Work of breathing (WOB) refers to the effort required by an individual to inhale and exhale air during normal breathing. It is a measure of the energy expended by the respiratory system in order to maintain adequate ventilation. The work of breathing is influenced by various factors, such as lung compliance, airway resistance, and respiratory muscle strength.
In a healthy individual, the work of breathing is minimal, as the lungs and airways are able to freely expand and contract. However, in individuals with respiratory conditions, such as chronic obstructive pulmonary disease (COPD) or asthma, the work of breathing is significantly increased, requiring more effort to move air in and out of the lungs.
The work of breathing is determined by the elastic properties of the lungs and chest wall, as well as the resistance encountered during airflow. Lung compliance refers to the ability of the lungs to stretch and expand, while airway resistance refers to the opposition encountered by airflow within the air passages. An increase in either lung compliance or airway resistance can elevate the work of breathing.
Clinicians often assess the work of breathing by observing respiratory effort, including the use of accessory muscles, retractions, or increased respiratory rate. Additionally, specialized respiratory function tests can be conducted to measure various parameters that contribute to the work of breathing, helping in the diagnosis and management of respiratory disorders.
