Related Experiment Video
Updated: Aug 7, 2026
08:44
Dual Test Gas Pulmonary Diffusing Capacity Measurement During Exercise in Humans Using the Single-Breath Method
Published on: February 2, 2024
Exercise-induced bronchoconstriction alters airway nitric oxide exchange in a pattern distinct from spirometry
Hye-Won Shin1, Christina D Schwindt, Anna S Aledia
1Department of Biomedical Engineering, Division of Pulmonary and Critical Care, 3120 Natural Sciences II, University of California-Irvine, Irvine, CA 92697-2715, USA.
Summary
Exhaled nitric oxide (NO) dynamics are altered in asthma patients with exercise-induced bronchoconstriction (EIB). These changes in NO exchange occur through distinct mechanisms and are not directly linked to spirometry results.
Area of Science:
- Respiratory Medicine
- Pulmonary Physiology
- Biomarkers in Asthma
Background:
- Exhaled nitric oxide (NO) is a known biomarker in asthma, but its interpretation is complicated by flow dependency and difficulty in localizing NO production.
- Exercise-induced bronchoconstriction (EIB) is a common asthma symptom, and its relationship with airway NO dynamics requires further elucidation.
Purpose of the Study:
- To estimate flow-independent NO exchange parameters to differentiate proximal and peripheral airway contributions in asthmatic subjects with EIB.
- To investigate changes in NO exchange parameters at baseline, post-exercise, and post-bronchodilator in steroid-naive mild-intermittent asthmatic subjects with EIB compared to healthy controls.
Main Methods:
- Utilized flow-independent NO exchange parameters to partition exhaled NO into proximal and peripheral contributions.
- Measured NO exchange parameters, spirometry (FEV(1), FVC, FEF(25-75)), and responses to exercise challenge and bronchodilator administration.
- Included steroid-naive mild-intermittent asthmatic subjects with EIB and healthy controls.
Main Results:
- Asthmatic subjects with EIB showed elevated baseline maximum airway wall flux and airway diffusing capacity, alongside reduced spirometry measures (FEV(1), FEF(25-75), FEV(1)/FVC).
- Exercise challenge significantly decreased FEV(1), FEF(25-75), FVC, FEV(1)/FVC, and maximum airway wall flux in the EIB group compared to controls.
- Bronchodilator administration showed limited improvement in spirometry and did not significantly alter NO exchange parameters.
Conclusions:
- Mild-intermittent asthmatic subjects with EIB exhibit distinct alterations in airway NO exchange dynamics at baseline and post-exercise.
- The mechanisms underlying these NO exchange alterations appear distinct from those affecting spirometry.
- NO exchange parameters do not correlate with spirometric changes in this cohort.
Related Concept Videos
01:24Chronic Obstructive Pulmonary Disease III: Chronic Bronchitis Features
Chronic bronchitis is a key phenotype of chronic obstructive pulmonary disease (COPD), characterized by airway-centered inflammation and mucus overproduction. It develops from long-term exposure to harmful particles or gases, most commonly cigarette smoke, which triggers a persistent inflammatory response.Cellular and Structural ChangesInflammation initially affects the large bronchi and later the smaller airways, with infiltration by immune cells, including neutrophils, macrophages, and...
01:20Chronic Obstructive Pulmonary Disease-II: Pathophysiology
Chronic Obstructive Pulmonary Disease (COPD) pathophysiology is intricate and multifaceted, involving a complex interplay of physiological processes. Understanding these mechanisms is crucial for effectively managing and treating COPD. Here is an in-depth look at the critical elements in the pathophysiology of COPD:
Chronic Inflammation
Chronic Inflammation
01:28Nitric Oxide Signaling Pathway
Nitric oxide (NO), an inorganic gas, acts as a potent second messenger in most animal and plant tissues. NO diffuses out of the cells that produce it and enters the neighboring cells to generate a downstream response. NO synthase (NOS) catalyzes NO production by the deamination of the amino acid arginine. There are three isoforms of NOS. Endothelial cells have endothelial NOS (eNOS), nerve and muscle cells have neuronal NOS (nNOS), and macrophages produce inducible NOS (iNOS) upon exposure to...
01:19Factors Affecting Pulmonary Ventilation
Besides the pressure difference between the external environment and the lungs, the airflow rate and ease of pulmonary ventilation are also influenced by three other factors: surface tension of the fluid in the alveoli, compliance of the lungs, and airway resistance.
Alveolar Surface Tension
The alveolar fluid lines the luminal surface of the alveoli and exerts a force called surface tension. This force is caused by the polar water molecules in the liquid being more strongly attracted to each...
Alveolar Surface Tension
The alveolar fluid lines the luminal surface of the alveoli and exerts a force called surface tension. This force is caused by the polar water molecules in the liquid being more strongly attracted to each...
01:20Asthma: Pathogenesis and Management
Asthma is a chronic pulmonary condition involving inflammation of the airways, hyper-reactivity, and reversible obstruction of the airways. This condition can significantly impact a person's quality of life, making breathing difficult and leading to distressing symptoms.
Asthma is classified as allergic and non-allergic. Allergens such as dust mites, pollen, and pet dander trigger allergic asthma, while factors like cold air, intense emotions, or exercise can induce non-allergic asthma.
Asthma is classified as allergic and non-allergic. Allergens such as dust mites, pollen, and pet dander trigger allergic asthma, while factors like cold air, intense emotions, or exercise can induce non-allergic asthma.
01:17Pulmonary Cycle: Exhalation
In terms of human respiration, the act of expelling air, known as exhalation (or expiration), operates on the principle of pressure gradients. During expiration, the pressure within the lungs exceeds that of the surrounding atmosphere. Under normal conditions, quiet breathing involves passive exhalation and is free of muscular contractions. This is because the exhalation process is driven by the natural elastic recoil of the lungs and chest wall, both of which have an inherent tendency to...