How can i get heart rate data by 1sec?

[sofiapark]

I am developing application which get heart rate data by 1sec using charge2

It seems that we can get heart rate data by 1sec like below

But actually I can get heart rate data by 1-3sec irregulary like below(excercise mode-running).

Anyone know how to get heart rate data by 1sec?

[EdsonFitbit]

Welcome to the Fitbit Community @sofiapark. It's great to have you here. I've moved your post to the API board since these type of questions are handled by our developers team. 

Catch you later. 

[AndrewFitbit]

@sofiapark Looks like you're getting the data correctly, it just varies depending on the HR readings.

[Sergey1]

I have the same question and I am not sure I understand this answer. The FitBit API documentation says that HR data is available at 1 second minimum granularity, which to me means it must be sampled in 1 second intervals. Is that not correct? If it is correct, then why are the timestamps (even in the API documentation examples) suggest that sampling is done at 5 seconds or so. Furthermore, I just tried getting my HR data for a 14 hour period which at 1 second should result in about 50400 samples. I only see 5346 samples in the json returned from the server, which suggests that HR was actually sampled at 10 second intervals even though the request was for 1 sec. Could anyone shed some light on this? Is there a setting on the device itself (Charge 2) that controlls the sampling rate? If not can someone explain how the HR is actually acquired or point to the documentation that explains the process other than the Fitbit API documentation which seems misleading?

[AndrewFitbit]

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Sergey1 wrote:

The FitBit API documentation says that HR data is available at 1 second minimum granularity, which to me means it must be sampled in 1 second intervals. Is that not correct?

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@Sergey1 It will give you second-level granularity, but doesn't necessarily mean you'll always have data at 1 second intervals. From what I've observed with my own data, I've consistently seen 1-3 second intervals similar to @sofiapark's data. That's why I said it depends on the HR readings.

[catch_catch]

So in other words, We cannot not get the heart rate in each second,right?