Is rr_interval_ms available for Fitbit?

Fitbit does not expose raw inter-beat (RR) intervals through its HRV endpoint; it returns low-to-high frequency band ranges rather than IBI values directly, so…

Fitbit does not expose raw inter-beat (RR) intervals through its HRV endpoint; it returns low-to-high frequency band ranges rather than IBI values directly, so rr_interval_ms is unavailable for Fitbit.

Apple, by contrast, does provide beat-to-beat data.