Interrelation of Respiratory Responses to $\dot V$co₂, Pedal Rate and Loading Force During Cycle Exercise

Abstract

During steady-state exercise at moderate intensities, pulmonary ventilation ($\dot V$ _E) has been confirmed to be a linear function of the CO₂ production ($\dot V$co₂). In human experiments using ergometer devices, changes in $\dot V$co₂ during exercise can be achieved by changing the magnitude of two components of exercise performed on the devices, i.e., limb movement speed and limb loading force. As to how these types of exercise exert influences on the $\dot V$ _E-$\dot V$co₂ relationship during steady-state exercise, most previous studies have been carried out mainly by varying the limb movement speed^2–6, except for the study of Dejours⁷ in which both speed and force were varied. Recently, Casaburi et al.^8,9 systematically studied the influences of speed and force on the $\dot V$ _E-$\dot V$co₂ relationship in sinusoidal exercise on a cycle ergometer and found that the dynamic interrelation of $\dot V$ _E and $\dot V$co₂ was independent of the speed and force imposed during exercise.