This is very strange but....I tried the Charge 5, the Luxe, the inspire 3 and the Sense 1 and 2 and had the same problem on all of them. The problem does not exist on the Charge 4 I own or the Inspire 2 which I also own. I have very thin wrists and the Charge 5, Luxe, Inspire 3 and Sense all have very erratic heart beats for me - jumping from 70 to 100 and continuing to climb to very high numbers (all while seated). I have had to return all of these fitbits for the same reason. I restarted many times and it never fixed the problem. Does anyone know why this would occur on the recent models and not on the own. I wouldn't even think of trying the Charge 6 because of this issue.
