Hi John. Thank you for the reply.
Maybe it is hyperventilation, which I don't have much experience with, so I didn't know to consider it. As I read about the symptoms of it, I didn't really seem to have any dizziness, headache, tension or some other common items. But maybe I didn't pay enough attention to them or my threshold is higher, so I don't faint or something. The tingling in the hands and feet had similarities with the feeling when you sleep in a position where arms go numb from lack of circulation. And when moved, this strong and unpleasant tingling feeling comes with improved circulation. But it seems to consist many different sensations together. What I was feeling with my exercise was just a strong tingling without unpleasant painful feeling. Who knows, maybe it was just related to hyperventilation. I'll pay more attention next time if it happens.
Regarding my mention about important books, I don't think this has been put together with the Illuminati phenomenon, or any sort of a secret at all. It's not so well know because of lack of interest to the topic from people (which in my opinion comes down to the persons (and society's) current evolution and growth). What I'm talking about is the phenomenon of out-of-body experiences and the dimensions that lie beyond from our known world. There are a lot of people who have personal experiences and also few institutions that have been doing some serious research and experimentation on the topic. One of them is the Monroe Institute in US, that has been the pioneer in this field for decades already. And it all started with the founder Robert Monroe, who wrote 3 diary style books about his 'travels' and experiences. Since he seemed a normal healthy minded person (not a drug user) and after him there has been thousands of people following his footsteps, I for now, feel like this to be the most important information about our world and outside of it to be known. The knowledge about 'afterlife', could have a lot of benefit to the current civilization, from just the simple point of eradicating the fear of life/death, which directs the decisions in much of our lives. Living without that fear makes life a lot more easier (personal experience).
If you haven't yet, then the book that I consider the most important that I have read, is his last book titled Ultimate Journey. It summarizes his first two books and 4 decades of out-of-body travels with all the accumulated and thought trough knowledge, to form what he calls a 'interstate map' (or something along these lines), which gives a bit of overview and insight for what lies beyond once we leave this physical body (and why and how we decide to come back for another game of life, either here or some other planet).
Anybody with a bit of open mind will find this very fascinating read.
PS. Adding here that it doesn't seem to be clearly understood why some people can induce the obe experience with ease, while others struggle for years without results. Maybe it has something to do with the energy flow between the chakras, and if they are blocked, it simply wouldn't work. But that's just my own theory.
Best of luck