Magnitude Perception of Added Inspiratory Resistance During Steady-State Exercise

Abstract

Eleven subjects were studied during steady-state bicycle exercise at 50 W with each of 6 added inspiratory resistances of 37, 181, 310, 607, 731 and 1216 Pa 1-1 s [1 Pa = 0.1 mm H2O] at a constant airflow. Increasing inhalation resistance did not reveal any significant influence upon mean heart rate response to work at a given submaximal work rate. Subjects responded by progressively lowering ventilation, inhalation time being prolonged. The power function which described the relations between magnitude estimation of perceived respiratory resistance (ME) and mean inspiratory pressure (P) has an exponent which is the inverse of that in the power function relating P and added inspiratory resistance (R). A linear relationship was found between ME and R. The experiment yielded a power function with an exponent of 1.6 relating ME to added inspiratory work. This confirms previous psychophysical studies of muscular effort and suggests that exponents around 1.6-1.7 are characteristic of Stevens'' power function irrespective of the muscle group involved.