This randomized, parallel-group clinical trial will enroll adults with COPD and assign them 1:1 to either the RESP-FIT intervention or enhanced usual care. The RESP-FIT intervention includes respiratory muscle strength training using a commercially available inspiratory muscle trainer, remote spirometry, physical activity monitoring, ecological momentary assessment of symptoms, and a mobile application for monitoring and feedback. Primary and secondary outcomes include dyspnea, dyspnea-related kinesiophobia, respiratory muscle strength, physical activity, lung function, and quality of life, assessed over a 6-month follow-up period. All study activities are conducted remotely.
