High Intensity Duration
High Intensity Duration is a health-education page for Yuelu Body Age. High intensity duration records recent minutes in Z4-Z5 heart-rate zones, helping assess upper-cardio stimulus and recovery load. Read it as trend context rather than a judgment from one day.
Role in Body Age
High Intensity Duration contributes to the activity dimension of Body Age. Yuelu combines it with the other sleep, activity, and fitness signals so one weak or missing signal does not define the whole result.
Current Yuelu Method
| Field | Current rule |
|---|---|
| Data source | Apple Health workouts and workout heartRate samples |
| Lookback window | Last 7 days |
| Metric | Accumulated minutes in heart-rate zones Z4-Z5 |
| Missing-data rule | A workout needs at least 10 heart-rate samples to contribute; missing when workout heart-rate data is insufficient |
About 15 to 75 minutes per week often provides meaningful training stimulus. Too little may mean limited upper-end stimulus; too much may increase fatigue.
How to Improve
- Reduce long sedentary blocks first.
- Build low/moderate aerobic work before chasing intensity.
- Wear Apple Watch during workouts so heart-rate zones are available.
- Increase load gradually when sleep and recovery are stable.
When Data Is Missing
Check Apple Health permissions, source priority, Apple Watch battery and wear time, and whether the relevant samples were recorded recently.
Rule Basis
- Yuelu Body Age follows the current in-product calculation rules for sleep, activity, and fitness signals.
- Data is read from authorized Apple Health and Apple Watch samples when permission is granted.
- Interpretation is for wellness education and product explanation, not medical diagnosis.
Disclaimer
This material is for health education and product explanation only. It is not medical diagnosis or treatment advice. Consult a qualified clinician for persistent symptoms or health concerns.