That was never the claim. The claim was that it helps with brain fog and mental clarity in general, not specifically that caused by long-COVID, which had been proven to be true.

And a cursory look at the literature for PEM[1] will show you that the recommended path to recovery isn’t “avoid physical exertion at all costs”, but to do what you’re capable of and slowly ramp up the intensity, in which case small amounts of exercise could play a vital role.

[1] http://www.phsa.ca/health-info-site/Documents/post_covid-19_...