Personal Health Index (PHI)
Data-driven composite of four health pillars from daily Apple Watch data, each graded against Mike's own 2023-2025 baseline (100 = normal for Mike). Recovery (HRV + resting heart rate), Sleep (duration + night-to-night consistency), Activity (energy, steps, exercise), and Fitness (VO2 max + cardio recovery). Rebuilt in 2026 as PHI 2.0; the legacy sleep/activity/weight index is preserved as PHI-Classic. See the methodology report.
Current Value
110.1
Index (2023-2025 avg = 100)
Change
↓ -6.5%
vs. previous period
Last Updated
Oct 1, 2026
monthly frequency
Next Update
Nov 1, 2026
Scheduled
Recent Observations
Download Full Dataset →| Date | Value | Notes |
|---|---|---|
| October 1, 2026 | 110.1 | Strong month but down from August. Activity and fitness stayed well above baseline, with steps 60% above the 2023-25 norm and the step score at its 160 ceiling. Sleep was the drag: nights ran shorter and far less regular than August, and travel to Kosovo at month's end made both worse. |
| September 1, 2026 | 117.8 | Strong month. Activity and fitness both ran well above baseline, with steps 71% above the 2023-25 norm. First full month in Oakland, with walking replacing the Portland cycling. |
| August 1, 2026 | 111.6 | Strong month: activity strong. Portland, with 25 rides and steps 48% above baseline. Cycling stopped July 26 with the move to Oakland, CA. |
| July 1, 2026 | 106.0 | Near baseline — recovery and activity strong; sleep soft. Living in Kosovo. |
| June 1, 2026 | 113.2 | Strong month — activity and recovery strong; sleep soft. Living in Kosovo. |
| May 1, 2026 | 101.6 | Near baseline — fitness and recovery strong; sleep soft. Based in Koreatown, LA. |
| April 1, 2026 | 102.6 | Near baseline — fitness and recovery strong. Based in Koreatown, LA. |
| March 1, 2026 | 102.7 | Near baseline — recovery strong. A nomadic stretch between cities. |
| February 1, 2026 | 91.2 | Soft month — activity floored; sleep soft. New year; settling into a new home. |
| January 1, 2026 | 90.7 | Soft month — activity floored; fitness soft. Holidays; moving into a new home. |
Indicator Details
- Category
- Health & Wellness
- Data Source
- Apple Watch / Apple Health (via Health Auto Export)
- Update Frequency
- monthly
- Calculation Method
- PHI = 0.30·Recovery + 0.25·Sleep + 0.25·Activity + 0.20·Fitness. Each metric's monthly mean is scored vs its 2023-2025 baseline (direction-corrected, capped 60-160); the index is re-based so the 2023-2025 mean = 100. Data begins 2023-01 (Apple Watch sleep-stage tracking availability); rows carry the release-lag date, so the first row is 2023-02. Full method: /reports/phi-2.0-methodology.