Explanation of the effects of orthostatic hypotension? When I get up fast from sitting or lying down, almost always I will experience orthostatic hypotension. The most common effect is that everything becomes "black" or so. But I've outright passed out as well.

But there are some weirder effects. One time I experienced the most bizarre thing. Everything in my field of vision was transposed with the other side. "Left" became "right", vice versa. Very hard to explain.

Other times I've shaken a little bit. This usually happens if I pass out, but also happens on it's own. Usually part or all of my body will just twitch or shake a little.

I am **not** asking for medical advice. What I do want to know is a scientific reason for why it happens at all, and why the effects occur.