['Patients with severe COPD suffer from impairments of exercise capacity which affects daily activity. Conversely, activity might exert effects on the functional state. We studied whether a short-term intervention by regular phone calls caused an increase in activity at home and whether this resulted in a gain in exercise capacity.', 'Over a 2-week period (P1) normal daily activity was assessed in 21 patients with stable severe COPD (GOLD III/IV). After this, the individual setting was explored in a short home visit. The subsequent 2-week period (P2) involved phone calls every other day to raise home-based activity (target: 3x15 min daily at 75% of maximum dyspnea). During the study, patients wore an actograph plus pedometer and kept a diary. Before P1 and after P2, 6-min walking distance (6MWD), lung function, the Borg score and quality of life (SF-36, SGRQ) were determined.', 'Compared to P1, actograph counts (p<0.05) were higher in P2. There was also an increase in 6MWD (p<0.05) and quality of life scores (SF-36, p<0.05) between initial and final visit, whereby improvements in 6MWD correlated with changes in activity (p<0.01). Conversely, four patients who experienced an exacerbation in P2 showed no increase in activity or 6MWD.'] Does intervention by phone calls raise domiciliary activity and exercise capacity in patients with severe COPD?