Although converging evidence has demonstrated that exposure to fine particulate matter (PM_2.5) caused adverse effects on brain structure and cognitive function, the association between the short-term exposure to PM_2.5 and cognition dysfunction remained underexplored, especially possible neurophysiological mechanisms. We conducted a longitudinal observational study with four repeated measurement sessions among 90 young adults from September 2020 to June 2021. During each measurement session, we measured participants' personal-level air pollution exposure for one week with portable monitors, followed by executive function assessment and electrophysiological signal recording at an assessment center. Standard Stroop color-word test was used accompanied with electroencephalogram (EEG) recording to assess performance on executive function. We used linear mixed-effect model with lagged values of PM_2.5 levels to analyze the association between PM_2.5 exposure and changes in executive function, and mediation analysis to investigate mediation effect by EEG signal. Adjusted mixed-effect models demonstrated that elevated PM_2.5 exposure three days prior to cognitive assessment (lag-3) was associated with (1) declined performance in both congruent and incongruent tasks in Stroop test, (2) reduced lower and upper alpha event-related desynchronization (ERD) during 500-1000 ms after stimuli, both indicating impaired executive control. Lower and upper alpha ERD also mediated observed associations between short-term PM_2.5 exposure and executive function. No significant associations were found between short-term PM_2.5 exposure or aperiodic exponents in tonic and phasic states, or periodic alpha oscillations in tonic state. Our results provided evidence that short-term PM_2.5 exposure was associated with executive dysfunction. Reduced alpha ERD was likely to be the underlying pathway through which PM_2.5 induced adverse effects on neuron activities during cognitive tasks.

This study aimed to assess the effectiveness of an online high-intensity interval training (HIIT) intervention and health education on the behaviors, mental health, and cognitive function of sedentary young females. A single-blinded, six-week, randomized controlled pilot trial involving 70 sedentary young Chinese females, aged 18–30 years, was conducted. An intervention group (IG) (n = 33) underwent a HIIT intervention and health education, while a waitlist group (WG) (n = 37) only received health education. In pre-, mid-, and post-tests, both groups filled out questionnaires about physical activity, sedentary behavior, and mental health. Cognitive functions were assessed at the pre- and post-tests by computer-administered cognitive tests. A mixed-effect model with repeated measures was used to analyze outcomes of interest. The retention rate of the IG and WG was 100% and 78.38%, respectively. The IG were found to have significantly increased rates of moderate-to-vigorous physical activity (MVPA) (M_diff = 940.61, p < 0.001, 95% confidence interval (95% CI): 576.67, 1304.55) from pre-test to post-test, while the WG demonstrated a more marked reduction in sedentary time (M_diff = −73.02, p = 0.038, 95% CI: −141.90, −4.14) compared with the IG in the post-test. Moreover, anxiety and stress levels were shown to significantly reduce in the IG over the six-week period (M_diff = −4.73, p = 0.002, 95% CI: −7.30, −2.15 and M_diff = −5.09, p = 0.001, 95% CI: −8.29, −1.89, respectively). In addition, we observed a significant improvement in verbal ability (p = 0.008, ${\mathsf{\eta }}_p^2$ = 0.19) following the HIIT intervention and effects of the interaction with time on processing speed (p = 0.050, ${\mathsf{\eta }}_p^2$ = 0.10) and episodic memory (p = 0.048, ${\mathsf{\eta }}_p^2$ = 0.11). Moreover, the IG had better global cognitive performance than the WG in the post-test (M_diff = 8.28, p = 0.003, 95% CI: 3.06, 13.50). In summary, both an online bodyweight HIIT intervention combined with health education, or health education alone, can effectively improve health-related behaviors, but the behavioral consequences may differ based on the emphasis of different intervention modalities. Furthermore, the “bodyweight HIIT plus health education” modality might be a more promising online intervention strategy to mitigate against negative emotions and improve cognitive function.

As physical activity benefits brain health whereas air pollution damages it, the cognitive response to these exposures may interact. This study aimed to assess the short-term joint effect of physical activity and air pollution on cognitive function in a panel of healthy young adults. We followed ninety healthy subjects aged around 22 years from September 2020 to June 2021 and measured their personal exposure to fine particulate matter (PM_2.5) (μg/m³) and daily accelerometer-based moderate-to-vigorous physical activity (MVPA) (min/day) in 4 one-week-long sessions over the study period. At the end of each measurement session, we assessed executive function using Stroop color-word test and collected resting-state electroencephalogram (EEG) signals. We found short-term PM_2.5 exposure damaged executive function (β_PM25 = 0.0064, p = 0.039) but physical activity could counterbalance it (β_MVPA = -0.0047, p = 0.048), whereby beta-3 wave played as a potential mediating role. MVPA-induced improvement on executive function was larger in polluted air (β_MVPA = -0.010, p = 0.035) than that in clean air (β_MVPA = -0.003, p = 0.45). To offset the negative effect of air pollution on cognitive function, individuals should do extra 13.6 min MVPA every day for every 10 μg/m³ increase in daily PM_2.5. This study implies that physical activity could be used as a preventive approach to compensate the cognitive damages of air pollution.

Physical activity (PA) and sleep are both important to mental health. However, their joint effects on mental distress have not been well explored. The aim of this study was to investigate the joint effects of PA and sleep on mental health, as well as the dose-response relationships between PA and mental health under different sleep health statuses. A longitudinal panel study was adopted to evaluate the relationship between PA, sleep, and mental health among 66 healthy Chinese college students with four online questionnaire surveys. A mixed-effect model with individual-level random effect was used to analyze the interactive regulation effect of PA and sleep on mental health, and a generalized additive model with splines was further fitted to analyze dose-response relationships between variables. When sleep was at a healthy level, no significant difference in mental health was observed between different levels of PA (p > 0.05). However, poor sleepers with moderate and high PA levels indicated significantly fewer negative emotions than those with low PA levels (p = 0.001, p = 0.004). Likewise, poor sleepers who engaged in more moderate intensity PA could significantly reduce negative emotions (β = −0.470, p = 0.011) in a near-linear trend. In summary, both sleep and PA benefit mental health, and they probably regulate mental health through an interactive compensation mode. For good and poor sleepers, PA plays a different role in maintaining and improving mental health. Increasing moderate intensity PA up to moderate-and-high levels is recommended for those who simultaneously suffer from sleep and psychological health problems.

Global warming is intensifying, exacerbating associated health issues. Heat-related illness, a critical risk during heatwaves, significantly impacts public health, yet its long-term health effects remain poorly understood. We established a cohort to investigate these health impact and explore the mitigative role of heatwave warnings. Our cohort study enrolled 9,658,745 participants free of cardiovascular disease (CVD) at baseline from 1332 hospitals and 922 primary care centres in Shenzhen, China. The cohort was observed and followed up from January 1, 2017, to July 31, 2023. We utilized Cox proportional hazards model to analyse CVD incidence among participants who had heat-related illness versus those who did not, and further assessed causal relationship using instrumental variable approach. We employed stratified logistic regression to explore the protective effects of heatwave warning policies. Among 9,658,745 participants followed up to 6 years, 238,278 (2.47%) developed CVD. People who developed CVD were generally older, male, with a higher degree of education, and with more hospital admissions before baseline. Heat-related illness was associated with CVD, with a hazard ratio of CVD 2.526 (95% CI = 2.301–2.773) among patients with heat-related illness compared with those without heat-related illness, and instrumental variable approach analysis suggested causation. Issuing heatwave warnings reduced hospital admissions for heat-related illness (OR [95% CI] = 0.902 [0.832–0.977]) and future CVD risk (OR [95% CI] = 0.964 [0.946–0.982]). The mitigative role of heatwave warnings suggested delayed effect, with mitigative effect at greatest magnitude one to two days after issuance for heat-related illness admission and three to four days for CVD. Our study suggested that heat-related illness has significant long-term impacts on future CVD incidence, which can be mitigated by heatwave warnings. This study was supported by the 10.13039/501100001809 National Natural Science Foundation of China (No. 42277419), the 10.13039/501100012151 Sanming Project of Medicine in Shenzhen (No. SZSM202111001), and the Research Fund of Vanke School of Public Health in Tsinghua University.