What can cause an increase in Work of Breathing (WOB)?

An increase in Work of Breathing (WOB) can be attributed to factors that make it more difficult for a person to ventilate. Increased airway resistance directly leads to a higher WOB because it requires more effort to move air in and out of the lungs. When airway passages are constricted or obstructed, whether due to conditions like asthma, chronic bronchitis, or simply increased secretions, the respiratory muscles must work harder to overcome this resistance.

In contrast, improved lung compliance and decreased airway resistance would facilitate ventilation, thereby reducing the WOB. Obesity can complicate respiratory mechanics and lead to increased WOB due to factors such as decreased lung volumes and restricted diaphragm movement, but it does not directly represent an increase in airway resistance like the chosen answer does. Therefore, increased airway resistance is the most direct and clear reason for elevated Work of Breathing.