Effect of Inspiratory Muscle Training on Exercise Performance and Quality of Life in Patients With Chronic Obstructive Pulmonary Disease

Inclusion Criteria: * Exsmokers * Low PImax compared to reference values \[lower limits of normal: 80 cmH2O for patients less than or equal 54 years old; 71 cmH2O for patients' age between 55-64 years; and 65 cmH2O for patients 65 years old \]. * Stable patients without history of exacerbation or hospitalization four weeks before starting the study. Exclusion Criteria: * Lack of motivation and compliance. * Patients with significant reversibility following bronchodilation defined as an increase in FEV1 of more than 12% and 200 ml from the pre-bronchodilator value * Unstable cardiac disease \[severe heart failure, dangerous dysrhythmias, recent myocardial infarction or unstable angina (within 4 weeks)\]. * Uncontrolled hypertension * Recent pneumothorax (within 6 weeks) * Recent abdominal or thoracic surgery (within 6 weeks) * Known progressive neuromuscular disorders * Recent gastrointestinal bleeding (within 4 weeks) * Current smokers * Active cancer * Patients with advanced liver diseases, or renal impairment. * Known connective tissue diseases * Significant endocrinal abnormalities