I was watching some of the media on this website and a question arose. Not specifically about the media, but they'd described Orthostatic Intolerance, where a person faints or has a dizzy spell upon changing body position from lying down to sitting to standing. Apparently the blood pressure lowers temporarily but severely and the person's brain can't get oxygen and plop. I've never fainted, but I've felt faint and OI has solved a mystery for me. Even when I was young, I would occasionally feel a need to just lie down immediately wherever I was. I've done it on city streets, subways, in the gymnasium at school, etc. I never knew why. Then I was fine. It was like a rush or roar of water in my ears and I knew I'd have to stop for a minute. If I was in a car, I'd have to ask the person to stop so I could get out and lie down! It's very memorable and many of my friends from back then remember it. It seemed to stop after about age 25, but I also had more control over my schedule, so I might have planned around it without realizing it. I remember around that age spending entire days in bed "recharging" and mostly reading and napping. I had a rule that every weekend I'd do that for a day, or I'd be exhausted the next week. I never considered it to be odd. My mom did the same but much less frequently, maybe once a month. Her productivity the rest of the time made up for it in spades. Ditto for me, as long as I got this higher requirement for rest, I was a firecracker. But when it became aches and pains, and mind fog, and I had to fight to focus my eyes, then the check bounced. The part that I don't understand is this: If this is a documented obvious fact that people have this OI thing, then why do we tell patients that they're "ok" if their blood is oxygenated to 90% or higher? It seems like the clippy thing for my finger is just telling a lie. It's a tool that shouldn't be used with CFS patients I think. It can tell us nothing helpful. We need a way to know whether we've had a drop in bp, not whether our blood has sufficient oxygen. Is there such a tool? Or one that can tell us if our brain is oxygenated sufficiently? or has enough blood flow? What if the vascular headaches are due to the body attempting to up the blood pressure so the brain can get enough blood?