Happy holidays to y'all.
This paper on recovery after 2-day CPET test might shed some light on the important topic of rest-vs-activity on long term prognosis. ME/CFS group took 12.7 days while the control took 2.1 days to recover according to the paper. What could be of particular interest is that one patient did not recover after 1 year. Assuming that the patient will never recover, it could mean that there is a small chance that you will get permanently worse after a PEM. 2-day CPET, however, is an extreme example. I wouldn't/couldn't have subjected to such an exertion voluntarily when I was in the severe/moderate side of the spectrum. Pedaling 10-100W for 10 minutes would've been unthinkable even in the mild stage.
So, let's say that the chances for becoming permanently worse after a (nominal) exertion is very small. But that also means that there is non-zero chance of getting permanently worse. On the flip side, there is no evidence that inactivity or under-activity improves the ME/CFS either. If anything, most of the literatures out there point to worse outcome for inactive patients. Assuming that those are the cases, I suppose prudent thing would be to leave it up to individual patients. (I'm preaching to the choir on this, I'm sure). It would be a somewhat similar situation as vaccination in which some people are left permanently worse off, except that there is public health implication since ME/CFS is not communicable.
My personal choice would be, as it has been, to be as active as possible without triggering PEM. For one thing, our "energy" is so limited that we end up leaving A LOT on the table when we curtail 50% to be on the safe side. (Just a little difference sometimes meant returning home vs getting marooned and "die"). For another, my mood used to improve tremendously after slowly walking 1km to a cafe whenever I can. No idea if that aided or delayed my eventual recovery, but that certainly was a lifesaver for me at the time. The benefit/cost for me was such that I was willing to risk a possible PEM of 3-4 days.
Sorry for the rambling. I rebounded from a short COVID relapse, and I had to type something.
