The purpose of this 3 month randomized intervention study is to investigate the additional effect of a physical activity telecoaching program on physical activity in patients with COPD, compared with usual care.

In this 3 month, randomized (1:1 ratio), parallel-group, multicenter trial, patients in both groups (control and coaching) will receive information and guidance on the benefits associated with increased physical activity in COPD patients and their health status. Patients in both groups will use two PROactive monitors (ActiGraph® and DynaPort®) and a PDA to complete the PROactive questionnaire. In addition to above, the patients in the coaching group will receive daily coaching by a semiautomated system and coaching by the investigator during study visits.

Inclusion Criteria:

• Written informed consent must be obtained before any assessment is performed
• Male and female patients ≥ 40 years of age
• Diagnosis of COPD (GOLD criteria: post bronchodilator FEV1/FVC< 70%)
• Current or ex-smokers with a smoking history equivalent to at least 10 pack years
• Patient should have at least 4 days of physical activity data recorded via PROactive monitors during 7 days prior to the baseline measurement

Exclusion Criteria:

• Orthopedic, neurological or other complaints that significantly impair normal biomechanical movement patterns, as judged by the investigator. Specifically if the patients' condition/ co-morbidities are such that physical activity cannot be increased, then they should not be enrolled
• Respiratory diseases other than COPD (e.g. asthma)
• Cognitive reading impairment and/or difficulties to manage electronic devices precluding interaction with the smartphone and PDA, as judged by the investigator
• Participating in or scheduled to start an outpatient rehabilitation program during the study. If the patient wishes to participate in pulmonary rehabilitation for any reason the patient can be enrolled in the study only at the end of rehabilitation