Yes. I hold my breath without realizing, when I do things during the day. I believe it's from my anxiety. When I realize, I have to really concentrate on my breathing, and tell my self to deep breathe. I know this may sound crazy, but I really do believe it stems from when I was little, and became frightened, and would just hold my breath. I have anxiety and panic attacks. I believe this is the reason I do it. I know I will eventually realize it, by feeling like I'm going to pass out. I'm a shallow breather also. Most people breath so the air reaches their lower stomach. My breathing in just in my chest (shallow breather). I'm just glad to hear, that other people do it also.