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 active moving/exercising time only.

So an activity recorded over many hours can have a much shorter active duration. Both match what the provider's own app shows.

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.