END-EXPIRATORY LUNG-VOLUME DURING ARM AND LEG EXERCISE IN NORMAL SUBJECTS AND PATIENTS WITH CYSTIC-FIBROSIS

There are no reports concerning the regulation of end-expiratory lung volume (EELV) and flow-volume relationships during upper limb exercise in health and disease. We studied EELV during such exercise in 22 adu lts with cystic fibrosis (CF) and nine age-matched healthy control sub jects. Subjects with CF were grouped according to the severity of thei r lung disease, as follows: mild = FEV1 > 80% predicted; moderate = FE V1 40 to 80% predicted, and severe = FEV1 < 40% predicted. EELV was ca lculated from measurements of inspiratory capacity (IC) made at each w orkload during an incremental arm and leg ergometer test to peak work capacity. In the control group, the decrease in EELV was significantly smaller for arm than for leg exercise at peak work (-0.13 L versus -0 .53 L, p < 0.001) and for arm than for leg exercise at an equivalent s ubmaximal ventilation (-0.13 L versus -0.46 L, p < 0.01). In the group s with moderate and severe CF, arm exercise resulted in an increase in EELV from resting levels (dynamic hyperinflation) that was not signif icantly different from the increase observed for leg exercise. For CF subjects there was a significant inverse relationship between FEV1 and changes in EELV from rest to peak arm exercise (r = -0.46, p < 0.05). In normal subjects, there was a difference in the EELV response for a rm versus leg exercise. In CF subjects with airflow limitation, dynami c hyperinflation occurred with both forms of exercise.