But how, o Monks, must inhalation and exhalation be practiced and cultivated introspectively in order to establish the Four Foundations of Introspection? "At a time, o Monks, when the monk drawing in a long breath knows 'I am drawing in a long breath,' exhaling a long breath knows 'I am exhaling a long breath,' drawing in a short breath knows 'I am drawing in a short breath' exhaling a short breath knows 'I am exhaling a short breath'; 'Perceiving the whole body will I breathe in, perceiving the whole body will 1 breathe out,' thus trains himself; 'Calming down this body compound will I breathe in, calming down this body compound will 1 breathe out,' thus trains himself; at such a time, o Monks, the monk examining the body observes the body, unremittingly, with perspicacity and insight, after having conquered worldly desires and worry. I call this, o Monks, a transformation of the body, namely inhalation and exhalation. Thus, therefore, o Monks, at such a time, the monk examining the body observes the body, unremittingly, with perspicacity and insight, after having conquered worldly desires and worry.

(Buddha Sakyamuni)