The present study is planned to evaluate the effect of the aclidinium bromide/formoterol fumarate 400/12 μg FDC BID on the hyperinflation, exercise endurance and physical activity in patients with moderate to severe COPD. Additionally, the effect of the behavioural intervention on top of aclidinium bromide/formoterol fumarate 400/12 μg will be assessed both on the exercise endurance and the physical activity.

Inclusion Criteria:

1. Males and non-pregnant, non-lactating females aged ≥ 40.
2. Patients with a clinical diagnosis of COPD according to GOLD guidelines 2014, with a post bronchodilator FEV1 ≥ 40% and < 80% of the predicted value and FEV1/FVC < 70% at Visit 1.
3. Functional residual capacity (FRC) measured by body plethysmography at Visit 1 ≥ 120% of predicted value.
4. Patients with modified Medical Research Council dyspnea scale (mMRC) ≥ 2 at Visit 1.
5. Current or former cigarette smokers with a smoking history of at least 10 pack-years at Visit 1
6. Patients willing to participate in the telecoaching program during the four last weeks and to enhance their physical activity
7. Patients who understand and are able to follow the study procedures, are cooperative and are willing to participate in the study as indicated by signing the informed consent.

Exclusion Criteria:

1. History or current diagnosis of asthma.
2. Any respiratory tract infection (including upper respiratory tract) or COPD exacerbation in the 6 weeks prior to Visit 1 or during the run-in period.
3. Patients who have been hospitalised for an acute COPD exacerbation within 3 months prior to Visit 1 or during the run-in period.
4. Clinically significant respiratory conditions other than COPD.
5. Use of long-term oxygen therapy (≥ 15 hours/day).
6. Oxygen saturation ≤ 85% as measured by pulse oximetry during exercise testing at Visit 1, Visit 2 or Visit 3 prior to randomisation.
7. Patients with a Body Mass Index (BMI) ≥ 40kg/m2.
8. Patient who may need to start a pulmonary rehabilitation program during the study and/or who started/finished it within 3 months prior to Visit 1 or during the run-in period.
9. Patients with clinically significant cardiovascular conditions.
10. Patients with Type I or uncontrolled Type II diabetes, uncontrolled hypo-or hyperthyroidism, hypokalaemia, or hyperadrenergic state, uncontrolled or untreated hypertension.
11. Patient with known non-controlled history of infection with human immunodeficiency virus (HIV) and/or active hepatitis.
12. Patients with clinically relevant abnormalities in the results of the blood pressure, ECG, or physical examination at Visit 1.
13. Patients with any serious or uncontrolled physical or mental dysfunction that could place the patient at higher risk derived from his/her participation in the study or could confound the results
14. Patients with conditions other than COPD that may contribute to dyspnoea and exercise limitation or with contraindications to clinical exercise testing according to ATS recommendations for CPET
15. Patients with other relevant comorbidities that make the patient nor suitable to follow-up study procedures and/or could affect physical activity
16. Patients who cycled < 2 minutes or > 15 minutes during the constant work-rate exercise tests conducted at Visit 2 (Run-in Visit) or at Visit 3 even after adjustment of the work load.
17. Patients with history of hypersensitivity reaction to inhaled anticholinergics, sympathomimetic amines or inhaled medication or any component thereof (including report of paradoxical bronchospasm)
18. Patients for whom the use of anticholinergic drugs is contraindicated (acute urinary retention, symptomatic prostatic hypertrophy, bladder neck obstruction or narrow-angle glaucoma)
19. Patients unable to properly use a multidose dry powder inhaler or a pressurized metered-dose inhaler (pMDI).
20. Patients using any prohibited medication (including IMP within 30 days (or 6 half-lives, whichever is longer) before Visit 1) or who have not undergone the required washout period.
21. History of malignancy of any organ system (including lung cancer), treated or untreated, within the past 5 years other than basal or squamous cell skin cancer).
22. Patients who do not maintain regular day/night, waking/sleeping cycles (e.g., night shift workers, sleep apnea).
23. Patients unable to give their consent, or patients of consenting age but under guardianship, or vulnerable patients