interpreting fitbit workout session results - i’m not getting it

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Hi,

I am a Versa 3 user x many months.

During my workout today, for example, i get:

1. 70 active zone minutes, fat burn, 575 calories

2. 900 total cals burned

that leaves 900 - 575 = 325 calories unaccounted for.

what does the 325 calories represent?

[JohnnyRow]

You get active zone minutes only for that part of your workout when your heart rate was equal or above lower limit of fat burn zone.  You can see this zone limit by tapping zone minutes circle on phone app.  You would still be burning calories when heart rate was below that.

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Thank you for the reply. What fuel source is tapped by the remainder calories, those NOT accounted for in AZM? Total Cals - AZM = “remainder”

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[JohnnyRow]

Pretty much the same source.  "Fat burn zone" is really a misleading description; not accurate to think burning just fat when in that zone and no fat when not in that zone.  Originally fat-burn zone was meant to distinguish aerobic training which would burn fat more efficiently, as  distinguished from high intensity anaerobic training which burned glycogen, carbohydrates stored in the muscles, which got burned quickly and inefficiently.  That original term has been kept, though it really does not have the literal meaning it once did.  It is not accurate to thing that in fat-burn zone you are burning fat and only fat, and out of that zone, not burning fat.  Now really it's just a convenient demarcation zone.

In a practical sense, just think of it all as just calories.

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oh yeah, we are in the same page about the myth of the fat burning zone. You know 35% of total calories may be quantitatively more in fat grams then 50% of a much lower total calories of lower intensity exercise.

That being said I just don’t understand what fitbit does with total calories versus Active Zone Minites which i use every day. What is your take on what to do with the total calories versus AZM?

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[JohnnyRow]

Guess I'm not understand your question then.  Calories and AZM are totally different measurements and units;  don't understand how you are trying to relate them.  AZM is time spend in certain heartrate zone, doubled for aerobic zone.

Going back to your original post, maybe a screencap would help, but even then I'm not sure.

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sorry to frustrate

are they 2 entirely different constructs? i am trying to figure out the relationship between total calories spent in an exercise session versus AZM. If we subtract the AZM calories for the session from total calories from the session, what is it that we have?

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[JohnnyRow]

I don't know what you mean by AZM calories.  If there is a screen that shows that, you would have to show me.  It might just be something I'm not used to looking at.  There are lots of views of exercise and calories; views that some people take as "the standard view", others might not even look at.

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okay total calories and AZM minutes appear at the same time on the exercise watch face

AZM are active zone minutes. They are awarded during a workout based on heart rate, which is dependent on exercise intensity. It keeps track of the “quality minutes” you produce and the corresponding calories. In this case it’s 48 minutes and 398 calories. However the total calories are 799 calories. My question is wha do the two calorie values 398 and 799 calories represent. Why aren't they the same or not?



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[JohnnyRow]

Do you see this info info anywhere on the phone app, or is it only on the Versa 3 watch face? Are you seeing this as you are exercising or after you finish?  Are you using the Exercise App on the Versa 3 to record the exercise session, or relying on  auto-recognition?  I'm trying to think of that display but I can't picture it.  I don't have the Versa 3 but wouldn't think that would be the difference.  I'm used to looking at workout displays on the phone app after the workout where it is a static display that is kept and can be looked at to understand afterward.

But like I said in my first reply, you would still be burning calories when you were below the required heart rate to earn AZM.

I know occasionally I am surprised by a phone app display that I have never looked at before, but if this on wrist, I must have just missed it.  Sorry but I'm no help here.

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But like I said in my first reply, you would still be burning calories when you were below the required heart rate to earn AZM

This is the key to my question I think. Of these calories that are below the required heart rate to earn AZM, do we know what fuel source is burned for these “non-AZM” calories? Or is the advantage of AZMs is that the fuel source is predictable where it is not so for calories under this range.

 I think based on my talk with a nutritionist that it’s impossible right now to know the mix composition of under-zone calories  from a watch although you can know these calories as part of the total calories from the workout session. But the proportion or absolute amount is unknown. It can be significant carb/fat burn. The under-range calories as a part of the overall calories from a workout can be measured though, just not the proportion, which is guesswork.

What do you think about these observations ? I think it explains things. Basically these under-range cals are a black box.

I’ll post the additional info as well but this is the heart of my question.

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Oh, the workout session calories and the heart rate are both displayed together on the watch face and initiated by the user at workout start. This information and the AZM for the same workout session is also displayed in the fitbit app along with total daily calories.

Sorry for the lengthy replies. 

[JohnnyRow]

So your whole point is trying to determine the body's fuel source of these calories, right?

Until now, I thought you were questioning Fitbit's data display, wondering that they they were displaying data wrong and not totaling calories correctly or such.  That is why I was trying to figure out where the display came from so I could take a look at it to analyze it better.

I would argue against what seems to be your basic premise: that you know the fuel source of the calories burned when in AZM zones.

And even if you did, what difference would it make, unless you were a truly elite athlete, in which case I doubt you would be using a Fitbit for your serious training.

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I think your response is at best outdated and at worse in the pejorative. I’ve recomped over 100 lbs culminating in what has turned out to be an athletic endeavor. I use those minutes together with the lumen to tune my diets metabolic flexibility. I use carb cycling to match energy supply with energy demand, which is connected to the quality of those session minutes , also known as AZM. The lumen app in determining your plan for the day uses those quality minutes to adjust the carbs and recovery. It is stratified to accept fat burn and higher intensity minutes. It is very effective and i wholeheartedly disagree this is reserved for elite athletes. 

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ok, fair enough

if this is turning into a discussion about debunking the myth of the fat burn zone i’m up to speed

fat burn is whatever heart rate range for my age that is fat burn.. it's been well studied.

cardio range is 50/50 carbs/fat

objectively i’ve dropped fat so it’s very likely the fuel source is correctly matched to the heart rate

but these are proportions of total calories, not absolute amounts



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[JohnnyRow · Accepted solution]

I would also say below the fat-burn zone, you are also burning fat, just fewer total calories.  Maybe that was your original question.

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I agree with that. Yet I can't find any information on the fat/carb burn proportions for calories burned *under* that zone. I think what you might be saying is that it gets academic at that point, but i am curious nonetheless. My suspicion is that it is unknown.
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