Even In Polluted Cities, Walking and Biking Are Good For You

The health benefits of walking or biking in polluted cities outweighs the risks.

Posted May 05, 2016

Chetty Thomas/Shutterstock
Source: Chetty Thomas/Shutterstock

As a native New Yorker, and ultra-endurance athlete, I did practically all of my aerobic conditioning for international competitions on the island of Manhattan. Oftentimes, I would say to myself, “Breathing in all of this air pollution must be really bad for me.” Well, as it turns out, although doing aerobic exercise in polluted cities isn’t ideal—a new study reports that the benefits of cycling or walking for 'active travel' outweigh the risks.

For many urban dwellers, living in an active-friendly city can be a matter of life or death. Other studies have found that people who live in active cities—with access to large parks, green spaces, bike paths, and pedestrian walkways—that facilitate active travel, are healthier and live longer. Now, the latest research appears to confirm that even with air pollution, it’s healthier to walk or bike around town than to take a taxi, bus, or the subway.

The May 2016 study, “Can Air Pollution Negate the Health Benefits of Cycling and Walking?” was published today in the journal Preventive Medicine.

For this study, the researchers used computer simulations to compare the risks and benefits for different levels of intensity and duration of active travel and air pollution in various locations around the world. The study was led by researchers at the University of Cambridge in the UK.

trekandshoot/Shutterstock
Source: trekandshoot/Shutterstock

The researchers believe that their findings on the benefits of active travel, even in polluted cities, strengthens the case for city planners to promote cycling as a viable and preferable form of transportation in all types of urban environments.

Obviously, the ultimate potential win-win outcome of this study would be to have masses of people traveling actively in the future, which could lead to a tipping point that reduces vehicle emissions to a point where pollution becomes less of an issue and the health benefits of walking and biking become even greater. 

Unfortunately, air pollution remains one of the leading environmental risk factors for the well-being of urban dwellers around the world. In fact, a recent report from the Royal Colleges of Physicians and of Pediatrics and Child Health suggested that in the UK alone, air pollution contributes to approximately 40,000 early death.

That said, Marko Tainio from the MRC Epidemiology Unit at the University of Cambridge, who led the study, said in a statement, "Even in Delhi, one of the most polluted cities in the world—with pollution levels ten times those in London—people would need to cycle over five hours per week before the pollution risks outweigh the health benefits."

Based on the global data collected by the researchers, they calculated that only 1% of cities in the World Health Organization's Ambient Air Pollution Database had pollution levels high enough so that the risks of air pollution might start to outweigh the benefits of physical activity after 30 minutes of cycling every day.

Senior author, James Woodcock, added a cautionary statement, saying: "We should remember, though, that a small minority of workers in the most polluted cities, such as bike messengers, may be exposed to levels of air pollution high enough to cancel out the health benefits of physical activity."

Conclusions: Reducing Air Pollution Must Remain a Top Priority

There is an important caveat regarding this study. The researchers emphasize that although the health benefits of active travel in polluted cities outweighs the risks, these findings should not be interpreted as an excuse to neglect the importance of lowering emissions and greenhouse gases around the globe. 

In conclusion, Woodcock, said, "Whilst this research demonstrates the benefits of physical activity in spite of air quality, it is not an argument for inaction in combating pollution. It provides further support for investment in infrastructure to get people out of their cars and onto their feet or their bikes—which can itself reduce pollution levels at the same time as supporting physical activity."

To read more on this topic, check out my Psychology Today blog posts, 

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