Therapists working with clients who have problems with anxiety or panic have known for decades that controlled breathing can help their clients deal with these responses to stress. Some of these relaxation exercises have been around for thousands of years.
Now, a new study at Northwestern sheds some light on the neurobiological mechanisms that tie breathing and relaxation. They found that subjects were better at identifying fearful faces and remembering objects when breathing in than breathing out. It’s suggested rapid breathing (which speeds up breath intake through the nose) may have survival value in dangerous situations.