I have had 3 episodes of blacking out, but they are spaced 3-4 months apart and seem completely random. Every time it has happened I was about to eat dinner and hadn t eaten for several hours. I also had been sitting on the couch for a long time before getting up to help with dinner. Wondering if maybe it could be either poor circulation or low blood sugar? It starts out with me feeling very weak and hungry, then my extremities start tingling and I break out in a sweat all over my body. After that, my vision gets very blurry and my ears start ringing very loudly. Then I blackout completely. After I come around it takes a while for me to feel normal again. One thing my husband notices when it happens is that my pupils get very big, but they go back to normal after I start to feel better. The reason I think it might be poor circulation is because I have always had problems with leg pains and cramps for as long as I can remember. Especially at night when I m sleeping or if I have been sitting for a long time. The blackout episodes happen very quickly and I have almost no warning time before I pass out. I have had an EEG, EKG, MRI, CAT scan, and all came back normal. Is this low blood sugar? poor circulation? or something else?