In the respiratory training for pat

In the respiratory training for patients with chronic obstructive pulmonary disease, lip retraction breathing can relieve the pressure of respiratory tract, exhale more stagnant gas, and can make the pressure balance point tend to shift to the center. Abdominal breathing can prevent the small airway from closing or narrowing during exhalation, reduce the resistance of breathing, and increase the movement of diaphragm. Breathing exercise and aerobic training can enhance muscle strength and endurance to hypoxia, make the respiratory tract more unobstructed, and improve cardiovascular and pulmonary functions.