As air pollution increases, a big question that looms is whether or not it is still safe or worth it to exercise outside in heavily polluted areas. Few studies have looked at the interaction between air pollution and physical exercise when it comes to the risk of mortality. Researchers at the Brown University School of Public Health decided to address this question using the Elderly Health Service Cohort, a large prospective cohort in Hong Kong, which collected health information on residents aged 65 and older from 1988-2001 and then followed them up until 2011 or death.
The study was led by research associates in epidemiology, Dr. Shengzhi Sun and Dr. Wangnan Cao from the Center of Evidence Synthesis in Health. The type, duration, and frequency of physical activity were collected through structured interviews. The annual PM2.5 concentration was estimated at the residential address for each participant using a satellite-based spatiotemporal model.
They found that the benefits of physical activity were more pronounced for participation in traditional Chinese exercise (e.g., Tai Chi) and aerobic exercise (e.g., cycling). They also found that long-term exposure to PM2.5 increased risk of mortality, but they found little evidence of interaction between physical activity (volume and type) and long-term PM2.5 exposure. The authors suggest that this may mean that the benefits of physical activity may outweigh the risks of exercising outdoors in areas with relatively heavy air pollution.The authors recommend additional studies, especially for a younger population, to confirm these findings.Friday Letter Submission, Publish on October 04