I think by now everyone knows that fitbit's calories burnt number in a day is nowhere near the real amount. However, I thought it was at least internally consistent, that is to say, if one day it showed that I burnt 3000 calories and another day it showed that I burnt 3300 calories, I thought I could assume that I burnt more calories the second day, maybe not 300 calories more but definitely more calories. However, after paying close attention, I've realized that this is not true. I've checked how many calories it says I burn when I walk 3 miles in an hour and it logs about 500 calories, which is almost double what any chart I found only says that kind of walk would burn. However, that wouldn't be too bad if calories calculated for all exercises were exaggerated, but when I log a workout where I'm consistently maintaining zone 2 heart beat for the entire hour fitbit says I burnt around 400 to 420 calories, so I'm burning less calories while doing exercise in zone 2 than when I'm walking with an average heart beat of around 100. How does that make any sense, how can they get the simplest of calculations so wrong? It's not even about the sensors giving bad data because, as I said, while walking I'm getting a way lower average heart beat and yet I'm somehow burning more calories than when exercising in zone 2. Absolutely absurd
