Exercise Performance and Breathing Patterns in Cystic Fibrosis

Abstract

where VE is pulmonary ventilation, VT the tidal volume (the volume of air inhaled and exhaled during one respiratory cycle) and f b the frequency of breathing. In normal subjects during exercise the increase in VE is achieved by increases in VT at low and moderate work load, up to 50-60% of vital capacity (Jones and Rebuck , 1979). This is achieved by gradual increases in end inspiratory lung volume to about 80% of total lung capacity (TLC) and reductions in end expiratory volume to about 40% of TLC (Cotes, 1979).