An increase in which factor is associated with obstructive lung diseases?

In obstructive lung diseases, such as asthma and chronic obstructive pulmonary disease (COPD), an increase in airway resistance is a hallmark characteristic. These conditions typically involve inflammation, bronchoconstriction, or structural changes in the airways that impede airflow.

As the airways become narrowed or obstructed, it becomes more difficult for air to move in and out of the lungs, leading to increased resistance during expiration. This results in trapped air, decreased exhaled airflow rates, and difficulties in fully emptying the lungs, which can ultimately cause symptoms like wheezing, shortness of breath, and reduced exercise tolerance.

Other factors such as lung volume, gas exchange, and oxygen saturation are not directly increased in obstructive lung diseases. Instead, obstructive conditions may lead to alterations in these areas—such as decreased lung volumes and impaired gas exchange—because the obstruction affects how air is exchanged in the lungs. Therefore, the increase in airway resistance is a key indicator of these diseases and significantly contributes to their pathophysiology.