The prevalence of lung conditions, such as COPD and pulmonary fibrosis, and lung infections, such as pneumonia, increases sharply with age. The physiologic, cellular, and immunologic changes that occur during aging contribute to the development of lung disease. Studies of age-related changes in physiology and function are not only key to preventing or ameliorating disease, they are also essential for understanding healthy aging. Individuals with good lung function live longer, healthier lives, although the mechanisms by which this scenario occurs are not understood. The present article reviews changes in the aging lung that facilitate development of disease and the evidence supporting the idea that robust lung function reduces the risk of developing chronic inflammatory conditions that occur with age.