Dr. Pamela Ohman-Strickland, associate professor of biostaticstics at Rutgers School of Public Health, in collaboration with Dr. Jim Zhang, professor, global and environmental health, and his team at Duke University, and Dr. Kian Fan Chung, professor of respiratory medicine, and his team at the Imperial College in London have published a new study that compares pollution levels to cardiorespiratory performance persons over age sixty with chronic obstructive pulmonary disease (COPD). This study finds that the benefits of light exercise, like walking, are suppressed by the effects of pollutants like fine particulate matter, black carbon, and nitrogen dioxide.
Over the course of nearly two years, researchers recruited 40 healthy volunteers, 40 individuals with COPD, and 39 people with ischemic heart disease. The participants were asked to take a two-hour walk in either Hyde Park or on Oxford Street in London. Traffic on the western end of Oxford Street is restricted to buses and taxicabs, most of which are powered by diesel, while nearby Hyde Park is traffic free; black carbon, particulate matter, and nitrogen dioxide are all significantly higher on Oxford Street. Before each of these walks, researchers established each participant’s cardiorespiratory baseline and measured concentrations of particulate matter as well as ambient temperature and humidity.
After their walk, participants were asked to report any symptoms they experienced. While healthy participants reported no symptoms, those with ischemic heart disease reported increases in coughing; volunteers with COPD reported increases in coughing, sputum shortness of breath, and wheezing, with measured increases in pulse wave velocity (PWV). In contrast, walking in Hyde Park led to an increase in lung function and a decrease in pulse wave velocity. Notably, participants with ischemic heart disease that was controlled by medication showed no significant differences in PWV at either of these sites.
Further studies are needed to examine the medium- and long-term effects of walking in polluted environments, but the current data suggest that older adults and adults with cardiorespiratory conditions should consider avoiding walking in highly polluted environments like city streets to preserve their health; instead, exercising in urban green spaces away from traffic or indoor facilities with effective air filtration systems can be beneficial. Finally, policies that reduce traffic pollution may help ensure that everyone can enjoy the benefits of outdoor physical activity.
“Respiratory and cardiovascular responses to walking down a traffic-polluted road compared with walking in a traffic-free area in participants aged 60 years and older with chronic lung or heart disease and age-matched healthy controls: a randomized, crossover study” appeared recently in The Lancet.