Calorie Count with different FItbits

[writergal28]

For those who have two or have used more than one Fitbit:  Have you noticed a calorie count difference between devices?  I've JUST switched to a Versa (from a Charge 3 - yes, I KNOW, I've only had the Charge 3 for a few months.  The Versa was a gift, so I'm trying it out) and I've noticed a 200 difference day-to-day.  Is it because I'm tracking my workouts differently (e.g. using the "workout" mode rather than not using any mode)? 

[Baltoscott]

@writergal28 -- I often notice a difference, maybe 5-10% on a given day, between steps and energy burn between different tracker types worn at the same time (You can test by putting them on different Fitbit accounts and wearing them at the same time on different arms.  Do a couple of days and switch between arms and then take an average to account for the difference between wearing the device on the hand you use more often).  Over the course of a week, however, everything tends to average out. 

On the other hand, it could be that you are tracking activities more often now.  When you track and label your workouts as activities of some type, Fitbit (and others, like Garmin) take that information into account and use it in addition to the information gleamed from tracker recorded movement and HR.  You can see this in action by deleting the activity and seeing how it affects your total calorie burn and activity minutes for the day (deleting the activity takes away the 'extra information' but not the underlying step, hr, and motion data recorded by the device).  I don't know if labeling an activity gives a more or less accurate or daily energy burn than just letting the tracker work things out on its own, but it is more work ;-).  

For my part, I mostly track activities on my Fitbit to have a better historical record of what kinds of activities I've been doing lately, and don't worry too much about the reported calorie burn.  Over the course of a day it never amounts to all that much, and whether I am gaining or losing weight/muscle is better reflected by the scale, mirror, and tape measure over time.

[writergal28]

@Baltoscott: Does tracking and NOT tracking an activity make a difference?  Even if you're doing the exact same thing?  Why would that be, anyway?

[SunsetRunner]

@writergal28 I don't see it as something strange. I have seen such difference during first days of using Ionic together with Charge 2. Then I just removed Charge 2 from my account. Neither is more accurate, any gives just estimates. I believe the algorithms used to calculate calories may have been slightly adjusted between different watches. It may matter how well HR works and as you noticed - type of exercise you are tracking. The last factor in fact may be crucial as each activity engages your body different way. Different groups of muscels have different needs for energy to perform work. In fact, it is very hard to show complexity of our "machinery" just with a simple algorithm that should work for everyone. Hence, always look at these numbes as a guide. Make sure you provide enough details ( weight, height, age etc. ) so the estimates may get closer to the truth. I use numbers from 3 sources. I found out that for me, the closest to the reality is Polar, Ionic underestimates calories, Suunto overestimates. But I am sure none is accurate.

[Baltoscott]

---

@writergal28 wrote:

@Baltoscott: Does tracking and NOT tracking an activity make a difference?  Even if you're doing the exact same thing?  Why would that be, anyway?

---

Yes.  It makes a difference because tracking (and telling the tracker that the activity is of a certain type like yoga or walking) provides more information.  HR and tracker movement are not a perfect proxy for actual energy expenditure. In practice HR and movement are a pretty good proxy, however, and I don’t think recording as an activity makes enough difference to be meaningful for weight management, but companies that make trackers will try to make them as accurate as technology within the price point will allow.  (As an aside, Fitbit does sample HR more often if you start an activity, so you will get a better HR record for that time period if you do that).