Evaluating Cardiovascular Response and Air-Pollutant Exposure in Marathon Runners Using Low-Cost Urban Air Sensors

Abstract

This study investigated the acute cardiovascular effects of urban air pollution on professional marathon runners using a controlled, simulated exposure protocol and low-cost air quality sensors. Twelve elite athletes (mean age 29 ± 4 years) completed two 60-minute treadmill runs at 70% VO₂max in an environmental chamber under “Polluted Air” (PM₂.₅ ≈ 50 μg/m³, NO₂ ≈ 100 ppb, O₃ ≈ 80 ppb) and “Clean Air” (PM₂.₅ < 5 μg/m³, gases < 5 ppb) conditions. Portable Plantower optical particle counters and electrochemical gas sensors continuously monitored inhaled pollutant levels. Cardiovascular metrics—heart rate (HR), blood pressure (BP), and heart rate variability (HRV)—along with oxygen uptake (VO₂) and ratings of perceived exertion (RPE) were recorded. Compared to the clean-air trials, polluted-air runs elicited significantly higher steady-state HR (+6 bpm, p = .012), elevated post-exercise systolic BP (+9 mmHg, p = .01), and greater RPE (+1.4 points, p < .05), despite equivalent VO₂. HRV analysis revealed a trend toward delayed autonomic recovery after polluted runs. Exploratory correlations indicated a moderate positive association (r ≈ 0.6) between inhaled PM₂.₅ dose and systolic BP increase. These findings demonstrate that moderate urban pollution imposes an extra cardiovascular load on elite endurance athletes. The use of low-cost sensors provided high-resolution exposure data, underscoring their utility for athlete monitoring and training adjustments. Strategies to mitigate pollution exposure—such as scheduling workouts in cleaner environments or using filtration masks—may help preserve performance and cardiovascular health in urban settings.