Breathing for stress control

At some point in our lives, we've all been told to 'take a deep breath & count to 10', usually by a friend or colleague who senses we are getting stressed about something. Without really knowing why, they are repeating the traditional wisdom. It is useful, but will probably take more than 1 breath to have the desired effect. Since breathing is something we do all day every day, you would think we'd be pretty good at it. Let's face it, we can do it in our sleep. The truth is, we're not. In fact most of us rarely breath correctly when we're awake.