Now looked at that full text, and it's bizarre that Joyner should cite it as evidence that deconditioning helps POTS because the study gave no information at all about the effect of exercise training on POTS. All it found was that, as is widely found in healthy people, a sustained moderate exercise programme led to modest gains in VO2max. No mention of any effect on POTS. It's hard to see how anyone could conceive of a study on POTS that didn't measure POTS as an outcome; perhaps they did measure this and chose not to publish the findings or perhaps they just came up with a bizarre study design. We don't know (will email the authors, for fun). Anyway, turns out a separate thread was set up the editorial last year (also turned out I had read and even contributed to that thread, but forgotten all about it..).