Air Quality, Running and Outdoor Exercise

We’ve had several days over the last couple of years where the air quality in Minnesota has been of concern, prompting warnings and cancellations of outdoor activities. However, what is poor air quality, and what does it mean as it pertains to running and exercising outside? Like many things related to health, the answer is nuanced and “depends.”

Air quality in essence refers to the relative level of air pollution and is measured via an Air Quality Index or AQI. The AQI ranges from 0 to 500, with higher numbers reflecting high levels of ozone and air pollutants.

Figure: Air Quality Levels, AQI Basics | AirNow.gov

The decision to forgo the health benefits of running in order to prevent the adverse health effects of exercise in polluted air is not particularly straightforward. Most available scientific literature points to the need for further research. Notably, there was a systemic review of studies published by authors from India and Sweden in 2022 that concluded that exercise in polluted environments still provides some benefits, though the benefits are reduced. The authors acknowledge the lack of available data and call for additional research on the topic. A European study published in 2021 reached a similar conclusion, particularly when the level of air pollution is low-to-moderate but interestingly found that exercise in high-pollution environments can adversely affect health.

For high-mileage runners and marathoners, air quality is also a matter of performance. A Chinese study published in 2019 concluded that doubling the AQI could increase a runner’s marathon finishing time by 4%. I did not find this association for those running shorter distances.

A Polish study in 2021 concluded that marathons can increase the rate of pollutants deposited in the respiratory tract of runners. The long-term effects here are unclear.

What’s interesting and worth pointing out is that the adverse of effects of running in poor air quality are not limited to the lungs and respiratory system but the heart and cardiovascular system as well. That said, those with lung disease and those with heart disease should especially heed air quality warnings.

If you are ever concerned about the air quality or other environmental issues and you have access to indoor running, simply choose the latter. Otherwise, if you do not have heart or lung disease occasional exercise when the air quality is less than ideal still does your body some good. As the duration of exposure and the AQI levels increase however, the risk begins to outweigh the benefit.

Websites that you can track for further, detailed information on air quality include AirNow.gov and the Minnesota Pollution Control Agency, Current air quality conditions | Minnesota Pollution Control Agency.

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Kenneth G Poole, Jr, MD, is an internal medicine physician with a special interest in running. He is one of the team of Motion Experts TCM has gathered to help its subscribers and participants get the most out of their running. Instagram: @renaissance_doc; X: @KPooleMD