Effect of frequency on perceived magnitude of added loads to breathing

Using open-magnitude scaling, six normal subjects estimated the perceived magnitude of a range of added elastic loads (20-76 cmH2O/l), applied for a sequence of five breaths, at frequencies varying from 5 to 26.4 breaths/min. Two experiments were performed. In the first, frequency was increased by a reduction in expiratory duration (TE), and the duty cycle (ratio of inspiratory duration to total breath duration, TI/TT) ranged between 0.10 and …