Running in Polluted Air Is a Two-edged Sword

Physical Exercise in Low Air Pollution Areas Is Cardioprotective But Detrimental for the Heart in High Air Pollution Areas

Thomas Münzel; Omar Hahad; Andreas Daiber


Eur Heart J. 2021;42(25):2498-2500. 

In This Article

Running in Areas With Low Air Pollution is Cardioprotective, Whereas in Highly Air Polluted Areas Exercise has Detrimental Effects on the Heart!

The critical questions remain regarding the trade-off between the health benefits of physical activity (PA) and the potential harmful effects of increased exposure to air pollution during outdoor PA. To address this question, Kim et al.[10] performed a nationwide cohort study, published in this issue of the European Heart Journal, including 1 469 972 young adults aged 20–39 years. Air pollution exposure was estimated by the annual average cumulative level of particulate matter. PA was calculated as minutes of metabolic equivalent tasks per week (MET-min/week) based on two consecutive health examinations from 2009 to 2012. Compared with the participants exposed to low to moderate levels of PM2.5 or PM10 who continuously engaged in ≥1000 MET-min/week of PA, those who decreased their PA from ≥1000 MET-min/week to 1–499 MET-min/week and to 0 MET-min/week (physically inactive) had an increased risk of CVD (P for trend <0.01). Among participants exposed to high levels of PM2.5 or PM10, the risk of CVD was elevated with an increase in PA above 1000 MET-min/week. The authors concluded that reducing PA may lead to subsequent elevation of CVD risk in young adults exposed to low to moderate levels of PM2.5 or PM10, whereas a large increase in PA in a high-pollution environment may adversely affect cardiovascular health.

The present study, however, has some limitations. The survey of PA was not sufficient to estimate the amount of outdoor PA because of the absence of data on whether the participants engaged in PA outdoors (e.g. running in a park) or indoors (e.g. running in a gym). Second, recall bias may occur because the data on the PA level were collected using self-reported questionnaires. Finally, the authors did not investigate the short-term effects of exposure to air pollution. Therefore, further studies are necessary to identify the association of the combined effects of short-term exposure to air pollution and changes in PA with CVD risk.