Cardio fitness declines with exercise

[SunsetRunner]

I'm using an Ionic and for 3 months my app was showing the Cardio Fitness as 47. All this time I was continually hitting or exceeding my weekly exercise goals and waiting for the score to improve, as that is what regular exercise is supposed to do, according to the description.

Upon checking today I found my new score reading on "between 41 and 45".

Thanks for your support and inspiration, Fitbit.

[WavyDavey]

Hi @SunsetRunner ,

It sounds like your cardio fitness score went from 47 to a range between 41-45. The range tells us that the Fitbit needs a specific exercise to recalculate your score. Just go on a run on a flat surface, at least 10 minutes, and it will give you a new calculation.

I've noticed mine fluctuates a bit, especially if I don't go on the 10 minute runs. Best of luck.

[SunsetRunner]

Hi Dave, I run at least 2 (often 3) times every week for 35-45 minutes. My usual distances are 5-7k at around 5:30 per km. Heart rate during exercise is always 140-160bpm.

No idea how this much data could be insufficient for the Fitbit to do its calculations.

By the way, whoever in Fitbit decided that this belongs in the help forum for the Ionic and not in the general Dashboard discussion, clearly does not understand their own products. Calculations of the cardio fitness score are not made by the device. The problem lies within the algorithm.

[WavyDavey]

It's hard to know what's in the secret sauce of Fitbit's version of VO2Max, but it's probably proprietary so hush hush and all.

 I have seem posts describing what you're experiencing. I'm not much of a runner, but if I recall correctly, when I took longer runs, it would have an effect on the score also.  I had to reset the score with the 10 minute run.

There's something about the 10 minutes. This actually makes sense, as VO2Max scores are done on standardized equipment.  So Fitbit's standard seems the 10 minute run. If you find a smartwatch that can dynamically calculate VO2Max across any number of exercises of varying lengths, let me know. 🙂

I could move your thread, but honestly you'll get a lot more views and help in the Ionic forum. The Dashboard is mostly for the web front end at fitbit.com. But let me know.

[SunsetRunner]

I have searched everywhere and could not find any references to the 10-minute runs bearing any significance for Fitbit calculations. Care to share a link where you read that?

[Colinm39]

@SunsetRunner  It's all in this link for the explanation and calculation of Cardio Fitness Score

If you have a single Vo2max number it has used the 10 minute running on flat terrain, if it's a range, it's using your physical details like RHR and sleep etc,,,

This is all covered in the link..  and this link goes straight to your Help topics where you can search..

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@SunsetRunner wrote:

I have searched everywhere and could not find any references to the 10-minute runs bearing any significance for Fitbit calculations. Care to share a link where you read that?

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[SunsetRunner]

Actually, in that article it repeatedly says "long runs (AT LEAST 10 minutes)" which is by definition not the same as "10 minute runs".

I specifically mentioned earlier that I run for 35-45 minutes which I would classify as being included in the "at least 10 minute runs" category.

The algorithm for their calculation is broken, and Fitbit needs to realise that, admit the issue and fix it. Simple as that. 

[SunsetRunner]

Just to update this. In the month since my last post I've done four GPS runs: 5km, 5.3, 5.4 and 5.7km. (not counting numerous treadmill runs in between). 

I am now in a much better shape cardio wise than I was 3-4 months ago when my fitness score was showing 47. Still, my current figure is sitting unchanged on 41-45.

Choosing Fitbit Ionic over Garmin Vivoactive looks more and more like a big mistake to me.