false readings

patriciafoley1

twice this week my fitbit has shown abnormally high zone readings - a total of 312 minutes today and 572 on wednesday. of course it added a lot of exercise calories for periods that I may have been tense and doing things, but not "Exercising". Is this a common thing with fitbit and how do you handle it since it seems to screw up the stats. I did exercise both days, three long, fairly brisk walks. I usually walk 5-7 miles a day, but that wouldn't account for the minutes in active zone

heybales

Those levels are based on how may calories did you burn, compared to sleeping rate of burn.
I believe still 3x and 6x - Moderate and Intense, over your BMR rate of burn.

So, if your walks increased your HR enough to auto-start a workout, or you manually started a workout for them - then HR-based calorie burn calculation was used.
This is the inflated side of the formula for HR calories (not a measurement, calculated), right above daily life HR, and right below going anaerobic - both are inflated sides of the Aerobic exercise range.

So if you were hot as summer can cause, that increases HR merely to help cool body, but HRM doesn't know that, it just sees increased heart rate and thinks you were working harder - so bigger calorie burn.
That's inflated too.

If you were dehydrated, higher HR and inflated calorie burn too.

Higher HR, then of course hitting Active zone not that hard.
Besides which those HR zones are based on a potentially very inaccurate HRmax based on 220-age.
Likely wasn't really Active for you, so your HRmax is actually higher, and Active should have been higher, and you never would have reached that level.

So many reasons that HR-based calorie burn not a great estimate.
But it must have been high enough to give you some time in Moderate & Intense.

Are you sure it didn't auto-start an exercise?