My Cardio Fitness Score changed rapidly-Charge 3

[Pril85]

So, I have been monitoring my cardio fitness score.  It has been consistently on the border of poor to fair and had gotten all the waynup into the fair category.  Last week it jumped all the way up to good.  But now over the last few days it has been falling again by a lot.  I am really overweight, but have been working out doing at least 45 minutes of cardio at least 5 days per week.  Nothing has changed.  So, why would my score change so much so fast?  I was excited and feeling that it had finally paid off , but am really discouraged now seeing it fall again.  

Moderator edit: updated subject for clarity

[EdsonFitbit]

Welcome to the Fitbit Community @Pril85.

Thank you for the information provided.

Increased exercise may help you improve your Cardio Fitness Score by up to 20 percent over a period of two to three months. If you consider that you are not getting accurate readings, please restart your Fitbit Charge 3.

For tips on how to improve your Cardio Fitness Score, please visit this article.

Please let us know if you have any question.

[Pril85]

That's the part that gets me.  I workout at least 5 days per week.  Each workout,  I get at least 45 minutes of cardio in and am within the cardio  range.  I feel like the readings are accurate during my workouts and when at rest.  I am on my 3rd Charge 3 for different reasons.  And it has been the same with all 3.  I've been working out since May.  So, I figured that my cardio score should have improved more with as much cardio exercise as I'm doing.  

[EdsonFitbit]

Thanks for your response @Pril85.

Please be aware that if you don’t use connected GPS for runs, your cardio fitness score is an estimate based on your profile and heart-rate data, for example: 30-33. If you use connected GPS for runs, the cardio fitness score is a single number, for example, 33. 

In this case, please continue performing your workouts as you've done and check your Cardio Fitness Score once in a while. If during the next weeks you are still encountering the same problem please let us know to further investigate.

If you have any question, please let us know.

[Pril85]

I always have the GPS on even when I just walk.  It still shows a range.  It shows the map and where I completed the exercise.  

I've been tracking and watching this information for about 6 months now without much improvement.  

Since it factors in your profile, could it be that my weight is keeping it down?  I've lost minimal weight, but have noticed other improvements (such as improved times per mile, inches lost  etc).  

[EdsonFitbit]

Thanks for the update @Pril85.

Your cardio fitness score is determined by your resting heart rate, age, gender, weight, and other personal information. For best results, please make sure your weight is correct in your Fitbit profile. Also, make sure to wear your Charge 3 to sleep for a better resting heart rate estimate. For instructions on how to track your sleep with your Fitbit Tracker, please visit this article.

Please let us know if you have any question.

[Pril85]

Yep.  I know.   I read up on the articles about getting the most accuracy.  I keep everything up to date and wear it all the time, unless it is charging.