Answer from Garmin:
All messages and fields previously documented in the FIT SDK are still available. Undocumented messages and fields are being removed before files are sent to third-party platforms.
We are currently investigating an issue affecting activities imported via the Garmin API. The first reports started appearing around March 7.
Several users noticed that certain metrics are missing from the FIT files we receive via the Garmin API, including:
- VO₂max estimate
- Recovery time
- Performance condition
- Sweat loss
- GCB (in some cases)
- Workout information
The Data Is Not Completely Gone
The data itself does not seem to be completely lost.If you manually export the activity from Garmin Connect and re-upload the FIT file, the missing values appear again. This indicates that the data is still stored within Garmin.
However, these values are not always included in the FIT files delivered through the Garmin API, which is why they are missing when activities are imported automatically.
This Is Not a Practical Workaround
While manually downloading and re-uploading FIT files can restore the missing metrics, this is obviously not a practical long-term solution.
It would require users to manually export and re-upload activities for every workout, which is not something we expect or want users to do.
At the moment, this workaround is mainly useful for verifying that the data still exists within Garmin, rather than serving as a realistic solution.
You can still get all data from Garmin by requesting a Data backup at https://www.garmin.com/account/datamanagement/ . This will contain the original files from your Garmin device.
What We Observed So Far
During our investigation we noticed several interesting details.
Different FIT files via API vs Garmin Connect
The FIT files delivered via the Garmin API differ from the files downloaded directly from Garmin Connect.
This behavior is expected to some extent. Garmin forces FIT protocol version 2.0 when providing activities through the API.
However, we did not find a clear difference in the profile version between files where the metrics are present and files where they are missing.
Possible Change on Garmin’s Side
More recently it appears that the issue may now affect all newly imported activities, not only specific devices.
This raises the possibility that Garmin may have changed how certain metrics are included in FIT files delivered through the API.
If this is intentional, it could mean that these values will no longer be available via the Garmin API going forward, even though they are still visible inside Garmin Connect.
At the moment we cannot confirm whether this is a bug or an intentional change.
Contact with Garmin
We have contacted Garmin about the issue and provided them with:
- Debug information
- Example FIT files
- Detailed descriptions of the missing metrics
Unfortunately, we have not yet received a response to our questions since Wednesday. We are currently waiting for further clarification from Garmin.
We will update this post as soon as we receive more information.
Temporary Workaround
If you need the missing metrics immediately, the following workaround currently restores them:
- Download the FIT file from Garmin Connect
- Delete the activity
- Re-upload the downloaded FIT file
After re-uploading the manually downloaded file, the missing metrics should appear again.
Next Steps
We are continuing to investigate the issue and are awaiting a response from Garmin.
As soon as we receive more information or confirmation about the cause, we will update this article.
