Apple Watch Ultra 4: Everything You Need to Know

Apple Watch Ultra 4 introduces the new Health Sensing System, bringing together updated optical and electrical heart sensors with the S11 chip. Together, they allow Ultra 4 to monitor your heart rate more frequently and provide a more detailed picture of your health and fitness throughout the day.

Apple says Apple Watch Ultra 4 offers the most accurate heart rate sensing in a wearable. A study involving more than 1,000 people compared its heart rate sensing with other leading wearables, with Apple Watch recording the highest accuracy across the devices tested.

The optical heart sensor now uses larger, more power-efficient green LEDs and measures your heart rate every five seconds throughout the day. This continuous monitoring can provide more insight into how your body is responding to activity and rest, while also helping make features such as the Exercise and Move rings more accurate. A new heart rate complication also lets you see your current heart rate directly from your watch face.

Apple Watch Ultra 4 also measures heart rate variability (HRV) up to 24 times more frequently than before. HRV can provide useful insight into how your body is responding to stress, activity and recovery, and Ultra 4 gives you two ways to understand this data.

Recovery HRV focuses on day-to-day changes that may be linked to stress and recovery, while overall HRV provides a broader view of your health, including cardiovascular health. Generally, higher HRV is associated with better recovery, while lower values can be associated with stress.

Overnight vitals now includes Recovery HRV measurements compared with your personal baseline, giving you more context around your health data. A new daytime vitals view also lets you switch between overnight and daytime measurements, making it easier to spot changes in your metrics throughout the day.

Together, these updates give Apple Watch Ultra 4 a more detailed view of your heart health and physiological state, helping turn individual measurements into information that's easier to understand and use

Apple Watch Ultra 4 introduces Readiness, a new feature designed to give you a clearer idea of how prepared your body is for the day ahead. It looks at factors including your recent activity, training load, vital signs and sleep score to give you a single score from 0 to 10.

Rather than leaving you to interpret all that data yourself, Readiness turns it into a simple recommendation: Recover, Pace Yourself, Ready or Go For It. Whether you're heading into a busy day at work or planning your next workout, it gives you another way to understand when you might be ready to push yourself and when taking things a little easier could be the better choice.

Your Readiness score updates throughout the day as new information comes in. For example, an intense workout or a change in your daytime vitals can affect your score. You can also see which factors are influencing your score and tap through for more detail.

The scoring system was developed using data from the Apple Heart and Movement Study, alongside input from exercise scientists and physicians at Apple. The result is a simple daily snapshot that helps turn the wealth of health and fitness data collected by Apple Watch Ultra 4 into something you can actually use.

Apple Watch Ultra 4 now offers up to 50 hours of everyday battery life, giving you more than two days between charges. In Low Power Mode, that increases to up to 84 hours.

Charging is faster too. Just 15 minutes on the charger can provide up to 18 hours of additional battery life, making it easier to top up before heading out or starting a workout. For longer outdoor sessions, Apple Watch Ultra 4 introduces Extended Workout mode, which provides up to 25 hours of battery life while continuing to record GPS and heart rate data. That's a 25% increase compared with the previous generation.

If you're taking on something even bigger, Max Extended Workout mode can track outdoor runs, walks and hikes for up to 45 hours, while still recording GPS every second. That's typically enough battery life to get you through a 100-mile race, without having to compromise on workout tracking.

Whether you're using Ultra 4 throughout the day or pushing yourself over much longer distances, the improved battery life means more time tracking what matters and less time looking for a charger.

Whether you're walking around town, running indoors or heading out on a longer adventure, Apple Watch Ultra 4 is designed to give you a more accurate record of how far you've gone and how much you've moved.

Its pedometer has been redesigned using new machine learning algorithms and the S11 chip, improving step counts throughout the day as well as distance measurements during indoor walking and running workouts. Apple says this makes Ultra 4 the most accurate smartwatch for step tracking.

The S11 chip also brings a new Steps complication, so your current step count can be displayed directly on your watch face. It means you can keep track of your progress at a glance, whether you're working towards a daily target or simply curious how much you've moved.

The redesigned Health app on iPhone brings information from Apple Watch Ultra 4 together to help you spot useful patterns and changes over time.

A new Insights tab uses Apple Intelligence to surface timely information, while the Longevity tab looks at longer-term trends. Health Age, found within Longevity, shows how certain metrics are tracking compared with your actual age.

The app also introduces new movement evaluations, using vision-based AI on iPhone alongside Apple Watch heart rate data to assess areas such as flexibility, strength and balance. This gives you a broader picture of how you're moving, beyond individual measurements.

The redesigned Health app is due to arrive later this year. It adds another layer of context to the information collected by Apple Watch Ultra 4, making it easier to follow changes and trends over time.

Apple Watch Ultra 4's new Audio Intelligence features have been designed with privacy built in from the start. Audio is processed using the Secure Exclave in the S11 chip, a hardware-isolated part of the system that processes raw audio separately before immediately deleting it. The audio isn't recorded or stored, and Apple doesn't have access to it.

You also remain in control of how these features are used. Audio Intelligence features are optional, and you can choose when to use Siri Recap and switch it on or off directly from Control Center.

Privacy extends to the people around you, too. The features don't identify individual speakers, while Siri Recap creates a short summary rather than a full transcript and is designed to leave out sensitive information. Live Rewind also provides an audible chime and on-screen indicators when it's active, so people nearby can see and hear that it's being used.

Live Rewind snippets and Siri Recap summaries are end-to-end encrypted when synced with iCloud, meaning they aren't accessible even to Apple. Siri Recap and Live Rewind will arrive in beta later this year.

Apple Watch Ultra 4 has been designed with a focus on reducing its environmental impact, using 45% recycled materials overall. That includes 100% recycled titanium in the 3D-printed titanium case and 100% recycled cobalt in the battery.

Apple has also focused on using renewable energy throughout the manufacturing process. Electricity used to manufacture Apple Watch Ultra 4 comes from renewable sources such as wind and solar across the supply chain. Apple has also invested in renewable energy projects around the world to match the electricity customers use to charge their Apple Watch.

The packaging is 100% fibre-based, making it easy to recycle at home. These steps are part of Apple's wider goal to become carbon neutral across its entire footprint by 2030.

Apple Watch Ultra 4 brings together more capable health and fitness tracking, improved heart rate sensing, longer battery life and features designed for everything from everyday workouts to much bigger adventures.

From Readiness and more detailed heart rate and HRV measurements to improved GPS, advanced workout tracking and up to 45 hours of battery life during extended workouts, Ultra 4 is built to keep up when you're pushing yourself further.

There are plenty of thoughtful updates for everyday use, too. New Audio Intelligence features, a redesigned Health app and the ability to see more of your activity at a glance make Ultra 4 a more useful companion throughout the day.

Whether you're training for a new challenge, exploring somewhere unfamiliar or simply want a smartwatch that can do more, Apple Watch Ultra 4 combines serious capability with the features you need for everyday life.