CPFT Practice Exam 2025 – Complete Test Prep Guide

During a Methacholine challenge test, the primary physiological change that occurs is induced bronchoconstriction to measure airway responsiveness. Methacholine is a bronchoconstrictor agent that, when inhaled, stimulates the bronchial smooth muscle, leading to narrowing of the airways. This response is particularly significant in individuals with asthma or hyperresponsive airways, as they will show a greater degree of bronchoconstriction compared to those without airway hyperreactivity.

The test allows healthcare providers to assess how sensitive a person's airways are and is commonly used in diagnosing asthma and other reactive airway conditions. By measuring lung function before and after administering Methacholine, clinicians can evaluate changes in airflow and determine if bronchial hyperreactivity is present.

In contrast, increased lung volumes, activation of immune responses, and decreased heart rate do not directly occur as outcomes of the Methacholine challenge test. This test is specifically designed to provoke bronchoconstriction and measure airway responses, making it a valuable tool in respiratory medicine.