You are correct that it does not measure heart rate. There are probably few of these still running. Newer Fitbits base calorie burn on heart rate. Yours must base it just on step count, and frequency of steps. And being worn on the wrist, no tracker is not precise on counting steps. It cannot tell what your legs are doing and only infers steps from steady rhythmic movement of your wrist, such as in the swinging of your arms when walking. Generally over a full day it comes fairly close, but some activities, such as playing as guitar or drums or knitting, can give many extra false steps. Perhaps some of your cleaning activities were like that, such as if you were cleaning windows might have counted as extra steps leading to extra calorie burn. With heart rate sensor, the extra steps would still be there, but not the extra calories. But perhaps you were actually doing that much walking, tough to tell.
Before posting, re-read to see if it would make sense to someone else not looking at your Fitbit or phone.
Platinum Fitbit Product Experts share support knowledge on the forums and advocate for the betterment of Fitbit products and services. Learn more
Best Answer