Smoggy Streets May Make Daily Walk a Health Hazard

From - December 6, 2017

Smoggy Streets May Make Daily Walk a Health Hazard

WEDNESDAY, Dec. 6, 2017 -- It's common doctors' advice to the elderly: Walk around the block each day to help stay fit.

Trouble is, that advice might do more harm than good if you live in a neighborhood with smoggy air, a new study shows. British research suggests the unhealthy effects of breathing dirty air might outweigh whatever benefit the daily walk brings.

"For many people, such as the elderly or those with chronic disease, the only exercise they very often can do is to walk," noted lead researcher Dr. Kian Fan Chung, of the National Heart and Lung Institute at Imperial College London.

But "our study suggests that we might advise these people to walk in green spaces, away from built-up areas and pollution from traffic," Chung said in a news release from Duke University. "But for those living in inner cities, this may be difficult to do, and there may be a cost associated with it as they have to travel further away from where they live or work."

The study was conducted in London, but one U.S. expert in respiratory health said the findings probably hold true everywhere.

"It is no surprise that traffic-polluted streets may negate the cardio-respiratory effects of walking in older adults," said Dr. Len Horovitz, a pulmonary specialist at Lenox Hill Hospital in New York City.

He advises that "peak traffic times should be avoided for walking for this [older] group, who also may suffer from COPD, and indoor exercise may be preferable and safer."

The new study was published Dec. 5 in The Lancet, and involved 119 adults aged 60 years and older. Of these people, 40 were healthy, 40 were being treated for chronic obstructive pulmonary disease (COPD) and 39 were being treated for heart disease. None of the patients were current smokers.

Each participant was randomly assigned to walk for two hours -- either along a street with a lot of traffic or a quiet section of a park. Three to eight weeks later, the volunteers swapped and did the other walk.

Before and during each walk, the researchers assessed levels of traffic-related air pollutants, such as black carbon, particulate matter and nitrogen dioxide. They also measured the lung function and heart health of the participants.

The study showed that walking in the quiet park improved the older people's lung capacity and eased stiffness in their arteries for up to 26 hours.

But on the other hand, walking on the busy street provided less benefit to the participants' lungs, and it was also linked to a stiffening of their arteries. According to the researchers, that's probably due to greater exposure to carbon soot and other forms of air pollution associated with diesel exhaust.

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