© 2014 Royal Australasian College of Physicians. In health and disease, the benefits of regular participation in moderate to vigorous intensity physical activity are well documented. However, individuals with chronic conditions, such as those with chronic obstructive pulmonary disease (COPD), typically do very little activity at a moderate or vigorous intensity. Much of their day is instead spent in sedentary behaviour, such as sitting or reclining, which requires very little energy expenditure. This high level of time spent in sedentary behaviour can have serious health consequences, including increased risk of diabetes, cardiovascular disease and premature mortality. There is emerging evidence to suggest that participation in light intensity physical activities (e.g. standing or slow walking) may have benefits for cardio-metabolic health. Given the low aerobic capacity of individuals with moderate to severe COPD, increasing light intensity activity (through reducing sedentary time) may be a feasible additional strategy to improve health in this population, alongside traditional recommendations to increase the time spent in moderate to vigorous intensity physical activity. This review provides an overview of physical activity and sedentary behaviour, with a particular emphasis on these behaviours for people with COPD. It provides suggestions for the measurement of these behaviours within the clinical setting, as well as for interventions that may be effective at increasing physical activity and reducing sedentary behaviour in this population.