The Influence of Climate and Air Pollution on Physical Activity of Chinese People in Shenyang and Shenzhen

Physical activity (PA) refers to bodily movements that result in a significant increase in energy expenditure due to the contraction of skeletal muscles. Physical inactivity has become a major global public health concern and is currently the fourth leading cause of death worldwide. The World Health Organization (WHO) recommends that adults engage in at least 150 minutes of moderate-intensity physical activity (MPA) or 75 minutes of vigorous-intensity physical activity (VPA) per week.

Although some studies suggest that individual differences in PA may have a genetic basis, PA is generally considered to be largely under voluntary control and influenced by climatic and environmental factors. For instance, extreme temperatures-either hot or cold-can increase health risks and reduce individuals' willingness to engage in physical activity. In addition, air pollution, particularly fine particulate matter (PM2.5), poses serious health risks. Exercising in polluted environments may trigger asthma, cardiovascular, or pulmonary conditions.

Since the Industrial Revolution, fossil fuel emissions have contributed to a global surface temperature increase of approximately 1.1°C, with projections suggesting a further rise of 2.5-2.9°C by the end of the century. At the same time, PM2.5 pollution has become a pressing issue, contributing to an estimated 7 million deaths globally in 2012-over one-third of which occurred in rapidly developing Asian countries.

Given the seasonal and geographic variability in climate and air quality, physical activity levels are likely to be affected accordingly.This study aims to investigate the extent to which climatic and environmental factors influence physical activity levels and intensity.