> For the complete documentation index, see [llms.txt](https://docs.tryterra.co/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.tryterra.co/faq/help-topics/no-data/historical-backfill-returns-nothing/garmin-historical-export-toggle-off.md).

# Why is Garmin historical backfill returning empty?

Garmin historical retrieval requires the **historical-data sharing option** to be granted on Garmin's consent screen, which can default to OFF (and was defaulted off for some users who authenticated before a recent provider change). Without it you only get live data going forward.

Garmin also fires its historical backfill **once per OAuth subscription**, so a reauth that reuses the same credential will not re-deliver history.

**The fix:** have affected users **disconnect and reconnect, ticking the historical-data sharing option** during reauthorization.

To pull older Garmin data, call the [historical data-retrieval endpoints](https://docs.tryterra.co/health-and-fitness-api/managing-user-health-data/requesting-historical-data) (e.g. `/v2/activity`, `/v2/menstruation`) with a `start_date` and `to_webhook=true`. This triggers Garmin's backfill, which Terra then pushes to your destination asynchronously. Garmin allows up to **5 years** into the past, subject to Garmin's own backfill limits, so some older activities may not be returned.


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