Fitbit isn't accurately tracking anymore

[QHMom]

I have tracked my runs on the treadmill with my Fitbit Sense for probably the last 4 years or so. Recently, I've noticed my Sense is under tracking speed and distance. I haven't changed any of my settings but have noticed a difference of 1-1.5 mph from what my treadmill is set at and generally a .25-.5 mile difference in finished distance. I don't hold handles and my arms swing naturally as they would if I was running outside. 

My Sense has always been fairly accurate but the last few weeks it has been getting gradually worse. I did get this Fitbit for Christmas in 2020, so I'm wondering if maybe it's time for a newer model? Has anyone else had this happen and needed to upgrade? The battery life is still fairly good and everything else seems to be working normally.   

[Guy_]

Hi @QHMom - have you tried restarting with the watch display on hold the watch button for 10 seconds till the display blanks or it vibrates, release and wait for the logo to appear and it to start. Your watch is probably ok.

[LZeeW]

@QHMom  A treadmill measures distance from the belt movement.  Treadmills require regular maintenance to prevent damage and maintain accuracy.  Do you do regular maintenance?  Your issue might be your treadmill, not your Fitbit.