International Journal of Environmental Research and Public Health

Background: Since World War II, the number of motorized vehicles has increased dramatically. Yet, few studies have evaluated how perceptions of single and multiple motorized traffic variables, in different combinations, influence pedestrians’ appraisals of the route environment in relation to whether it facilitates or deters walking. We have previously illuminated this in an inner urban area of a metropolitan region. This study aims to scrutinize these matters in the suburban–rural parts of the same metropolitan area. For comparative reasons, we use the same methods as used for the inner urban area. Our hypothesis is that these kinds of perceptions, to some extent, may be context-specific. Methods: Relations between pedestrians’ perceptions of motorized traffic variables (flow and speeds of motor vehicles, noise, and exhaust fumes) and combinations of them, as well as if appraisals of route environments hinder–stimulate walking and are unsafe–safe for reasons of traffic, have been evaluated. This was studied in the suburban and rural areas of Greater Stockholm, Sweden. The pedestrians (n = 233) rated their route environment with the Active Commuting Route Environment Scale (ACRES). Correlation, multiple regression, and mediation analyses were used to study the relationships. Results: The regression analyses showed that noise was the primary negative predictor variable in relation to hindering–stimulating walking. With respect to the other outcome, unsafe–safe traffic, none of the variables had a significant relation. The mediation analyses showed that (1) vehicle speed had an indirect effect on unsafe–safe traffic via noise, (2) both vehicle speed and vehicle flow had, via noise, indirect effects on hinders–stimulates walking, and (3) vehicle speed had, via vehicle flow, an indirect effect on noise and exhaust fumes. Conclusions: In suburban–rural route environments, noise protrudes as a hindering variable for walking. The mediation analyses showed that vehicle speed intensified noise and had negative effects on both outcomes. Therefore, by reducing vehicle speed, noise levels will be lowered, and the walking experience is likely to be enhanced, which can influence the amount of walking. The results are further illuminated through the exploration of existing and potential future research strategies.

Depression is a major public health concern, and evidence continues to show that environmental toxicants may contribute to its development. This study evaluated the association between depressive symptoms and per- and polyfluoroalkyl substances (PFAS), heavy metals, phthalates, and organophosphate metabolites using data from NHANES 2017–2018. Depressive symptoms were measured with the Patient Health Questionnaire-9 (PHQ-9). Environmental exposure variables were analyzed using multivariable linear regression and Bayesian Kernel Machine Regression (BKMR). All models adjusted for demographic, socioeconomic, behavioral, and clinical covariates. In multivariable linear regression models adjusted for demographic, socioeconomic, behavioral, and clinical covariates, higher urinary dimethylphosphate concentrations were significantly associated with increased depressive symptom scores (β = 0.15; 95% CI: 0.04, 0.27; p = 0.0098). Mono-(2-ethylhexyl) phthalate (MEHP) was also positively associated with PHQ-9 scores (β = 0.001; 95% CI: 0.0003, 0.0019; p = 0.0043). Because environmental mixtures tend to follow non-linear patterns, BKMR analysis was run. BKMR analyses indicated that organophosphate metabolites exhibited the greatest overall contribution to depressive symptoms (group posterior inclusion probability = 0.7875), with diethylphosphate emerging as the most influential individual exposure within the group (conditional PIP = 0.7211). Exposure–response functions suggested non-linear and threshold relationships for several metabolites. These findings identify specific organophosphate and phthalate metabolites as potential contributors to depressive symptoms and support the importance of evaluating chemical mixtures rather than single exposures. Additional longitudinal studies are needed to clarify temporal relationships and to inform public health efforts aimed at reducing exposure to organophosphate pesticides and endocrine-disrupting chemicals.

Sleep is a fundamental aspect of physiological and psychological functioning, and the beneficial effect of exercise on sleep quality and quantity, depending on training modality, remains underexplored. This study compared the effects of high-intensity interval training (HIIT) versus a moderate-intensity continuous training (MICT) regime on sleep quality. Twenty-five participants (sixteen men, nine women) were randomly assigned to 8-week HIIT or MICT programs. Anthropometric data, blood pressure, and maximal exercise tests (VO_2max, lactate, heart rate) were conducted one week before and after training. Sleep quality was evaluated daily through self-reported perception and duration and via the Pittsburgh Sleep Quality Index (PSQI) at baseline, one week, and two weeks post-intervention. Data were analyzed in SPSS version 29 using repeated-measures ANOVA. PSQI scores improved significantly over time (p = 0.013), regardless of modality, with no significant group or interaction effects. Cardiorespiratory fitness improved for all participants, with significant gains in VO_2max (p = 0.009), maximal aerobic speed (p < 0.001), and reduced maximal heart rate (HIIT: p = 0.003; MICT: p = 0.021). Sleep perception showed no significant change during training (p = 0.063), with a slight improvement trend. In conclusion, exercise training improves sleep quality regardless of modality. Running three sessions per week for eight weeks enhances both aerobic and cardiorespiratory fitness, along with sleep quality. Physical activity is therefore an effective non-pharmacological strategy to improve sleep.