Stability of total respiratory resistance under multiple baseline conditions, isometric arm exercise and voluntary...

Little is known about total respiratory resistance (TRR) as a psychophysiological parameter in normal subjects. Therefore, we investigated TRR in 45 healthy students under multiple baseline conditions, isometric arm muscle tension and voluntary deep breathing (VDB). TRR was measured by the forced oscillation technique. In addition, heart rate (HR) as well as volume and time components of the respiratory cycle, respiratory timing and respiratory drive were monitored. Subjects repeated the protocol 14 days later. Coefficients of stability and dependability were calculated for 20 s measurement epochs within and between both sessions. Increases of HR and shortening of time components of the respiratory cycle were found during muscle tension, prolongation of time components and increases in volume were found for deep breathing. During both experimental tasks TRR increased significantly. Short-term as well as long-term stability of absolute TRR scores proved to be comparable or even better than reliability of other physiological parameters, however, difference scores from baseline revealed only low coefficients.