VO2 max, I am puzzled

[Berksrover]

I know it is only an approximate measurement on my Garmin 235 but the first measurement in early August was 40,went up to 41 but yesterday when I did a PB for 10k it was only 38, still not bad for my age (58) but going in the wrong direction whereas I would think my aerobic fitness is better than it was a few months ago. Not sure how to interpret this

[Sqkr]

I'm not super sure how Garmin estimate their VO2 max, but if you run with max heart rate (say in an event, or if you're pushing it quite hard) it doesn't like it much. I go down a point any time I do a race. Yet for some reason the marathon forum speed challenge was OK, so really there's no second guessing it! My graph has gone in the right direction overall, but with some blips when I've been doing what I consider to be decent event times. Way to burst my bubble, Garmin 🙄 It will also adjust over time to become more accurate, supposedly, so first readings are likely less realistic than subsequent ones, as it builds a better database of your personal readings.

[tony_a Graduate10]

I find something similar. The more effort I put into a run, for example when running longer than usual, it tends to drop. Usually pops back up after a few easier runs.

[Berksrover Graduate10 in reply to tony_a]

The other thing I find strange is that it only gives a reading on outdoor runs, for various reasons I have to use treadmills a fair amount and that never generates a reading

[tony_a Graduate10 in reply to Berksrover]

Not noticed that but I don’t do very much treadmill running. The help says it uses exercise data as well as heart rate so possibly it needs the gps for some part of the calculation.

I do find my score is more likely to go up on the very rare occasions I think about breathing properly

[siabod Graduate10]

Hi, I loved watching my VO2max as I was doing couch to five k, I wasn't even sure what it was but a nice upward graph really builds confidence. I had a huawei proband 2 and it steadily rose to 50. About a month ago it dropped to 47, I am sure it knew I had a cold before I did, I struggled around a 10 k and it dropped to 44, I also did my first park run while i was still feeling rough unfortunately I had tech failure so didn't get a reading but i was gagging at the end. I bought a garmin 235 after that and, sure enough after my first run with it my VO2 max was 46, but as I felt better after the next few runs it climbed again my last six runs were 49,49,50,51,50,50. It is nice to see that two different bits of tech put it at the same level. I have just lowered my weight on the garmin from 92kg down to 90kg (target is 67kg!) and i am wandering how this affects the VO2 max reading.

[Dexy5 Graduate10]

An article on the runners connect website says :

Because a VO2max value needs to be tested in a lab (you can’t get VO2max without measuring ventilation, oxygen and carbon dioxide concentration of the inhaled and exhaled air), readings from your Garmin are just a rough guess, so ignore them.

So I think that although interesting to look at , you shouldn’t base your training on it.

[Macmac Graduate10]

Check the heart rate graph for this run. Does it look normal? Occasionally I just get a perfect straight line so it’s not got a good reading. This has led to big apparent drops in my vo2 max reading, but it’s fine the next time. As vo2 max is a measure of oxygen per kg, as weight changes, this will also vary accordingly if you alter the weight on the garmin. I’ve seen mine increase quite significantly since starting c25k and going on to regular 20k runs plus losing around 16kg. Strangely, unlike others report on here, when I’ve hit pb’s (like my 10k last week) i’ve seen highest readings yet for vo2. I’ve also had the full test done in a lab before and results were similar to when I started c25k, and I know it’s only a guide but still reasonable to see how hard your heart is having to work to deliver enough oxygen for the speed and distance covered.

[WannabeAthlete]

Hi, you're not the only one baffled by Garmin's VO2 max readings. I don't think they're accurate. I've been doing spin classes for 3 months and my resting heart rate has dropped from normal to 53 and I'm definitely fitter. However it hasn't affected my VO2 max reading at all. I've concluded it's an inaccurate feature of the watches.