VO2Max overestimated

Oh dear, I wish these studies would have some better insight into how the watches work. It's something DC Rainmaker mentioned recently on a similar theme - a study that had 2 OHR devices on each wrist - a definite no no.

You can't just give somebody a watch, do a run and then take the first VO2 Max value as their definitive estimated VO2 Max. The watch needs to "learn" you over a fair few runs for at least a week and preferably two. No indication that they actually did this.

If the researchers had spent some time on these forums they would know that the rule of thumb seems to be that the VO2 Max settles down around 3 "points" more than what seems sensible based on the corresponding race predictions.

For sure your first couple of VO2 Max estimates are typically too low but they soon go up as the watch learns you and, as mentioned, tend to settle a bit high.

I have not seen any compelling evidence to suggest there is a huge difference in results from OHR and HR straps.

PS gpardo123 - note the researchers say the VO2 Max is underestimated by the Garmin but I hope I tried to explain why that was the case.

Barely an overestimate. If you take OHR out of the equation (you always should, where absolute accuracy is concerned) then an overestimate on the 630 - which I presume uses the same FB algorithms as the 935 - was about 0.8-1.2 overestimate, or 2% That's pretty damned accurate in my book. Given that FB say 95% accuracy, and that study suggests closer to 98% accuracy.

So a pleasant surprise then - limited studies suggest the accuracy of VO2 max estimation is better than manufacturers claims.

And this is moot. Aside from the fact that the effectiveness of VO2 max as a performance indicator is being debated currently, it's not actually that expensive to go and have a lab test done if you really do feel the need to rely upon it. Personally I'm just happy to have it there as a very loose indicator of progress - I certainly won't be using it to mark progress in my training though.

It does seem that my hunch was correct and the protocol used for this study is invalid.

https://www.facebook.com/sweatscience1/posts/1754101171296574?comment_id=1755809314459093&reply_comment_id=1755814841125207&notif_t=share_reply&notif_id=1497723561824650

PS gpardo123 - note the researchers say the VO2 Max is underestimated by the Garmin but I hope I tried to explain why that was the case.

Tim we all have noticed in this forum since this data was implemented in the Garmin that either the Garmin VO2max is underestimated OR the race time estimations are too aggressive. You may remember 3 years ago a big post where people posted their estimations which were compiled in this blog:

https://cicerunner.wordpress.com/2014/07/11/garmin-fr620-race-times-from-vo2-max/

I am aware of the post you referred from DC on the methods used in some other studies. In my case I am fan of checking the VO2max provided by Garmin not necessary for the accuracy, I like to see its trend which basically tells me the level of fitness.

Yes agreed if you just look if the number is going up or down for yourself then it can provide a useful indicator of our current fitness.

I think part of the problem is that the race predictors are not Firstbeat provided but something Garmin "found" that supposedly correlates a VO2 Max value with a race time.

Yes, based on the post in Facebook the methodology was wrong, as you pointed out you need to give the watch at least 2 weeks to know you and not only a 10 minutes run.

So the prediction race table is the culprit?!!

Lately I have been noticing a very good correlation of the fitness status and the VO2max value. For work reasons I have to travel to a place where is cold (end of Fall season) different than my Florida hot and humid place. When running in this cold weather immediately my VO2max rises at least 2 points and my trying status goes to Productive; Once I come back home, my VO2max goes down one point, my training status goes to Maintaining and a week after that another point down and the training status goes to Unproductive. Everything with the same training load from my 80/20 plan.

Still I am trying to figure out the best use of the this new data point.

VO2Max from Garmin has always been pretty well correlated with my fitness/injury status. (I wear an HR strap.)

But the number itself has always been 5-10 units too high for me, assuming that the online VO2Max-to-race predictor calculators are correct. I think most or all of them are based on the Jack Daniels tables, which were derived from testing real runners (including elites). For what it's worth, the Garmin race predictions (apparently based on VO2Max) match those calculators pretty closely.

Maybe my excessively high numbers mean that I'm limited by injury/strength and therefore rarely hit my HRmax. Or that I'm not "trying" hard enough during races.

Anecdotally, a few other runners I know with Garmins that actually look at their metrics also have Vo2Max/predictions that are too high, but usually "only" by 4-5 units.

Yes, based on the post in Facebook the methodology was wrong, as you pointed out you need to give the watch at least 2 weeks to know you and not only a 10 minutes run.

So the prediction race table is the culprit?!!

Lately I have been noticing a very good correlation of the fitness status and the VO2max value. For work reasons I have to travel to a place where is cold (end of Fall season) different than my Florida hot and humid place. When running in this cold weather immediately my VO2max rises at least 2 points and my trying status goes to Productive; Once I come back home, my VO2max goes down one point, my training status goes to Maintaining and a week after that another point down and the training status goes to Unproductive. Everything with the same training load from my 80/20 plan.

Still I am trying to figure out the best use of the this new data point.

That's another problem! In hotter weather, your HR will tend to be higher for same pace/effort so nearer your max HR and so a lower VO2 Max according to the algorithm.

It might actually be valid to raise and lower your max HR when are at home or not.

I think part of the problem is that the race predictors are not Firstbeat provided but something Garmin "found" that supposedly correlates a VO2 Max value with a race time.

In indoor rowing, VO2max is correlated with the 2000m test score (your best time in race conditions) according to Essentials of Exercise Physiology, McArdle et al.

There is a calculator here.

Perhaps there is a related study for running, just not by FirstBeat.