Wearable sync is the process of pulling physiological data (HRV, resting heart rate, sleep stages, activity, body temperature) from a wearable device into Unfair so dose events can be compared against the biomarkers they may be affecting. The mechanism differs by device — Oura, Whoop, Apple Watch, Garmin, and Fitbit each expose their data through distinct APIs.
Why it matters
Without wearable data, supplement evaluation is stuck at the subjective level. With it, a stack's claimed benefit for recovery or sleep can be compared against HRV baseline, resting heart rate, and sleep efficiency trends — the objective proxies that make evaluation defensible rather than vibes-based.
How Unfair pulls data
Unfair uses the path of least friction per device:
| Device | Primary path | Notes |
|---|---|---|
| Apple Watch | Apple HealthKit integration | Native, no third-party account required |
| Oura | HealthKit (preferred) or Oura API | HealthKit lands most metrics; Oura's own Readiness score requires the direct API |
| Whoop | HealthKit (partial) or Whoop API | Recovery and Strain require the Whoop API |
| Garmin | HealthKit (partial) or Garmin Connect API | VO2 max and Body Battery require direct API |
| Fitbit | Fitbit Web API | Limited sleep staging granularity |
HealthKit is the preferred path wherever possible because it concentrates permissions, handles background updates, and survives app restarts cleanly.
Sync cadence and staleness
Wearable data rarely arrives in real time. Typical freshness:
- Heart rate and steps — within minutes.
- Sleep staging — 30–90 minutes after wake.
- HRV baseline, VO2 max estimate, readiness — 1–6 hours after the measurement window.
Unfair's review screens respect this delay: the previous night's metrics are usually available by mid-morning, not at 6am. Charts mark unsynced days explicitly so absence of data is not misread as a biomarker dip — see data gap handling for how gaps are treated.
Common sync failures
- Background refresh disabled on iOS kills passive sync.
- Third-party OAuth tokens expire and need periodic re-auth.
- Device firmware updates occasionally change API responses in non-backward-compatible ways.
- Timezone changes during travel can double-count or miss a day until the device catches up.
Unfair runs a daily reconciliation sweep to catch most of these, and surfaces a sync-health indicator on the settings screen.
How this appears in Unfair
Synced metrics appear alongside dose logs on the review screen with timestamps and source labels so the user always knows which device produced which number — important when evaluating compounds against ranked output.
Clinical safety note
Wearable data is consumer-grade, not medical-grade. Trends are useful; individual numbers should not drive clinical decisions without corroboration from a validated device or lab measurement.