Walking remains highly beneficial for COPD patients in polluted environments

Regular walking reduces symptom flare ups for people with chronic obstructive pulmonary disease, even if they live in an area with poor air quality, according to a study published in ERJ Open Research.

COPD is a common, long-term lung condition. It cannot be cured; however, plenty of research shows that regular physical activity, such as walking, can help manage symptoms such as coughing, wheezing and feeling short of breath.

Until now, doctors have been concerned about recommending walking if they know their patients live in areas with high levels of air pollution. The new research suggests walking is beneficial, regardless of air quality.

The research was led by Dr Alícia Josa-Culleré and Professor Judith Garcia-Aymerich from the Barcelona Institute for Global Health (ISGlobal), Spain, a center supported by the "la Caixa" Foundation. Professor Garcia-Aymerich said: "In people who already have COPD, walking in a traffic-polluted area may increase their daily respiratory symptoms. 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: can we recommend physical activity in people with COPD living in polluted environments?"

To answer this question, the researchers carried out a study with 262 COPD patients from five European countries: the UK, Spain, Belgium, Switzerland and Greece. All participants wore a movement sensor for a period of seven days that could monitor how many steps each person took, how long they walked for and how fast they walked.

The researchers also collected data on levels of air pollution at the patients' home addresses over the two previous years. This included levels of particulate matter smaller than 2.5μm (PM2.5), black carbon, nitrogen dioxide and ozone.

Finally, they asked patients to keep a diary of flare ups and used patients' medical records over two years to see whether patients had any moderate or severe symptom flare ups (known as COPD exacerbations).

The researchers found that regular walking was associated with fewer symptom fare ups, regardless of the levels of air pollution at the patients' home address. Walking 1000 steps per day reduced the likelihood of flare ups by around five per cent. Regularly walking at a faster pace (more than the participants average speed of one metre per second) increased the benefits of walking.

We found no differential effects depending on the severity of COPD. 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.

The take home message from our study is not that we don't need to worry about air pollution; 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. And of course, it's better if people try to walk in low-pollution areas whenever possible."

Dr. Alícia Josa-Culleré, Barcelona Institute for Global Health (ISGlobal)

The researchers acknowledge that the size of the study was modest, meaning they may not have been able to detect small differences in the relationship between physical activity, air pollution and COPD exacerbations. They plan to conduct a similar study including more people and covering areas with very high levels of pollution.

Dr Marc Miravitlles, President of the European Respiratory Society, senior researcher and consultant at Vall d'Hebron University Hospital, Barcelona, Spain, who was not involved in the research, said: "We know that walking and being active can really help people with COPD. 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. 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."