V02 max and altitude

[Alexco2539]

Does Fitbit take high altitude (Colorado) into consideration when determining your V02 max? V02 max decreases with altitude from what I understand. 

[Baltoscott]

It does not appear to.  According to the help article on VO2 Max the main factors affecting Fitbit's estimate of your VO2 max are RHR, age, gender and weight.  There is a reference to "other personal info" which would not include an external factor like altitude.  By implication, it must also evaluate your running HR and distance covered in GPS running activities.  Note also that "only the flat sections of your run count to your [fitness] score [estimate]."   Excerpt below:

HOW DOES FITBIT MEASURE MY CARDIO FITNESS SCORE?

Your cardio fitness score is determined by your resting heart rate, age, gender, 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.

HOW DO I GET A MORE PRECISE ESTIMATE OF MY SCORE?

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. (Fitbit Charge 2, Fitbit Blaze, and Fitbit Versa customers should use Exercise mode or app with connected GPS; Fitbit Ionic customers should use the Exercise app). 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.