Re your reference: most of this refers to increasing fluids, not specifically water. It is also titled 'GENERAL INFORMATION BROCHURE ON ORTHOSTATIC INTOLERANCE AND ITS TREATMENT'. It appears to relate to NMH and classic POTS. I do not have these. Not all people with ME/CFS have. I have hypertension, and possibly the opposite postural changes to people with POTS, as I get tachycardia when I lie down rather than when I stand up. Also, it is advice from a clinic, not a scientific paper, and it does not have in-text references to scientific papers on which the advice is based, just a bibliography at the end from which it is impossible to ascertain which article/paper relates to which statement. Basing your own advice on someone else's unreferenced advice risks disseminating incorrect information, as well as a possible 'Chinese whispers' effect in which each person who repeats info gets something slightly wrong, and so on. I find it odd to take diverse bits of info from diverse sources, some being advice from other sources which do not show clearly their own evidence base, and some derived from scientific papers (yet even these have not been carefully analysed for rigour and credibility), then collate them together and put one's own name (or even more strangely, an assumed name) to the results. I consider that science-related advice, especially when people's health and welfare are at stake, should be based predominantly on original scientific papers which the writer has analysed and shown that s/he understands.