THE BLOG
05/29/2013 10:12 am ET | Updated Jul 29, 2013

Exercise and Air Pollution

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Just recently, the American Lung Association published its report on the latest measurements of soot particles and ozone in the air for almost 1,000 countries and cities in the United States.

The results come as no surprise, especially for measurements in major cities like Los Angeles. In fact, the latter has been found to be one of the most polluted in the U.S., and not too far behind are the highly urbanized cities of Houston, Washington, New York, Cincinnati and Philadelphia. On the other hand, cities in North and South Dakota, as well as Palm Beach, Fla., are considered cleanest as of the moment.

Whether you live in a polluted city or not, you've surely had to make do with working out along busy polluted roads at some point in your life. Whether you're a serious athlete or a recreational cyclist or runner, it's but prudent to educate yourself if working out in polluted areas causes damage to your lungs and your health overall.

Air Pollution's Effect When You're Exercising

According to a 2004 Australian review of pollution studies worldwide, during exercise, even very minimal concentration of air pollutants can damage the lungs. Said harming effect to the lungs is as severe when exposed to high concentrations of soot and air pollutants when not working out. The researchers therefore concluded that individuals who work out outdoors, especially in highly polluted areas, should be worried about their health.

This happens because harmful particles from the air can get past the nasal hairs, the body's first line of defense. Ultimately, these particles end up in the lungs thus causing inflammation and irritation. These particles sometimes end up in the bloodstream as well. When this occurs, the risk for heart attack and stroke then increases. So since working out means you'll have to breathe deeper, then more of these particle pollutants get to pass through your nasal filtering.

Yet another study that got featured in the New England Journal of Medicine concluded that females who live in areas with high levels of air pollution in the form of soot have higher likelihood of dying from heart attacks as compared to females who lived in cleaner air. Said researchers then concluded that soot particles are very harmful, most especially to athletes who take in higher concentrations during exercise.

A similar study at the University of Edinburgh was conducted in 2005 as well. Healthy subjects were made to exercise for 30 minutes on stationary bikes inside a laboratory that had been piped-in with diesel exhaust fumes at levels similar to that of a busy highway during rush hour. Researchers then found that the subjects' blood vessels were affected in that the latter's ability to distribute blood and oxygen to the muscles were negatively compromised. The subjects' levels of "tissue plasminogen activator," which are naturally-occurring proteins that function by dissolving clots in the blood, significantly decreased as well. Because of these findings, the researchers concluded that working out along polluted roads may possibly set in motion the preliminary stages of heart attack or stroke.

But new research offers some glimmer of hope to athletes and sports enthusiasts who have no choice but to exercise in polluted urbanized areas.

A recent study entitled "Anti-Inflammatory Effects of Aerobic Exercise in Mice Exposed to Air Pollution," which was featured in the journal Medicine and Science in Sports and Exercise, an extended timeline was utilized to study the effects of air pollution during exercise. It's crucial to note that this latest research is quite unlike the previous studies wherein the latter only measured the negative effects immediately after the exercise. For this most recent research, two groups of laboratory mice were utilized. Both groups were subjected to regular doses of diesel exhaust fumes for five straight weeks. The first group, though, did not exercise, while the second did. Researchers found that an alarming spike in lung inflammation and free radicals were seen in the mice that did not perform exercise. Astonishingly, the other group of mice, the ones that were made to exercise while exposed continually for five weeks to diesel exhaust fumes, seemed to have undergone changes that allowed their bodies to combat the harmful effects of the pollution.

These findings had researchers conclude that long-term aerobic exercise may just offer protective effects, potentially due to the body's ability to naturally produce antioxidants that are crucial for combating the harmful effects of pollution.

Of course, the study was conducted on mice. So what about the effects of pollution during exercise on humans?

It's no secret that the higher the air pollution in the area, the higher the hospital admissions for patients seeking relief or treatment from cardiovascular and respiratory issues as well. But on the other hand, the health benefits of exercise seem to more than just balance out the harmful effects of air pollution. To demonstrate, a 2010 study in the Netherlands utilized epidemiological data and estimated that short daily trips using a bicycle in polluted cities would take away between 0.8 to 40 days from a person's average span of life. However, said researchers also found that the additional exercise would lengthen an individual's life span by three to 14 months. It then appears that working out is indeed better as compared to no exercise at all when living in an urbanized and polluted area.

Yet another study was conducted at the University of British Columbia's Environmental Physiology Lab. The research utilized two groups of individuals for seven straight weeks. The first group was made to cycle at various intensities while exposed to diesel engine exhaust. The second group, meanwhile, performed similar activity though in an environment with clean, filtered air. The results provide hope as the subjects made to cycle in polluted air appears to have adapted their bodies, and in fact showed signs of combating the harmful effects of pollution the way that the mice in the previous study did.

Of course, additional studies have to be conducted to truly establish as fact the anti-inflammatory effects of exercise against pollution. But the limited number of research available to us right now may help allay your concerns, as it appears going out to exercise is better than no exercise at all when living in a polluted area.

Tips for Lessening Damage When Working Out in Pollution

Your body may have a built-in mechanism to protect itself from the harmful effects of air pollution, but it's prudent to still take steps to lessen said damage. Opt to consider the tips below.

Know When to Exercise

As you probably already know, the quality of air is most compromised when temperatures are at its hottest. During high temperatures, the sunlight as well as the heat essentially charge up the air along with all the chemical compounds that are present in the atmosphere. This concoction then combines with the nitrogen oxide naturally existing in the air, resulting in smog which is a harmful combination of smoke, soot, and chemical fumes. Since this is the case, it would then be prudent to time your workouts during the cooler mornings or during early evenings.

Avoid Working Out Along Roads

Steer clear of roads, particularly busy streets, as these areas tend to have higher concentration of airborne pollutants. Simply choosing to run, walk, or cycle a few meters from the road can do wonders. Of course, altogether avoiding busy roads is by far the most ideal if you truly want to minimize your exposure to airborne pollutants.

Educate Yourself as to Your Community's Air Pollution Levels

Prior to planning your major run or bike sessions, opt to check airnow.gov first. Over at the site are the latest EPA air-quality forecasts for all the major cities in the U.S. This way, you can schedule your workouts during the least polluted hours of the day.

Don a Mask

Wearing a filtration mask is a smart move as well. Athletes who wear filtration masks during their workouts in polluted urban areas tend to have fewer incidences of "pollution nausea" as compared to those who don't wear masks.

Take Antioxidants Regularly

Though your body produces its own antioxidants, the latter may not be enough to combat the daily stress that your body is subjected to due to exposure to pollutants. To help your body fight against harmful free radicals, opt to boost your intake of antioxidant-rich fruits like cherries, pomegranates and blueberries, as well as vegetables like kale.

Do you have questions, comments or feedback about exercise and pollution? Leave your thoughts below.

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