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 VO2peak (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 VO2peak 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.