What is a characteristic of obstructive diseases?

In obstructive diseases, one of the hallmark characteristics is difficulty with exhalation. This occurs because the airways are narrowed or blocked, making it hard for air to flow out of the lungs. Conditions such as asthma, chronic obstructive pulmonary disease (COPD), and emphysema exemplify this phenomenon, where increased resistance during expiration is observed.

In contrast, the other options are associated with different patterns of respiratory dysfunction. Difficulty with inhalation typically characterizes restrictive lung diseases, where lung volumes are reduced but airflow may be normal. Normal lung volumes with reduced airflow might suggest a different type of disorder or a specific lung function impairment, rather than pointing towards obstructive pathology. Decreased lung compliance is also more characteristic of restrictive diseases, as it indicates stiff lungs that can’t expand properly, rather than problems with airflow obstruction. Thus, understanding that obstructive diseases primarily affect exhalation helps clarify the key features of these conditions.