Does anyone else find that the VO2 Max estimate is too reactive? Within the space of a week, my VO2 Max will increase from 58 to 60 after my tempo run or interval session, then reduce to 58 when I do my Sunday recovery long run. I find it a bit strange that the First Beat algorithm thinks I've lost fitness because I decide to do a slow run and presumably my heart rate is not as slow as it should be. My training status will change from increasing fitness to decreasing fitness in the space of two days. My usual rest day is Monday so I am usually most fatigued on Sunday. You would think that the watch looks at your training load and when it's over 1200 will know you are at the end of a hard week and the short term fatigue is outweighed by the long term fitness gains from those hard sessions earlier in the week. I also think the Race Predictor is rubbish - the watch thinks I can do a 17:43 minute 5k when my recent 5k best is only 19:30.
Logged a support call this morning after the Garmin perspn I spoke to admitted the VO2 Max changes from 56 to 62 and back to 56 within a few days were incorrect.
Looks to me like the VO2 Max on GCM is plotting the max values from both cycling and non-cycling activities on the same graph. Join the high points and you get the same graph as the Cycling Max VO2, join the low points and I reckon that’s what the Max VO2 graph should show.
Curious what Garmin's response will be to this. I now have the same issue here after picking up the Vector 3 pedals and getting Cycling VO2 values from the 935. I did a cycling activity at threshold on Monday, got a VO2 of 60 and followed that up with a recovery 12 mile run Tuesday and a VO2 of 56. The values independently are roughly what I expect, my run prior to the 12 miles returned VO2 of 57 so a drop of 1 mL/kg is not unusual.
The downside to this, as you pointed out, is that the VO2 max reading is moved by both running and cycling activities. And since Training Status is dependent on change in VO2 max, the "Unproductive" status is inaccurate. Annoying to say the least.
Another question about this.. Is there a way to erase the cycling VO2Max without performing a master reset? I do not have a power meter anymore and the value is now meaningless, and if it still impacts calculations I rather erase it.
The first beat analysis of VO2 max simply correlates your HR with PACE and extrapolates this data to your MAX HR. So, if you go for a long run easy run and your HR beats a little higher because of increased load for the week it would make sense that you see a decrease in VO2 MAX. On that run in this instance your VO2 is not as good. I also do long runs on Sunday and pace at a given HR can be 15-30 seconds different and I would expect my VO2 value to change. Keep in mind the VO2 calculations are only approximations based on PACE and HR. Yes it is true that your actual VO2 MAX wouldn't change like that, but based on how they calculate the value it will. All these valves are good approximations and great to use as a training tool, but they will never replace lab tested values.
As I've said many times, VO2max is not a metric to be checked daily. It's a 'trend' metric that should be checked every 4 to 6 weeks or so. Even then, unless you are a beginner athlete the changes are likely to be minimal. Starting out you could expect to see changes up tp 20%. Over time as you reach your potential the changes will be minimal, or even non-existent. What matters then is not your absolute VO2max, but how much of percentage of it you can use without going anaerobic.
