Dyspnea (air hunger) arises from the integration of chemoreceptor sensing and respiratory muscle mechanics: central chemoreceptors in the medulla, more sensitive to carbon dioxide than oxygen, detect CO2 changes via diffusion into cerebrospinal fluid, where the carbonic anhydrase reaction (CO2 + H2O ⇌ H2CO3 ⇌ H+ + HCO3-) lowers pH and triggers increased ventilatory drive (hypercapnia/hypercarbia). This central sensing mechanism is coupled to motor output driving the diaphragm and accessory respiratory muscles, and dyspnea more broadly results from pulmonary, cardiac, metabolic, neurological, or hematologic disturbances that disrupt this oxygen/carbon dioxide sensing-and-response system within respiratory physiology.
Dyspnea (air hunger) arises from the integration of chemoreceptor sensing and respiratory muscle mechanics: central chemoreceptors in the medulla, more sensitive to carbon dioxide than oxygen, detect…