Breathing is one internal function that the conscious mind can control with comparative ease. The effect of controlled breathing is almost like communication with all conscious parts of one's being saying to them, "Simmer down and listen; there is something beyond the turmoil". It is communication in action that often works when words merely go in one ear and out the other, not even changing the cognitive mind. In essence, the effect is to turn all the elements of our will toward stillness and waiting.
Peace is love resting in order to be renewed. The renewal takes place in the inner silence. In the desert we see things as they are. We are face to face with reality. The silence we observe externally does then become also the inner silence when the miracles of grace take place. Here we are stripped of the outward garments hiding our true selves. Here we can embrace the awfulness of our human condition and the awesomeness of the offered gift of grace. We are in touch at last with our reality.