RESPIRATORY SENSATION AND RESPIRATORY MUSCLE ACTIVITY

Abstract

Publisher Summary This chapter focuses on respiratory sensation and respiratory muscle activity. In the study described in the chapter, magnitude scaling methods were used to compare, in a group of normal subjects, the sensations produced by ventilatory elastic and resistive loading. In keeping with the psychophysical power law, the relationships between the physical magnitude of the load and the subjective intensity of the sensation were linear when plotted on log-log coordinates. The exponent for the magnitude estimation of elastic loads in the normal subjects was 1.02 ± SE 0.06 while the exponent for the estimation of resistive loads was 0.71 ± 0.05. The exponents for the estimation of elastic and resistive ventilatory loads were closely correlated, suggesting a common basis for the sensation produced by the two types of loads. However, the perceptual acuity for elastic loads was greater than that for resistive loads; a twofold change in elastic load produced the equivalent change in sensation as a 2.7-fold change in resistive load. This difference in perceptual sensitivity was consistent with the observations that the maximum tolerable resistive load greatly exceeds the maximum elastic load and may in part explain the finding that hypercapnic ventilatory responses are better maintained during elastic loading than resistive loading.