Getting a workout is hard enough without the added stress of air pollution.
The health benefits of living an active lifestyle are well known and biking is a particularly popular choice when it comes to city-living, but is it possible that riding through the polluted air of heavily trafficked roadways can outweigh the positive health benefits of exercise?
The jury is still out, but a new study by a team of researchers from the University of British Columbia and Portland State University suggests that at the very least, bicyclists should avoid riding on the busiest of streets and stick to less traveled roads to limit their exposure to air pollutants from vehicles.
According to a press release by the American Chemical Society, researcher Alexander Bigazzi of the University of British Columbia and colleagues studied the breath of three cyclists in Portland, Oregon, who rode on off-street bike paths, local streets with lighter traffic, and main streets with heavier traffic.
Using a pollution detector mounted on the bicycles, the team found that the on-road exposure levels (above the urban background) of volatile organic compounds — a kind of pollution — were 100 to 200 percent higher when the cyclists took routes through high-traffic or industrial areas as compared to low-traffic or off-street routes. Using breath analysis, the team found that absorbed compounds in the body were 40 to 100 percent higher in these situations.
However, in a relatively large 2015 study from the University of Copenhagen, researchers found that despite the hazards posed by air pollution from congested roadways, the benefits of outdoor exercise, namely longer lifespan, outweigh the negative impacts.
The Danish study included 52,061 people, aged 50-65 years, from the two main cities Aarhus and Copenhagen, who participated in the cohort study Diet, Cancer and Health. From 1993-97, they reported on their physical leisure activities, including sports, cycling to and from work, gardening, and walking. The researchers then estimated air pollution levels from traffic at their residential addresses.
According to the university, 5,500 participants died before 2010, and the researchers observed about 20 percent fewer deaths among those who exercised than among those who didn’t, even for those who lived in the most polluted areas in central Copenhagen and Aarhus, or close to busy roads and highways.
“Air pollution is often perceived as a barrier to exercise in urban areas. In the face of an increasing health burden due to rising physical inactivity and obesity in modern societies, our findings provide support for efforts in promoting exercise, even in urban areas with high pollution,” said study researcher Zorana Jovanovic Andersen, an associate professor from the Centre for Epidemiology and Screening at the University of Copenhagen. “Even for those living in the most polluted areas of Copenhagen, it is healthier to go for a run, a walk or to cycle to work than it is to stay inactive.”
She acknowledged that the study’s implications may be skewed by the significantly better air quality of the two Danish cities compared with other cities in the industrialized world, particularly large cities known for their poor air quality, yet ultimately, her conclusion was similar to that of Bigazzi and his colleagues.
“We would still advise people to exercise and cycle in green areas, parks, woods, with low air pollution and away from busy roads, when possible.” she said.
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