Apple unveils Apple Watch Ultra 4 with longer battery life and new health sensing

Apple Watch Ultra 4 is the company’s new heavyweight smartwatch for athletes, hikers and anyone who thinks a normal watch is not sufficiently prepared for a minor expedition. The new model adds Apple’s Health Sensing System, an S11 chip, more accurate GPS and enough battery for outdoor workouts that run into serious weekend territory.

Apple says Ultra 4 can track outdoor workouts for up to 45 hours in its most extended mode, while everyday battery life reaches up to 50 hours. Pre-orders are open now, with availability from 18 September, in natural and black titanium.

Health tracking gets more serious

The Health Sensing System uses new optical and electrical heart sensors to measure heart rate every five seconds throughout the day, according to Apple. Heart-rate variability can be measured up to 24 times more often, with daytime and overnight views designed to show changes against a user’s personal baseline.

Ultra 4 also introduces Readiness, a 0–10 daily score based on recent activity, training load, vitals and sleep. It produces recommendations such as Recover, Pace Yourself, Ready or Go For It. Apple says the algorithm was developed using data from its Heart and Movement Study with exercise scientists and physicians, but the score is still guidance rather than a medical assessment.

Apple repeats its claim that Ultra 4 offers the most accurate heart-rate sensing in a wearable, supported by a study of more than 1,000 participants. That is an Apple-reported comparison and should not be confused with independent testing of every competing sports watch.

Battery and GPS for long days outside

Ultra 4 offers up to 50 hours of normal battery life and up to 84 hours in Low Power Mode, Apple says. Fifteen minutes of charging adds up to 18 hours of battery life. Extended Workout mode provides up to 25 hours with full GPS and heart-rate readings, while Max Extended Workout mode can track runs, walks and hikes for up to 45 hours with GPS readings every second.

The watch also brings a redesigned pedometer model, with machine-learning algorithms intended to improve step counts and distance estimates. Apple calls it the most accurate step tracking of any smartwatch, another claim that will need independent comparison before it earns more than a raised eyebrow.

Safety, software and design

The S11 chip powers new Audio Intelligence features due later this year, designed to help users remember parts of conversations and stay alert to important sounds. With watchOS 27, Apple Intelligence adds Siri AI features with personal context and broader question answering. Apple also retains health notifications, ECG, sleep tracking, fall detection, Emergency SOS and satellite communications.

The watch comes in natural and black titanium, with a large bright display and improved charging. It is positioned as Apple’s most capable outdoor wearable, rather than a cheaper fitness tracker with delusions of grandeur.

Our opinion

Ultra 4 looks like a meaningful upgrade for people who genuinely spend long hours training or outside, particularly if the 45-hour workout tracking figure survives real-world GPS use. The health-sensing system and readiness score are intriguing, but Apple’s accuracy claims still need independent scrutiny. For ordinary daily wear, the standard Series 12 is likely the saner choice; for endurance athletes and adventurers, Ultra 4 finally has the battery story to match the rugged casing.