12/14/2012 12:04 pm ET Updated Dec 06, 2017

Jogging Outside Could Make You Dumber


By Erin Hicks

You think you're doing a good thing for your body by going out for a run, but according to Belgian researchers, you could be hurting your brain in the process.

Researchers from Vrije Universiteit Brussel in Belgium split a group of 24 runners into two groups: those from urban areas and those from rural areas.

More from Everyday Health:
Can Too Much Fruit Stall Weight Loss?
A Blood Test To Diagnose Alzheimer's Disease
The Health Risks Of Smoking For Women Vs. Men

During a 12-week period, the two groups were asked to run three days a week around noon. One group exercised in a rural area, the other group in a busy urban setting. Then, researchers gave the subjects a test to measure their response time and attention span.

They found that those that ran in the city had lower IQ scores and had a higher risk of brain inflammation, according to the Daily Mail.

These results are consistent with a study last month that found people who live in areas with a high level of air pollution scored worse on tests of mental skills like word recall, knowledge, language, and orientation.

Researchers at the U.S. National Institute on Aging studied nearly 14,000 men and women age 50 and older and found the association between high levels of fine particulate matter -- the stuff that causes air pollution -- and reduced mental ability remained even after scientists accounted for factors like age, race, ethnicity, education, smoking, and lung and heart conditions.

This doesn't get you off the hook for having to exercise, however. Study researcher Romain Meeusen, head of the department of Human Physiology and Sports said not only should you still exercise, but you should try to run in the wind and the rain, since those weather conditions tend to blow fine particles away.

He also recommends avoiding exercising outdoors during rush hour to try to avoid pollution from exhaust fumes, and says to exercise in a park whenever possible, according to the Daily Mail.

Another reason not to skip your morning run: It could add about six years to your life.

Danish researchers compared the mortality of jogger and non-joggers in a study of 20,000 people age 20 to 93 and found that after 35 years, 10,158 non-joggers and 122 joggers died. The researchers noted this was a 44 percent drop in the risk of death for male and female joggers.

They found that male joggers can extend their life by 6.2 years, and women by 5.6 years.

"Jogging Outside Could Make You Dumber" originally appeared on Everyday Health.