Health effects of exercise outweigh negatives of air pollution, study finds

Don't stop riding because the air quality is bad, but if you can, ride away from main roads. That's the message of research from the University of Copenhagen which has found that the benefits of exercise outweigh the harmful effects of air pollution.

The study shows that despite its adverse effects on health, air pollution should not stop people from exercising in urban areas.

"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," says Associate Professor Zorana Jovanovic Andersen from the Centre for Epidemiology and Screening at the University of Copenhagen.

Professor Andersen says that physical activity reduces the risk of premature mortality, while air pollution increases it. But when we exercise we take in more airborne pollutants, and they accumulate in our lungs.

"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," says Professor Andersen.

"However, 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."

The study looked at data from 52,061 subjects, 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.

5,500 participants died before 2010, and the researchers observed about 20% fewer deaths among those who exercised than among those who didn't exercise, even for those who lived in the most polluted areas, in central Copenhagen and Aarhus, or close to busy roads and highways.

However, Andersen sounds a mote of warning that might make you think twice about doing laps of Oxford Street.

"It is also important to note that these results pertain to Denmark and sites with similar air pollution levels, and may not necessary be true in cities with several fold higher air pollution levels, as seen in other parts of the world," she says.

The research results have been published in the journal Environmental Health Perspectives.