Backup
Restore
Note: you do not have to put the backed up files into their respective folders on the fēnix 5, just put them all into the hidden NEWFILES folder and the fēnix 5 will do the rest for you once it is disconnected from your computer and powered on.
From Garmin forum by rweckhoff
Where are the fit files for all day heart rate monitoring, steps, and floors climbed stored?
History of steps, RHR and VO2Max are all saved to Garmin Connect.They will be lost on the watch
From Garmin forum by chunkywizard