Is Exercising in Pollution Bad for You?

Find out if exercising in pollution is bad for you and what you can do if you need to run or bike near polluted roads or exercise in polluted environments. Plus, Get-Fit Guy’s 5 tips to minimize the damage.

Ben Greenfield
5-minute read
Episode #137

Is Exercising in Pollution Bad for You?

This week, The American Lung Association reported the results of their measurement of levels of ozone and soot particles in the air in almost 1,000 U.S. cities and counties.

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No surprises here, but Los Angeles is near the top of the most-polluted list, and not too far behind are the cities of Houston, Dallas, Oklahoma City, Cincinnati, New York, Washington, Philadelphia, and St. Louis.

The cleanest cities (which actually did not have a single day of unhealthy levels of ozone or particle pollution) were Bismarck, North Dakota; Rapid City, South Dakota; and the Fort Myers and Palm Beach areas of Florida.

Whether your city is clean or dirty, you’ve no doubt at some point in your life been walked or run by the side of the road and experienced an intoxicating inhale of truck or car exhaust. And if you’re a recreational runner, cyclist, walker, or do any other mode of exercise in a polluted area or near a busy road, you should know whether that polluted air may be causing some damage to your body or your lungs.

So in today’s episode, you’ll discover how pollution affects exercise and what you can do about it.

How Pollution Affects Exercise

Let’s first take a look at what research has to say about what happens to your lungs, body, and bloodstream when you exercise in a polluted environment.

A 2004 review of pollution studies worldwide conducted in Australia found that during exercise, even low concentrations of airborne pollutants caused lung damage similar to the damage caused by high concentrations of airborne pollutants in people not working out. The researchers concluded that people who exercise outdoors, especially in polluted areas, should probably be more worried than they actually are.

How does this happen? The polluted particles in the air can sail past your nasal hairs (the body's first line of defense) and settle deep in your lungs. Some particles remain there, causing irritation and inflammation, and others migrate into your bloodstream, which can increase your risk of a heart attack and stroke. Because exercise means deeper breathing, more of these particles bypass your nasal filtering.

Another study that appeared in The New England Journal of Medicine found that women who lived in communities with relatively high levels of air pollution (in the form of tiny particles known as soot) were more likely to die from heart attacks compared to women who lived in cleaner air. Researchers concluded that fine soot particulates are definitely something to worry about, especially for athletes, who can take in elevated doses during exercise.

In addition, a 2005 study at the University of Edinburgh had healthy volunteers ride exercise bikes inside a laboratory for 30 minutes, while at the same time breathing piped-in diesel exhaust fumes at levels approximately similar to those you’d find beside a city highway at rush hour. Afterward, the researchers found that the blood vessels of the subjects were abnormally affected, specifically in a way that didn’t allow blood and oxygen to flow easily to the muscles. At the same time, levels of something called “tissue plasminogen activator,” a naturally-occurring protein that dissolves blood clots, significantly fell. Researchers concluded that exercising by a polluted road created ideal conditions for a heart attack, which can start when arteries constrict and a clot forms. Without sufficient levels of that tissue activator, the clot is not dissolved, the artery is blocked and the heart is damaged.

It’s Not all Bad News

In a recent study published in the Medicine and Science in Sports and Exercise, entitled “Anti-inflammatory effects of aerobic exercise in mice exposed to air pollution,” a longer timeline was used to study exercise in polluted environments. In previous studies, effects of polluted air were studied immediately after exercise, but not for an extended period of time. But in this study, a 5-week timeline was used. It turns out that mice exposed to diesel exhaust fumes (those poor mice!), in the absence of an exercise program, saw a dramatic spike in lung inflammation and free radical damage to their cells. But a group of mice that exercised while being exposed to the same level of pollution seemed to undergo changes over the 5 weeks that almost completely protected them from the pollution!

Researchers concluded that long-term aerobic exercise presents protective effects, possibly by the body creating natural antioxidants that fight against the damage caused by pollution.

So what about the effects of exercise and pollution in humans, and not in mice?

In humans, studies have found that daily hospital admissions for respiratory and cardiovascular problems correlate with air-quality readings, as you might expect. But upon closer inspection, the health benefits of exercise seem to outweigh the risk of pollution. For example, in 2010, researchers in the Netherlands used epidemiological data to estimate that the effects of switching from a car to a bike for short daily trips in polluted cities would subtract between 0.8 and 40 days from the average life span – but the additional exercise would extend average life span by 3 to 14 months. So ultimately it turns out that when presented with the decision to exercise or not exercise in a polluted environment, it’s better for your overall lifespan to exercise!

Another study at the University of British Columbia’s Environmental Physiology Lab investigated subjects for 7 weeks. While cycling at a variety of intensities, one group was exposed to air with exhaust from a diesel engine, while another group breathed clean, filtered air. Researchers found that exercise could literally overpower the effect of the pollution in a similar manner that was noted previously in the mice!

Ultimately, the more research that is done on exercise and pollution, the more it’s appearing that the potent anti-inflammatory effects of exercise can counteract the damage from air pollution – and if you have to make a choice between exercising in polluted air or simply canceling your workout, it’s actually better to go out and exercise.

How to Minimize the Damage from Exercising in Pollution

Even if you are indeed going to make the decision to trust your body’s built-in protective abilities and exercise in polluted air, you should still take steps to minimize the damage. Here are 5 quick and dirty tips to keep you even safer from pollution while exercising:

Tip #1: Time Your Workouts

Due to heat from the sun and ozone-affecting pollution, air quality is lowest when the temperature is highest, so plan your outdoor exercise in the cooler morning or evening times. 

Tip #2: Steer Clear of Roads

Avoid walking or biking along busy streets, where levels of pollutants tend to be significantly higher. By moving just a few feet away from the road, or preferably avoiding busy roads altogether, you can significantly lower airborne particle inhalation.

Tip #3: Do Your Research

At airnow.gov, you can check the EPA's daily air quality forecast for most major cities, and then you can decide which day might be best for your big outdoor run or bike ride.

Tip #4: Wear A Mask

I’ve personally resorted to wearing a filtration mask when I’m exercising in busy, polluted cities such as Bangkok and Hong Kong. Although I don’t get any fashion points, I have found that my “pollution nausea” tends to be significantly lower after a run in which I’ve worn a filtration mask.

Tip #5: Use Antioxidants

Sure, your body produces it’s own antioxidants, but it’s smart to give your body some help with food or supplements too. Look for foods high in antioxidants, such as pomegranates, blueberries, cherries, kale, and tomatoes – all of which can help you fight those free radicals even better!

If you have more questions about exercise and pollution, then be sure to listen to another recent podcast that I recorded about exercise and pollution, and for more conversation on this topic, head over to Facebook.com/GetFitGuy. See you there!

Pollution and Man Running images from Shutterstock

All content here is for informational purposes only. This content does not replace the professional judgment of your own health provider. Please consult a licensed health professional for all individual questions and issues.

About the Author

Ben Greenfield

Ben Greenfield received bachelor’s and master’s degrees from University of Idaho in sports science and exercise physiology; personal training and strength and conditioning certifications from the National Strength and Conditioning Association (NSCA); a sports nutrition certification from the International Society of Sports Nutrition (ISSN), an advanced bicycle fitting certification from Serotta. He has over 11 years’ experience in coaching professional, collegiate, and recreational athletes from all sports, and as helped hundreds of clients achieve weight loss and fitness success.