A:Answer My answer depends on how snugly your Fitbit Sense 2 is held to your wrist by the watch's wristband. If your Sense 2 moves easily over your wrist, then you must tighten it up until it does not move easily on your wrist. If your Sense 2 was tightly secured to your wrist when you experienced the erroneous pulse rate readouts, then it is possible your Sense 2 was detecting palpitations in your heart beat, such as atrial fibrillation or atrial flutter. If, during the time your Fitbit appeared to be reporting an erroneous heart beat rate, you were monitoring your pulse rate manually and you felt no additional heart beats beyond your regular sinus rhythm of 60 per minute, then your watch may be faulty and should be brought to Best Buy for fault analysis. If, however, you did detect additional, though faint, beats in addition to your basic sinus rhythm of 60 beats per minute, then you were experiencing heart palpitations that your watch correctly reported; and you should see your family doctor immediately for referral to a consulting cardiologist.