VO2

https://support.garmin.com/en-US/?faq=lWqSVlq3w76z5WoihLy5f8

„VO2 max is the maximum volume of oxygen (in milliliters) you can consume per minute per kilogram of body weight at your maximum performance. This is an indication of aerobic fitness and should increase as your level of fitness improves.“

In short: It does not matter how often your girlfriend uses the watch. If she is fitter than you in aerobic dimension, the watch will show that. Also, the weight does matter, as it is VO2 per minute/ bodyweight in kg

VO2 max could be (at least partially) genetic, there'll be probably a difference in your lactate threshold (LT), 2 people with same vo2 max can have very different results in pace and bpm due to different LT. How to measure LT? add a chest strap to your garmin and run the guided LT test, the chest strap need to measure hrv in order to do that, so garmin hrm pro/pro plus/ polar h10 etc...

Another one link to figure out were you are. Compare  the tables for a man and a women. There are big differences. The tables are good but here is missing an upper row - with a name - superior ;). 

I understand how its calculated, I guess I'm just surprised that after a handful of runs, it was able to say "welp, you're in excellent shape" 

One run should be enough, if it contains running at different intensities. But as you noticed, if it has a previous value, it will change very slowly.

Thank you! Do you have any recommendations for the watch to "recalculate" your VO2? I feel like mine is unrealistically low. I ran a 5k not too long ago and it did nothing for my VO2 calculation, up or down.

The only thing I can think of, it is to make a new profile and start from scratch. It will take weeks to calibrate the heart rate variability again.

Josh said:

I feel like mine is unrealistically low

May I ask, why?

it just doesn’t seem right to me. I don’t have anything to base it on but if i ran right next to my girlfriend, who’s two years younger than me, i could outrun her in both speed and distance. She would stop and huff and puff and I’d still be running. Yet at the end of the day I am in a below average category and she’s performance elite. It just doesn’t make sense to me. 

i also breath slowly and controlled when I run, maybe that’s taken into account that my resp rate is slower, maybe the Watch thinks i can’t take in as much oxygen when really it’s just controlled breathing? 

I’m just trying to understand it. Maybe garmin algorithm saw she did a really great “first run ever” on her FR and based the rest of her runs on that and i did a really poor first run and all of my other runs are based off that.  

sorry for rambling!

Josh said:

maybe the Watch thinks i can’t take in as much oxygen when really it’s just controlled breathing?

Josh said:

Maybe garmin algorithm saw she did a really great “first run ever” on her FR and based the rest of her runs on that and i did a really poor first run and all of my other runs are based off that.

No, that is not how it works. And VO2Max is not fixed after first run, but changes over time, believe me. 

This is a description:

“The pace you are running is placed into the context of how hard your body is working to produce your performance. Mostly, the relationship between internal and external workloads (intensity of effort versus the pace you are running) is linear and stable. To run faster, your body needs to work harder.“

Josh said:

I’m just trying to understand it.

https://www.garmin.com/en-US/garmin-technology/running-science/physiological-measurements/vo2-max/

https://www.garmin.com/en-US/blog/fitness/whats-a-good-vo2-max-for-me/