Performance condition and VO2max calculations

My understanding is that they only use the gradient information to discard the parts of a run, which have too much gradient. They do not try to correct for gradient in the parts, which they actually use in the calculation.

But this is only based on a post from HermanB from Firstbeat, where he wasn't completely certain.

Thanks Alan. Let's hope that this will be clarified in the future, as I think it is quite important.

www.firstbeat.com/.../

Yes, they do include hills in the VO2 Max calculation. See the link for much more information. Obviously there's limitations to what the watch can tell you but that first beat link will explain well how they get the information.

I wouldn't take the v02 max results too seriously.  My garmin says that I'm at 59 but my recent lab test says just over 70.

I wouldn't trust the v02 calculation as in my group of friends it isn't accurate at all.  My watch says 58, my lab test repeatedly say just over 70.

Many thanks for the link. I will have a look. 

Thanks Nick. I am a recreational runner so I do not have access to labs and medical teams. GARMIN is all I got and I go by its readings. The most important thing for me is to reflect the CHANGES in the performance rather than giving me the medically correct value (although it would be great to know both).

I believe it is a good number for most people, but also that for some it is way off. Speaking only for my data I don't believe the V02 max calculation either, it says my V02 max is that of someone 35 years younger which prima facie seems somewhat ridiculous (I'm almost 60). If something is off that much, is it even reasonable to use it for "trending" analysis?

IIRC from their white paper, its estimation of V02 max depends a lot on resting HR and max HR. From that I took that if these are "unusual", the calculated V02 max is more likely to be off. For example: my resting HR is often in the low 40s BPM, and my max HR is almost 180 (15-20 BPM or more higher than most formulae predict). In my case however I don't think either is a reflection of a particularly high level of physical fitness, just some weird anomalies. I base this last sentence on the fact that my running times are nothing to write home about, certainly not times a fit person who is 25 years younger than I would have (they are even a lot slower than my times from 10-15 years ago!).

FWIW, the changes in my lactate threshold seem to correlate with my fitness levels pretty well. If I take some time off, they get worse, if I'm pretty good about staying on schedule running, they improve. 

I like FirstBeat. They put their white papers out there and let us draw our own conclusions, and it seems like they are always trying to improve their modeling. Reassuring scientifically! 

They do account for hills but it’s unclear whether that’s using elevation change data (I would think more objective/preferred) or just capturing the change in effort resulting from elevation changes (less preferred, as changes in level of effort could also result from differences in fitness level).

HermanB commented here and seemed to focus on effort and not on elevation but still not clear: forums.garmin.com/.../altitude-adjusted-vo2-max