Awareness of the detrimental effects of smoking, environmental factors and pollution on lung health are well established. There is also awareness of the impact of obesity on the cardiovascular system with, for example, the development of diabetes, raised cholesterol levels and hypertension, but less attention is given to obesity and the association with respiratory symptoms, particularly breathlessness (both exertional and at rest) and cough, with the potential to cause either under or over diagnoses of respiratory conditions. The  relationship between obesity and respiratory diseases is complex, as it is not simply related to the physical and mechanical impact of obesity, but also associated with inflammatory cellular function and mediator activity. This article explores the evidence for the impact of
obesity on lung health.