In this study, the investigators will test Veterans with COPD in Pulmonary Rehabilitation. Between two groups, the investigators will give one group a device that assists with breathing and symptoms and the other receives a 'sham' device which does not provide these benefits. The investigators will test to see if the symptoms and exercise capacity of the group who receives this device improves faster in Pulmonary Rehabilitation and has longer lasting benefits after the end of Pulmonary Rehabilitation.

In this randomized, double-blinded, sham-controlled clinical trial, the investigators will test the effectiveness of the use of a positive expiratory device (PEP Buddy) vs. sham in participants with COPD in Pulmonary Rehabilitation and after discharge from Pulmonary Rehabilitation for up to one year. The investigators will compare changes in quality of life metrics and measurements of functional capacity between the intervention and sham groups over the course of the study.

Inclusion Criteria:

• Veteran
• Referral to Pulmonary Rehabilitation for COPD
• FEV1 <80% predicted
• Participants must be able to exercise on 4L/m nasal cannula O2

Exclusion Criteria:

• Those deemed by the study personnel to have a lung disease other than COPD impacting their daily dyspnea
• Those that are unable to perform study procedures or are unwilling or unable to use PEP Buddy
• Those that have a component of lung disease driven by aspiration or neurological conditions affecting the face or oropharynx
• Those with a life expectancy of <1 year
• Those with a known surgical intervention that will require a prolonged recovery in the year after enrollment
• Those with a malignancy beyond Stage I or non-melanoma skin cancer
• Those shown shown to have memory loss of MOCA testing

The investigators will share data with VA researchers that will be de-identified via Safe Harbor approach. However, if a non-VA researcher requests aggregate data, the investigators will work with local research office, facility privacy officer, and information security officer to identify an applicable agreement for data sharing. No VA data will include any PHI to any non-VA researchers requesting VA data.

Data will not be shared until the close of the study (March 2025). The investigators will then share data for six years after close of study.

The investigators ask that any requesting entity contact the Primary Investigator by e-mail to begin a request for data via VA processes.

Both participants and research team will be blinded. Participants will be provided with a device in an opaque box, both PEP Buddy and sham packaging will be the same. The dives themselves will look similar and the difference between PEP Buddy and sham will not be able to be determined by the naked eye.