How to read Body Age
Body Age is a wellness education summary built from recent sleep, activity, and fitness signals. It is designed to make trends easier to understand, not to diagnose a condition or judge one isolated day.
Read how Body Age and aging rate are calculated.
Signal groups
| Group | What it explains |
|---|---|
| Sleep | Whether recent sleep duration and timing are stable enough to support recovery. |
| Activity | Whether recent movement includes baseline steps, aerobic work, and higher-intensity stimulus. |
| Fitness | Whether cardio fitness and low-load heart signals are moving in a healthier direction. |
Data and interpretation
Yuelu reads authorized Apple Health and Apple Watch samples when permission is granted. If a signal is missing, Body Age avoids letting one incomplete metric dominate the result and explains which data source may need attention.
Body Age is for health education and product explanation. It is not medical diagnosis or treatment advice.