Comparison of Breathing Pattern and Subjects' Perception during Resistive Loads Applied to Inspiration,Expiration or Whole Breathing Cycle

Using a 2-factor 6×3 factorial experimental design and the MultistageEvaluation Scale(MES)to estimate the respiratory sensation,we systematicallystudied in 17 healthy young men the physiological and psychological effects of sixlevels of suprathreshold added resistive loads,appliedeparately to eitherinspiration or expiration,or throughout the breathing cycle.We observed that(1)no matter what phase of the breathing cycle was impeded,mask cavity pressureswingas well as total external respiratory workrate(r)was a curvilinearfunction of the total resistive load added(R_T),which exhibited an upwardconvexity;(2)the perceived magnitude(PM)of the respiratory sensation estimatedby using MES(S_(MES))was directly related to intensity of the physiologicalstimulus and indirectly related to the intensity of the resistance added;and(3)under different loading conditions,S_(MES)was a curvilinear function of theintensity of the physiological stimulus,which exhibited an upward concavity.These results suggest that when we derive the standards of allowable resistancefor respiratory protective equipment,in addition to the total load intensity,theimportance of the ratio between inspiratory and expiratory resistance should alsobe considered.

Comparison of Breathing Pattern and Subjects' Perception during Resistive Loads Applied to Inspiration,Expiration or Whole Breathing Cycle