Why do humans sigh?

Why do we laugh? Why do we yawn? Why do we sigh? Science finally has some answers for that last one. Of course we do it when we're blissfully content or totally exasperated- but what's the point?

A new study published in Psychology & Behavior examined the effects of sighing, physiologically and psychologically.

They found that it's a way for the body to "restore balance" after experiencing some kind of stress. It actually reduces muscle tension and increases relaxation- particularly in those who have high levels of anxiety. That's right, spontaneously sighing is nature's xanax. There were even benefits when the anxious participants were told to intentionally sigh.

Feeling stressed? Hit the reset button. Take a deep breath... now sigh it all out. Better?