What does the change of active zone minutes say about my progress?

[MarcianoNL]

Hi all,

i ve ben wearing my fitbit for over two months now. 
last week my active zone minutes ranges (fat burn,cardio and peak) went up, probably because i was ill. Now they are down again even slightly lower than my normal level.

i would love to get updates from fitbit what those changes mean related to my health and fitness progress. 
can someone explain me what those changes mean? Just curious.

Marciano

[Julia_G]

Hi, @MarcianoNL , your guess that your Active Zone Minutes ranges changed because you were ill - and then again when you got better - is likely correct.  

Your AZM ranges are personalised to you based on your heart rate reserve.  Your heart rate reserve is the difference between your theoretical maximum heart rate (220-your age) and your resting heart rate.  When a person is ill, their resting heart rate (RHR) is likely to go up as their body works harder to fight the illness.

Conversely as you get fitter, your heart rate tends to go down.

As you can see, when your RHR changes, so will the calculation of your heart rate reserve, and that will cause a shift in the active zone minutes (AZM) thresholds from moving from one Zone to another.

You can read more about this in this help article which explains the calculations and thresholds.  Please also see the help article that gives a full explanation of Active Zone Minutes and how they are calculated .

As you are aware you can see Fitbit’s calculations of your personalised heart rate zones in your app.  From the opening, Today, screen click on the person photo/icon top left.  Scroll down to “activity and wellness” and then choose “heart settings” and then “heart rate zones”. 

I hope this helps.  Welcome to the forums!

[MarcianoNL]

Thanks a lot Julia, this helps a lot. I get more insights in my progress.

have a good day!

[t.parker]

@MarcianoNL In general, AZM say nothing but that your HR is elevated below/above a certain threshold for a certain time (in mind that cardio/peak zones count minutes x2). The context of those changes is known only to you (a very individual thing). It may align with what @Julia_G said but doesn't have to. AZM takes into account your whole HR range yet it tries to compress it into two data fields losing lots of information in that process. It rarely can tell you anything useful about your health or fitness because it's not made for that. It's made as an indicator of the intensity of exercise (how much time you spend exercising easy or intense) but even in that aspect, AZM is too simplified to provide any information about the health or progress of your fitness. Also, it requires you to know your max HR. Formula 220-Age may work, but most likely won't. By my own example 220 - 42 = 178, yet my real max HR is 191bpm 🙂 - a huge difference when it comes to defining zones resulting in wrong AZM distribution and then leading to false conclusions. Also, that requires an accurate HR sensor which in certain cases will be affected (my yesterday's 82min bike ride gave me only 4AZM because the watch wasn't able to read my HR properly). To draw any conclusions from AZM you need to make sure your zones represent what you really want (so that you understand what AZM means to you) and make sure HR readings are correct (as my bike ride, 4AZM should in reality be 73). Personally, I'm not a big fan of using AZM for any serious fitness/health analysis. All it tells me is: "I exercised this much" and I see it as a good reward item for beginners who just start moving more but are not quite sure yet how to tackle more complex data.

[MarcianoNL]

Thanks for those insights @t.parker it kinda shines another light on it. From your answer perspective; how can I use my fitbit inspire 3 the best if I want to have a view on my fitness/health progress? What data can tell and give me the most acurate information? 
just curious and willing to learn a little more about it.

all the best, 

Marciano