Cardio Fitness Level

[DaltonL]

Hello,

I’ve had my Blaze for almost a year now. I do CrossFit 4-5 days a week for the past 2 yrs.  My cardio fitness level has stayed at 40. It’s hasn't changed once. I typically choose the workout option in the Exercise section. Is the only way to get an accurate cardio fitness score through running with GPS for at least ten mins? I feel like I am much more fitter than what my Fitbit is telling me. What’s the point of the workout option if it doesn’t accurately calculate your cardio fitness score. 

[SilviaFitbit]

Welcome to the Community @DaltonL. Thanks for the detailed information shared. Sorry for the delayed reply. 

I appreciate the research that you did before posting. Your cardio fitness score is determined by your resting heart rate, age, sex, weight, and other personal information. For best results, make sure your weight is correct in your Fitbit profile. Also, wear your tracker or watch to sleep for a better resting heart rate estimate. Your cardio fitness score will be shown as a range unless you use GPS for runs.

As you mentioned, If your Fitbit device connects to GPS, we can provide a more precise estimate of your score using the relationship between pace and heart rate during your runs. This is because individuals with higher VO2 Max have a lower heart rate while running at the same pace compared to individuals with lower VO2 Max. If you're able to run at a comfortable pace for at least 10 minutes, track a run with GPS. We recommend running on flat terrain as much as possible since only the flat sections of your run count towards your score estimate. You may need to go on several runs that are at least 10 minutes in length to affect your score.

Can you let me know if your heart rate information is being recorded properly? 

Let me know how it goes, after reviewing the information provided above. 

[DaltonL]

Hi Silvia,

I believe my Fitbit is recording my heart rate info properly. It is my understanding the only way to get a proper reading/estimate of the VO2 max is running at least ten mins with GPS, correct?

Thanks,

Dalton

[LZeeW]

@DaltonL   There is a common misconception that your cardio fitness score is a "physical fitness score", but in its purest sense, it isn't.  It's your maximum aerobic capacity.  That number represents ml O2/kg body weight/min.  It is part heart, part lungs, part genetics, etc.

The better estimate does come from GPS connected runs.  Here is why.  There are equations that estimate VO2max with run tests/run-walk tests/walk tests, etc.  There are probably equations for cycling, too.  Endurance cyclists need a high VO2 max.  If you ask Fitbit what they use for their algorithms, you will probably be told that it is proprietary. 

IMHO, I must emphasize that your cardio fitness score is an estimate, at best.  Some might say that trying to estimate your cardio fitness score using any other exercise type on the Fitbit is an exercise in garbage in, garbage out.

[DaltonL]

Thank you for your in-depth response.