Inspiratory muscle training in COPD patients.

This is a review of physiological and clinical aspects on training of the respiratory muscles in chronic obstructive pulmonary disease (COPD) patients. Three types of exercise training have been used: strength, endurance, and co-ordination. With each type, intensity of the stimulus, specificity and the proper evaluation of the training are important. The rationale for training respiratory muscles is not well defined in the literature. It should include increase in strength of expiratory muscles to produce an effective cough and of inspiratory muscles to increase their force reserve. Training in endurance by breathing against resistances is appropriate, because it mimics some lung pathology, such as bronchospasms. Training for co-ordination of respiratory muscles allows maximization of the use of abdominal muscles as inspiratory accessory muscles and of the lips to regulate the closing pressure point of the airways as in pursed-lips breathing. Reviews of work done on training the respiratory muscles in COPD patients often show partial objectives, non-specific techniques of evaluation, absence of control groups, subthreshold loads, and neglect of dyspnoea and nutrition. There is enough information proving that respiratory muscles can be trained both for endurance and strength, and sufficient evidence that new imaginative training programmes can improve the quality of life of COPD patients.