Susceptibility of Cardiorespiratory Responses to Ozone During Cycling Exercise
Study Details
Study Description
Brief Summary
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.
| Condition or Disease | Intervention/Treatment | Phase |
|---|---|---|
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N/A |
Study Design
Arms and Interventions
| Arm | Intervention/Treatment |
|---|---|
| Experimental: Ozone (O3) 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
Submaximal and maximal exercise
Other: Ozone
Delivery of ozone air pollution at 170ppb
|
| Sham Comparator: Room air 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
Submaximal and maximal exercise
Other: Room air
Delivery of room air
|
Outcome Measures
Primary Outcome Measures
- Change in FEV1 post-exercise [Immediately and 30-minutes post exercise]
Measurement of pulmonary function: forced exhaled volume in the first second (FEV1) in liters
- Change in FVC post-exercise [Immediately and 30-minutes post exercise]
Measurements of pulmonary function: forced vital capacity (FVC) in liters
- Change in FEF25-75 post-exercise [Immediately and 30-minutes post exercise]
Measurements of pulmonary function: forced expiratory flow at 25-75% of pulmonary volume in liters per second (L/s).
- Time-to-exhaustion on maximal cycling bout [From the beginning of the maximal constant work-rate cycling bout until volitional exhaustion occurs (roughly 1-5 minutes)]
Measurement of time (in seconds) to volitional exhaustion on a constant work-rate cycling trial at 110% of previously determined maximal power output.
- Change in spirometry post-resting ozone exposure (FEF25-75) [Immediately and 30-minutes post resting ozone exposure]
Measurements of pulmonary function: forced expiratory flow at 25-75% of pulmonary volume in liters per second (L/s).
- Change in spirometry post-resting ozone exposure (FEV1) [Immediately and 30-minutes post resting ozone exposure]
Measurement of pulmonary function: forced exhaled volume in the first second (FEV1) in liters.
- Change in spirometry post-resting ozone exposure (FVC) [Immediately and 30-minutes post resting ozone exposure]
Measurement of pulmonary function: forced vital capacity (FVC) in liters.
- Change in ventilatory pattern during exercise (tidal volume) [10, 20, and 30-minutes into the submaximal constant work-rate cycling bout]
Changes in the volume of air through each breath during submaximal exercise bouts at 10% below previously determined anaerobic threshold power output.
- Change in ventilatory pattern during exercise (breathing frequency) [10, 20, and 30-minutes into the submaximal constant work-rate cycling bout]
Changes in the number of breaths taken per minute during submaximal exercise bouts at 10% below previously determined anaerobic threshold power output.
- Change in ventilatory pattern during exercise (inspiratory capacity) [10, 20, and 30-minutes into the submaximal constant work-rate cycling bout]
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.
Secondary Outcome Measures
- Change in fraction of exhaled nitric oxide (FeNO) [Immediately and 30-minutes post-exercise and resting ozone exposure]
Non-invasive airway inflammation biomarker (in part per billion, ppb)
- Change in dyspnea [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.]
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.
- Change in symptoms [Immediately and 30-minutes post-exercise and resting ozone exposure]
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.
- Change in rating of perceived exertion [10, 20, and 30-minutes into the submaximal constant work-rate cycling bout]
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.
- Change in blood lactate values [10, 20, and 30-minutes into the submaximal constant work-rate cycling bout]
Indication of exercise intensity and energy system contribution via measurement of blood lactate via finger-prick.
Eligibility Criteria
Criteria
Inclusion Criteria:
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Healthy males between the age of 18 and 50
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Currently training and/or competing in endurance sport
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VO2max >60 ml/kg/min
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Able to communicate sufficiently using the English language
Exclusion Criteria:
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History of smoking
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Upper respiratory tract infection within the last 4 weeks
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Presence of any chronic respiratory disease
Contacts and Locations
Locations
No locations specified.Sponsors and Collaborators
- University of British Columbia
- Natural Sciences and Engineering Research Council, Canada
Investigators
- Principal Investigator: Michael Koehle, MD, PhD, University of British Columbia
Study Documents (Full-Text)
None provided.More Information
Publications
None provided.- H22-01389