You connect a health app, run an export, and the data starts about a month ago. You have years of history in Apple Health, so something looks wrong. On iOS 27 the cause is probably not a bug in the app. It is a permission you granted, possibly without noticing.
What changed in iOS 27
iOS 27 lets you give an app limited Health access: Past 30 Days and Future Data. If you choose that option, the app can read samples from roughly the last 30 days and anything recorded afterward. It cannot see anything older. For that app, your earlier history does not exist.
This is a reasonable privacy feature. The side effect is confusing: an export or backfill from that app looks like it begins about 30 days before the day you granted access, and then continues normally.
How to tell it is this
- The earliest date in the export is close to 30 days before you first connected the app.
- Everything after that date looks fine and keeps updating.
- Apple Health itself still shows years of data.
If all three are true, the app is probably working. It is just not allowed to look further back.
How to fix it
You change the permission, and then the app needs to fetch history again.
- Open Settings, go to Privacy & Security, then Health, and choose the app. Alternatively, open the Health app, tap your profile picture, and look under Apps for the app.
- Look for the data access option and choose all data instead of the past 30 days.
- Return to the app and trigger a sync, or wait for the next one.
Apple words these options differently between iOS versions, so look for the data access choice and pick all recorded data.
Step 3 depends on the app. Some apps notice the change and fetch the older history themselves. Others only pick up new samples and need a reset or a re-export. If an app keeps showing only 30 days after you widen access, check its documentation or support.
This applies to every Health app
Nothing here is specific to one product. Any app that reads HealthKit can hit the limit: fitness trackers, sleep apps, coaching apps, and export tools. If a metric seems to start suddenly one month back, check the permission first.
What health4ai does about it
health4ai moves Health data to a Google Sheet in your own Drive or to your own Postgres or Supabase database. Because limited access makes data look missing, the app handles it in two ways.
It warns you. Since version 1.0.1, health4ai tells you when iOS is sharing only recent Health data, so you do not have to guess from the dates.
It repairs the destination when you widen access.
- For Google Sheets, the sheet rebuilds itself when access widens. That has been true since 1.0.1.
- For database users, health4ai 1.0.2 and later re-import the hidden history automatically when you widen access, as long as you widen it after installing 1.0.2. On an earlier version, update the app first, then widen access.
- The notice also tells you where to change the setting: iOS Settings or the Health app.
A rebuild can take a little while for a long history. The first sync can backfill up to 10 years of data, and one real account reached 3,653 days. Sync History in the app shows when the work finished.
Background sync is best effort, and iOS chooses when it runs. Opening the app is the dependable way to prompt a catch-up.
A quick checklist
- Is the earliest row about 30 days before you connected the app? It is likely limited access.
- Change the app’s Health data access to all data in Settings or the Health app.
- Sync again and look at the earliest date.
- If the date has not moved, check that specific app’s behavior.
For a walkthrough of getting daily Health data into a spreadsheet, see Apple Health to Google Sheets with health4ai. For the database route, see the setup page, and for what the app does and does not see, the privacy page.
health4ai is free on the App Store: Download on the App Store.