@turquoise-- I think those symptoms are not the earliest symptoms to be seen. I'm not a doctor, but I suffered from hypoxia while hiking. As I went up to higher elevations, I had more and more difficulty breathing and started wheezing at one point.
I thought that I was just going too fast but the rest of the people in my group were worried and so I had to go back down with one other person. I felt a little better going down but still made a visit to the nearest ER. The doctor there told me that I did the right thing. He said that if I had insisted on going up, I would have developed severe hypoxia symptoms like confusion and difficulty walking.
Apparently once these more severe signs start, it means that the brain has started getting damaged from the lack of oxygen. So it's very serious. I think people should not wait until the confusion hits to seek treatment.