New fitbit giving different readings from previous device

[Mark_1982]

Hi all

I got a new Fitbit Versa 4 for Christmas and after wearing it for just over a week I've noticed it's giving me completely different readings regarding heart rate and calories burnt from my previous Surge device.

For example my previous device was saying i have a resting pulse in the mid to high 50's (i do like to keep fit and exercise a lot) but my new device is saying my resting pulse is in the top 60's very close to 70.  I can't ever remember it being this high.

I noticed that i burn fewer calories as well.  I use to burn around 3,500 now i barely make over 3,000.

I also noticed that a walk i use to go on in the morning was showing as being roughly 5.2 miles (previous device had GPS) but new device is showing the same walk as only being 4.4 miles? 

So question is, what's going on?  Is my new Fitbit "getting use to me" or was/is one of them widely off the mark?  Anybody else had this when they got a new model of Fitbit?

Any advice, guidance appreciated!

Mark

[Guy_]

Hi @Mark_1982 - the Versa 4 can over read or under read during exercise, depending on the movement and person, this will affect calories.

However heart rate when not moving should be accurate and that does seem an odd and unexpected difference for RHR.

Have you tried a walk without GPS and with in the Versa 4 and see the difference? How does the step count match too between the 2 devices?

[Mark_1982]

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@Guy_ wrote:

Hi @Mark_1982 - the Versa 4 can over read or under read during exercise, depending on the movement and person, this will affect calories.

However heart rate when not moving should be accurate and that does seem an odd and unexpected difference for RHR.

Have you tried a walk without GPS and with in the Versa 4 and see the difference? How does the step count match too between the 2 devices?

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Hi Guy

I've had a further look at the information and would the difference between when my Surge and Versa detect Fat Burn, Cardio and Peak may have something to do with my resting pulse and calories?

With my Surge, anything over 90bpm seemed to be logged as Fat Burn and over 127 was cardio.  Where-as my Versa only sets Fat burn when i get over 112 bmp for fat burn and 134 for cardio.  Not sure if this would affect my calories and resting pulse?

With the walk, the number of steps is the same (roughly 9,500ish steps on both devices) and when the GPS on the Surge isn't turned on, the distance isn't logged but it's the same number of steps.  Just the time, calories and bmp.

When i went for my walk yesterday morning (which is roughly 1 hour and 25 minutes) it did say that I've only added 26 minutes to my "Active Zone" as my bmp only got above 112bmp for that amount of time.  With my Surge, the same walk (1 hour 26 minutes) added 84 minutes to my active minutes.

Not sure if this is relevant but it does say on my Versa 1 that my heart rate zones are now personalized to my cardiovascular fitness and age on the Versa 4.

[t.parker]

@Mark_1982 you seem to be mixing up active minutes (Surge) and active zone minutes (modern Fitbits). You have been granted AM sometimes regardless of the HR zone. I know it should be granted for more intense activity but my experience with Charge 2 tells me that just by starting tracking exercise manually, the AM were piling up. I think the intensity factor was used only outside of regular exercises. In other words, getting AM was dead easy. When Fitbit introduced AZM, it was harder to earn minutes because your HR must be elevated to reach any zone. It depends on how accurate HR tracking is and whether your zones are set correctly. See how readings may differ on the following example (my 1hr bike ride):

This has been recorded with Sense 2. The purple line is HR from Fitbit Sense 2. It's not only inaccurate but it misses plenty of data points. I don't know how Fitbit treats those. I think it may just be interpolating HR between known data points. The blue line is PolarH10, the gold standard of HR accuracy. 

Dashed lines represent borders between my HR zones, yellow range - Fat Burn (AZMx1), orange - Cardio (AZMx2), and red - Peak (AZMx2). Now, see the table. If it was tracked with an old device, I would earn 50 Active Minutes, just for the sake of tracking the activity. However, Sense 2 gave me only 27 because HR is ridiculously inaccurate (and it's no different on Versa 4, it's the same sensor and the same technology). If I count AZM using PolarH10 data, I should receive 121 AZM. This is a huge difference.

So double check:

- Whether your HR looks correct (and my bet is that it is a probable source of the problem)

- Whether your zones are correct (this is harder to check)

- Count AZM not AM. There are no more Active Minutes on modern devices.