AGING AND THE RESPIRATORY SYSTEM
Perhaps the most important way to help your respira-tory system age gracefully is not to smoke. In the absence of chemical assault, respiratory function does diminish but usually remains adequate. The respira-tory muscles, like all skeletal muscles, weaken with age. Lung tissue loses its elasticity and alveoli are lost as their walls deteriorate. All of this results in de-creased ventilation and lung capacity, but the remain-ing capacity is usually sufficient for ordinary activities. The cilia of the respiratory mucosa deteriorate with age, and the alveolar macrophages are not as efficient, which make elderly people more prone to pneumonia, a serious pulmonary infection.
Chronic alveolar hypoxia from diseases such as emphysema or chronic bronchitis may lead to pul-monary hypertension, which in turn overworks the right ventricle of the heart. Systemic hypertension often weakens the left ventricle of the heart, leading to congestive heart failure and pulmonary edema, in which excess tissue fluid collects in the alveoli and decreases gas exchange. Though true at any age, the interdependence of the respiratory and circulatory systems is particularly apparent in elderly people.