OzoneNCT06513754
Investigating Changes in Responses to Controlled Effective Doses of Ozone at Different Exercise Intensities
A study testing Ozone, Heavy Intensity and Moderate Intensity in people with Ozone and Exercise Intensity, run by Michael Koehle at 1 site in Canada.
Trial summary
The project will look to investigate whether exercise during ozone exposure performed for a shorter duration at a higher intensity is more harmful than exercise performed for a longer duration at a lighter intensity. Read more about this study
- Who is it for?
- Ages 18 to 50 yearsHealthy volunteers can take part
- Conditions the study is for
- Ozone, Exercise Intensity
- What is being tested?
- Ozone, Heavy Intensity and Moderate Intensity
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 0 participants
- Where
- 1 siteCanada
- Study dates
- Sep 2024to Aug 2025
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 50 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Currently training and/or competing in endurance sport
- Maximal oxygen consumption (VO2max) greater than 60 ml/kg/min (males) or 50 ml/kg/min (females)
- Between the ages of 18 and 50
- Able to communicate sufficiently using the English language
- Taking hormonal birth control (female participants only)
Who cannot join
- History of smoking
- Upper respiratory tract infection within the last 4 weeks
- EIB, Asthma
- Presence of any chronic respiratory disease
- Current symptoms of, or current infection with COVID-19
- Pregnant or suspected pregnancy
Trial locations and contacts
1 site in 1 country.
Canada1 site
Environmental Physiology Laboratory
Vancouver, British Columbia, V6T 1Z1
About this study
The project will look to investigate whether exercise during ozone exposure performed for a shorter duration at a higher intensity is more harmful than exercise performed for a longer duration at a lighter intensity. To assess this, participants will perform these exercise conditions with and without ozone exposure and researchers will assess changes in lung function, subjective symptoms, and breathing mechanics to determine which is more harmful.
Read the detailed description
Purpose and Hypothesis The purpose of the study is to investigate whether exercise performed at a higher intensity for a shorter duration during ozone exposure results in greater decrements in pulmonary function, subjective symptoms, and dyspnea than low intensity exercise performed for a longer duration. The researcher's hypothesize that high intensity exercise will result in worsened responses as a result of changes to breathing mechanics resulting in greater penetration of ozone into smaller airways of the lungs.
Justification Due to the growing incidence of wildfires, temperature increase with climate change and increased urbanization, more people are exposed to high levels of ozone despite standards set by international and national agencies. Despite health warnings, many choose to continue engaging in exercise during high ozone levels. Results from this study will better inform practitioners and exercisers how to engage in exercise during ozone conditions to minimize it's deleterious effects on health.
Research Design This is a double-blinded randomized cross over design with pre- and post-measures. Ozone status (room air and 180 parts per billion (PPB) ozone) and exercise intensity (moderate and heavy) are the independent variables each with two levels. Testing will take place over 5 laboratory visits separated by at least 7 days. During the first session, subjects will undergo body plethysmography, spirometry, and a Step-ramp-step test on a cycle ergometer to determine subject characteristics and exercise thresholds. During visits 2-5, participants will be randomized to 1 of 4 exercise conditions manipulating exercise intensity and ozone status. They will then be asked to exercise for a duration that incurs the same effective dose of ozone across conditions with ozone exposure. If the participant is exercising in a non-ozone condition, they will be asked to exercise for however long it would take to incur the same effective dose had they been exposed to 180 ppb of ozone during the exercise bout. During the exercise bout, participants will be asked to rate their subjective symptoms associated with ozone exposure, dyspnea, and RPE every 15 minutes. Once the exercise bout is complete, participants will immediately perform pulmonary function testing and will be asked to rate their subjective symptoms associated with ozone exposure, dyspnea, and RPE.
Statistical Analysis To analyze changes in pulmonary function, dyspnea, and subjective symptoms within exercise conditions a repeated measures ANOVA will be conducted. To analyze changes in these variables across conditions relative to ozone status, exercise intensity, sex, and lung size, a multivariate ANOVA will be conducted. To test for significance within and across conditions, a Tukey test will be performed. All data analysis will be conducted in R. The sample size employed for the study will be 18 (n = 9 male, n =9 female)
- Conditions
- Ozone, Exercise Intensity
- Being tested
- Ozone, Heavy Intensity, Moderate Intensity, Filtered Air
- Keywords
- Ozone, Exercise Intensity, Pulmonary Function, Ventilation, Dyspnea
- Medical subject headings
- Respiratory Aspiration, Dyspnea
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
OzoneOther
Also called O3
Ozone is a pollutant that forms as a result of nitrogen oxides or volatile organic compounds interacting with UV radiation. Ozone will be created via a generator in the lab
Heavy IntensityBehavioural
Heavy intensity exercise between the first and second ventilatory threshold for 45 minutes
Moderate IntensityBehavioural
Moderate intensity exercise below the first ventilatory threshold for approximately 75 minutes
Filtered AirOther
Exposure to filtered air (<10 ppb ozone)
| Study group | Role | What they receive |
|---|---|---|
| Ozone, High Intensity | Experimental | Participants will exercise for 45 minutes in the heavy intensity domain while exposed to 180 ppb ozone Receives: Other: Ozone; Behavioral: Heavy Intensity |
| Ozone, Moderate Intensity | Experimental | Participants will exercise for 75 minutes in the moderate intensity domain while exposed to 180 ppb ozone Receives: Other: Ozone; Behavioral: Moderate Intensity |
| Filtered Air, Heavy Intensity | Sham comparator | Participants will exercise for 45 minutes in the heavy intensity domain while exposed to filtered air. Receives: Behavioral: Heavy Intensity; Other: Filtered Air |
| Filtered Air, Moderate Intensity | Sham comparator | Participants will exercise for 75 minutes in the moderate intensity domain while exposed to filtered air Receives: Behavioral: Moderate Intensity; Other: Filtered Air |
What is being measured
The primary outcome is the main question the study is designed to answer.
Pulmonary function
forced vital capacity, forced expiratory volume in 1 second, forced expiratory flow over the middle half of FVC.
Measured: Measured before, during, and after exercise (before, 45th minute of exercise, immediately after, and every 30 minutes after for an hour)
Secondary outcomes (3)
Rating of perceived exertion
How hard does the exercise feel rated on a scale of 6-20 with each increase representing an increase in perceived exertion while exercising
Measured: Measured during and after exercise (every 15 minutes during, immediately after, and every 30 minutes after for an hour)
Sensations of Dyspnea
Sensations of breathlessness as measured by the multidimensional dyspnea profile. Increased scores represent worsened sensations or severities of dyspnea.
Measured: Measured before, during, after exercise (before, every 15 minutes during, immediately after, and every 30 minutes after for an hour)
Subjective Symptoms
Subjective symptoms associated with ozone exposure using a questionnaire previously used by the Environmental Physiology Laboratory. This scale measures the presence and severity of eye, throat, lung irritation in response to ozone exposure. Higher scores indicate worsened symptoms.
Measured: Measured before, during, after exercise (before, every 15 minutes during, immediately after, and every 30 minutes after for an hour)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted22 Jul 2024
- Study startSep 2024 (estimated)
- Primary completionApr 2025 (estimated)
- Study completionAug 2025 (estimated)
Why it stopped: Study is not a clinical trial.
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for OzoneStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- The study design to be employed for this study can be characterized as a double-blind cross over. ozone status (room air (\<10 ppb ozone) and 170 ppb ozone), exercise intensity (moderate and heavy), sex, lung size, and time will be independent variables
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 0 participants (actual)
Sponsor and investigators
- Lead sponsor
- Michael Koehle
- Sponsor type
- University, hospital or other
- Collaborators
- Natural Sciences and Engineering Research Council, Canada
- Responsible party
- Sponsor-investigator, Michael Koehle, University of British Columbia
- Investigators
- Michael Koehle, MD, PhD, Principal investigator, University of British Columbia
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06513754
- Sponsor's protocol ID
- O3ED
- Status last verified
- Mar 2025
- First submitted
- 25 May 2024
- Last updated
- 30 Mar 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 30 Mar 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Investigating Changes in Responses to Controlled Effective Doses of Ozone at Different Exercise Intensities
- ClinicalTrials.gov ID
- NCT06513754
- Acronym / sponsor ID
- O3ED
- Conditions
- Ozone, Exercise Intensity
- Keywords
- Ozone, Exercise Intensity, Pulmonary Function, Ventilation, Dyspnea
- Study type
- Interventional
- Recruitment status
- WithdrawnReason stopped: Study is not a clinical trial.
- Enrolment
- 0 participants (actual)
- Lead sponsor
- Michael KoehleUniversity, hospital or other
- Collaborators
- Natural Sciences and Engineering Research Council, Canada
- Study start
- Sep 2024 (estimated)
- Primary completion
- Apr 2025 (estimated)
- Study completion
- Aug 2025 (estimated)
- First posted
- 22 Jul 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The project will look to investigate whether exercise during ozone exposure performed for a shorter duration at a higher intensity is more harmful than exercise performed for a longer duration at a lighter intensity. To assess this, participants will perform these exercise conditions with and without ozone exposure and researchers will assess changes in lung function, subjective symptoms, and breathing mechanics to determine which is more harmful.
Detailed description
Purpose and Hypothesis The purpose of the study is to investigate whether exercise performed at a higher intensity for a shorter duration during ozone exposure results in greater decrements in pulmonary function, subjective symptoms, and dyspnea than low intensity exercise performed for a longer duration. The researcher's hypothesize that high intensity exercise will result in worsened responses as a result of changes to breathing mechanics resulting in greater penetration of ozone into smaller airways of the lungs.
Justification Due to the growing incidence of wildfires, temperature increase with climate change and increased urbanization, more people are exposed to high levels of ozone despite standards set by international and national agencies. Despite health warnings, many choose to continue engaging in exercise during high ozone levels. Results from this study will better inform practitioners and exercisers how to engage in exercise during ozone conditions to minimize it's deleterious effects on health.
Research Design This is a double-blinded randomized cross over design with pre- and post-measures. Ozone status (room air and 180 parts per billion (PPB) ozone) and exercise intensity (moderate and heavy) are the independent variables each with two levels. Testing will take place over 5 laboratory visits separated by at least 7 days. During the first session, subjects will undergo body plethysmography, spirometry, and a Step-ramp-step test on a cycle ergometer to determine subject characteristics and exercise thresholds. During visits 2-5, participants will be randomized to 1 of 4 exercise conditions manipulating exercise intensity and ozone status. They will then be asked to exercise for a duration that incurs the same effective dose of ozone across conditions with ozone exposure. If the participant is exercising in a non-ozone condition, they will be asked to exercise for however long it would take to incur the same effective dose had they been exposed to 180 ppb of ozone during the exercise bout. During the exercise bout, participants will be asked to rate their subjective symptoms associated with ozone exposure, dyspnea, and RPE every 15 minutes. Once the exercise bout is complete, participants will immediately perform pulmonary function testing and will be asked to rate their subjective symptoms associated with ozone exposure, dyspnea, and RPE.
Statistical Analysis To analyze changes in pulmonary function, dyspnea, and subjective symptoms within exercise conditions a repeated measures ANOVA will be conducted. To analyze changes in these variables across conditions relative to ozone status, exercise intensity, sex, and lung size, a multivariate ANOVA will be conducted. To test for significance within and across conditions, a Tukey test will be performed. All data analysis will be conducted in R. The sample size employed for the study will be 18 (n = 9 male, n =9 female)
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind (participant, investigator)
- Number of arms
- 4
- Model description
- The study design to be employed for this study can be characterized as a double-blind cross over. ozone status (room air (<10 ppb ozone) and 170 ppb ozone), exercise intensity (moderate and heavy), sex, lung size, and time will be independent variables
| Arm | Type | Receives |
|---|---|---|
| Ozone, High Intensity | Experimental | Other: Ozone, Behavioral: Heavy IntensityParticipants will exercise for 45 minutes in the heavy intensity domain while exposed to 180 ppb ozone |
| Ozone, Moderate Intensity | Experimental | Other: Ozone, Behavioral: Moderate IntensityParticipants will exercise for 75 minutes in the moderate intensity domain while exposed to 180 ppb ozone |
| Filtered Air, Heavy Intensity | Sham comparator | Behavioral: Heavy Intensity, Other: Filtered AirParticipants will exercise for 45 minutes in the heavy intensity domain while exposed to filtered air. |
| Filtered Air, Moderate Intensity | Sham comparator | Behavioral: Moderate Intensity, Other: Filtered AirParticipants will exercise for 75 minutes in the moderate intensity domain while exposed to filtered air |
Who may qualify
- Ages
- 18 to 50 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (5 listed)
- Currently training and/or competing in endurance sport
- Maximal oxygen consumption (VO2max) greater than 60 ml/kg/min (males) or 50 ml/kg/min (females)
- Between the ages of 18 and 50
- Able to communicate sufficiently using the English language
- Taking hormonal birth control (female participants only)
Key exclusion criteria (6 listed)
- History of smoking
- Upper respiratory tract infection within the last 4 weeks
- EIB, Asthma
- Presence of any chronic respiratory disease
- Current symptoms of, or current infection with COVID-19
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| OzoneAlso: O3Ozone is a pollutant that forms as a result of nitrogen oxides or volatile organic compounds interacting with UV radiation. Ozone will be created via a generator in the lab | Other | Ozone, High Intensity, Ozone, Moderate Intensity |
| Heavy IntensityHeavy intensity exercise between the first and second ventilatory threshold for 45 minutes | Behavioural | Filtered Air, Heavy Intensity, Ozone, High Intensity |
| Moderate IntensityModerate intensity exercise below the first ventilatory threshold for approximately 75 minutes | Behavioural | Filtered Air, Moderate Intensity, Ozone, Moderate Intensity |
| Filtered AirExposure to filtered air (<10 ppb ozone) | Other | Filtered Air, Heavy Intensity, Filtered Air, Moderate Intensity |
Primary outcome
Pulmonary function
Time frame: Measured before, during, and after exercise (before, 45th minute of exercise, immediately after, and every 30 minutes after for an hour)
forced vital capacity, forced expiratory volume in 1 second, forced expiratory flow over the middle half of FVC.
3 secondary outcomes
Rating of perceived exertion
Time frame: Measured during and after exercise (every 15 minutes during, immediately after, and every 30 minutes after for an hour)
Sensations of Dyspnea
Time frame: Measured before, during, after exercise (before, every 15 minutes during, immediately after, and every 30 minutes after for an hour)
Subjective Symptoms
Time frame: Measured before, during, after exercise (before, every 15 minutes during, immediately after, and every 30 minutes after for an hour)
Results and safety
The study was withdrawn before enrolling participants, so there are no results.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 30 Mar 2025.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Michael Koehle, MD, PhD principal investigator
University of British Columbia
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Ozone, Heavy Intensity and Moderate Intensity in people with Ozone and Exercise Intensity, run by Michael Koehle at 1 site in Canada.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 6 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: withdrawn, as of the sponsor's last update on 30 Mar 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Canada. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study was withdrawn before enrolling participants, so there are no results.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Pulmonary function (time frame: Measured before, during, and after exercise (before, 45th minute of exercise, immediately after, and every 30 minutes after for an hour)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 30 Mar 2025.