How To Record HRV Data from The 910XT
Enable RR recording
Turn on the FR910XT. Press ‘Menu’ to go into the menu screen. Press UP then DOWN and repeat 10 times. You will enter the “diagnostic menu”. Select and change HRV on the top right hand side. HRV Enabled…cool! This drains the battery a bit faster than normal but does not particularly affect the .FIT file size too much.
How To Analyze HRV Data from The 910XT
Use SportTracks. Use FirstBeat.
Alternatively consider looking at your HRV with an app like BioForceHRV.