Physical activity has been shown to improve metabolic health and lower the risk of cardiovascular and metabolic disorders.

According to a new analysis, those who do vigorous physical activities like running or competitive sports in areas with higher levels of air pollution may see less benefit from those activities when it comes to certain brain diseases markers.

White matter hyperintensities, a sign of damage to the brain’s white matter, and gray matter volume were two of the markers studied in the study. Smaller hyperintensity levels and larger gray matter volumes indicate better brain health.

“Vigorous exercise may increase exposure to air pollution and prior studies have shown adverse effects of air pollution on the brain,” says study author Dr. Melissa Furlong.

“We did show that physical activity is associated with improved markers of brain health in areas with lower air pollution. However, some beneficial effects essentially disappeared for vigorous physical activity in areas with the highest levels of air pollution.

“That’s not to say people should avoid exercise. Overall, the effect of air pollution on brain health was modest—roughly equivalent to half the effect of one year of aging, while the effects of vigorous activity on brain health were much larger—approximately equivalent to being three years younger.”

The study looked at 8,600 participants from the UK Biobank, a major biological database, with an average age of 56. The exposure of people to pollution, such as nitrogen dioxide and particulate matter (liquid or solid particles suspended in the air), was calculated using land use regression. A land use regression analysis analyzes air pollution levels based on air monitors and land use features such as transportation, agriculture, and industrial air pollution sources.

The participants’ exposure to air pollution was divided into four equal groups, ranging from the least to the most.

For one week, each person’s physical activity was tracked using an accelerometer. The researchers next classified their physical activity patterns based on how much vigorous physical activity individuals got per week, which ranged from none to 30 minutes or more.

People who did the most vigorous physical activity each week had 800 cm3 gray matter volume on average, compared to 790 cm3 gray matter volume in people who didn’t do any vigorous exercise. Researchers discovered that exposure to air pollution had no influence on the effects of physical activity on gray matter volume. When looking at white matter hyperintensities, researchers discovered that exposure to air pollution affected the impact of vigorous physical activity. After controlling for age, gender, and other factors, researchers discovered that intense physical exercise reduced white matter hyperintensities in low-pollution areas, but not in high-pollution ones.

“More research is needed, but if our findings are replicated, public policy could be used to address people’s exposure to air pollution during exercise,” Furlong added.

“For example, since a significant amount of air pollution comes from traffic, promoting running or bicycling along paths far from heavy traffic may be more beneficial.”

The study’s limitation is that it only examined air pollution levels from one year, and levels can vary from year to year.

Source: Neurology

Image Credit: Getty

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