Oxygen uptake kinetics during postexercise recovery are impaired in long COVID-19 patients: a cross-sectional study, 2025, Zamorano-Vargas et al.

Just to be clear, this isn't a reference to graded exercise therapy. This is the protocol used for the CPET, with the effort required to cycle increased over the length of the test.

 

Looking at Figure A in SNT's post #4, you can see the resting VO2 increasing over the time of the exercise test to the Vo2 peak. And then they have measured how long each person took for their VO2 (their oxygen extraction) to reduce to half of the peak value.
There's a very clear difference in the peak VO2 between the LC and control groups, and in the time taken to recover to 1/2 VO2 max.

But, notice that the y axis doesn't have kg in the measurement, it's not actually the VO2 numbers that we know, it's not adjusted for the mass of the person.

And I assume that the chart is of one individual LC participant and one healthy control. So, perhaps the mean differences were not so starkly different?


If you look at Figure D in post#4, the differences are not nearly so exciting, suggesting that Figure A may have been cherry picked. There, they plot the VO2 max (per kg) versus the time taken to recover to 1/2 Max. It's a bit hard to differentiate the LC and control points. But, yeah, I don't think there is much of a difference in recovery times for a given VO2 max.