Apple Watch health system
Apple has equipped the Apple Watch Series 12, Apple Watch Ultra 4 and newer with an advanced Health Measurement System. Thanks to new optical and electrical heart rate sensors and the powerful chip, these models can continuously collect more accurate information about your health. According to Apple, the latest generation of Apple Watch models have the most accurate heart rate measurement currently available in a wearable.
The optical heart rate sensor uses larger, energy-efficient green LEDs to shine light into the skin. Photodiodes then measure how the blood volume in the wrist changes with each heartbeat. This allows the Apple Watch to measure the heart rate every five seconds throughout the day, without you having to start a workout. The larger LEDs provide more measurement information, while energy consumption remains limited.
The electrical heart rate sensor uses electrodes in the back of the Apple Watch and in the Digital Crown. When you place a finger on the Digital Crown, the Apple Watch can record the electrical signals from your heart and create an electrocardiogram. In combination with the optical sensor and the S11 chip, a more comprehensive picture of your heart rate and heart rate variability is created.
Readiness: Find out what your body can handle
Readiness is a new app for Series 12, Ultra 4 and newer. This provides a daily indication of how well you are physically prepared for the day ahead. The function analyzes your recent activity, training load, vital functions and sleep score, among other things.
Based on that data, you get a score from 0 to 10. This is linked to clear advice: Recovery, Take it easy, Ready or Go for it. This way you can immediately see whether your body is ready for an intensive workout, or whether it is wiser to take it a bit easier that day.
How the Readiness score is calculated
The Readiness app not only looks at how many hours you’ve slept, but analyzes a combination of vital signs and historical training data:
- Heart rate variability (HRV): A higher HRV compared to your personal average indicates a well-recovered nervous system.
- Resting heart rate: An elevated resting heart rate at night can indicate fatigue, oncoming illness or stress.
- Sleep stages and continuity: The app takes into account deep and REM sleep, as well as how often you were awake during the night.
- Training load: Your recovery needs are based on the intensity of your workouts over the past seven days.
Set up and read the Readiness app
Available on Apple Watch Series 12, Ultra 4 or later
To get an accurate recovery score, it’s important that you also wear your Apple Watch at night with Sleep mode enabled.
- Open the Readiness app on your Apple Watch
- At the top of the screen you will see your current score (expressed as a number from 1 to 10) with an associated label: Recovery, Take it easy, Ready or Go for it.
- Scroll down with the Digital Crown to view the specific factors that influenced your score that day.
Additional Tip: Add the Readiness complication to your favorite watch face. This way you can see immediately when you get up whether you can go for a run or take a leisurely walk.
More details in Condition app
For a comprehensive analysis of your long-term recovery trends, switch to your iPhone. Open the Condition app and look for the ‘Readiness’ section in the ‘Overview’ tab. Here you see graphs of your recovery progress over the past weeks and months.
Apple also provides personalized advice via this view. Does the app indicate a low recovery score? Then the fitness app automatically suggests adjusting your daily Exercise goal (the red ring) for that day or starting a guided mindfulness session.
Score is continuously updated
The information behind Readiness is updated throughout the day. For example, your score can change after an intensive workout, but also when your vital signs deviate from your personal reference values during the day.
For each score, Apple Watch shows which factors influenced the result. This allows you to better understand why you are receiving certain advice and, if necessary, look up more information about the individual measurements.
Apple developed the Readiness algorithm in collaboration with sports scientists and physicians. The feature also uses insights from the Apple Heart and Movement Study.