Impact of ambient air pollution on physical activity and sedentary behavior in children.

BACKGROUND: Exposure to air pollution has become a serious environmental issue affecting children's health and health-related behavior in China. Previous studies have focused on the associations between air pollution and physical activity among adults; however, few have examined the relationship between air pollution and health-related behavior among children, which are particularly susceptible population subgroups. The present study aims to examine the impact of air pollution on daily physical activity (PA) and sedentary behavior (SB) among children in China. METHODS: PA and SB data were collected by actiGraph accelerometers for eight consecutive days. PA and SB data from 206 children were matched to daily air pollution obtained from the Ministry of Environmental Protection of the People's Republic of China, including the average daily air quality index (AQI), PM2.5 (µg/m³), and PM10 (µg/m³). Associations were estimated using linear individual fixed-effect regressions. RESULTS: A 10-unit increase in daily AQI was associated with a reduction in daily PA by 5.94 (95% confidence interval [CI] = -8.79, -3.08) minutes of moderate to vigorous physical activity (MVPA) and 229.82 (95% CI = -345.35, -114.28) walking steps and an increase in daily SB by 15.77 (95% CI = 9.01, 22.53) minutes. A 10 µg/m³ increase in air pollution concentration in daily PM2.5 was associated with a reduction in daily PA by 7.51 (95% CI = -11.04, -3.97) minutes of MVPA, 295.69 (95% CI = -438.46, -152.92) walking steps and an increase in daily SB by 21.12 (95% CI = 12.77, 29.47) minutes. A 10 µg/m³ increase in air pollution concentration in daily PM10 was associated with a reduction in daily PA by 13.18 (95% confidence interval [CI] = -15.98, -10.37) minutes of MVPA, 518.34 (95% CI = -631.77, -404.91) walking steps and an increase in daily SB by 19.87 (95% CI = 13.10, 26.64) minutes. CONCLUSION: Air pollution may discourage physical activity and increase sedentary behavior among children. Policy interventions are needed to reduce air pollution and develop strategies to decrease risks to children's health.

Healthy cities initiative in China: Progress, challenges, and the way forward.

China implemented the first phase of its National Healthy Cities pilot program from 2016-20. Along with related urban health governmental initiatives, the program has helped put health on the agenda of local governments while raising public awareness. Healthy City actions taken at the municipal scale also prepared cities to deal with the COVID-19 pandemic. However, after intermittent trials spanning the past two decades, the Healthy Cities initiative in China has reached a crucial juncture. It risks becoming inconsequential given its overlap with other health promotion efforts, changing public health priorities in response to the pandemic, and the partial adoption of the Healthy Cities approach advanced by the World Health Organization (WHO). We recommend aligning the Healthy Cities initiative in China with strategic national and global level agendas such as Healthy China 2030 and the Sustainable Development Goals (SDGs) by providing an integrative governance framework to facilitate a coherent intersectoral program to systemically improve population health. Achieving this alignment will require leveraging the full spectrum of best practices in Healthy Cities actions and expanding assessment efforts. Funding: Tsinghua-Toyota Joint Research Fund "Healthy city systems for smart cities" program.

Impact of COVID-19 on 1000 m Running and Pull-Up Performance among College Men Living in China.

BACKGROUND: This study aimed to estimate the impact of the COVID-19 lockdown on fitness performance among Chinese college men during the pandemic period and to explore how fitness changed with a different college grade. METHODS: We conducted repeated measures of 1000 m running and pull-up testing on students from one university in China before and after the lockdown. A total of 7107 (age 19.21 ± 1.17 yr.) male students who completed the same 1000 m running and pull-up testing in 2019 and 2020 were included in the analysis. RESULTS: The paired t-test result indicates a reduction in 1000 m running and pull-up performance by 10.91% (95% CI = 0.89, 0.95) and 23.89% (95% CI = -0.36, -0.31), respectively. Interestingly, college men in the 2017 grade (the third-year college men) had more decreases than in the 2019 grade (the first-year college men). The 1000 m running performance was decreased by 14.43% and 6.48% in the third- and the first-year college men, respectively. The pull-up performance was decreased by 39.11 % in the third-year college men while increased by 10.98% in the first-year college men. CONCLUSIONS: The COVID-19 lockdown reduced 1000 m running and pull-up performances among Chinese college men. The reduction varies by grade and it seems to be particularly seriously decreased for the third-year college men while being modest for the first-year college men. Public policy was urgently needed to improve Chinese college men's fitness performance after the lockdown.

The Impact of COVID-19 Restrictions on Physical Activity among Chinese University Students: A Retrospectively Matched Cohort Study.

Objectives: In this study, we estimated the impact of COVID-19 on physical activity (PA) for Chinese university students during the pandemic period. Methods: The International Physical Activity Questionnaire was completed online by 1487 students (947 males and 513 females; age 19.72 ± 1.32 years, BMI = 21.12 ± 4.50) from one university in China during the pandemic period, and students retrospectively recalled pre-pandemic PA levels (March 29- April 15, 2020). We analyzed the data using a paired-samples t-test. Results: Overall, COVID-19 produced a 27.89% reduction in total weekly minutes (40.62) of vigorous PA, a 43.38% reduction in total weekly minutes (73.92) of moderate PA, and a 24.36% reduction in total weekly minutes of walking (44.69). Results by sex showed that moderate PA decreased the most, by 47.15% (males) and 37.13% (females), and total PA decreased by 48.29% (males) and 40.18% (females). Conclusions: COVID-19 led to a reduction in PA among Chinese university students. PA decreased more for male than female students. Public policy action might be needed to increase the level of PA of Chinese university students.