What is the mechanism of pursed lip breathing?

Pursed lip breathing is a technique that involves inhaling through the nose and exhaling slowly through pursed lips, similar to blowing out a candle. This method increases airway pressure during exhalation, helping to keep the airways open longer and facilitating the removal of trapped air in the lungs. It also promotes relaxation and can improve oxygen exchange by slowing down the breathing rate, making it particularly beneficial for individuals with respiratory conditions like COPD. Overall, it enhances breathing efficiency and can reduce feelings of breathlessness.