Susceptibility of Cardiorespiratory Responses to Ozone During Cycling Exercise

Study Overview
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Brief Summary
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Ground level ozone (O3) is a common airborne pollutant that is well recognized to cause negative respiratory symptoms and impair pulmonary function. The proposed study aims to have participants perform submaximal and maximal cycling exercise protocols exposed to both O3 and room air in a crossover design to evaluate how ventilatory patterns, pulmonary function, development of symptoms, and cycling performance are impacted by O3 exposure. Additionally, the investigators look to compare responses between O3 at rest and during exercise to predict which subjects may be most susceptible to adverse response, as considerable interindividual variability exists.

Official Title
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Investigating Susceptibility of Cardiorespiratory Responses to Ozone During Cycling Exercise Based on Resting Ozone Exposure

Conditions
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Ozone Exposure During Rest and Exercise

Intervention / Treatment
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* Behavioral: Exercise
* Other: Ozone
* Other: Room air


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy males between the age of 18 and 50 Currently training and/or competing in endurance sport VO2max >60 ml/kg/min Able to communicate sufficiently using the English language Exclusion Criteria: History of smoking Upper respiratory tract infection within the last 4 weeks Presence of any chronic respiratory disease

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 50 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Ozone (O3)<br>Participants of the experimental group will perform sub-maximal exercise (power output associated with 10% below anaerobic threshold for 30 minutes) and maximal exercise (time-to-exhaustion test at 5% above previously determined maximal power output) on a cycle ergometer while inhaling 170ppb ozone delivered continuously during each exercise session. | Behavioral: Exercise<br>* Submaximal and maximal exercise<br>Other: Ozone<br>* Delivery of ozone air pollution at 170ppb<br>|
| Sham Comparator: Room air<br>Participants of the sham group will perform sub-maximal exercise (power output associated with 10% below anaerobic threshold for 30 minutes) and maximal exercise (time-to-exhaustion test at 5% above previously determined maximal power output) on a cycle ergometer while inhaling room air during each exercise session. | Behavioral: Exercise<br>* Submaximal and maximal exercise<br>Other: Room air<br>* Delivery of room air<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in FEV1 post-exercise | Measurement of pulmonary function: forced exhaled volume in the first second (FEV1) in liters | Immediately and 30-minutes post exercise | 
| Change in FVC post-exercise | Measurements of pulmonary function: forced vital capacity (FVC) in liters | Immediately and 30-minutes post exercise | 
| Change in FEF25-75 post-exercise | Measurements of pulmonary function: forced expiratory flow at 25-75% of pulmonary volume in liters per second (L/s). | Immediately and 30-minutes post exercise | 
| Time-to-exhaustion on maximal cycling bout | Measurement of time (in seconds) to volitional exhaustion on a constant work-rate cycling trial at 110% of previously determined maximal power output. | From the beginning of the maximal constant work-rate cycling bout until volitional exhaustion occurs (roughly 1-5 minutes) | 
| Change in spirometry post-resting ozone exposure (FEF25-75) | Measurements of pulmonary function: forced expiratory flow at 25-75% of pulmonary volume in liters per second (L/s). | Immediately and 30-minutes post resting ozone exposure | 
| Change in spirometry post-resting ozone exposure (FEV1) | Measurement of pulmonary function: forced exhaled volume in the first second (FEV1) in liters. | Immediately and 30-minutes post resting ozone exposure | 
| Change in spirometry post-resting ozone exposure (FVC) | Measurement of pulmonary function: forced vital capacity (FVC) in liters. | Immediately and 30-minutes post resting ozone exposure | 
| Change in ventilatory pattern during exercise (tidal volume) | Changes in the volume of air through each breath during submaximal exercise bouts at 10% below previously determined anaerobic threshold power output. | 10, 20, and 30-minutes into the submaximal constant work-rate cycling bout | 
| Change in ventilatory pattern during exercise (breathing frequency) | Changes in the number of breaths taken per minute during submaximal exercise bouts at 10% below previously determined anaerobic threshold power output. | 10, 20, and 30-minutes into the submaximal constant work-rate cycling bout | 
| Change in ventilatory pattern during exercise (inspiratory capacity) | Changes in the maximal volume of air that can be inspired after a normal breath out during submaximal exercise bouts at 10% below previously determined anaerobic threshold power output. | 10, 20, and 30-minutes into the submaximal constant work-rate cycling bout | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in fraction of exhaled nitric oxide (FeNO) | Non-invasive airway inflammation biomarker (in part per billion, ppb) | Immediately and 30-minutes post-exercise and resting ozone exposure | 
| Change in dyspnea | Feelings of shortness of breath measured via Modified Borg Dyspnea Scale, where a response of 0 represents no feelings of breathlessness, and a response of 10 indicates maximal breathlessness. | Immediately prior to exercise, 10, 20, and 30-minutes into the submaximal constant work-rate cycling bout, immediately and 30-minutes following maximal cycling bout. | 
| Change in symptoms | Development of symptoms related to the eyes, nose, throat, or general health, measured via a questionnaire developed by the investigators. A response of 0 indicates no feelings of the symptom, whereas a response of 5 indicates that the symptom is as bad as the participant has ever experienced it. | Immediately and 30-minutes post-exercise and resting ozone exposure | 
| Change in rating of perceived exertion | Feeling of effort measured via Borg Rating of Perceived Exertion, measured from 6 to 20. A response of 6 represents no exertion, while a response of 20 indicates maximal exertion. | 10, 20, and 30-minutes into the submaximal constant work-rate cycling bout | 
| Change in blood lactate values | Indication of exercise intensity and energy system contribution via measurement of blood lactate via finger-prick. | 10, 20, and 30-minutes into the submaximal constant work-rate cycling bout | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Ozone, Air pollution, Exercise, Cycling, Susceptibility, Ventilation