Which factor(s) increase the risk of respiratory complications in older adults? Select all that apply

Several age-related physiological changes impair the respiratory system in older adults and increase susceptibility to complications. A reduced ability to cough effectively is correct because aging weakens respiratory muscles and reduces mucociliary clearance, meaning secretions and pathogens are less efficiently expelled — a major factor contributing to pneumonia risk. Increased residual volume is correct because the lungs lose elastic recoil with age, causing air trapping and leaving more stagnant air in the lungs after exhalation, which impairs efficient gas exchange. Loss of intra-alveolar septa is correct because aging causes structural breakdown of alveolar walls, reducing the surface area available for gas exchange, similar to the mechanism seen in emphysema. Improved protective airway reflexes is incorrect — in reality, aging diminishes the cough reflex and gag reflex, increasing aspiration risk. Enhanced gas exchange surface area is also incorrect; the opposite is true, as the destruction of alveolar septa reduces surface area. Together, reduced cough effectiveness, increased residual volume, and alveolar septal loss represent the primary structural and functional changes that make older adults significantly more vulnerable to respiratory infections and complications.