Heart Rate Interday: Missing Data? 1Hz update = 86,400 sample/day yet I see only 9378?

[fvuser]

Using a Charge 2 and the Web API and with the Heart Rate sampling set at 1Hz, I expect to see 86,400 (24 hrs * 60 min/sec * 60 secs) entries in the list found when downloading HeartRate data. I only found 9378 entries. Is the Fitbit not collecting the data (fitbit malfunctioning or user not wearing correctly) or is the data collected but only reported if there's a change in the data or is it that the BEST that can be collected is at 1Hz but it may be at a lower rate?

Sample Data:

"activities-heart-intraday":{"dataset":[{"time":"00:00:00","value":76},{"time":"00:00:05","value":77},{"time":"00:00:20","value":77},{"time":"00:00:35","value":77},{"time":"00:00:40","value":76},

I read these but I'm still confused:

--https://community.fitbit.com/t5/Web-API-Development/Heart-Rate-Intraday-Time-Series-of-samples-retur...

--https://community.fitbit.com/t5/Web-API-Development/Sampling-time-of-intraday-Heart-Rate-Data/m-p/18...

[Gondwana]

"the BEST that can be collected is at 1Hz but it may be at a lower rate" is the case. To my experience (which is mostly on Surge, with Alta HR, Ionic and Versa to lesser extents), sampling is usually every one to three seconds during activity sessions, but every 5 or 10 seconds at other times. When there is no reading (eg, watch not on wrist or not worn correctly), there will be no readings.

You can cross-check your data with my attempt here, but it sounds like you've already cracked it.