We probably all acknowledge that regular spontaneous physical activity plays a large role in maintaining health and physical fitness. In health, the promotion of regular physical activity has been a feature of active living since at least the time of Ancient Greece. In more modern times we have continued this tradition by encouraging our children to play sport and sustaining recreational physical activity through to old age.

Although the health benefits of maintaining spontaneous physical activity in otherwise healthy people are evident, it is only in more recent times that we have realised its importance in people with chronic disease. In people with chronic obstructive pulmonary disease (COPD), the reduction of physical activity is both a consequence and a symptom. Advancing airway obstruction leads to breathlessness that impedes activities of daily living and may naturally be compounded by the physical deconditioning induced by inactivity. We now understand that reduced physical activity is associated with a poorer prognosis in those with COPD, as well as a higher risk of hospital admission.1^–3 In addition, therapies such as pulmonary rehabilitation are beneficial because they improve health status indirectly through the medium of physical exercise training and the increase in functional exercise capacity. Apart from slowing down the rate of decline of airway function, the main aims of treatment in COPD are to increase the quality of life and to improve symptoms of breathlessness during activity. To have a sustained beneficial effect, any therapy will have to bequeath a change in lifestyle which results in increased spontaneous physical activity. The simple provision of improvements in airway function or physical exercise capacity is insufficient to ensure sustained benefit unless the new capacity continues to be used. The recording of spontaneous daily physical activity therefore adds a different dimension to patient assessment that …