Physical Activity, Air Pollution, and High Blood Pressure

Impact of Traffic-related Air Pollution on the Cardiovascular and Pulmonary Response to Physical Activity in Patients With Hypertension

The investigators are investigating the effects of traffic-related air pollution (TRAP) on the cardiovascular and pulmonary response to exercise in patients with hypertension using a real world randomized, crossover study design. Participants will be exposed to 2 conditions: a low TRAP environment and a high TRAP environment. Each exposure will consist of 30 min of moderate-intensity exercise. Cardiovascular and pulmonary health outcomes will be measured before, during, and up to 24 hours following exposures. A minimum washout period of 1 week will be used to minimize carryover effects.

Study Overview

• Status: Completed
• Conditions: Essential Hypertension
• Intervention / Treatment: Behavioral: Exercise

• Study Type: Interventional
• Enrollment (Actual): 21
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Canada
  • British Columbia
    • Vancouver, British Columbia, Canada, V6T 1Z3
      • University of British Columbia

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 36 years to 66 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Age between 40-70 years of age
2. Previously diagnosed with elevated blood pressure or hypertension by a physician

Exclusion Criteria:

1. Current or ex-smokers (abstinent for less than one year)
2. Lives with an individual who currently smokes cigarettes, e-cigarettes (i.e., vaping), or cannabis
3. Hormone replacement therapy use
4. Currently on beta-blocker or angiotensin receptor blocker (ARB) therapy
5. Currently using over the counter drugs or supplements that may alter cardiovascular measures (as per the principal investigator's discretion)
6. Prior diagnosis of any other existing cardiovascular or pulmonary diseases and/or conditions (other than hypertension)
7. Musculoskeletal injury or lower limb limitation preventing safe engagement in moderate-intensity exercise

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: High traffic-related air pollution first; Participants will exercise in an environment with high levels of traffic-related air pollution first. Afterwards, participants will complete the same exercise in an environment with low levels of traffic-related air pollution.	Behavioral: Exercise; Participants will engage in moderate-intensity (40-59% HRR) exercise for 30 min
Experimental: Low traffic-related air pollution; Participants will exercise in an environment with low levels of traffic-related air pollution first. Afterwards, participants will complete the same exercise in an environment with high levels of traffic-related air pollution.	Behavioral: Exercise; Participants will engage in moderate-intensity (40-59% HRR) exercise for 30 min

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change from Baseline Blood Pressure at 2 Hours Post-Exposure	MAP, SBP, and DBP	Baseline and 2 hours post-exposure

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
24-Hour Blood Pressure	MAP, SBP, and DBP	24 hours post-exposure
Heart Rate Variability	Indices of heart rate variability	Baseline and up to 24 hours post-exposure
Change from Baseline Arterial Stiffness at 2 Hours Post-Exposure	Pulse wave velocity and augmentation index	Baseline and 2 hours post-exposure
Change from Baseline Microvascular Responsiveness at 2 Hours Post-Exposure	Microvascular responsiveness (measured by near-infrared spectroscopy)	Baseline and 2 hours post-exposure
Muscle Oxygen Saturation	Muscle oxygen saturation (measured by near-infrared spectroscopy)	Continuously throughout the 30 minute exercise bouts (during exposure)
Change from Baseline FEV1 and FVC at 2 Hours Post-Exposure	Forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) measured by spirometry (in L)	Baseline and 2 hours post-exposure
Change from Baseline FEV1/FVC at 2 Hours Post-Exposure	FEV1/FVC ratio measured by spirometry	Baseline and 2 hours post-exposure
Change from Baseline FEF25-75 and PEFR at 2 Hours Post-Exposure	Forced expiratory flow at 25-75% of forced vital capacity (FEF25-75) and peak expiratory flow rate (PEFR) measured by spirometry (in L/s)	Baseline and 2 hours post-exposure
Severity of Symptoms	Severity of respiratory symptoms (e.g., dyspnea, cough, wheeze, chest tightness) and headache on a 0-5 scale	Baseline and 2 hours post-exposure

Collaborators and Investigators

• Sponsor: University of British Columbia
• Investigators: Principal Investigator: Michael Koehle, MD, PhD, PROFESSOR

Study record dates

Study Major Dates

• Study Start (Actual): November 15, 2021
• Primary Completion (Actual): August 1, 2024
• Study Completion (Actual): August 1, 2024

Study Registration Dates

• First Submitted: September 28, 2021
• First Submitted That Met QC Criteria: October 21, 2021
• First Posted (Actual): October 25, 2021

Study Record Updates

• Last Update Posted (Actual): August 12, 2024
• Last Update Submitted That Met QC Criteria: August 9, 2024
• Last Verified: August 1, 2024

More Information

Terms related to this study

• Keywords: Exercise; Physical activity; Arterial stiffness; Blood pressure; Lung function; Heart rate variability; Microvascular responsiveness; Traffic-related air pollution; Muscle oxygen saturation
• Additional Relevant MeSH Terms: Cardiovascular Diseases; Vascular Diseases; Hypertension; Essential Hypertension
• Other Study ID Numbers: H21-01487

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No