Fitbit Activity Intensity

DemoraFairy

How does Fitbit decide whether an activity was light, moderate or intense? I assumed it was number of steps done in each period, but got a few graphs where I've got more steps in moderate periods than intense periods. I also wondered if it was to do with incline but that doesn't seem to be the case either. I tried searching and found one thread on the Fitbit forums asking the same thing with no answers. Anyone know?

CoachJen71

I'm not entirely certain either, but it amuses me that my Zumba has the same value as a slow walk to my Flex. I pretty much log any exercise that isn't walking/running for that reason.