My VO2 max has dropped drastically since last year. Is the Garmin app detecting VO2 max accurately? Thanks.

7792802 said:

Is the Garmin app detecting VO2 max accurately?

The accuracy of the VO₂max estimate is determined by the accuracy of the entry data - namely the HR, the HR Variability, the GPS, power, PulseOx, etc. However, a decreasing VO₂max may be also a consequency of an inadaquate training structure. I am afraid you will only know whether it is real or not, if you do a test in a lab. 

You may also want to have a look at the following whitepaper from FirstBeat, the provider of the technology Garmin uses:

Why Isn’t My VO2max Increasing? Tips for Improving Faster

7792802 said:

and my training has gotten more rigorous

Not telling it is the case with you, but the overtraining can be one of reasons for decreased VO₂max

Makes sense. Strength has improved but I haven't been doing as much body-weight cardio as I previously did. That could be another reason. It's a tough one - I am just praying that my old levels return asap! Sorry, would you also know why Garmin detects a lesser amount of active calories? A workout which for normal people would burn 200 calories only shows 100 calories on my watch (and I am reasonably fit). Would appreciate any feedback. Thank you!

7792802 said:

Sorry, would you also know why Garmin detects a lesser amount of active calories?

Besides the HR and the HR Variability, this is greatly depending on the Activity Class you set in your User Settings. Also the Max HR parameter may have an influence, but unlike with the Activity Class, I am not sure about it - just saw it in some documents, but it was unclear whether the measured max HR is used, or the one from your User Settings » HR Zone (more probably the measured one, though)

Thank you so much! This is extremely helpful. Thanks again! I was considering switching watches for accuracy but this gives me more insight into the workings of Garmin!

Hi, Mine has gone the same way, it now shows my vo2 age older that what I am, But my fitness has definitely improved, all my training is done on a mountain bike, I’m wondering if it thinks I’m not doing anything when I’m not peddling, when reality is I’m very active down hill, ‘peddling up, jumping cornering on way back down’ but obviously not peddling, so not getting data from the power meter on the bike, can you help ?

Hi, I think Garmin doesn't detect all activities especially cycling. Your heart rate needs to be consistently high for it to detect activity and calories being burnt. I have also found discrepancies in the calorie tracker - it says that based on my activity I have burnt 300 calories but then when you look at the active calorie count it's 230. Guess it's about just listening to your body and seeing how your clothes fit as against tracking every metric!