The main reasons for the unexpectednumber of dropouts may lie in the low esteem still given to physical exercise in geriatric facilities in our country, the ignorance of its potential long-term benefits and the difficulties in maintaining a stable participation during 15 months. A further limitation to consider is that effective single blinding was not feasible for the functional mobility measure. Due to the logistics, the physiotherapists could not be held blind to participant’s performance on the TUG since they obviously knew to whom they were admin isteringthe exercise program. No information was obtained regarding the specific type of dementia diagnosis among the participants. Finally,lack of brain neuro imaging and biochemical data hinder further assessment of the physiological mechanisms involved in the effects of physical activity.