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

University of British Columbia

Status: Unknown

Conditions: Exercise Induced Asthma; Asthma; Exercise Induced Bronchospasm; Asthma, Exercise-Induced

Treatments: Behavioral: Exercise; Other: Ozone; Other: Filtere Air

Study type: Interventional

Funder types: Other

Identifiers

NCT05105529

H21-01183

Details and patient eligibility

About

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.

Enrollment: 40 estimated patients

Sex: All

Ages: 18 to 50 years old

Volunteers: No 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

Trial design

Primary purpose: Basic Science

Allocation: Randomized

Interventional model: Crossover Assignment

Masking: Triple Blind

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40 participants in 2 patient groups

Ozone (O3) group

Experimental group

Description:

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.

Treatment:

Behavioral: Exercise

Other: Ozone

Filtered Air

Sham Comparator group

Description:

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.

Treatment:

Behavioral: Exercise

Other: Filtere Air