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K5 Gus
K5 Gus
Nov 2018
12:43pm, 28 Nov 2018
2,777 posts
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K5 Gus
Garmin licences the VO2 max algorithms from Firstbeat Technologies Ltd

Here's their white paper on VO2 max calculations assets.firstbeat.com
larkim
larkim
Nov 2018
12:48pm, 28 Nov 2018
6,100 posts
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larkim
On runalyse, if you have an account (free) and grab your FIT files from Garmin, then upload them, you need to select the column header "VO2 Max (by file)" so it shows the run by run calculation.

I'm not entirely sure if it is retrospective or calculated on each run - i.e. does the watch do the calc during the run / before upload and report the output based on that, or does the watch grab the calculated figure afterwards in part of the handshake with the servers at Garmin, and then report it in the .fit file with the next run. And of course, this could be watch by watch dependent (bearing in mind I only use the Runalyse service because my watch doesn't show the VO2 max record, as its suppressed in the firmware).
HappyG(rrr)
HappyG(rrr)
Nov 2018
1:00pm, 28 Nov 2018
29,598 posts
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HappyG(rrr)
That paper effectively just says it's speed divided by HR. (with all the cleverness really just trying to remove dodgy, rogue HR data and pauses for traffic lights!)

star So lower HR for same speed (or higher speed for same HR) = higher VO2.

Fetch's "beats per mile" is effectively the same thing (well, inverted)

I think there's something about running quicker that is "more efficient" so you get more speed with less HR gain and these very simplistic VO2 calcs would reflect that.

Interestingly, the Polar one support.polar.com is very similar and emphasizes that you have to be going at a decent speed to be valid (but below your VO2 threshold - so not eyeballs out).

But your improvement will come when you have done lots of easy, slow running, with sprinkles of speed on top and Ta Da! you can run faster, without your HR going up = better VO2. :-) G
Chrisull
Chrisull
Nov 2018
1:16pm, 28 Nov 2018
13,563 posts
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Chrisull
Bazo - You have my VO2 readings. Mine was 54, 56 after the Drogo 10 race, then back down to 54 since then. Of course this is based on the optical HRM stuff which is a load of baloney anyway, which makes my Vo2 max readings a load of baloney. You're faster than me, so I should expect that. Probably time to pair the new watch with the chest strap and do it the old fashioned way....
HappyG(rrr)
HappyG(rrr)
Nov 2018
1:28pm, 28 Nov 2018
29,600 posts
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HappyG(rrr)
If someone would invent a mini HR detector made out of skin like material, size of a 50p or so, that you stick to your chest in the optimal place to pick up accurate HR and would stay on, replace e.g. every month or year, I'd buy it. I'd pay... £100. And my watch could be £30 cheaper with no HRM on it. Go one someone, invent that please. :-) G
larkim
larkim
Nov 2018
1:39pm, 28 Nov 2018
6,101 posts
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larkim
@HG - I'm confident it doesn't simply do a calc on each run (even with the FirstBeat stuff behind it) as you don't get big leaps all over the place. Movements are typically less than 1 whole number, mostly in the region of 0.5 or so, though it did increase by 2.0 over 2 runs a couple of weeks ago (2xraces).
Badger
Badger
Nov 2018
2:21pm, 28 Nov 2018
10,060 posts
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Badger
The watches smooth the changes to VO2max. If you show Runalyze's own VO2max calculation, you'll see it bounces around much more. They do a smoothed version too for graphs.
HappyG(rrr)
HappyG(rrr)
Nov 2018
2:28pm, 28 Nov 2018
29,602 posts
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HappyG(rrr)
Yeah, exactly. Wot Badger said. Bet it's just linear, it's just rounded to a big whole number so you can't see! :-) G
larkim
larkim
Nov 2018
5:07pm, 28 Nov 2018
6,106 posts
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larkim
The Runalyze stuff is a VO2Max calc on a run by run basis though, so they get skewed by dodgy HR data etc. The consistency of the Garmin watches is good in the sense that it allows outliers to be ignored and (assuming the overall algorithm is sound) should map trends and progress better though surely?

I imagine Garmin's approach is broadly "VO2 Max for this runner is XX.XX. They ran with an effective VO2 Max calculated as YY.YY today. New VO2 Max is XX.XX+(%age * (XX.XX-YY.YY))" or some logic along those lines.

Garmin's data is definitely not rounded to a big whole number. Friday it was 59.81, Saturday 59.50, Monday it was 60.47. An artificial level of accuracy, sure, but the detail is definitely there.
Badger
Badger
Nov 2018
6:37pm, 28 Nov 2018
10,061 posts
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Badger
Isn't that pretty much what I said, though? My point was just that the noise in the Runalyze data proves that Garmin are smoothing theirs from day to day...
One interesting thing from the Runalyze data is that it's clear that their algorithm, at least, gives higher values for shorter runs, where the time to get to steady state is a bigger fraction of the total time. The two-decimal-place values from Garmin hint that Firstbeat shows this effect, too, it's just harder to t lol with the smoothing.

About This Thread

Maintained by Elderberry
Everything you need to know about training with a heart rate monitor. Remember the motto "I can maintain a fast pace over the race distance because I am an Endurance God". Mind the trap door....

Gobi lurks here, but for his advice you must first speak his name. Ask and you shall receive.

A quote:

"The area between the top of the aerobic threshold and anaerobic threshold is somewhat of a no mans land of fitness. It is a mix of aerobic and anaerobic states. For the amount of effort the athlete puts forth, not a whole lot of fitness is produced. It does not train the aerobic or anaerobic energy system to a high degree. This area does have its place in training; it is just not in base season. Unfortunately this area is where I find a lot of athletes spending the majority of their seasons, which retards aerobic development. The athletes heart rate shoots up to this zone with little power or speed being produced when it gets there." Matt Russ, US International Coach
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