Accuracy of VO2 Max Estimate for "Slow" Runners

Is all the data correct on your watch? Weight, age etc? You’ve only had the watch a fortnight which is a short time, it’ll still be “learning” about you. 

There are plenty of back o the pack runners that use Garmin too. Garmin wouldn’t sell much if only competitive club runners and local champions bought their watches. Lol! 

About VO2Max absolute value:

Your metrics calculated by the watch about your estimated pace for 5k are near the truth?

About declining of Vo2Max value:

- Which kind of training are you doing and with kind of frequency?

- Could you post a screenshot of your training status pages (current and 4 weeks) and training load pages (all three pages)?

Hi,

if you are looking at Vo2Max deviations over two weeks, then just ignore it :). Vo2Max is a rather slow moving metric, you can look at trends over months, but certainly not much happens week by week.

Note that certain types of work-outs will always give the watch a "high impression" of your Vo2Max while certain others will give a "low impression", so depending on your workout mix, the numbers might dip or rise without any real change in fitness:

- Running fast and flat (e.g. intervalls on a track) always leads my watch to consider my Vo2Max as rising/improved

- Running technical terrain and hills [e.g. mountain trails] will always be considered very poor Vo2Max [which is probably the main reason why Garmin has "Trail Running" as dedicated sports mode - it basically skips the Vo2Max calculation for trail running, as it would be very low :)].

My bottom line for you is: The Vo2max guestimation on fitness watches is more of a ballpark and only useful as a trend line over months - if you want to track your fitness the gold standard is to do a test every few weeks. One easy to do test is to complete a defined fixed route that you like while shooting for a "easy" heart-rate that you have fixed. E.g. for me I might run my favorite loop with 145bpm as target. Note down the achieved heart-rate average and time. If the times go down (and you manage to hit the heart-rate goal), that's a good sign you are getting fitter :).

I suggest using Runalyze as a second opinion. It is free and produces very good estimates of VO2MAX and race times. 

i think with your BMI it's totally clear that your vo2max is so low, same with your pace for 5k, if you have a BMI arround 22-23 and a 5k time arround 30 minutes you could have a vo2max of 35-38

your body weight is very important for your vo2max!

One more thing to check is heart rate. I suppose you rely on optical HR monitor in the watch. This is not very accurate, at least in my case. Try wearing a strap which generally gives a more accurate readings.

In my case I use optical from spring to fall and strap in the winter. My VO2 Max readings for winter are higher despite a visibly less training and slower speeds given the conditions. So there could be some impact of this. My estimate would be of about 1-3 units lower  VO2 Max readings for optical HR vs. strap.

Great post. Speed at VO2max is a better measure than VO2max in isolation. As noted, as you get fitter, pace should increase for the same heart rate.