A study has concluded that even short-term exposure to air pollution in built up areas like London’s Oxford Street can negate the beneficial health effects of exercise in older adults.
The research by Imperial College London and Duke University, and published in The Lancet, adds to the growing body of evidence showing the negative impacts of urban air pollution on cardiovascular and respiratory health, and highlights the need for stricter air quality limits and greater access to green spaces.
“It’s possible that studies such as this could support new air quality limits, it shows that we can’t really tolerate the levels of air pollution that we currently find on our busy streets,” said senior author Fan Chung, Professor of Respiratory Medicine and Head of Experimental Studies Medicine at National Heart & Lung Institute at Imperial College London.
For the study, funded by the British Heart Foundation, researchers recruited 119 volunteers, aged over 60, who were either healthy, had stable Chronic Obstructive Pulmonary Disease (COPD) or had stable heart disease.
The volunteers were then split into two groups. One of the groups walked for two hours in a relatively serene part of Hyde Park, while the second group walked along a busy stretch of Oxford Street – which has regularly breached air quality limits set by the World Health Organization.
Physical measurements were taken before and after the walks to show the effects of the exercise on cardiovascular health, including measurements of lung volume exhaled, blood pressure and the degree to which the blood vessels could expand.
Environmental measurements were also collected, to track pollution levels and volunteers’ exposure.
Analysis revealed that all participants benefitted from a stroll in the park, with lung capacity improving within the first hour and a significant lasting increase for more than 24 hours in many cases.
By comparison, a walk along Oxford Street led to only a small increase in lung capacity in participants, far lower than recorded in the park.
Blood flow also increased after exercise, with decreases in blood pressure and an increase in heart rate. Arteries became less stiff in those walking in Hyde Park with a maximum change from baseline of more than 24% in healthy and COPD volunteers, and more than 19% in heart disease patients.
This effect was drastically reduced when walking along Oxford Street, however, with a maximum change in arterial stiffness of just 4.6% for healthy volunteers, 16% for those with COPD and 8.6% for heart disease.
“These findings are important as for many people, such as the elderly or those with chronic disease, very often the only exercise they can do is to walk,” said Chung.
“Our research suggests that we might advise older adults to walk in green spaces, away from built-up areas and pollution from traffic.”