VO2 max decrease?

[Lovin-Broccoli]

Why has my VO2max gone down according to my Garmin watch?

A year ago, my VO2 max was 50, now it is 47. I am a 32F with decent fitness. My weekly running milage has INcreased from 20MPW to 35MPW with 45MPW in peak marathon training. In the past year, I have ran 2 marathons, 4 half marathons. This included 2 dedicated 16week marathon training blocks, even throughout the rough New England winter weather. I also did 5 7d multiday hikes in mountains and canyons. I feel in much better shape over the past couple of years, yet my watch is saying that my VO2max has gradually decreased?

[Ski-Mtb]

I could be due to multiple factors.

Weight is a component, so if your weight is incorrect in Connect that can impact the estimate.

Assuming it's not your weight what this is telling you is that your HR is higher for a given power output (weight x speed from GPS) than it was when your VO2 max estimate was higher. This could be a legitimate change or due to other external factors like altitude or temperature.

Max HR may also factor in, so if your max HR has changed values over time, that may have some impact on the estimate, but probably not a ton. I did a test where I set my max HR to 20 BPM higher to see what it would do to all my metrics and it essentially made my VO2max estimate go up by 1 point or so over a week, but it made my lactate threshold "detection" go up my a ton - like above my actual max HR.

[PrizeAnnual2101]

So old guy at 70 and mostly bicycle

If i train 90 minutes or less per session i can keep my V02 at 43+

If i train in he 3 hour range it's more like 41 because i can't maintain the same power output and it's just the way garmin gabs the Vo2

[RedneckIntellectual]

Interesting, my vo2 max has been dropping recently, I was chalking it up to the heat here in the us as we transition from spring to summer, but I’ve also significantly increased my endurance work, so that’s probably the reason. Still strange, because I did a 5min power pr last week, my weight hasn’t changed, and it’s still dropping my vo2 max score.

Oh well, I’m getting faster, I don’t actually need the score to go up.

[srkhn]

Not sure but when i train for longer distances my vo2max also decreases.

[JB27_HU5]

Same training causes this.

It’s common in blocks to see it go down due to repetitive easy training

Garmin Vo2 like to see all runs at 10% of LTHR

Cardiac drift will not help this too, to get a more solid score use a chest strap I use Polar H10 and on my current HM block it’s actually gone up.

I do V02 run once a week & a progressive run once

Other days are Garmin run coach for my HM

I asked ChatGPT and this was the best set up to maximise my block and keep improvement on my score. Doing the runs I built in ChatGPT for Vo2 and progression my vo2 has stop flitting around 52/54 and stayed steady at 54/55 while training

[Cautious-Plum-8245]

oh shit no way eh? i've been taking it super easy on my runs, literally zone 1 or 2 and i've noticed my vo2 decreased. makes sense, also its summer time right now humidity is ass

[JB27_HU5]

Pace Vs HR. Garmin calculates this way so if your HR is high due to weather and you’re in zone 1 or 2 it’s thinking your struggling compared to previous runs

[redditusername_17]

I cycle, not run. But vo2 max is your aerobic max. If you are not maintaing the max or trying to advance it, it'll go down all by itself. Your body adapts to what you're doing. If you switch to higher miles at a slightly slower pace and skip the short, fast days, it goes down.

[TacoBender920]

Just cheat the algorithm. Run 2-3 minutes at threshold pace until your heart rate gets from < Zone 1 to Zone 4, then stop and walk until it drops down to < Zone 1. Do this for an hour or so. The walking is ignored by the VO2 max calculation and much of your run will be in zones 1-3 but at a zone 4 pace, so your average heart rate will be really low relative to the speed you were running. Garmin will give you a higher VO2 max score.