The human lung is a resilient and complex organ, capable of uninterrupted functioning without defect over a lifetime. While there is a body of knowledge regarding macroscopic and physiological changes that occur in the lung with age, there is still much to be understood. In itself this is not surprising given the complex interaction of intrinsic and extrinsic factors that might play a role in these changes. Lung tissue is highly susceptible to environmental factors, which can have an impact over the course of a lifetime, including smoking, pollutants, occupation and nutrition.