Effects of focusing attention on breathing with and without apparatus on the face

In an attempt to identify a cause for the alteration in breathing pattern seen when conventional respiratory apparatus is applied to the face, we have studied the effects of causing the subject to focus attention on breathing by counting breaths in threes for 5 min. We used the respiratory inductance plethysmograph in 18 naive subjects who were unaware that their breathing was being measured. In the control periods, distraction was provided by a recorded story played through head-phones. The experiment was repeated with the rim of a facemask applied to the face. Focusing attention on breathing caused a prolongation of inspiration at a constant mean inspiratory flow, and lengthening of expiration. Tidal volume but not ventilation was increased. The facemask rim caused no significant change. It is concluded that conscious awareness of breathing could account for a major part of the effect of conventional respiratory apparatus.