I'll have to rewatch it because I don't remember the actual tests to show where the blood is pooling. I've been trying to figure this out for myself. I don't think my leg colour changes when I stand....but I didn't notice my HR was raising a lot either so I don't really trust my observations now. I have however had probably 20 years of severe leg cramps (calves) - and I finally understand now why it is much worse in the summer! I've really hated the thought of wearing something constricting on my legs (like pantyhose), because it's caused more pain, possibly because it trapped blood in my legs.
People talk about abdominal pooling and pain with OI but I don't notice that, maybe because my abdomen is already fat. D'oh! Instead when I stand at times I now get severe pelvic pain, low just above the pubic bone or on the flanks. A year ago I started getting a new, intense (burning, nerve type) of pain and there is also a pressure involved. At first I thought it involved nerve entrapment because it's at night and I didn't even like to touch my skin in that area. I find it worse during my cycle when estrogen is the highest, and estrogen makes everything swell.
I'm able to touch my skin now, but I'm wondering if it could be pelvic congestion syndrome, where the veins of the ovaries (or pelvis??) fill will blood (like vericous veins in the legs). With PCS it is suppose to be worse at night because of being upright during the day and the pressure that would put on the veins.
I have yet to read about pooling in the pelvis with OI, only mention of abdomen and legs. But, I think it may be all intertwined, and if I have blood pooling in that area that would complicate things and I have been thinking of wearing an abdominal binder/corset because of it. If I do pelvic tilts or apply pressure (hold a pillow tightly against my pelvis) at that time it does seem to help. Now I need to see when OI symptoms happen in regards to my cycle too.