Aging and Human respiratory system

Effects of Aging 
Respiratory fitness decreases with age. Maximum breathing capacities decline, while the likelihood of fatigue increases. Inspiration and expiration are not as effective in older per­sons. With age, weakened intercostal muscles and in­creased inelasticity of the rib cage combine to reduce the inspiratory reserve volume, while the lungs' inability to re­coil reduces the expiratory reserve volume. More residual air is found in the lungs of older people.
With age, gas exchange in the lungs is not as efficien not only due to changes in the lungs but also due to changes in the blood capillaries. The walls of the alveoli and capillaries thicken, and the gases cannot diffuse as rap­idly as they once did.
In the elderly, the ciliated cells of the trachea are re­duced in number, and those remaining are not as effective as they once were. Respiratory diseases, such as those dis­cussed in the chapter, are more prevalent in older people than in the general public. Pneumonia and other respira­tory infections are among the leading causes of death in older persons.