In 262 patients across five European countries, every extra 1,000 daily steps was associated with roughly 5 per cent lower odds of a flare-up — and home air pollution did not change the benefit.

People with chronic obstructive pulmonary disease are told to stay active and told that polluted air damages their lungs. For anyone living beside a busy road, those two pieces of advice pull in opposite directions, and clinicians have had little evidence to resolve the conflict.

“In people who already have COPD, walking in a traffic-polluted area may increase their daily respiratory symptoms,” said Professor Judith Garcia-Aymerich of the Barcelona Institute for Global Health, who led the research with Dr Alícia Josa-Culleré. “But, until now, there has been no research on whether physical activity practiced in air polluted settings could have any harmful effects over the longer term.”

“The purpose of this research was to find an answer to a very simple question that health professionals face every day,” she said: “can we recommend physical activity in people with COPD living in polluted environments?”

The answer the study reports, published in ERJ Open Research, is yes. Regular walking was associated with fewer COPD flare-ups regardless of the air pollution levels at participants’ homes.

Seven days of steps, two years of outcomes

The study followed 262 people with COPD in the United Kingdom, Spain, Belgium, Switzerland and Greece. Each wore a movement sensor for seven days, which recorded step count, how long they walked and how fast. Air pollution was estimated for each participant’s home address over the preceding two years, covering fine particulate matter, black carbon, nitrogen dioxide and ozone. Flare-ups were then tracked for two years through patient diaries and medical records.

Walking about 1,000 more steps a day was associated with roughly a 5 per cent lower likelihood of a flare-up. Walking faster than the group’s average pace of about one metre per second increased the benefit. The association did not differ by how severe a participant’s COPD was.

“We found no differential effects depending on the severity of COPD,” said Josa-Culleré. “Our study included concentrations of air pollution above the recommendations from the World Health Organization. However, our findings may not be applicable to areas with extremely high concentrations of air pollution.”

What exacerbations cost

Flare-ups are the right outcome to measure. A COPD exacerbation is not merely an uncomfortable week: each one can cause a step down in lung function that is not fully regained, and the frequency of exacerbations is among the strongest predictors of how the disease will progress. Reducing them is the central goal of COPD management, which is what gives a 5 per cent reduction per thousand steps its practical weight — modest per increment, cumulative across a habit.

The finding that speed matters is consistent with how exercise intensity generally works, though it carries a caveat the release does not raise: walking faster means breathing harder, and breathing harder in polluted air means inhaling more of it. That the net effect still favoured faster walking is the study’s result, within the pollution range it covered.

Not a reason to stop worrying about air

Josa-Culleré was pointed about how the result should not be read. “The take home message from our study is not that we don’t need to worry about air pollution,” she said. “Exposure to air pollution has been linked to multiple health outcomes. Reducing exposure to air pollution should still be recommended.”

“Rather, our findings suggest that walking is still better than remaining regularly inactive, even for people living in relatively polluted areas,” she said. “And of course, it’s better if people try to walk in low-pollution areas whenever possible.”

That framing matters because a study like this is easily misreported as evidence that pollution does not harm people with lung disease. It shows nothing of the kind. It compares active with inactive people at a given level of pollution, and finds activity wins; it does not compare clean air with dirty air.

The limits

The study is observational, with the usual consequence: it cannot establish that walking more causes fewer flare-ups. People who walk more may be less ill in ways the measurements did not capture, and milder disease produces both more walking and fewer exacerbations. The seven-day activity measurement is also a snapshot used to characterise two years of behaviour.

The researchers acknowledge the sample is modest and may have missed small differences, including small differences in how pollution modifies the benefit. A larger study including areas of very high pollution is planned, which is where the question becomes most pressing — the pollution levels in these five Western European countries exceeded WHO guidance, but they are not what people breathe in the most polluted cities in the world.

Dr Marc Miravitlles, President of the European Respiratory Society, who was not involved in the research, made the same point. “We know that walking and being active can really help people with COPD,” he said. “We also know that breathing polluted air is bad for our lungs and can be especially damaging for people living with long-term lung conditions such as COPD.”

“This study can give people living with COPD some reassurance, as it suggests walking is still beneficial, whether you live in the countryside or in the centre of a city,” he said. “However, this study looked at different levels of pollution in Western European countries, and we know that in other parts of the world, air pollution levels can be much higher. We still need more research for patients living in those areas.”

The release does not identify who funded this specific study, noting only that ISGlobal is supported by the ‘la Caixa’ Foundation. Several authors declared interests, including shareholding in a health company, personal fees from a pharmaceutical company, honoraria from pharmaceutical and medical device firms for educational events, and editorial board membership at the publishing journal.

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Notes

1. “Interaction of walking activity and long-term air pollution on exacerbation rate in COPD.” ERJ Open Research, 5 October 2026. DOI: 10.1183/23120541.00813-2026.
2. European Respiratory Society. “Regular walking is good for people with COPD, even if they live in areas with higher air pollution.” EurekAlert!, 5 October 2026. https://www.eurekalert.org/news-releases/1146294.