From what I understand about my own hyperventilation experience, is that a person aware of it won't consciously do it. In other words, if you're hyperventilating, you're in such a panic attack that you don't realize you're doing it. I've only done it twice, I think. My mom (RN for almost 40 years) explained that it is basically rapid breathing where you start inhaling your own carbon monoxide. I've never researched it.
When I had my very first anxiety/panic attack on 3/18/13, I went to the ER and they took me straight to the back, laid me down, and a nurse immediately began giving me instructions on how to breath. I wasn't aware that I was having a panic attack, like others here, I thought it was a stroke or heart attack, something way more serious. After I calmed down and all the tests were ran, they explained that I was hyperventilating when I came in. I had no idea. The nurse also said that she felt it caused my acid reflux to flare up, based on the chest and stomach x rays they took.