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Sleep Regularity

Sleep regularity measures whether recent sleep onset times are stable; smaller deviation usually means a steadier body rhythm.

Last updated2026-06-10

Sleep Regularity

Sleep Regularity is a health-education page for Yuelu Body Age. Sleep regularity measures whether recent sleep onset times are stable; smaller deviation usually means a steadier body rhythm. Read it as trend context rather than a judgment from one day.

Role in Body Age

Sleep Regularity contributes to the sleep 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 sleepAnalysis
Lookback window Valid nights from the last 14 days, using up to the 7 most recent main sleep samples
Metric Mean absolute deviation of sleep onset time from the recent average, in minutes
Missing-data rule Missing when fewer than 3 valid nights are available

Smaller deviation is better. Within about 30 minutes usually indicates a stable rhythm; deviations beyond 90 to 120 minutes can noticeably affect the sleep dimension.

How to Improve

  • Keep bedtime and wake time as consistent as practical.
  • Reduce bright screens, alcohol, and late heavy meals before bed.
  • Leave a larger sleep window when training load increases.
  • Watch several nights of trend before reacting to one short night.

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.