Exercise is best when the air is fresh.

  • Running helps reverse some brain ageing linked to increased risk of dementia
  • People who live in areas polluted do not reap the same benefits.
  • The innermost layer of the brain was more damaged by those who were active.

Going for a jog is good for the brain – but not if you do it in a polluted area, researchers have found.

Running, playing tennis, and football outdoors can reverse the effects of brain ageing that is linked with an increase in dementia risk.

A study showed that people who are actively involved in pollution areas do not reap the same benefits.

More than 8600 Britons were surveyed by researchers. Their activity levels were measured using a fitness tracker worn on their wrists for one week.

Going for a jog is good for the brain but not if you do it in a polluted area, researchers have found (file image)

Researchers have discovered that running is good for brain. However, it can be dangerous if the area you are exercising in is polluted.

Those who were most active had reduced levels of white matter lesions – damage to the inner layer of the brain which connects its different regions.

This was true only for people who lived in low-pollution areas. However, similarly active people living in more polluted places saw no brain boost. 

Even tiny particles of pollution could cause inflammation or blood vessel damage, and this can affect the brain.

Dr Melissa Furlong, who led the study from the University of Arizona, said: ‘Vigorous exercise may increase exposure to air pollution, and prior studies have shown adverse effects of air pollution on the brain.’

This study was published in Neurology. It looked at the health of people between 40 and 69 as well as their exposure to pollution. The study looked at people who exercised for up to fifteen minutes per week, as well as those who were active for up to thirty minutes.

These people were then compared to others who had not done any physical activity.

Grey matter is a measure of how active people are. This may protect them against dementia. 

MRI scans indicated that people living in lower-pollution areas were more active. Also, there was less evidence of white matter lesion. These lesions are more prevalent in seniors and can increase your risk for stroke or dementia.

Even if age and sex are taken into consideration, however, white matter lesions were not affected in individuals who lived in high concentrations of polluting particles and nitrogen dioxide.

Dr Furlong said: ‘Public policy could be used to address people’s exposure to air pollution during exercise. 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.’