I've just been diagnosed at my doctor's surgery with OI - not quite sure which sort (and nor is he) but after 30 mins standing I had a 36 bpm rise in heart rate, a drop in DBP of 20mmHg and a drop of SBP of 28mmHg (can't remember what he said about pulse pressure change but I don't think it fit the criteria). I think that's POTS? Or is it NMH? Or both? Anyway, he agreed that we ought to increase my salt &/or water intake, but then he asked me how! I don't know! NHS! :worried: I'm already having about 2.5L of water and 4g salt a day as part of my normal diet. Can anyone refer me to a detailed protocol from a credible source (preferably a specialist) about how to increase salt/water intake for OI? How much, how fast to build up, when to stop, whether potassium might also be necessary, are blood volume tests necessary to tell when you've got a better volume, etc.? I've seen figures as high as 12g/day which seems a heck of a lot.