You cannot get HRV from an optical sensor accurately. Not even at idle, but definitely useless in motion. And definitely not at the wrist. Optical at the wri

You cannot get HRV from an optical sensor accurately. Not even at idle, but definitely useless in motion. And definitely not at the wrist. Optical at the wrist is all manipulated data via the watch software that is guessing what it is seeing or not. The only real way is via a heartrate strap that is electrical. And the next generation of sensors is going to be even more amazing with EKG https://www.movesense.com/movesense-flash/ https://www.movesense.com/movesense-flash/