I just did a short workout and I know for sure that my heart rate went over 100 during the workout, according to my fitbit. When I afterwards went into the app to log the workout I realised I'd switched bluetooth off accidentally so had to switch it back on. But it seems (a) the fitbit doesn't store heart rate history so this was lost and (b) the gap was filled in with noisy but extrapolated false data. I would understand much better if there was a gap - why is it filling in the gap with incorrect data?
