Air pollution. Car exhaust. Wildfire smoke. You want to go out for a walk, jog a few miles or ride your roller blades around the park, but you can’t help but wonder: Is it safe to be breathing that stuff?
When you engage in aerobic exercise, you naturally take in more air. You breathe harder and faster and inhale more of the air around you to fuel your body. If that air is heavily polluted or filled with smoke, it can cause problems. You may notice a sore throat, for example, or find yourself coughing more than usual.
Some studies, however, have indicated that regularly exercising in poor air quality conditions may have long-term negative effects. Exercise is one of the best things you can do for your health and vitality.
What’s the answer? Must you stay inside and run another boring couple of miles on the treadmill, or is it worth it to brave the smog?
That air pollution affects you while exercising is no longer a question. We have several studies showing that poor air quality can diminish your performance and potentially damage your heart and lungs.
Women marathoners, for example, had slower running times when they were exposed to higher levels of air pollution. Researchers evaluated marathon race results and air pollutant concentrations in seven marathons during a period of eight to 28 years. They found that even though pollution levels rarely exceeded national standards for air quality, the women’s performances were still affected.
When running a marathon, athletes inhale and exhale much more air than they would typically, so they’re exposed to greater amounts of pollutants. But even non-athletes who go out for a walk on a polluted day can be affected by the junk in the air.
In a 2017 study, researchers had middle-aged participants take a walk either in the park or along a busy street. Some of the participants had mild heart or lung disease while others were perfectly healthy. The scientists then measured how much pollution the volunteers inhaled and checked their heart and lung function.
Results showed that regardless of whether the participants were healthy or had mild lung or heart disease, walking in the park led to an increase in lung function. It also helped open up the blood vessels, reducing measurements connected to stiffened arteries by 24 percent. In other words, it created measurable physical benefits that scientists could see and, better yet, the benefits lasted up to 26 hours for many of the participants.
Those who walked on the busy street, however, failed to experience the same level of benefits. There was only a minor increase in lung function, and artery stiffness actually got worse. Those who already had mild lung disease experienced reduced lung function. In fact, the pollution seemed to weaken the usual positive effects of exercise significantly.
“When you walk, your airways open up,” said lead author Dr. Fan Chung, “and your blood vessels dilate, or open up … and these effects can last for a few days. When you do this in a polluted place, these effects are much smaller, so you’ve lost the benefits of exercise.”
Another thing to consider: Often, when we’re running or engaging in other types of aerobic exercise, we breathe through the mouth rather than the nose, bypassing the built-in filter that the nasal passages provide and exposing the lungs to more pollutants.
Does that mean you shouldn’t exercise outdoors in polluted areas?
Some studies on pollution and exercise have found conflicting results. In a 2016 study, for example, researchers examined the health effects of walking and cycling around town in different levels of air pollution.
They found that the benefits of physical activity far outweighed the risks of air pollution under all but the most extreme conditions. The scientists still agreed, however, that avoiding busy streets and walking in parks or other green spaces was a good idea, and would likely create more health benefits. However, they stated that exercise is so important to health, that choosing to walk or bike is still preferable over choosing to drive.
Danish researchers came to a similar conclusion after they examined physical activity and air pollution in elderly urban residents. They looked at data from more than 50,000 people aged 50 to 65 between 1993 and 2010, examining their physical activity levels and their exposure to air pollution.
They found that exercising — gardening, cycling, and participation in sports — had a positive effect on mortality, regardless of exposure to air pollution. They also found, however, that participants who were exposed to less air pollution experienced greater reductions in mortality associated with respiratory problems.
More specifically, people who exercised regularly in low- or moderately polluted areas were 45 percent less likely to die from respiratory diseases than non-exercisers, while those who exercised in highly polluted areas experienced a lower level of benefits — they were 19 to 23 percent less likely to die.
7 Ways to Protect Yourself from Polluted Air When Exercising
Although we still need more research to know exactly what long-term effects exercising in polluted areas may have, we can see from the studies that have been done so far that we can get the most out of our exercise routines when we avoid air pollution. Here are seven tips to help you maximize your workouts.
1. Check Air Pollution Levels
Before you step out, check air quality levels in your area. If levels are high, consider rescheduling your exercise for another time — pollution levels are typically highest near midday or early afternoon — or choose to exercise indoors.
How do you know if levels are high in low? Check the “air quality index”:
- 1-50: Good (green)
- 51-100: Moderate (yellow)
- 101-150: Unhealthy for sensitive groups (orange); includes those with asthma, allergies, or existing respiratory issues, as well as young people and the elderly, and those who are active outdoors
- 151-200: Unhealthy for all (red)
- 201-300: Very unhealthy for all (purple)
- 301-500: Hazardous (dark red or maroon)
To find out what the levels are:
- Contact your local or state air pollution control agency
- Check your local newspaper or news website
- Look at other sites like AirNow or the Real-Time Air Quality Index
- Download apps like the American Lung Association’s State of the Air app on your mobile device or through the Google Play or Apple iTunes stores
2. Don’t Exercise Near Busy Streets
Car exhaust contains a lot of air particles that can irritate your lungs. Pollution levels are usually highest within one-quarter mile of a busy road, so choose areas with lower traffic levels or head out to a green park if you can. Going just 1 or 2 miles away from the main flow of traffic, for example, can help reduce your exposure. Consider driving a few blocks away and start there.
3. Stay Away from High Buildings and Traffic Lights
Tall buildings, particularly if they line both sides of the street, tend to trap pollution between them, exposing you to more unhealthy air particles. Traffic lights are spots to avoid too as cars give off more emissions as they accelerate away from them.
You may not have realized it, but weather can affect air pollution levels. It may seem tempting to head out on a hot, sunny day, but that’s exactly the kind of day when air pollution tends to be at its highest. Wind and rain clear out the air. Check your local forecast. If you can, exercise after a nice rain to enjoy the fresh air or wait until the wind stirs things up a bit. If you’re looking at a nice calm day, head out when it cools down a little, either first thing in the morning or later in the evening.
5. Think about Getting a Wearable Air Quality Device
These are new on the market, but they may help you determine the best places to exercise around your home. The “Flow” device, for example, maps air pollution variations around you in real time, so you can find clearer air to exercise in. It also helps measure real-time concentrations of various pollutants like volatile organic compounds (VOCs), nitric oxide (NO2), and other particles, helping you gain the information you need to optimize your healthy exercise routines.
Wynd Technologies has also created an air quality tracker that monitors air quality on the go. It senses airborne particulate matter including dust, allergens and industrial pollution in real time.
6. Be Extra Cautious if You Have Lung or Heart Disease
If you’re already managing asthma, chronic obstructive pulmonary disease (COPD), heart disease or other related conditions, you’re more vulnerable to the negative effects of exercising in polluted areas. Researchers reported in 2011 that long-term exposure to traffic-related air pollution could actually contribute to the development of COPD. Those with diabetes or asthma were most at risk. Those with existing disease were also found to experience negative results from exercising in polluted areas like reduced lung function and stiffer arteries.
Other groups that are particularly sensitive to pollution include the elderly, young children and people with diabetes.
The United States Environmental Protection Agency (EPA) states that a growing body of scientific evidence “has indicated that the air within homes and other buildings can be more seriously polluted than the outdoor air in even the largest and most industrialized cities.” Household products, mold and mildew, animal dander, house dust mites, pollen, woodstoves, gas space heaters and stoves, fireplaces and more can all produce pollutants that are released and trapped inside the home.
That means if you’re going to exercise indoors, it’s important to evaluate your exposure to pollutants there, whether you’re working out at home or in the gym. At home, you can take steps to reduce pollutants by dusting and vacuuming regularly, opening windows to increase air exchange, installing an air purifier and avoiding the use of synthetic air fresheners as they release polluting chemicals.
If you’re headed out to the gym, check their air quality too. Does it smell fresh and open or is it funky and stuffy? Find the one that pays more attention to cleanliness and fresh air, and enjoys your workouts there.
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