Walking, jogging, or biking down polluted streets has “negligible” benefits on health, a new study finds. The research was published in the medical journal The Lancet.
"When you walk, your airways open up ... and your blood vessels dilate, or open up... and these effects can last for a few days. When you do this in a polluted place, these effects are much smaller, so you've lost the benefits of exercise," said study leader Dr. Fan Chung, professor of respiratory medicine at Imperial College London. "When you exercise in polluted areas, you breathe in more, and you get more of the particles and gases getting to your lungs," he said.
Park Vs. City Street
The effects are worse for those with heart and lung disease, most of whom are over 60 years old.
The study looked at 119 adults randomly asked to walk down London’s Oxford Street or Hyde Park for two hours. Two weeks later they were asked to walk in the opposite space, also for two hours. Every participant experienced lung health improvement walking in Hyde Park versus the city street clogged with cars, taxis, and buses. This is because those in the city were exposed diesel exhaust soot and particles.
Working Out Indoors
"If people cannot find a green place or a park to exercise, I think they probably should exercise indoors," Chung said.
"We're not talking about very high levels of pollution that you see in India or China. We're talking about pollution you get on an ordinary day walking up and down the high street," he continued. "At that level, we are seeing effects that are negating the benefits of walking."
Those with heart and lung disease should take extra care to avoid polluted city streets.