When is a wheezing lung sound most commonly heard?

Wheezing is a high-pitched, musical sound often associated with the movement of air through narrowed airways. It is most commonly heard during expiration, as the air passages are typically more constricted during this phase of respiration. In conditions such as asthma or bronchitis, inflammation and bronchospasm can create these narrowed passages, leading to wheezing sounds when the patient exhales. Although wheezing can sometimes be present during inspiration, it is primarily associated with the expiratory phase due to the higher airflow resistance encountered as the air exits the lungs. When bronchioles are obstructed or narrowed, the turbulence of airflow during expiration accentuates the wheezing sound, making it a hallmark sign of respiratory distress in patients suffering from conditions that affect airway patency.