Apple Watch Ultra 4 gets new Readiness score that changes throughout the day

Apple Watch Ultra 4 is gaining a new Readiness feature designed to give users a simple daily indication of how prepared their body is for exercise and other activity.

Rather than focusing on a single measurement, Readiness combines recent activity, training load, vitals and sleep information to produce a score between zero and 10.

Apple then turns the score into one of four straightforward recommendations: Recover, Pace Yourself, Ready or Go For It.

The feature is intended to make the large amount of health and fitness information collected by Apple Watch easier to act on. A lower score could encourage a user to take a lighter day, while a higher score could indicate that their body is prepared for a more demanding workout.

Unlike a once-a-day recovery measurement, Readiness can change as the day progresses. Apple says the score updates as new information becomes available, including after an intense workout or when the watch detects changes in daytime vitals.

Users can see which individual factors are influencing their score and open those measurements for additional detail.

The feature takes advantage of the substantially increased health monitoring offered by Apple Watch Ultra 4. The new Health Sensing System measures heart rate every five seconds, while HRV can be measured up to 24 times more frequently than before.

Apple says the Readiness algorithm was developed using data from the Apple Heart and Movement Study alongside work with exercise scientists and physicians at the company.

Readiness is one of several health-focused additions arriving with Apple Watch Ultra 4, alongside redesigned heart-rate sensing, daytime Vitals and a forthcoming redesigned Health app on iPhone.