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

Sponsor

University of British Columbia (Other)

Overall Status

Recruiting

CT.gov ID

NCT05105529

Collaborator

(none)

Enrollment

Locations

Arms

Anticipated Duration (Months)

Patients Per Site

0.8

Patients Per Site Per Month

Study Details

Study Description

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.

Condition or Disease	Intervention/Treatment	Phase
Asthma Asthma, Exercise-Induced Exercise Induced Asthma Exercise Induced Bronchospasm	Behavioral: Exercise Other: Ozone Other: Filtere Air	N/A

Study Design

Study Type:

Interventional

Anticipated Enrollment :

40 participants

Allocation:

Randomized

Intervention Model:

Crossover Assignment

Masking:

Triple (Participant, Care Provider, Outcomes Assessor)

Masking Description:

Air quality condition (Ozone and filtered air) will be double-blinded; Participants will not be told at any time before the study completion to which group they are assigned (intervention or sham)

Primary Purpose:

Basic Science

Official Title:

Pulmonary and Vascular Adaptations to a 5-days Exercise Protocol in Ozone in Physically Active Individuals With Asthma and Exercise-induced Bronchoconstriction

Actual Study Start Date :

Jan 1, 2021

Anticipated Primary Completion Date :

Jan 1, 2023

Anticipated Study Completion Date :

Feb 1, 2023

Arms and Interventions

Arm	Intervention/Treatment
Experimental: Ozone (O3) group 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.	Behavioral: Exercise Cycling at 60% of VO2max on a cycle ergometer for 30 minutes Other: Ozone Breathing 170ppb ozone
Sham Comparator: Filtered 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.	Behavioral: Exercise Cycling at 60% of VO2max on a cycle ergometer for 30 minutes Other: Filtere Air Breathing filtered air

Arm

Intervention/Treatment

Experimental: Ozone (O3) group

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.

Behavioral: Exercise

Cycling at 60% of VO2max on a cycle ergometer for 30 minutes

Other: Ozone

Breathing 170ppb ozone

Sham Comparator: Filtered 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.

Behavioral: Exercise

Cycling at 60% of VO2max on a cycle ergometer for 30 minutes

Other: Filtere Air

Breathing filtered air

Outcome Measures

Primary Outcome Measures

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 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
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)

Secondary Outcome Measures

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)

Eligibility Criteria

Criteria

Ages Eligible for Study:

18 Years to 50 Years

Sexes Eligible for Study:

All

Accepts Healthy Volunteers:

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