First this isn’t a post to brag. I’ve had a Fitbit charge 2 and 3 since July 2018 and my cardio score has always been in the low 80s and The score hasn’t fluctuated in the two Years I’ve been wearing charge devices. This score seems way way too high. I do ride the stationary bike 4 days a week for for 35 minutes but I am far from an Olympic athlete. Heck I probably couldn’t even do a 10 minute mile. The charge devices have always recorded my resting heart rate at 39 which is about what my physician measured (42-44). Does this seem strange? I’d hope the score would be based on more than just my resting heart rate.
