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The tale of two Fitbits (Charge 3 and 4)

PAV8888
PAV8888 Posts: 9,206 Member
I now have a complete week with my new Fitbit Charge 4. I am wearing it side by side with my gimpy screened Charge 3.

Basically I broke my charger while out of town and it was +$80 to end up with a new charge 4 including a charger and strap vs buying just a charger and strap for my gimpy screened Charge 3. But, this resulted in TWO Fitbits, since with a bit of care one can charge a charge 3 on the charge 4 charger, and duct tape fixes everything!

I admit to not liking the reduction in "active" time inherent in this "active zone minutes for me" vs "active from the perspective of what is universally considered as moderate level of exercise)... I am now feeling "inadequate" when it comes to my "active" level of activity!

But my "validation" results of the new Fitbit Charge 4--to the left--vs the old gimpy screened Charge 3--to the right--seems to be... "in the ball-park".

I am not happy that the new Charge 4 seems to have a few more "I am not counting anything" heart rate drop offs. And I'm at the cusp of "is it worth the effort to get the manufacturer to do something about this and what is the likelihood of a refurb unit yielding more reliable results. The power reserves on the Charge 4 are.... yeah... let's say the Charge 3 lasts longer!

But in terms of the calorie, sleep, automatic exercise detection, and steps metrics... they seem to be very close. The screen is larger and brighter. The resting heart rate rate is within a beat a minute on both watches both before and after the metric is corrected by the "cloud". And it has GPS that can suck battery faster than a speeding bullet ensuring your long walk will result in a powered off fitbit!

All in all I would say the results and insight offered seems to me to be close enough for my purposes. As long as I am not relying on that altimeter for anything!

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Replies

  • PAV8888
    PAV8888 Posts: 9,206 Member
    Yes, I *am* wondering if the RHR increase was caused by second Covid shot which was the day before the side by side week.

    Heart rate variability (with my highest at below the lowest 'normal' for my age group) has been alarmingly low. But I don't have prior data as to what may be normal for me.
  • BarbaraHelen2013
    BarbaraHelen2013 Posts: 1,727 Member
    It’s interesting to see the difference between the way your two devices are counting activity.

    I had a 4 year old Fitbit Alta (now deceased) which used ‘active minutes’ and a month ago replaced it with the newly launched Luxe. The Luxe uses ‘active zone minutes’ just as your new device does.

    My experience is the opposite of yours, however. I’m registering a lot more ‘zone minutes’ than I ever have when it counted ‘active minutes’. It seems to be much keener to ‘count’ semi-vigorous daily activity than the older method.

    I’m feeling unsure because it’s obviously sending a bigger calorie adjustment over to MFP and my daily calorie burn on the Fitbit dashboard is higher than it’s ever been (I actually broke 2,200 a few days ago!) 😂 I just don’t believe it’s realistic for a very short, older woman who loses super slowly anyway.
  • PAV8888
    PAV8888 Posts: 9,206 Member
    Barbara, check/double check on your stats (height, age, weight) and that you've selected dominant (even though you may be wearing the fitbit on a non dominant) hand. These are common adjustments (especially the dominant/non dominant) that could affect counts.

    The only situation where I can envision what's happening with you with active minutes is if the default max heart rate formula (220-age) is not representative for you, in which case your heart zones may be getting reached under lower than expected activity loads.

    The old activity minutes I believe were not determined by heart rate but rather by the deduced activity level from the accelerometer, orientation, and gyroscope sensors
  • BarbaraHelen2013
    BarbaraHelen2013 Posts: 1,727 Member
    Wait, what? I should set it to ‘dominant’ even though I’m right handed and wear it on my left wrist? Have I understood that correctly? What’s the rationale behind that?

    Using your HR formula my max heart rate should be 160 I guess. If what you suggest was true, that would suggest my cardio vascular health was poor? Or am I misunderstanding the relationship between the two things?

    4bcscjc6881y.jpeg

    That image shows that Fitbit rates my cardio fitness as excellent for my age. But now you have me concerned!
  • PAV8888
    PAV8888 Posts: 9,206 Member
    You mentioned that the Fitbit detected your calories at higher than expected.

    A pretty common minimal adjustment to reduce spurious steps recorded by hand movement and/or as a consequence of the reduction to reduce the calories Fitbit detected as expended is to lie about the offhand being dominant.

    This adjustment was especially making the runs of the Fitbit forums during the first and second generation of fitbits.

    By default new trackers seem to ignore that setting when first connected onto the account and revert to not having it set as I discovered the first day when there was a considerable step count difference between my two trackers, the old one having been spun off to a new account with the setting explicitly set, while I assumed that the old one had inherited the "existing" setting.

    So I figured it was worth asking if you had done that given that you changed trackers. It is not something you have to do. It is something that makes the Fitbit less sensitive to occasional soft steps.

    220 - age as maximum heart rate is not my formula, it is the formula that Fitbit uses by default unless you override it with your own maximum heart rate setting if it happens to be different and you know it.

    You mentioned that you spent a lot of time in the zones and that as a consequence you were getting a lot more calories that based on your previous logging you didn't feel would make life easier for you.

    One of the reasons I've ran both fitbits was not only that I had the chance but that I wanted to validate how close the calories would be between the two.

    To me anyway (and in my particular case) it looks like these calories are pretty close.

    And since in general Fitbit is about 100 calories too generous for me, the direction of the slight divergence between the two is closer to my own reality so I'm happy enough with the comparison. This is in spite of the reduction in active minutes which is probably exacerbated by my having manually input +15 as my maximum heart rate, which of course correspondingly shifts up the various zones.

    It was not random that I shifted up to that level, but it does make it harder to reach the zones and much more in keeping with how I feel about my level of exertion and ease.

    Having said that your Fitbit certainly things that you have a good level of cardiovascular health.

    If you do not have GPS on your unit and if you're able to sustain a run of a few minutes on flat terrain with an unobstructed view to the sky you can start a run using the app and GPS on your phone. And after just one or two of them or so (and they only have to be a few minutes as a minimum) the cardiovascular health level should collapse to a single number.

    In no way am I suggesting anything or expression concern or doubts about what looks to be excellent catdiovascular health.

    I'm just reacting to your observation that you're getting too many minutes in zones as compared to before where these zones were not defined the same way.

    Also to remember in the big scheme of things that fitbits are estimators and so is our base metabolic rate and everything else.

    Statistically most of us are close to the estimated average but that doesn't mean that quite a few of us aren't either below or above it.

    That's why we look at longer term trends and correct our goal setting based on results!
  • heybales
    heybales Posts: 19,330 Member
    The prior Active method was 3 x your BMR rate of burn.
    Obviously to decide what the calorie burn was to see if hitting 3x, it did use your HR during workouts.
    But didn't you also have to hit it for like 5 or 10 min solid to get any time to count?

    Whereas now you have a HR zone based on your HRmax entered figure, so that effects the calorie burn and where the default zone lies.

    That's pretty good that the distance the steps took you is so close in comparison.
    The distance per step did drop a tad.
  • heybales
    heybales Posts: 19,330 Member
    edited July 21
    Wait, what? I should set it to ‘dominant’ even though I’m right handed and wear it on my left wrist? Have I understood that correctly? What’s the rationale behind that?

    Using your HR formula my max heart rate should be 160 I guess. If what you suggest was true, that would suggest my cardio vascular health was poor? Or am I misunderstanding the relationship between the two things?

    4bcscjc6881y.jpeg

    That image shows that Fitbit rates my cardio fitness as excellent for my age. But now you have me concerned!

    That score is based on attempting to estimate a VO2max score.
    Which is based on an estimated HRmax figure, and what your workouts do to your HR and frequency of workouts, and your restingHR.

    That 220-age is what Fitbit is already using BTW for HRmax.
    Unless you have a better estimate and changed it.

    If you've surpassed 160 - then it's wrong. If you've held around 160 for more than a few second where you felt like passing out right afterwards - then it's wrong.

    Which means anything based on it is wrong. HRzones, that fitness score, calorie burn during exercise.

    ETA:
    Fitbit doesn't send an adjustment to MFP. It sends a daily burn figure, MFP does the math and creates the adjustment.
    Of course you said Fitbit is showing bigger daily burn, hence MFP will get a bigger adjustment.

    Did you create a new account, are you within the first 2 weeks of using new device?
  • MsFraggleRed
    MsFraggleRed Posts: 10 Member
    Interesting comparison. It looks like they fixed the altimeter with the Charge 4 again. I have a Charge 2 and 3. Wearing my Charge 3 I always end up with a ridiculous floor count compared to my 2. :D
  • PAV8888
    PAV8888 Posts: 9,206 Member
    heybales wrote: »
    The prior Active method was 3 x your BMR rate of burn.
    Obviously to decide what the calorie burn was to see if hitting 3x, it did use your HR during workouts.
    But didn't you also have to hit it for like 5 or 10 min solid to get any time to count?

    Whereas now you have a HR zone based on your HRmax entered figure, so that effects the calorie burn and where the default zone lies.

    That's pretty good that the distance the steps took you is so close in comparison.
    The distance per step did drop a tad.

    @heybales I think you've mixed the two units based on what you're saying.

    The new unit is on the old account and to the left.

    The old unit (itself a replacement unit but used on the original account for 19 months almost to the day) was spun off to a brand new account. There was a one and a half day period where there was a 0.1 centimeter height difference between the accounts and where I had forgotten to mark the new unit as dominant hand. That height difference ought to have made the old unit, to the right, strides shorter as opposed to longer. I did one GPS open air walk successfully on the new unit... and one where the whole thing came crashing down due to lack of battery. My normal walks are in forested areas and not great for GPS tracking

    I'm interested to see if the same "cloud corrections" (+1 on unit detected resting heart rate for example) happen on the new/clean account. We're now on the 10th day where both accounts are running.

    I am somewhat disappointed that there was one extra day where the new tracker did not get sleep data whereas the old one did.

    Even though the new tracker is now getting the better wrist position it has more frequent cutoffs for heart rate than the old one :(

    This of course could be an individual unit variation, or because the new version has a bigger screen.

    To be honest I think they're pretty close when you take into account what they're trying to do based on wrist input
  • NorthCascades
    NorthCascades Posts: 10,716 Member
    PAV8888 wrote: »
    A pretty common minimal adjustment to reduce spurious steps recorded by hand movement and/or as a consequence of the reduction to reduce the calories Fitbit detected as expended is to lie about the offhand being dominant.

    I have to tell my Fitbit I'm a raccoon for it to work? What? It can give you useful data but only if you hide enough about the world and make it think you live on a moon of Jupiter?
  • PAV8888
    PAV8888 Posts: 9,206 Member
    But which hand do you use to rub your belly and which one rubs your head? What happens when you change directions? Are consistently under-or-over estimated data better or worse than random data? Is it easier to not gesture with your Fitbit hand, or to "lie" about that hand being dominant? If you're Mediterranean and gesture a lot, would lying about your hand being dominant make you closer to a Northern European user, or should ethnicity be a distinct question and category that your Fitbit considers, or it is OK to just fib to your Fitbit? Do you swing your Fitbit hand when pushing a shopping cart, or do you rest your chin on your hands while you push? What happens if the shopping cart is a buggy? With one? With two? With THREE children inside? These are all very interesting questions... we should maybe get some time on Azure AI to investigate them! Oh wait, Google Cloud machine will probably get on that
  • heybales
    heybales Posts: 19,330 Member
    PAV8888 wrote: »
    heybales wrote: »
    The prior Active method was 3 x your BMR rate of burn.
    Obviously to decide what the calorie burn was to see if hitting 3x, it did use your HR during workouts.
    But didn't you also have to hit it for like 5 or 10 min solid to get any time to count?

    Whereas now you have a HR zone based on your HRmax entered figure, so that effects the calorie burn and where the default zone lies.

    That's pretty good that the distance the steps took you is so close in comparison.
    The distance per step did drop a tad.

    @heybales I think you've mixed the two units based on what you're saying.

    The new unit is on the old account and to the left.

    The old unit (itself a replacement unit but used on the original account for 19 months almost to the day) was spun off to a brand new account. There was a one and a half day period where there was a 0.1 centimeter height difference between the accounts and where I had forgotten to mark the new unit as dominant hand. That height difference ought to have made the old unit, to the right, strides shorter as opposed to longer. I did one GPS open air walk successfully on the new unit... and one where the whole thing came crashing down due to lack of battery. My normal walks are in forested areas and not great for GPS tracking

    I'm interested to see if the same "cloud corrections" (+1 on unit detected resting heart rate for example) happen on the new/clean account. We're now on the 10th day where both accounts are running.

    I am somewhat disappointed that there was one extra day where the new tracker did not get sleep data whereas the old one did.

    Even though the new tracker is now getting the better wrist position it has more frequent cutoffs for heart rate than the old one :(

    This of course could be an individual unit variation, or because the new version has a bigger screen.

    To be honest I think they're pretty close when you take into account what they're trying to do based on wrist input

    No, I knew the newer units and methods is the Active Zone minutes, on the left.

    Active minutes on the right had that minimum 10 minutes requirement before it would count any.

    https://help.fitbit.com/articles/en_US/Help_article/1379.htm



  • BarbaraHelen2013
    BarbaraHelen2013 Posts: 1,727 Member
    PAV8888 wrote: »
    You mentioned that the Fitbit detected your calories at higher than expected.

    A pretty common minimal adjustment to reduce spurious steps recorded by hand movement and/or as a consequence of the reduction to reduce the calories Fitbit detected as expended is to lie about the offhand being dominant.

    Ahh ok, makes sense, however the step count doesn’t seem to overinflated compared to the old device. I’ve calibrated my stride length using the standard ‘walk a known mile’ method and I do regularly do rough and ready spot checks while counting steps out loud and checking the app every 100 steps. I have checked all the settings and they seem not to have been effected by simply deleting a device and adding a new one to my Fitbit account.
    220 - age as maximum heart rate is not my formula, it is the formula that Fitbit uses by default unless you override it with your own maximum heart rate setting if it happens to be different and you know it.

    You mentioned that you spent a lot of time in the zones and that as a consequence you were getting a lot more calories that based on your previous logging you didn't feel would make life easier for you.

    This seems to be spot on for where the ‘problem’ may lie. When I checked the HR zone settings it has my max rate at 143 rather than 160. Consequently the other thresholds (fat burning & cardio)?are also set lower. It has me entering fat burning at 105bps. It’s not hard to raise my HR to that while deep cleaning the bathroom, doing moderate gardening, running up and downstairs cleaning and tidying etc. So I’ve tweaked those settings and so far today the active zone minutes seem to be more realistic. 😊

    So far it’s only registering the 21 minute dog walk and not the time I’ve spent clambering around on the kitchen benches scrubbing and polishing the glass splash back along the kitchen wall! Perfect!

    Thanks for your help in pointing me in the right direction to get my numbers back into a realistic zone.