Final answer:
The statement is true; aging typically results in a decreased vital capacity and an increased residual volume due to factors like reduced lung elasticity and chest wall stiffening.
Step-by-step explanation:
The statement 'PFT tests on aging persons typically show a decrease in vital capacity and an increase in residual volume' is true. Pulmonary function tests (PFTs) assess the health and function of the lungs. As individuals age, aging affects lung function in several ways. Vital capacity (VC), which is the maximum amount of air a person can exhale after a maximum inhalation, tends to decrease because of factors like reduced lung elasticity and muscle strength. Conversely, the residual volume (RV), which is the air that remains in the lungs after a person has exhaled completely, usually increases because the lungs are less able to fully empty, in part due to the stiffening of the chest wall and a decrease in the strength of respiratory muscles. Lung fibrosis, a condition that can occur with age or due to disease, causes the lungs to become less pliable and can further aggravate the decline in vital capacity.