HealthKit Data Deep-Dive
HealthKit Data Deep-Dive
Rubric syncs 10 data types from Apple HealthKit, uses non-midnight day boundaries to match how you experience your day, and deduplicates overlapping data from multiple devices.
What Rubric Syncs
| Data Type | What Is Synced | Unit |
|---|---|---|
| Steps | Daily total (deduplicated) | count |
| Active Calories | Daily total (deduplicated) | kcal |
| Basal Calories | Daily resting energy | kcal |
| Exercise Time | Daily total | minutes |
| Distance | Walking and running distance | km or mi |
| Sleep Duration | Total sleep time with stage breakdown | minutes |
| Resting Heart Rate | Daily average | bpm |
| Heart Rate Variability | SDNN measurement | ms |
| VO2 Max | Latest estimate | mL/kg/min |
| Workouts | Individual sessions with type, duration, heart rate, calories, and source app | varies |
Weight is also synced when a new measurement appears in Apple Health.
When Sync Happens
Rubric syncs HealthKit data at three points:
| Trigger | Behavior |
|---|---|
| App launch | Syncs every time you open Rubric. |
| App resume | Syncs when you return to Rubric after 30 or more minutes in the background. |
| Pull to refresh | Swipe down on the dashboard to force a sync. This bypasses the 30-minute rate limit. |
Under normal use, you do not need to think about sync. Open the app and your data is current. If something looks stale, pull to refresh.
Day Boundaries
Rubric does not use midnight as the boundary between days. Instead, it uses windows that match how most people experience their day:
| Metric Type | Day Window | Why |
|---|---|---|
| Sleep | 6 PM to 6 PM | Going to bed at 11 PM and waking at 7 AM is one night of sleep, attributed to the day you went to bed. |
| Activity | 4 AM to 4 AM | A late-night gym session at 11:30 PM counts toward that day’s activity, not the next calendar day. |
What this means for you: If you check your dashboard at 2 AM after a late workout, that workout appears under the previous day. Rubric’s boundaries match how you think about your day, not the midnight clock rollover.
Sleep Source Priority
If you wear multiple devices that track sleep (e.g., Apple Watch plus a dedicated sleep tracker), Rubric uses a priority system to avoid double-counting:
- Dedicated sleep trackers (e.g., Eight Sleep, Whoop) are preferred when available.
- Apple Watch is the fallback.
- [VERIFY] AutoSleep and other third-party Watch apps fall between dedicated trackers and raw Watch data.
The system selects the highest-priority source for each night rather than merging data from multiple trackers.
Deduplication
Apple HealthKit can contain overlapping data from multiple sources. Your Apple Watch and a Peloton bike might both record active calories for the same workout. Rubric uses Apple’s built-in deduplication, which correctly combines overlapping samples instead of summing them.
This is why your Rubric calorie count may differ from a simple total of your Watch and Peloton readings. Rubric shows the deduplicated number, which is the accurate one.
What Does Not Sync
The web app cannot access HealthKit. It displays health data that was previously synced from your iPhone. If your web dashboard looks stale, open the iOS app and pull to refresh.
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