Chest Physiotherapy and Cystic Fibrosis: Exercise
Exercise tolerance is limited in CF patients by a number of factors including obstruction of the peripheral airways leading to increased residual volume and increased physiologic dead space, hypoxemia, intolerable dyspnea, and uncontrollable coughing. However, certain factors that limit resting expiratory flow rates in children with CF are alleviated during exercise.
At rest, airway instability in expiration may result in airway collapse and resultant secretion and air trapping. Exercise results in alterations in bronchial smooth muscle tone leading to bronchodilation. Subsequent secretion clearance may improve the patency of airways and ventilation of the lungs. This may result in improved expiratory flow rates, increased secretion production, and reduced residual volume in exercise as compared with rest this
Exercise training has been shown to alter respiratory muscle strength and endurance, improve the perception of dyspnea, and increase secretion clearance in CF patients, with improvements in pulmonary function being attributed to the removal of secretions and a possible training effect of the respiratory muscles.” A variety of physical training exercises have been used, although swimming appears to produce the largest improvement in sputum clearance. While the volume of sputum expectorated appears to be greater if subjects are undertaking an exercise program, the effect of exercise on mucociliary clearance is still under investigation. Olseni et al (1992) compared the clearance of a radioisotope from the lungs of patients with bronchial hypersecretion before and after 15 mins of moderate exercise. There was no significant difference in mucociliary clearance rates between rest and exercise. Lannefors and Wollmer (1992) compared the effects of exercise, PEP, and FET on mucociliary clearance in a group of CF patients, but no significant difference was found in sputum clearance as measured by isotopic clearance between regimens.