[note - @Allyson posted this link in another thread but I thought it was worth repeating here in the POTS section] Dysautonomia International blog entry about recent POTS research: http://www.dysautonomiainternational.org/blog/wordpress/new-evidence-of-autoimmunity-in-pots/ From the first paragraph: Later on in the article the Dr. David Kem does a nice job of explaining the issue. And he mentions how it might eventually lead better testing as well as treatment. Obviously, more testing is needed first. If I understand things correctly (and that's a big "IF" ), it looks like this research into adrenergic autoantibodies applies to both POTS *and* NMH (and/or Chronic Orthostatic Intolerance --- so many names for all the various orthostatic issues!). The article talks about how these adrenergic autoantibodies cause changes to heart rate and the constriction/dilation of blood vessels. In short, it might be interesting reading even for those without a specific POTS diagnosis.