Sampling rate and sampling method of Heart Rate Intraday Time Series data.

[Tomoaki.ost]

Hi, I am working on the project to collect heart rate data measured by Fitbit Charge2/3.

I can obtain my heart rate data by using python3.7.4 and python-fitbit module.
When I obtain the data via web API, then specified "detail-level" as 1sec. Then I could get the data actually spaced 5 to 15 seconds apart as shown below.

Index	time	value
0	1:56:27	70
1	1:56:42	70
2	1:56:57	70
3	1:57:12	70
4	1:57:17	68
5	1:57:22	96
6	1:57:27	92
7	1:57:32	76

It seems minimum sampling rate is 5 seconds.
Now, My question is sampling method of these 5 seconds heart rate data.

Is it a instantaneous data of the time stamp? Or averaged data calculated from 1 sec sampling rate data?
In addition, if the 5sec data is averaged data, then how is the averaging process made?

Thanks in advance.

[Gondwana]

This doesn't answer any of your questions but, if you put your Charge in activity/exercise mode, the reporting interval will be typically 1 to 3 seconds (I think).