The effects of aging on the respiratory system are similar to those that occur in other organs: maximum function gradually declines. Age-related changes in the lungs include
Decreases in peak airflow (how quickly someone can exhale) and exchange of carbon dioxide and oxygen
Decreases in measures of lung function such as vital capacity (the maximum amount of air that can be breathed out following a maximum inhalation)
Weakening of the respiratory muscles
Decline in the effectiveness of lung defense mechanisms
(See also Overview of the Respiratory System.)
In healthy people, these age-related changes seldom lead to symptoms. These changes contribute somewhat to an older person's reduced ability to do vigorous exercise, especially intense aerobic exercise, such as running, biking, and mountain climbing. However, age-related decreases in heart function may be a more important cause of such limitations.
Older people are at higher risk of developing pneumonia after bacterial or viral infections. Thus, vaccines for respiratory infections such as influenza and pneumococcal pneumonia are particularly important for older people.
Importantly, age-related changes in the lungs are compounded by the effects of heart and lung diseases, especially those caused by the destructive effects of smoking.