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VO2 Max vs Fitness Classification

5915564
over 4 years ago

Why does my Vivoactive 4S interpret my VO2 MAX into a fitness classification that is different to the table that Garmin publish at https://www.garmin.com/en-US/blog/fitness/whats-a-good-vo2-max-for-me/

I'm in my sixties, reasonable fitness, and the VO2 MAX reading I get is 33, which is interpreted at POOR, and a fitness age of 74.

However using Garmin's table for my age, a reading of 33 is classified as GOOD. Which is right?

  • 0 over 4 years ago in reply to ovekvam

    I'm pretty sure it's based on measuring speed vs HR (assuming a linear relationship), taking max HR into account. i.e. It's measuring effort in relation to how fast you go.

    So if you run faster or with a lower HR, your VO2Max goes up.

    My VO2Max usually goes up after a (well-run) race, since ppl usually run faster with less effort during a race due to adrenaline, the crowd, other runners, etc.

    I think with newer watches, there may be adjustments for temperature or even elevation change / grade.

    assets.firstbeat.com/.../white_paper_VO2max_30.6.2017.pdf

  • 0 over 4 years ago in reply to WillNorthYork

    I think the Vivoactive 4 is among the newer watches in this respect. When I do hill runs, my VO2max comes out with similar values as when I run flat, and the speed is significantly different. I guess that Firstbeat uses what we see in Strava as GAP (Grade Adjusted Pace). 
    Garmin has a VO2Max for cycling too, which is based on power meters, so it could very well be that the running VO2Max is also running power based.

  • 0 over 4 years ago in reply to 2118263

    Don't take it too seriously. This kind of data is like the body fat percentage from a scale. It's not a very accurate measurement in lab/hospital or direct from watch sensor. It's just a estimated value. Always look at the long term change.

  • 0 over 4 years ago in reply to 9411878
    ovekvam said:
    Garmin has a VO2Max for cycling too, which is based on power meters, so it could very well be that the running VO2Max is also running power based.

    I'm fairly sure it's based on HR and not running power, since Garmin/FirstBeat has never mentioned running power for VO2Max, but that's just my two cents. Running power isn't even a natively supported metric on Garmin watches -- you need to use the Garmin running power app (and pair with the RD-Pod or HRM-RUN chest strap)

    Besides, the Garmin Connect IQ Running Power app isn't even available for Vivoactive 4. So it would be really weird if the VA4 was somehow able to internally calculate running power for the purposes of calculating VO2Max, but not expose running power itself to users. It wouldn't be impossible, but just unlikely IMO.

    In this Garmin support article, power is only mentioned for cycling.

    support.garmin.com/.../

    9411878 said:
    It's just a estimated value. Always look at the long term change.

    Agree 100%. I don't take the actual VO2Max value (or the race predictor values) seriously, I just look at how they change over time. My VO2Max definitely goes up and down as I get more or less fit.

  • 0 over 4 years ago in reply to WillNorthYork

    I didn't mean running power instead of heart rate. Heart rate is surely a factor. But since O2 usage seems to be proportional to running speed, it makes most sense to use heart rate on one axis, and grade adjusted speed on the other. 

  • 0 over 4 years ago in reply to ovekvam

    Okay, but grade adjusted speed is not the same as running power. Otherwise you wouldn't need a fancy chest strap, RD-Pod or stryd pod to measure running power.

    The firstbeat VO2max whitepaper (posted above) already shows running speed on the x-axis and heart rate on the y-axis.

    https://support.stryd.com/hc/en-us/articles/115003992194-How-Does-Stryd-Measure-Power-

    Stryd tracks your foot through three dimensional space and records the accelerations, impacts, and forces that are being applied. From that information, we calculate power, as well as provide other commonly used run metrics like distance, pace, cadence, ground contact time, vertical oscillation, etc. All of our calculations have been validated with high resolution motion capture systems, dual force plate treadmill, and metabolic testing.

  • 0 over 4 years ago in reply to WillNorthYork

    Yes, Stryd has their own complicated ways of calculating running power, based on acceleration sensors. It is easier to estimate it based on GPS velocity, grade and runner weight. But probably not necessary, as Firstbeat can calculate VO2Max directly from heart rate and velocity.

  • 0 over 4 years ago

    So I had my annual check-up with Cardiac Rehab yesterday, and I talked to my consultant about these VO2 Max readings. After doing my assessment (the beep test), she concluded that my VO2 Max was around 34, so pretty close to the 33 that my watch says. But she totally disagreed with Garmin's interpretation of what a 33-34 VO2 Max meant for my age.

    She showed me a chart that medical professionals use that showed that 33-34 puts me in the ABOVE AVERAGE category, not as Garmin says in the POOR category. And as for Garmin saying that my Fitness Age is 74, she said I would need to have a VO2 Max as low as around 20-22 to justify a Fitness Age of 74.

    Her conclusion was that Garmin's measurement of VO2 Max is pretty accurate, but their interpretation of that on a qualitive rating of POOR, AVERAGE, etc. was very misleading, and Garmin's calculation of Fitness Age was completely wrong.

    I have to say I'm very disappointed that Garmin use a flawed methodology to provide a qualitive rating of POOR, AVERAGE etc. and even more so about their method of calculating a FItness Age.