Needed recovery week, or weird readings?

Hello there,

I have been struggling with consistency and took an easy two weeks because life didn’t let me train .

Now, I am at the tail end of the second easy week. Two days ago I was supposed to go training to the 400m track but I was just too tired and stayed home and slept 11 hours.
I had an easy spin (HR average of 103) on the bike yesterday, I only pushed it a bit for a couple minutes on a short climb and didn’t go 100% anyway. The Garmin 530 with the power meter detected my cycling VO2MAX to have increased (cool). I noticed lower than usual HR during the activity.
Then, today I went for an easy run with 4 short sprints for “activation”, and lo and behold, my running VO2Max is detected as higher by the forerunner 255.
In the past, my VO2Max readings have tracked quite well with real lab tests. I just find it surprising that I get more VO2Max on lower volume, after feeling tired for a day or two… Any thoughts?

I find Garmin VO2 estimates are often a little higher when my HR is staying low because I’m fatigued. Easy workouts with a few short efforts also tend to push Garmin VO2 up a little, presumably because it’s setting high power/speed but with low HR because the efforts are short enough and spaced out enough to not push HR too high.

Conversely Garmin tends to drop my VO2 a little when I do something like a Sweetspot workout where power is never that high but the constant work causes cardiac drift and I end up with quite high HR. Similarly, elevated HR from doing an unusually hot ride will push VO2 estimate down.

These are the micro trends over days which I try to ignore, the macro trends over weeks and months correlate better to my overall training volume (and like you, they’ve also correlated well to VO2 tests I’ve done in the lab).


I’ve noticed something similar.

Vo2max always drops during/after a recovery week when I’m fresh and my heart rate is a little higher.

Then it shoots up when I get fatigued.

Similarly, anything long where hr drifts seems to cause it to drop but vo2 intervals outside where my hr spikes are massively delayed will cause it to rise.

While I like watching it go up, I try to ignore it these days.

1 Like