Have you wondered about your PH levels being too acidic as an O negative? Do you pay attention to this? I put plants around my house in an effort to increase oxygen levels things like Aloe Vera, Ivy & Snake plant. According to studies it cleans the particles in the air & gives off a more relaxed vibe & may help to increase alkalinity levels which may help us to be less stressed & to sleep better. Their are some good videos on YouTube about this & on carbon dioxide & O negatives.