Effects of ambient particulate matter on aerobic exercise performance

Abstract

Background/ObjectiveWintertime thermal inversions in narrow mountain valleys create a ceiling effect, increasing concentration of small particulate matter (PM2.5). Despite potential health risks, many people continue to exercise outdoors in thermal inversions. This study measured the effects of ambient PM2.5 exposure associated with a typical thermal inversion on exercise performance, pulmonary function, and biological markers of inflammation.MethodsHealthy, active adults (5 males, 11 females) performed two cycle ergometer time trials outdoors in a counterbalanced design: 1) low ambient PM2.5 concentrations (<12 μg/m3), and 2) an air quality index (AQI) ranking of “yellow.” Variables of interest were exercise performance, exhaled nitric oxide (eNO), c-reactive protein (CRP), forced vital capacity (FVC), and forced expiratory volume in 1 s (FEV1).ResultsDespite a significant difference in mean PM2.5 concentration of 9.3 ± 3.0 μg/m3 between trials (p < .001), there was no significant difference (p = .424) in the distance covered during low PM2.5 conditions (9.9 ± 1.7 km) compared to high PM2.5 conditions (10.1 ± 1.5 km). There were no clinically significant differences across time or between trials for eNO, CRP, FVC, or FEV1. Additionally, there were no dose-response relationships (p > .05) for PM2.5 concentration and the measured variables.ConclusionAn acute bout of vigorous exercise during an AQI of “yellow” did not diminish exercise performance in healthy adults, nor did it have a negative effect on pulmonary function or biological health markers. These variables might not be sensitive to small changes from acute, mild PM2.5 exposure.

The effect of upper respiratory allergy on acute respiratory response to ambient air pollution during physical exercise

“…Similarly, Kubesch et al [12] found a positive association between increased traffic-related air pollution concentrations and increased FeNO levels, both at rest and after exercise. In contrast, a recent study by Wagner and Clark [19] did not show any dose-response relationships for PM 2.5 and FeNO in young healthy adults when exercising outdoors. Inconsistent outcomes of different studies may be partly a result of different exposure levels.…”

“…However, in that case, the exercise lasted longer than in this study. Wagner and Clark [19] who examined direct post-exercise respiratory responses to brief exercise also did not observe any significant changes in FVC and FEV 1 . The strength of this study is the standardization of physical exercise.…”

“…Moreover, the study groups were relatively small. However, the published evidence is based on the results obtained in groups of similar sizes [7,9,12,19,23]. It is also possible that, within the allergic group, there were subjects with underdiagnosed asthma.…”

Historic and Modern Air Pollution Studies Conducted in Utah

“…Utah-based studies provide evidence that air pollution is associated with reduced lung function in susceptible populations. Studies of 16 healthy adults exposed to PM 2.5 below the federal 24 h health standard found no negative effects on respiratory function or aerobic performance after 20 min of heavy exercise [33,34], but multiple studies reported significant effects on lung function among children and adults with preexisting chronic obstructive pulmonary disease (COPD) [12,13,24]. Among fourth and fifth grade elementary students, 150 µg/m 3 increases in PM 10 were associated with a 3-6% decline in lung function [12].…”

Physical Exercise in the Context of Air Pollution: An Emerging Research Topic

“…Hence, it needs to be further clarified which exercise mode and intensity will bring better health effects under the AP context. Based on the acquired knowledge, it seems that doing one-bout aerobic exercise (a power bicycle) during an air quality index (AQI) ranking of “yellow” will not diminish exercise performance in healthy adults, nor has a negative effect on pulmonary function or biological health markers (Wagner and Clark, 2018 ). There is also evidence that the beneficial effects during exercise will be mitigated in PM 2.5 > 100 μg/m 3 (Tainio et al, 2016 ; Pasqua et al, 2018 ), which indicates that it should not be encouraged to exercise if PM 2.5 is greater than or equal to this value.…”