require opting in and are not enabled by default. When I activated music detection, it was impressively quick. A simple pinch brings up the Smart Stack, and the AI surfaces the Shazam widget, instantly identifying the song. I did encounter a minor hiccup when rapidly switching between songs, but that’s not likely to happen in a typical Shazam scenario.

Testing sound recognition, designed for accessibility, was less conclusive. It’s meant to alert you to sounds like doorbells, alarms, or sirens. Ironically, I didn’t have my doorbell ring during the week, but I did play several YouTube videos of doorbell chimes at various volumes, none of which triggered the feature. This is a positive outcome, as previous tests with other ambient listening devices struggled to differentiate between real sounds and TV noise. You wouldn’t want a fictional doorbell ringing in real life. A loud truck horn also didn’t activate the feature, as it wasn’t a siren. I’ve reached out to Apple for clarification on how they minimize false positives but haven’t received a response yet.

I’ll delve deeper into Audio Intelligence once all features are available. It’s clear that Apple is paying attention to the growing AI wearable market. Introducing these features on the Apple Watch, a well-loved device, is a strategic move. As other tech companies grapple with privacy concerns, Apple has published a privacy white paper and support documents to position itself as a leader in setting new standards. If successful, it’s not hard to envision similar features appearing in future smart glasses or AirPods with camera sensors. If not, it’s not a major loss; the Apple Watch is already a valuable, sometimes lifesaving device without Audio Intelligence.

The most intriguing aspect of this rollout is that it comes from Apple, a highly successful tech company known for its strong privacy reputation. If Apple can’t make this category of device work, it raises questions about the future of AI wearables as a whole.

**Testing the Waters**

In many respects, this review of the Series 12 is incomplete. Based solely on what’s available today, it’s a straightforward hardware upgrade that narrows the gap between Apple and the standout features of niche competitors like Whoop and Oura.

For those considering an upgrade, Apple has laid a solid foundation with its hardware for ambitious features in the future. If you have concerns about Audio Intelligence and privacy, remember that last year’s models are still excellent, likely available at a discount, and come with fewer privacy questions.

Otherwise, the Series 12 is a solid upgrade for anyone using a Series 6 or earlier. Users of Series 7 and 8 should weigh the importance of AI features against their current battery life, as watchOS 26 will continue to receive security updates. Series 9 and later don’t need to upgrade unless they have a chronic condition that could benefit from the enhanced continuous heart rate monitoring. The SE 3 remains my top recommendation for smartwatch newcomers seeking a basic fitness tracker. I’ll have a specific review for the Ultra 4 soon, but it’s clear that it’s aimed at those who prefer larger screens, better battery life, and an outdoor lifestyle.

Even if the Series 12 only featured a new sensor array, an updated Health app, and a more functional Siri, that would be a significant update. However, there’s much more in store that will fundamentally change this product in the coming months. I suspect Apple’s ambitions for the watch extend beyond just health tracking.

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**Agree to Continue: Apple Watch Series 12**

Every smart device now requires you to agree to a series of terms and conditions before use—contracts that often go unread. While it’s impossible to analyze every single agreement, we’ve started counting how many times you need to hit “agree” to use devices during our reviews, as these are agreements most people overlook and cannot negotiate.

The Apple Watch Series 12 can only be used with an iPhone, meaning you’ll have already agreed to the iPhone’s terms of service and privacy policies. Optional services like Apple Pay, Apple Music, or Fitness Plus come with their own agreements. The Health app also has its own terms and conditions. Audio Intelligence features are opt-in and not enabled by default.

If you choose to activate cellular service, you’ll need to agree to your carrier’s terms. I activated cellular on T-Mobile and was prompted to agree to one mandatory agreement. Adding any third-party apps or integrations will also require you to agree to their individual terms and privacy policies.

Specifically for the Apple Watch, you must agree to the following:
* Terms and Conditions

Some features, such as hypertension notifications, EKG, sleep apnea, or blood oxygen monitoring, may require you to disclose your location data, depending on local regulatory requirements.

**Final tally:** One mandatory agreement plus any mandatory agreements for your iPhone. Several optional agreements.