By: Sara Zipf

More than 131 million people in the U.S. live in counties that had unhealthy levels of ozone or particle pollution, according to the American Lung Association’s 2024 State of Air report. While several Miami area counties matched last year’s best-ever record for ozone pollution, year-round particle pollution “worsened and resulted in a failing grade.” For those preparing for the Key West Half Marathon and Runfest, training in polluted air — whether indoors or out — can have a surprising impact. From the health effects of poor air quality to how avid runners can train in a healthy and productive way.

Why air quality matters

While physical activity is generally an important part of reducing the risk of cardiovascular diseases, it can have the opposite effect in highly polluted air, according to a 2021 study published in the European Heart Journal. According to CBS News, the study looked at young adults exposed to particulate matter, and ultimately found that those exposed to high levels of PM2.5 or PM10, were at “an increased risk” of cardiovascular diseases. CBS goes on to note that in New York, for example, the smoke brought in by Canadian wildfires in 2023 presented less than ideal conditions for exercising outdoors — in fact, it’s noted that all five boroughs were put under an air quality health advisory. “This is not the day to train for a marathon or to do an outside event with your children,” said Mayor Eric Adams at the time. “Stay inside, closed windows and doors, and use air purifiers if you have them.”

While outdoor air quality can be a major element that can make or break a healthy outdoor training session, it’s imperative to take into account the impact of indoor air quality, too — whether you’re training inside or simply going about your daily routine. According to the Environmental Protection Agency (EPA), typical pollutants of concern range from pet dander to mold, particulate matter, pesticides, ozone (from some air cleaners), and “various volatile organic compounds from a variety of products and materials,” to name just a few. Several additional factors are also noted to affect indoor air quality — including the air exchange rate, outdoor climate, weather conditions, and occupant behavior. For the avid runner, symptoms associated with poor indoor air quality can be disruptive when aiming to successfully train for a half marathon. According to the EPA, health effects associated with indoor air pollutants include irritation of the eyes, nose, and throat, headaches, dizziness, and fatigue, while more serious effects include respiratory diseases, heart disease, and cancer.

Taking precautions (both indoors and out)

Running outdoors when the air quality is particularly poor can be risky — one NBC News article notes that this is the case once levels exceed 150 (the air quality index (AQI) runs from 0-500, with higher levels indicating greater levels of pollution). “It’s like swimming in polluted water,” elaborates Dr. Panagis Galiatsatos, a pulmonologist with the American Lung Association. Galiatsatos goes on to describe what exercise is like in such conditions: “You’re going to get irritated, probably 20 minutes into your jog,” he says. “You’ll develop a cough, some dryness and you may even get a little bit more breathless because what you’re trying to do is some level of endurance, but your lungs aren’t breathing in healthy air, they’re breathing in toxins, they’re breathing in noxious stimuli. You’ll feel that toll.” With that in mind, it’s imperative to understand the air quality in your area before heading out on a run — whether you’re training in Florida or elsewhere.

Staying indoors is ideal when the air quality outside is poor, though it’s imperative to maintain indoor air quality as much as possible. The American Lung Association notes several ways that homeowners can improve indoor air quality, from avoiding the use of chemicals like air fresheners and cleaning products (and instead opting for a healthier option), dusting and vacuuming regularly, and keeping your home smoke free — to highlight a few of many. With quality filtration, your air conditioner (AC) can also contribute to bettering indoor air quality, though regular maintenance is essential in order to avoid common problems. An AC unit that produces a bad odor when it’s turned on is just one common issue that can have a variety of causes, from mold and mildew growth to a dirty air filter. These issues can easily be avoided by keeping the air filter clean and regularly cleaning the interior of the unit. With that in mind, it’s imperative to note that an electrical, burning smell indicates a serious problem that requires the immediate help of a professional.

Training for the Key West Half Marathon and Runfest is a major endeavor that requires a variety of considerations in regard to any runner’s health — such as a healthy diet and proper rest. Air quality can play a significant role in a runner’s health as well, and highlights the importance of monitoring AQI while maintaining healthy indoor air quality at home.