Adaptation to Ozone in Individuals With Asthma/Exercise-induced Bronchoconstriction

Not Applicable

• Conditions: Asthma, Exercise-Induced; Asthma; Exercise Induced Asthma; Exercise Induced Bronchospasm
• Interventions: Behavioral: Exercise; Other: Filtere Air; Other: Ozone

• Registration Number: NCT05105529
• Lead Sponsor: University of British Columbia

Brief Summary

Researchers found that impairments in the cardiopulmonary system caused by acute exposure to ozone were outweighed by repeated exposures to ozone. The goal of this study is to confirm there will be an adaptation similar to what was previously proved but in individuals with asthma and exercise-induced bronchoconstriction (EIB). The purpose is to examine adaptive responses in a randomized cross-over trial in which physically active individuals will perform submaximal exercise on five days in ozone and filtered air exposures separated by a washout period.

Detailed Description

Not available

Study Timeline

• Study Start: 2021-01-01
• Study First Submitted: 2021-09-28
• Study First Submitted QC: 2021-10-22
• Study First Posted: 2021-11-03
• Status Verified: 2022-05
• Last Update Submitted: 2022-05-28
• Last Update Posted: 2022-06-02
• Primary Completion: 2023-01
• Study Completion: 2023-02

Recruitment & Eligibility

• Status: UNKNOWN
• Sex: All
• Target Recruitment: 40

Inclusion Criteria

• Recreationally active individuals
• Diagnosed asthma and/or mild exercise-induced bronchoconstriction: defined by an FEV1 fall equal to or greater than 10% but lower than 25% in the eucapnic hyperventilatory test.
• Able to securely perform a maximal exercise test (responded 'no' to all questions on the PAR-Q+ questionnaire)
• Able to communicate in English

Exclusion Criteria

• Diagnosed with any cardiorespiratory or vascular diseases
• Pregnant or potentially pregnant
• Non-smoking
• Lower limb musculoskeletal injury or lower limb limitation to cycle on a bicycle ergometer
• Recent respiratory symptoms or upper tract infection within 4 weeks
• On vitamin (e.g., C or E) supplementation

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Filtered Air	Filtere Air	Participants of the sham group will also perform sub-maximal exercise (60% of VO2max for 30 minutes) on a cycle ergometer similar to intervention. However, only in this group, the ozone generator will not be activated so that just filtered air will be delivered to the participant while performing each exercise session.
Ozone (O3) group	Exercise	Participants of the experimental group will perform sub-maximal exercise (60% of VO2max for 30 minutes) on a cycle ergometer while inhaling 170ppb ozone delivered continuously during each exercise session.
Ozone (O3) group	Ozone	Participants of the experimental group will perform sub-maximal exercise (60% of VO2max for 30 minutes) on a cycle ergometer while inhaling 170ppb ozone delivered continuously during each exercise session.
Filtered Air	Exercise	Participants of the sham group will also perform sub-maximal exercise (60% of VO2max for 30 minutes) on a cycle ergometer similar to intervention. However, only in this group, the ozone generator will not be activated so that just filtered air will be delivered to the participant while performing each exercise session.

Primary Outcome Measures

Name	Time	Method
Change in FEV1 from baseline to 10 minutes after exercise	Measured at baseline and 10 minutes after each exercise bout	Measurement of pulmonary function: forced exhaled volume in the first second (FEV1) in liters
Change in FEF25-75 from baseline to 10 minutes after exercise	Measured at baseline and 10 minutes after each exercise bout	Measurement of pulmonary function: forced expiratory flow at 25-75% of pulmonary volume in liters per second (L/s)
Change in FVC from baseline to 10 minutes after exercise	Measured at baseline and 10 minutes after each exercise bout	Measurement of pulmonary function: forced vital capacity (FVC) in liters

Secondary Outcome Measures

Name	Time	Method
Change in Pulse Wave Velocity (PWV) from baseline to 20 minutes after exercise	Measured at baseline and 20 minutes after each exercise bout	Velocity (in meters per second) at which the blood pressure pulse propagates through set points in the circulatory system
Change in Fraction of exhaled nitric oxide (FeNO) from baseline to 5 minutes after exercise	Measured at baseline and 5 minutes after each exercise bout	Non-invasive airway inflammation biomarker (in part per billion, ppb)

Trial Locations

Locations (2)

Environmental Physiology Laboratory; 🇨🇦 Vancouver, British Columbia, Canada

University of British Columbia; 🇨🇦 Vancouver, British Columbia, Canada