Chronic sustained hypoxia (CSH) is known to induce functional and structural changes in the respiratory system. The diaphragm, as the main inspiratory muscle of mammals, is particularly important in the neuromotor regulation of respiration. Diaphragm electromyography (dEMG) records the sum of motor unit action potentials (MUAP) and provides information regarding motor unit recruitment and frequency coding during muscle contraction. We aimed to assess changes in dEMG activity following CSH. Herein, eight male Wistar rats (2-3 months) were subjected to CSH (10 ± 0.5% O