Image Of A Female Runner Running Outdoors When The Air Quality Index Is High

High AQI: Is it Safe to Exercise Outside?

BY Dr. Jeff Sankoff

Is training outdoors safe when the AQI is high? Here are the answers to your most pressing air quality questions — including when to exercise indoors.

With the UN reporting that climatic disruptions — like wildfires — will likely continue to worsen, an end to poor air quality is probably wishful thinking. For athletes who want to continue training outdoors in a healthy, sustainable manner, it’s important to understand the health risks of training when air quality is poor. Here are the answers to some of your most pressing questions — including when to exercise indoors.

What Are the Health Risks Associated With Poor Air Quality?

Wildfires heavily impact air quality, even for communities far removed from the fires themselves. Wood smoke contains many toxic materials — in the form of particulate matter and gases — that can be dispersed for hundreds and even thousands of miles away from its point of origin.

Amongst the general population, studies have estimated that air pollution causes up to seven million premature deaths annually. Air pollution worsened by wildfire smoke has been known to exacerbate respiratory and cardiac diseases like asthma and chronic obstructive pulmonary disease (COPD). It’s even been associated with the onset of various inflammatory and rheumatic ailments, including inflammation of the lungs after inhalation.

Are Athletes at Risk From Poor Air Quality? 

Elite athletes have been shown to have significant impairment in lung function when air quality is poor, including when there is increased smoke in the air. A review published in Immunology and Allergy Clinics of North America noted that some athletes have even shown signs of developing asthma after prolonged exposure to poor air quality.

For endurance athletes who wish to be active and train outdoors as much as possible, this is a significant dilemma.

How Do I Know When Air Quality Is Bad?

The Air Quality Index (AQI) from the Environmental Protection Agency measures major air pollutants, including particle pollution (like those from smoke), ground-level ozone, sulfur dioxide and nitrogen dioxide, and carbon monoxide. The AQI is graded on a 500-point scale that includes various “Levels of Concern”. They include:

  • “Good” (0-50 AQI): Air quality is satisfactory, and air pollution poses little or no risk.
  • “Moderate” (51-100 AQI): Air quality is acceptable. However, there may be a risk for some people, particularly those who are unusually sensitive to air pollution.
  • “Unhealthy for Sensitive Groups” (101-150 AQI): “Members of sensitive groups may experience health effects. The general public is less likely to be affected.”
  • “Unhealthy” (151-200 AQI): “Some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects.”
  • Anything above 200 is considered “Very Unhealthy,” and above 300 is “Hazardous”.

Here’s an interesting and saddening fact: In 2019, the ACSM American Fitness Index issued a Summary Report that rated American cities in terms of health and fitness and included air quality as an indicator (for the first time). The report found that the 100 largest American cities only enjoyed “good” air quality for 62% of the year on average. For the populations living in those cities, that means breathing polluted air that can be harmful to human health for over four months of the year. 

Can I Exercise Outside When It’s Smoky?

To assist with this kind of decision-making, the previously mentioned AQI can be extremely helpful. Athletes can download the app or visit to review the AQI for an entered zip code in order to determine the air quality prior to a workout.

Healthy athletes should consider training indoors when the AQI exceeds 151. At this point, air quality is considered unhealthy for everyone. If you have an underlying health issue, then that threshold is lowered to 100.

Anything higher than an AQI of 100 could affect these “sensitive groups”, meaning it’s a good idea to work out indoors until the AQI falls below 100.

Shouldn’t Exercise Lower the AQI Thresholds?

There is neither evidence nor guidelines that suggest modifications in how to interpret the AQI based on activity. The NCAA, for instance, has a policy statement — meant for use by colleges and high school athletic departments — that references the AQI levels unchanged from how they are denoted on the EPA’s website.

Does Bad Air Quality Negate the Benefits of Exercise?

For the most part, exercising outdoors in lower-quality air is more beneficial than not for most healthy individuals. However, for those with an underlying respiratory illness such as asthma, the risks become higher. Even for healthy individuals, the harder you exert yourself in a workout, the more air you inspire, so it’s worth getting into the habit of checking the AQI before you exercise outdoors to reduce your risk of health problems associated with wildfire smoke and poor air quality. 

With the progression of climate change, these conditions are anticipated to continue to worsen. Athletes need to be aware of these important metrics in order to protect their health and ensure that exercise remains a healthy endeavor — not one that puts you at risk.

Train hard, train healthy.


Masson-Delmotte, V. et al. (2021). Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. Retrieved from 

Orru, H. et al. (2017, December). The Interplay of Climate Change and Air Pollution on Health. Retrieved from 

Patch, G.S. et al. (2019, May). 2019 Summary Report: ACSM American Fitness Index®. Retrieved from 

Reid, C.E. & Maestas, M.M. (2020, March 1). Wildfire smoke exposure under climate change: impact on respiratory health of affected communities. Retrieved from 

Rossiello, M.R. & Szema, A. (2019, May 28). Health Effects of Climate Change-induced Wildfires and Heatwaves. Retrieved from 

Rundell, K.W. & Sue-Chu, M. (2013, August). Air Quality and Exercise-Induced Bronchoconstriction in Elite Athletes. Retrieved from 

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About Dr. Jeff Sankoff

Jeff Sankoff is an Emergency Physician, long time triathlete and USAT/IRONMAN University Certified coach. He has completed 6 IRONMAN races (including Kona) and more than fifty races at the 70.3 distance including 5 World Championships. He produces the TriDoc Podcast that can be found on most popular podcast platforms and iWork’s with LifeSport Coaching. You can learn more about him at his website: TriDoc Coaching.

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