What now is Right Attentiveness? […] - Whenever the disciple is training himself to inhale or exhale (a) whilst feeling, rapture, or (b) joy, or © the mental functions, or (d) whilst calming down the mental functions. At such a time he is dwelling in contemplation of the feelings, full of energy, clearly conscious, attentive after subduing worldly greed and grief. For, the full awareness of in- and out breathing I call one amongst the feelings.

(Buddha Sakyamuni)