Pulmonary function and oxygen uptake during exercise in 11-year-old patients with cystic fibrosis

Ten patients with cystic fibrosis (CF), 5 girls and 5 boys, 11 years of age, underwent pulmonary function and bicycle exercise testing. The material includes all but 2 CF patients in this age group in southern and eastern Norway. The CF children had a moderately reduced pulmonary function, the girls more pronounced than the boys. The mean maximal oxygen uptake (max VO2) in the CF boys was 55 ml/kg/min (94% of age predicted value; range 79-105%), and the CF girls 42 ml/kg/min (79% of age predicted value; range 67-89%). The mean maximal peak heart rate was 195 beats/min. Only one CF girl showed apparent pulmonary limitation during exercise. Increased ventilatory equivalent for oxygen was found during both rest and exercise for the CF girls, but only during rest for the CF boys. Max VO2 was fairly well related to the habitudinal physical activity of the children (r = 0.79).