CPFT Practice Exam 2025 – Complete Test Prep Guide

A normal flow-volume loop graph indicates normal lung function as it demonstrates the normal progression of airflow during both inspiration and expiration. In a healthy individual, the graph shows a characteristic shape, with the ability to exhale a significant volume of air quickly, followed by a gradual decline as lung volume decreases.

The peaks of the curve represent the maximum flow rates attained during forced expiration, and the shape of the loop reflects adequate airway caliber and lung capacity. Deviations from this normal pattern typically suggest various respiratory conditions. Severe airway obstruction would display a concave shape in the expiration phase, restrictive lung diseases would show a reduced volume, and chronic obstructive pulmonary disease would also present with specific changes in the flow-volume loop that signify airflow limitation. Thus, a normal flow-volume loop graph is a strong indicator of unimpeded lung function.