I've had severe CFIDS for 14 years. I've never thought I had any orthastic intolerance until a little over a month ago. I was getting so faint and sweating when standing. Tested my blood pressure and it drops around 20 points when standing and my heart beat goes up by about 15 points. I used to have low blood pressure until about 6 years ago and then developed high blood pressure, A few weaks ago when I started getting faint, I realized my blood pressure has gone down. I've stopped taking my high blood pressure medicine and now with my blood pressure at about 130, it only drops to 110 when I stand vs below 100 while taking the blood pressure medicine. My question is that I am surprised that I am just now developoing orthastic intolerance, or maybe I had it all along and never noticed it since I never tested my blood pressure when standing vs sitting before. Anyone else develop orthostatic intolerance after having CFIDS for awhile instead of having it all along?