In both groups, initial physical activity levels (PALi) will also be established by assessing PAL with the DirectLife activity monitor (DirectLife, Philips, The Netherlands) throughout a whole week. The physical activity data collected by the DirectLife activity monitor will be used to facilitate the behavioural intervention in the S group, but not as an outcome of PAL for which a different activity monitor (Actigraph GT3x) validated in COPD will be used. The DirectLife activity monitor is a lightweight and portable device that can be worn in three different places (necklace, on the pocket or on the hip) and provides as main variables the active time (minutes) and energy expenditure (calories). DirectLife tracks the body motion with its triaxial sensor. It also provides feedback to the patients on PAL performed since the beginning of the day; a series of indicator lights on the Activity Monitor shows the accumulated activity at any particular moment of each day. It also shows the daily target of physical activity levels making it easy for them to keep on track towards their goals. The aim of the study will be to achieve increments in 50% of the initial PAL at the end of the 12 weeks programme in the S group.