Which of these is NOT a cause of hyperpnea?

Hyperpnea is characterized by increased depth and rate of breathing, often in response to increased metabolic demand, such as during exercise or a metabolic disorder. Among the potential causes listed, metabolic disorders and central nervous system (CNS) disorders are commonly associated with hyperpnea.

Metabolic disorders can lead to hyperpnea due to increased carbon dioxide production and the body's attempt to compensate by increasing respiratory effort. Similarly, CNS disorders can affect the brain's regulation of respiration, resulting in hyperventilation or hyperpnea as a compensatory response.

While respiratory infections can cause increased work of breathing, they typically lead to hypoventilation rather than hyperpnea, as the body may struggle to effectively ventilate due to obstruction or other pathological changes in the lungs. This distinction is key in understanding why respiratory infections do not primarily cause hyperpnea.

Therefore, the correct response indicates that respiratory infections are not a direct cause of hyperpnea, distinguishing them from the other categories.