The aging lung

Abstract

There are many age-associated changes in the respiratory and pulmonary immune system. These changes include decreases in the volume of the thoracic cavity, reduced lung volumes, and alterations in the muscles that aid respiration. Muscle function on a cellular level in the aging population is less efficient. The elderly population has less pulmonary reserve, and cough strength is decreased in the elderly population due to anatomic changes and muscle atrophy. Clearance of particles from the lung through the mucociliary elevator is decreased and associated with ciliary dysfunction. Many complex changes in immunity with aging contribute to increased susceptibility to infections including a less robust immune response from both the innate and adaptive immune systems. Considering all of these age-related changes to the lungs, pulmonary disease has significant consequences for the aging population. Chronic lower respiratory tract disease is the third leading cause of death in people aged 65 years and older. With a large and growing aging population, it is critical to understand how the body changes with age and how this impacts the entire respiratory system. Understanding the aging process in the lung is necessary in order to provide optimal care to our aging population. This review focuses on the nonpathologic aging process in the lung, including structural changes, changes in muscle function, and pulmonary immunologic function, with special consideration of obstructive lung disease in the elderly.

Keywords: COPD; aging; lung; pulmonary immunology.

Figure 1

The physiologic changes in aging which place elderly patients at risk for poor airway clearance.

Figure 2

Increasing age leads to elevated basal levels of inflammation (inflamm-aging) and increased immunosenescence, which are associated with changes in both innate and adaptive immune responses, contributing to the heightened morbidity and mortality seen in the elderly. Abbreviations: IL, interleukin; TNF, tumor necrosis factor.