> 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/help-center/help-topics/data-api-sdk/data-model-fields-and-units/activity-elapsed-vs-active-seconds.md).

# Why doesn't activity end time equal start plus active seconds?

The two durations measure different things, so a mismatch is expected.

**The two durations measure different things, so a mismatch is expected.**

* The `start_time` to `end_time` span is the total **elapsed** duration of the workout, including any pauses or inactivity.
* `activity_seconds` (under `active_durations_data`) is the provider's own duration figure, and **what it measures depends on the provider**.

For the providers below, `activity_seconds` is:

* **Oura:** the elapsed span from start to end.
* **Zwift:** moving time.
* **Hammerhead:** the timer time from the activity file.
* **Suunto:** Suunto's reported total time.
* **Wahoo:** Wahoo's accumulated active duration.
* **COROS:** COROS's reported duration.
* **WHOOP:** time in heart rate zones 1 to 5, so an easy workout can read 0.

When a provider gives no duration, `activity_seconds` is filled with the elapsed span.

`inactivity_seconds` is optional on activities. Oura, Zwift, Hammerhead, Suunto and Wahoo leave it empty. COROS fills it with the elapsed span minus COROS's duration, and WHOOP with time in heart rate zone 0. Don't use its presence, absence or a value of 0 as a sign that `activity_seconds` is a measured moving time.

The `low_intensity_seconds`, `moderate_intensity_seconds` and `vigorous_intensity_seconds` fields break down portions of `activity_seconds`, roughly relating as `activity = low + moderate + vigorous + rest`. Providers report these independently, so they are not guaranteed to sum exactly, and some providers do not support all buckets.

Field definitions are in the [activity data model](https://docs.tryterra.co/reference/health-and-fitness-api/data-models).