This proposal aims at evaluating an inspiratory muscle training (IMT) method not previously tested in COPD called the Test of Incremental Respiratory Endurance (TIRE). As a training method, TIRE promises to provide further benefits over standard IMT because it allows the user to adjust training loads as progress is made, adjusts the training based on day-to-day variations commonly noted in COPD, and provides a graphic representation of the inspiratory effort throughout all inspiration with real-time biofeedback in order to "coach" the user in performing the exercises. The TIRE device can also be used as an assessment tool, not only to measure the commonly used measure of inspiratory muscle strength Maximal Inspiratory Pressure (MIP), but also measuring the MIP variation generated throughout a maximal sustained inspiration. In this way, TIRE integrates MIP over the inspiratory duration (ID), providing a novel derivative measure called the sustained maximal inspiratory pressure or SMIP, that is likely a better surrogate of inspiratory muscle performance in COPD based upon preliminary data. The main goal of this trial is to fully evaluate the utility of TIRE as an IMT method in veterans with COPD. The investigators hypothesize that as a stand-alone therapy, TIRE training is superior to standard IMT in improving inspiratory muscle strength and endurance and in improving COPD-related clinical outcomes.

Inclusion Criteria:

• Male or female aged > 40 years with a confirmed diagnosis of COPD by a pulmonologist (presence of risk factors and airflow obstruction) and evidence of inspiratory muscle weakness as defined by the latest American Thoracic Society / European Respiratory Society statement on respiratory muscle training.

Exclusion Criteria:

• Refusal to participate in the study, subjects actively undergoing pulmonary rehabilitation, inability to perform the required maneuvers (i.e. patients with cerebrovascular accident or tracheostomy), subjects not in their stable state (i.e. having an acute exacerbation or within 4 weeks of having one) or presence of important comorbidities that may confound the interpretation of TIRE measures (i.e. decompensated heart failure, diaphragmatic paralysis, prior lung surgery, active cancer treatment, etc.). There will be no involvement of vulnerable populations.