VENTILATORY MUSCLE TRAINING IN CYSTIC FIBROSIS

Abstract

Ventilatory muscles (VM), like other skeletal muscles, can fatigue, and respiratory failure can result from inadequate VM power to overcome increased respiratory loads. Improving VM endurance may benefit chronic lung disease patients by making these muscles less susceptible to fatigue. Four Cystic Fibrosis (CF) subjects, with mean FEV1 68±12% predicted, participated in a specific VM endurance training program consisting of 25 min/day maximal normocapnetc ventilation 5 days/week for 4 weeks. They improved their VM endurance 51.6± 18.8 % (P< 0.02). Seven CF subjects, with mean FEV1 67±13 % predicted, participated in a 4-week physical activity training program consisting of 1 ½ hours/day of swimming and canoeing, without specific VM training. They increased their VM endurance 56.7±26.7 % (P <0.005). However, four normal subjects, on the same specific VM training program, increased their VM endurance only 22.1±7.3 % (P<0.005). The increased response of the CF subjects to training suggests either that they had reduced VM endurance initially, or that the training program superimposed on their increased respiratory load was a greater training stress. We conclude from these results that VM endurance can be rapidly improved in CF patients. Furthermore, a rigorous program of upper body endurance exercise is equally effective in improving VM endurance as specific endurance training.