We go on about the importance of exercise for older people like aging boomers. I've written about how horrible the suburbs are because people have to use a car for every trip instead of just walking to the bodega or to the doctor.

And if a recent study published in the Lancet is correct, much of what I've written is either wrong or contradictory.

The researchers studied 119 people over the age of 60; some were perfectly healthy while others had stable heart disease or stable COPD. Some were told to walk on a busy downtown London street full of buses and taxis, while the others walked in the park.

pollution levels Pollution is way higher on the high street. (Photo: From Lancet)

Thanks to all the diesels on Oxford Street in London, levels of nitrogen dioxide and fine particulates were high. When examined, those who walked in the park all benefited, with lower blood pressure and less arterial stiffness. Those who walked in the Main Street? All the benefits were drastically reduced. From the study’s abstract:

Short-term exposure to traffic pollution prevents the beneficial cardiopulmonary effects of walking in people with COPD, ischaemic heart disease, and those free from chronic cardiopulmonary diseases … Policies should aim to control ambient levels of air pollution along busy streets in view of these negative health effects.

From the Guardian:

These findings are important as walking is frequently recommended for older people. “For many people, such as the elderly or those with chronic disease, very often the only exercise they can do is to walk,” said Kian Fan Chung, professor of respiratory medicine at the National Heart and Lung Institute at Imperial and lead author of the study. “Our research suggests that we might advise older adults to walk in green spaces, away from built-up areas and pollution from traffic.”

A professor of environmental science noted that even under these circumstances, people should still get out there and walk.

“It’s important to that people continue to exercise. In the U.K., physical inactivity is the fourth largest cause of disease and mortality and contributes to around 37,000 premature deaths in England every year.”

But that's a hard sell after seeing a study like this. Fortunately for Americans, the situation in London is not necessarily analogous to the U.S.; In Europe, there is a far higher proportion of vehicles burning diesel, and the fuel sold in the U.S. is much cleaner than the fuel sold in Europe. But still, it's likely that a walk in Central Park is going to be better for you than a walk down Canal Street. The study concludes:

Although further studies are needed, particularly looking at the effect of regular walking in polluted environments, the current data are sufficiently compelling to advise older adults and chronic pulmonary and cardiac participants to avoid walking in highly polluted environments such as city streets with high traffic density. Exercise such as walking should be done in urban green space areas away from high density traffic or in indoor facilities with effective air filtration if located near polluted streets. Finally, it is important to impose policies and measures that can reduce traffic pollution so that every individual can enjoy the health benefits of physical activity.

walking dog in New York First you have to live in a walkable city; then you need to get a dog. (Photo: Yana Paskova/Getty Images)

This is, to be totally blunt, appalling. When I wrote an earlier post on the benefits of getting 30 minutes of exercise, I used this photo as a model of healthy living; I suggested that living in a walkable city was the ideal for health and longevity. Now this study tells us that the air quality negates many of the benefits. But if you live in the suburbs, it's almost impossible to live without a car, so the air quality there isn't much better, and as Matt Hickman notes, the parks aren't particularly senior-friendly. The study is actually implying that people should drive to the gym where the air is filtered.

The implications are pretty clear: cars are killing us, particularly as we age and need exercise and fresh air. The sooner we ban diesel and then go electric and invest in alternative active transportation, the better our health and the health of our older citizens will be.

Coincidentally, another study came out that concludes that air pollution is hurting human procreation. TreeHugger notes that “exposure to air pollution is indeed having a detrimental effect on babies' health, contributing to lower birth weights (at a 2- to 6-percent increase of risk) and premature birth (1- to 3-percent increase of risk).”

It's bad for everyone, but particularly those at either end of the population spectrum.

Lloyd Alter ( @lloydalter ) writes about smart (and dumb) tech with a side of design and a dash of boomer angst.

Air pollution may wipe out the benefits of walking for aging boomers
A study in the Lancet looked at over-60 walkers, and those who worked on a busy London street didn't fare as well as the park walkers.