Pace of Aging appears after you have enough weekly True Age data points to calculate a reliable trend.
Pace of Aging is a trend line calculated using linear regression over your True Age measurements. It appears after you have at least 4 weeks of True Age data.
Data requirements for True Age:
Lookback window: Past 4 complete weeks (Monday to Sunday)
Updates: Every Monday with data from the previous 4 full weeks
RHR and HRV: Need 4+ days with readings across the 4 weeks
VO2max and LBMI: Need at least 1 reading across the 4 weeks
For Pace of Aging:
Minimum: 4 weeks of True Age measurements
Calculation window: Up to 16 complete weeks of True Age data
Updates: Every Monday alongside your True Age update
When reThrive connects to Apple Health, it imports your historical data. If you have at least 4 weeks of historical True Age data, your Pace will appear immediately. Otherwise, it appears after you accumulate 4 weeks of True Age measurements.
To ensure your True Age updates each week so Pace can calculate:
Wear your device normally so Apple Health records fresh values
Open reThrive at least once after your device syncs to pull new data
Check that Apple Health permissions remain enabled for all four biomarkers
For VO2max, record qualifying workouts or walks if your device requires them
For LBMI, keep weight and body composition measurements current
After four consecutive weeks with complete True Age updates, Pace of Aging appears automatically.
Not enough weeks yet
You need at least four weeks with complete True Age data. If you're early in your journey, keep checking weekly.
Missing data this week
If any biomarker is missing fresh data, that week's True Age won't update and won't count toward Pace.
Permissions turned off
One or more Apple Health categories may be disabled, blocking a required input.
VO2max didn't refresh
Many devices only update VO2max after specific activities like outdoor walks or runs.
LBMI incomplete
Missing weight or body composition data prevents LBMI from calculating.
Background sync disabled
Battery or background restrictions can delay data flowing from your device to Apple Health to reThrive.
Follow these steps in order. After each step, open reThrive to check if data refreshed.
Confirm Apple Health permissions are enabled for all four biomarkers
Trigger a manual sync in reThrive (Settings > Apple Health > Sync now)
Keep the app open for 30–60 seconds to complete the sync
Record a workout to refresh VO2max if it hasn't updated recently
Add today's weight and body composition if LBMI is missing (see How to fix missing LBMI)
Check device battery and background settings, enable background refresh if needed
Verify you have at least four weeks with weekly True Age updates
Why does it take four weeks?
Pace uses linear regression to calculate a stable trend. Four weeks is the minimum needed for a meaningful trend line, and the calculation becomes more stable as you accumulate up to 16 weeks of data.
Does reThrive use my historical data?
Yes. When you connect Apple Health, reThrive imports your past data to calculate your initial True Age. The Pace trend still needs several weeks of ongoing updates to establish.
My Pace changed from last week. Is that normal?
Yes. As new weeks are added and older data ages, the trend line adjusts. Focus on the overall direction rather than week-to-week fluctuations.
Can I make it appear faster?
Ensure all four biomarkers update every week. Wear your device consistently, record activities that trigger VO2max updates, keep weight current, and open reThrive regularly to sync.
