Bronchial responsiveness to inhaled histamine and exercise

Area of Science:

• Pulmonology
• Respiratory Medicine
• Exercise Physiology

Background:

• Asthma is a chronic respiratory disease characterized by airway inflammation and hyperresponsiveness.
• Exercise-induced asthma (EIA) is a common trigger for asthma exacerbations.
• Understanding the relationship between airway responsiveness and EIA is crucial for effective management.

Purpose of the Study:

• To compare bronchial responsiveness to inhaled histamine and exercise in asthmatic patients.
• To investigate the correlation between histamine provocative concentration (PC20) and exercise-induced changes in forced expired volume in one second (FEV1).
• To determine the sensitivity of histamine and exercise challenges in detecting bronchial hyperresponsiveness.

Main Methods:

• Nineteen asthmatic patients underwent bronchial challenge testing with inhaled histamine to determine PC20.
• Patients performed exercise challenges on a treadmill and a cycle ergometer.
• Measurements included percent fall in FEV1 (delta FEV1) and exercise lability post-exercise.

Main Results:

• Both treadmill and cycle ergometry were equally effective in inducing EIA.
• PC20 showed a significant correlation with delta FEV1 and exercise lability.
• The correlation between PC20 and exercise lability was stronger than with delta FEV1.
• Histamine challenge was more sensitive in identifying bronchial hyperresponsiveness.

Conclusions:

• A strong correlation exists between bronchial responsiveness to histamine and exercise, suggesting mediator release is key in EIA.
• Histamine challenge is a sensitive method for assessing bronchial hyperresponsiveness.
• Both treadmill and cycle ergometry are effective protocols for evaluating EIA.