Unreasonably large jump in VO2max

Here is my VO2max chart so you can see the big jump.

Well, was going to insert a .jpg of the chart here but how do you do that?

toddsdn said:

how do you do that?

Drag and drop the image onto a new post or click Insert >> Image/video/file >> click Upload >> browse for file >> OK.

Above is a 2 point jump in VO2max

Where are you getting these numbers from? Runalyze? I know that with Connect, it's only possible to get numbers to 1 decimal place, and not with the frequency that you have in the posted graph [*]

Note that runalyze's "VO2 Max from file" numbers are a bit problematic:

- for running activities (which produce a VO2 Max), they represent the *activity VO2 Max* (which is related to, but not the same as the user VO2 Max which is what is seen in Connect and on the watch)

- for non-running activities (which do not produce a VO2 Max), they represent the user VO2 Max

For example, if I record basketball and running activities on the same day, runalyze's "vo2 max from file" numbers for the respective activities will be inconsistent because the running activity will show "activity vo2 max", and the basketball activity will show "user vo2max". A basketball activity recorded after a running activity might show a spurious 0.05 jump in VO2 max due to this (because the 2 numbers don't represent exactly the same thing) - this is especially spurious since VO2 Max is not calculated for basketball activities, which means it shouldn't be possible for a basketball activity to produce any change in VO2 Max.

So not only are runalyze's VO2 Max numbers not consistent with Connect (usually), they are not consistent with themselves (as runalyze vo2 max from file could be either activity vo2 max or user vo2 max).

If you really want to see the user VO2 Max (same as Connect) with 2 decimal places, you need to export your activity FIT files and open them in fitfileviewer.com. There you will see both user VO2 Max (at beginning of activity, matching what's in Connect) in the user metrics table, and activity VO2 Max (at the end of activity, matching what's usually in runalyze) in the activity metrics table.

[*] The Connect app's graphs will show unrounded graph points with decent frequency, but there's no way to get the unrounded *values* this way (hovering over the graph shows rounded values). The Connect website is similar to the app, but has fewer points (e.g. even the 7 day view has fewer than 1 point per VO2 Max-generating activity or day) - however, you can export the graph to CSV and see the few points that are graphed with 1 decimal place.

Anyway, I can guess a reason for the jump:

- You used FR630, and FR630 does not support unified training status / physio trueup, meaning its idea of your "user VO2 Max" (which appears to be some kind of rolling average) was not in sync with with the data from FR245. Therefore, it's perhaps not surprising that it produced an outlier value. However, this doesn't really explain why there was a sudden jump. I also think you must have been using FR630 for some runs recently, otherwise it wouldn't produce a VO2 Max at all.

If you want to see your actual user VO2 Max on your 630 (to 2 decimal places), I think you would have to record another activity, open the FIT file in fitfileviewer, and look in the user metrics table. This is assuming that user VO2 Max is recorded for FR630 at all.

I don't think resting HR is used for VO2 Max calculations, although I could be wrong. According to an - admittedly old - FirstBeat white paper, the main parameter for the algorithm is max heart rate. The algorithm measures speed and heart rate for your submaximal effort, and uses that to guess how fast you could go in a race (maximal effort), based on your max HR and an assumed linear relationship between speed and HR. Then it looks up your predicted VO2 Max in a table based on that hypothetical maximal effort. IOW, there have long been lookup tables translating a 10K race result time (for example) to VO2 Max (or as some would call it in this case, VDOT, to distinguish it from "real VO2 Max", which is literally the amount of oxygen you're able to consume in a given amount of time, and can be measured in the lab). What FirstBeat does is extrapolate your non-race effort to a race effort using your HR and pace data. runalyze does something similar for its own VO2 Max calculations.

It's also possible that FR630 uses a different, older VO2 Max estimation algorithm. I don't know how / if VO2 Max estimation has changed over time. I do know that the race predictor changed a lot - it used to be a straight lookup from VO2 Max to race prediction (meaning if you had the same VO2 Max as another user, you would both have the same race predictions), but now Garmin adjusts the predictions based on mileage, and they do seem a lot more realistic than in the past. I guess that also doesn't really explain a sudden jump, assuming you have used FR630 for other running activities recently.

In general, I really wouldn't trust data that's generated by two vastly different generations of watches (released 2015 and 2019), and I don't really think the absolute numbers mean much at all, either - only the trends matter. But I guess switching to an old watch can mess up the trends. (Unless it actually is something else that caused this jump).

Thanks for the great info.  This whole VO2max thing is a bit convoluted, but I take your same opinion on it - the trends are more meaningful and helpful than any singular value and whatever associated accuracy it may have.  This is true for many metrics.

But my ego is getting the better of me and if I hit 45.7 VO2max (age 61) I will achieve SUPERIOR status and be able to diss on all my friends who have merely excellent status.  Also I was obese and had VO2max of 34 seven months ago so hitting elite status would be a psychological boost.  Please allow me my indulgences here.....

But seriously, my real concern IS the trend, especially how it has exponentially decayed to little or no progress for VO2max. i have done 233 miles of biking and running in the last 6 weeks with almost no change in VO2max. (all values come from running, don't have a bike power meter).  This is a very prominent indicator and, aside from the actual value(s), I wish to explore what I can do to further improve my VO2max.  I am doing research on this now.

However, I was thrown a bit of a curve with the big jump.  And just today, I did a 2.5 mile run at my more normal pace of 10:35 and RUNALYZE chart shows value of 44.97, another big jump relative to the rest of the trend.  Please note - this time I used my FR245.  I plan to alternate my watches on future runs just to see what happens.  So last 2 runs, first with 630 then with 245, the values simply don't fit the historical curve, substantially.  My weight is the same, conditions similar, 2 different watches but I did change my resting heart input for zones from 75 to 60.  Beginning to think this has an impact.

Anyway, I appreciate your input on this and will read your message again to try to get more insight on this VO2max stuff.  However Garmin / Runalyze are coming up with values, I have a trend telling me I have really peaked in this area, aside from a couple of strange outliers.

Here is latest chart:  Last 2 points are from the 630 then the 245

From fitfileviewer, the last 4 dots in the chart are 43.47, 43.52, 45.00, 44.72 (user metrics)

And runalyze indicates 43.52, 43.56, 45.49, 44.97.

Just my 2 cents: as a runner, ultimately the main thing that matters to me is how fast I can run. In the end, this can be measured by race results, and to a lesser extent, my average pace for all runs (outside of workouts), my interval pace for workouts, and how fast I can sprint (although this is important for other sports like basketball).

Couple of secondary things:

- how I feel (mentally and physically) during runs

- my overall health 

(I probably have my priorities out of order there haha.)

All the other Garmin/runalyze/strava/etc stats are fun to look at, but ultimately meaningless. Garmin stats like hill score, endurance score, fitness age etc. are largely vanity stats. VO2 Max as well (to a lesser extent, since at least you can try to compare the Garmin estimate to a lab measurement). I hate to say this, but Garmin knows that many runners cannot (or will not) objectively improve, so they give us a bunch of stats to make us feel good about ourselves. I wouldn't take them too seriously.

When my garmin (or runalyze) VO2 Max estimate decreases, it does tell me that I'm running slower for the same heart rate aka losing fitness. Similarly, when it increases, I'm running faster for the same heart rate / gaining fitness. But it's just a trend. The absolute number is meaningless for comparing with my runner friends. The real way for us to compare performance is to look at race results and try to out-run each other in group workouts (although ofc runners would *never* compete with each other like that, right haha).

Measure your improvement based on how fast you run and how good you feel while you are running. If you wanna compete with your friends, try to outrun them in races and workouts. This will naturally push you to get faster.

Don't worry so much about the vo2 max numbers, except the general trends. You should be happy that your VO2 Max is either increasing or staying the same, as opposed to decreasing. You should also realize there are natural limits to how much you can improve, anyway.

If you want an *objective* "performance score" that's adjusted for age, run a race and plug your result into an age-grading calculator:

https://runbundle.com/tools/age-grading-calculator 

This compares your result to the world record for your gender and age group. e.g. a 50% age grade means you ran half as fast as the world record, 75% mean 3/4 as fast, etc.

A 60%-69% age grade is "local class", which means you could probably win a local race. 70-79% is regional class. 80-89% is national class. 90-100% is world class.

To me, age grade is more objective than anything Garmin spits out (other than time, distance, pace and heart rate). And it can be used by people of any age to measure their performance.

It is interesting to me that most runners have no idea what this number is, and if you tell them, they don't really care. To me that says that maybe people really aren't too interested in objectively measuring their performance....

I hear ya.  Yeah, I pay a lot of attention to how I feel and what my body is telling me and I am very happy with the progress I have made.  I wouldn't even need a watch to tell me that it has been a dramatic improvement.  But its nice to watch those numbers go up as further confirmation you are making progress.  I am well aware that there are natural limits to damn near everything, and perhaps I am hitting mine physically.  First world problems........

Oddly, I am never really worried about how fast I can run.  I have always been a poor runner so just being able to run a few miles, being outside, de-stressing, listening to music, counts for a lot. Alas, I am an engineer and numbers and data and charts and percentiles are always of interest - can't help it.  

Also, I never race or do much real speed or heavy work.  I only just started this month to do one tempo 5k per week.  Previous 6 months have been aerobic base building.  I hesitate to do the really hard stuff because the extra stress it puts on you.  I have zero issues with my legs right now and at my age I worry a bit about overdoing it and getting a setback.  Although from what I am researching, it appears the heavy stuff helps VO2 a lot.  Will see how my once per week tempo runs go and I might add some more stressful type of runs and workouts depending on how I feel.

Speaking of heart rate for a given pace, it would be cool if Garmin had a metric like:

arbitrary value = distance / (avg heart rate * pace)  

Roll the big 3 up into a single value for easier comparisons of different runs.