This is a study to provide an in-depth validation of the 1-minute sit-to-stand test as a measure of exercise capacity in patients with chronic obstructive pulmonary disease (COPD). Patients will perform the 1-minute sit-to-stand test and other validated exercise tests and questionnaires.

Exercise capacity is a strong predictor for mortality, exacerbations and health-related quality of life (HRQL) in patients with chronic obstructive pulmonary disease (COPD). The 1-minute sit-to-stand test (1-min STS test) is a promising exercise capacity test that is simple to conduct and requires few resources.

This study will provide an in-depth validation of the 1-min STS test, specifically evaluating the tests reliability, validity, responsiveness to change and minimal clinically important difference. The study will also assess the predictive properties of the 1-min STS test with regards to detecting exacerbations, as well as identify patterns of physical activity and patient-reported symptoms of exacerbations.

Inclusion Criteria:

• COPD diagnosis according to GOLD criteria; post bronchodilator FEV1/FVC<70%
• Male and female patients ≥40 years of age
• Able to do at least 5 repetitions in the 1-min STS test at baseline assessment
• Written informed consent by the participant

Exclusion Criteria:

• Lower limb joint surgery in the preceding 3 months
• Too unstable medically to perform exercise tests
• Predominant neurological or musculoskeletal limitation to walking
• Cognitive reading impairment and/or difficulties managing the eDiary and step-counter