We sigh when we're stressed, when we're in love and when we practice yoga and meditation -- but that's not all. Our brains signal for us to sigh every five minutes, often without us even realizing it. (Seriously, listen to your own breaths in a quiet room, it's like clockwork.) Sighing, or breathing more deeply than normal, is a vital part of our everyday lives, as it helps preserve the health and function of our lungs.