Ben Stothers’ MSc Thesis Proposal

Title: “Examining the Effect of Salbutamol Use in Asthma and/or Exercise Induced Bronchoconstriction Whilst Exercising in Ozone Air Pollution”

Supervisor: Dr. Michael Koehle
Committee members: Dr. Bill Sheel, Dr. Nadine Borduas-Dedekind

Introduction: As the world’s population continues to increase and become more industrialized more people are being exposed to ambient air pollution. Concurrently, an emphasis is being put on the importance of physical activity in a healthy lifestyle. This raises concerns for people with asthma and/or exercise induced bronchoconstriction (EIB) who’s airways are more sensitive to respiratory irritants. Ozone (O3) is a reparatory irritant generated in smog. Salbutamol (SAL) is a bronchodilator commonly prescribed to people with EIB and/or asthma. SAL use in O3 pollution may be contradicted because it increases the O3 exposure in the airways of individuals that are prone to inflammation. This has been shown previously in rodent studies.

Hypothesis: People with asthma and/or EIB who take salbutamol before exercising in ozone will have improved pulmonary function but higher levels of inflammation after exercise compared to placebo medication.

Proposed Method: In a double-blinded crossover design people with EIB and/or asthma will complete four 30-minute bouts of exercise at 60% of their VO2MAX on four separate days: [170]ppb O3 + SAL, [170]ppb O3 + placebo SAL, filtered air + SAL, filtered air + placebo SAL. A eucapnic voluntary hyperpnoea test will be done to confirm the presence of EIB in addition to a VO2MAX test. Lung inflammation will be measured before and after exercise using FeNO in addition to pulmonary function measured by spirometry. Measures of pulmonary function will be supplemented by generating maximal expiratory flow volume curves before and after exercise and comparing them to flow volume loops at 5 and 25 minutes of exercise. Post-exercise FeNO and spirometry measurements will be analyzed using mixed effects linear regression models. Baseline adjustments in these models will be made by using pre-exercise values as covariates in the regression models.