Air pollution inhalation during acute exercise is dependent of the body mass index and ventilation of young men

Using energy expenditure to estimate the minute ventilation and inhaled load of air pollutants: a pilot survey in young Chinese adults

Existing equations to estimate ventilation (VE) may not represent the Chinese population. The objective is to develop regression equations to predict the basal metabolic rate (BMR) for ventilation estimation. 80 participants underwent the incremental tests on a bicycle ergometer, wearing a fitted facial mask with an airflow sensor connected to the cardiopulmonary gas analyzer, where the energy expenditure, metabolic factors and VE were monitored simultaneously. Linear regression models were established between BMR and body weight, which were used to estimate energy expenditure and VE. Extrapolation of the regression model was evaluated by the five-fold cross-validation. And we also assessed the inhaled load of air pollutants in subgroups at the same exposure levels. Regression models for males and females were BMR (kJ/d) = 107.58 × weight (kg)-172.61 and BMR (kJ/d) = 105.61 × weight (kg)-26.94, respectively. The model showed good fitness between the measured and predicted VE. Differences between the measured and predicted VE of this model are smaller than that of other models. There were significant differences in inhaled load participants in the same exposure concentrations. The regression model showed that weight and BMR are highly correlated and can be used to estimate individual VE.

Fine particulate matter (PM2.5)-induced pulmonary oxidative stress contributes to increases in glucose intolerance and insulin resistance in a mouse model of circadian dyssynchrony

Results of human and animal studies independently suggest that either ambient fine particulate matter (PM2.5) air pollution exposure or a disturbed circadian rhythm (circadian dyssynchrony) are important contributing factors to the rapidly evolving type-2-diabetes (T2D) epidemic. The objective of this study is to investigate whether circadian dyssynchrony increases the susceptibility to PM2.5 and how PM2.5 affects metabolic health in circadian dyssynchrony. We examined systemic and organ-specific changes in glucose homeostasis and insulin sensitivity in mice maintained on a regular (12/12 h light/dark) or disrupted (18/6 h light/dark, light-induced circadian dyssynchrony, LICD) light cycle exposed to air or concentrated PM2.5 (CAP, 6 h/day, 30 days). Exposures during Zeitgeber ZT3-9 or ZT11-17 (Zeitgeber in circadian time, ZT0 = begin of light cycle) tested for time-of-day PM2.5 sensitivity (chronotoxicity). Mice transgenic for lung-specific overexpression of extracellular superoxide dismutase (ecSOD-Tg) were used to assess the contribution of CAP-induced pulmonary oxidative stress. Both, CAP exposure from ZT3-9 or ZT11-17, decreased glucose tolerance and insulin sensitivity in male mice with LICD, but not in female mice or in mice kept on a regular light cycle. Although changes in glucose homeostasis in CAP-exposed male mice with LICD were not associated with obesity, they were accompanied by white adipose tissue (WAT) inflammation, impaired insulin signaling in skeletal muscle and liver, and systemic and pulmonary oxidative stress. Preventing CAP-induced oxidative stress in the lungs mitigated the CAP-induced decrease in glucose tolerance and insulin sensitivity in LICD. Our results demonstrate that circadian dyssynchrony is a novel susceptibility state for PM2.5 and suggest that PM2.5 by inducing pulmonary oxidative stress increases glucose intolerance and insulin resistance in circadian dyssynchrony.

The role of O3 exposure and physical activity status on redox state, inflammation, and pulmonary toxicity of young men: A cross-sectional study

The exposure to traffic-related air pollutants, such as NO₂ and O₃, are associated with detrimental health effects, becoming one of the greatest public health issues worldwide. Exercising in polluted environments could result in harmful outcomes for health and may blunt the physiological adaptations of exercise training. This study aimed to investigate the influence of physical activity and O₃ exposure on redox status, an inflammatory marker, response to stress, and pulmonary toxicity of healthy young individuals. We performed a cross-sectional study with 100 individuals that, based on their exposure to O₃ and physical fitness (PF) level, were distributed in four groups: Low PF + Low O₃; Low PF + High O₃; High PF + Low O₃; High PF + High O₃. We evaluated personal exposure to NO₂ and O_3, physical activity level, variables of oxidative stress (SOD, ROS, CAT, GSH, TBARS), pulmonary toxicity (CC16), and inflammatory mediators (IL-1β, IL-4, IL-6, IL-10, TNF-α, HSP70). Spearman correlation test to check the association among the variables was used and to compare groups we used one-way ANOVA followed by Bonferroni's post hoc and Kruskal Wallis test followed by Dunn's post hoc. O₃ levels correlated with physical activity (r = 0.25; p = 0.01) but not with age or markers of body composition (p > 0.05). The individuals with high physical fitness that were less exposed to O₃ presented higher CAT activity (p < 0.001), lower TBARS (p < 0.01) and IL-1β concentrations (p < 0.01), higher IL-6 (p < 0.05) and IL-10 concentrations (p < 0.05), lower IL-6:1L-10 ratio (p < 0.05), lower CC16 levels (p < 0.05), and higher HSP70 concentration (p < 0.05). Physical activity could result in higher exposure to O₃ that could partially blunt some exercise adaptations, while high physical fitness improved the antioxidant defense system, systemic inflammatory mediators, and pulmonary toxicity.

Exposure to O3 and NO2 in physically active adults: an evaluation of physiological parameters and health risk assessment

The gaseous air pollutants ozone (O₃) and nitrogen dioxide (NO₂) have a large public health relevance and trigger environmental health risk. On the other hand, despite the health benefits, exercise practices might increase the susceptibility to air pollutants exposure. However, there are innumerous lifestyle factors besides physical activity habits that must be considered in the daily air pollution exposure and are still not fully comprehended. This study aimed to evaluate the effects of O₃ and NO₂ exposure on cardiorespiratory fitness, lipid accumulation product (LAP), and environmental health risk during the entire daily routine of physically active adults that exercise in outdoor and indoor environments. One hundred and twenty healthy young men were assigned to untrained (n = 52), indoor exercise (n = 36), and outdoor exercise (n = 32) groups, following their lifestyle exercise habits, and O₃ and NO₂ were assessed by personal monitoring. Exercised groups demonstrated higher healthy eating index (HEI) (p < 0.001), physical activity (PA) (p < 0.001), metabolic equivalent of task (MET) (p < 0.001), and peak oxygen uptake VO_2peak (p < 0.001), while outdoor group had lower LAP index (p < 0.001) and higher O₃ concentration (p = 0.0442). Environmental health risk demonstrated no difference (p > 0.05). The higher O₃ concentration was positively correlated with the risk quotient (p = 0.003) and MET (p = 0.020), and a negative correlation between LAP and VO_2peak was observed (p < 0.001). In conclusion, physically active individuals might have a lower risk of developing cardiovascular and metabolic diseases despite the higher O₃ concentration exposure, and the exposure during exercise did not represent an additional health risk.

O3 concentration and duration of exposure are factors influencing the environmental health risk of exercising in Rio Grande, Brazil

Ozone (O₃) represents a great threat to human health, contributing to respiratory diseases and premature mortality. This pollutant is often considered a critical pollutant in regions of southern Brazil. Exposure to this pollutant during vigorous physical activity should be the subject of thorough investigations due to the increased ventilation rate and altered breathing pattern present during vigorous physical activity that result in greater inhalation of O₃. Thus, this study aimed to evaluate the health risk of exposure to low, mean, and high concentrations of O₃ during different durations of exercise in the city of Rio Grande (southern Brazil). Healthy young men (n = 45) performed cardiopulmonary exercise testing, and ventilation rate data were collected to predict total ventilation and pollutant inhalation during a 5 km running session. The O₃ concentration in the city of Rio Grande was obtained from data reported by the Copernicus Atmosphere Monitoring Service (CAMS). The environmental health risk was calculated based on the potential intake dose. The lowest, mean, and highest concentrations of O₃ detected during the monitoring period were 32.5, 64.9, and 115.2 µg/m³, respectively. In all evaluated scenarios, there was a toxicological risk (RQ > 1), except when exercising when the O₃ concentration was lowest for the shortest length of time (p < 0.001). As the concentration of O₃ and the duration of the exposure increase, the health risk is increased. Therefore, O₃ concentration and duration of exposure are factors influencing the health risk of exercising. These findings are extremely relevant in cities that have high levels of O₃, such as the city of Rio Grande.

Exposure to fine particulate matter partially counteract adaptations on glucose metabolism, oxidative stress, and inflammation of endurance exercise in rats

BACKGROUND

Long-term exposure to air pollution triggers metabolic alterations along with oxidative stress and inflammation, while exercise interventions are widely used to improve those parameters.

OBJECTIVE

Our study aimed to determine the effects of subchronic exposure to particulate matter 2.5 (PM_2.5) and endurance exercise training on glucose metabolism, oxidative stress, and inflammation of the heart and gastrocnemius muscle of rats.

MATERIAL AND METHODS

Thirty-two male Wistar rats were assigned to 4 experimental groups: Untrained; Endurance training (ET); Untrained + PM_2.5; Endurance training + PM_2.5. Rats exposed to air pollution received 50 µg of PM_2.5 via intranasal instillation daily for 12 weeks. Exercised groups underwent endurance training, consisting in running on an electronic treadmill (70% of maximal capacity, 5 days/week, 5 times/week) for 12 weeks. Glucose metabolism markers, redox state, and inflammatory variables were evaluated in the heart and gastrocnemius muscle.

RESULTS

ET and ET + PM_2.5 group had lower body mass gain and higher exercise capacity, and higher glycogen concentration in the heart and gastrocnemius muscle. In the heart, ET and ET + PM_2.5 groups had higher levels of GSH, and lower TBARS and TNF-α concentrations. In the gastrocnemius muscle, the ET group showed higher leptin and lower TBARS and IL-1β concentrations, ET and ET + PM_2.5 showed higher superoxide dismutase activity and ROS content.

CONCLUSION

PM_2.5 exposure partially blunts metabolic and inflammatory adaptations in heart and gastrocnemius muscle tissues induced by exercise training.

Air pollution concentration and period of the day modulates inhalation of PM2.5 during moderate- and high-intensity interval exercise

The increase in minute ventilation during exercise led to higher inhalation of air pollution and, consequently, to exacerbation of health issues. Therefore, the intensity of exercise and the air pollution concentration of the environment could be determinant variables to poor outcomes. This study aimed to investigate the inhaled dose of particulate matter 2.5 (PM_2.5) during a moderate- and high-intensity interval exercise session performed in the morning and evening at different locations of Porto Alegre City. Eighteen individuals performed a cardiopulmonary exercise test, a moderate-intensity interval exercise (MIIE), and a high-intensity interval exercise (HIIE). Heart rate was monitored to estimate minute ventilation and total ventilation of the session. The concentration of PM_2.5 was measured during the morning (6-8a.m.) and evening (6-8p.m.) by fixed-site monitors placed at five points of Porto Alegre City. The PM_2.5 inhalation during MIIE and HIIE performed in the morning and evening in the monitoring points was estimated. HIIE showed higher minute ventilation (VE) (p = 0.0048) and total ventilation did not differ between groups (p = 0.4648). PM_2.5 concentrations were higher during the mornings (p < 0.001). Monitored point 1 had higher levels of PM_2.5 in the morning and evening (p < 0.001). The inhalation of PM_2.5 in the morning showed no difference in MIIE (p = 0.8172) and HIIE (p = 0.7306) groups among the points. In the evening, the inhalation of PM_2.5 was higher in point 1 in MIIE and HIIE group (p < 0.001). MIIE and HIIE had higher inhalation of PM_2.5 in the morning than in the evening (p < 0.001). Total ventilation of exercise is a crucial factor that contributes to the inhalation dose of air pollution.