Outdoor exercise with different PM2,5 concentrations exposure and heart rate variability effects in healthy individuals, São Paulo, Brazil

Introduction: Outdoor exercise is a common activity that may increase the load of inhaled pollutants. However, the effects in healthy human are not fully clarified. Objectives: To evaluate the effect of physical exercises in different PM 2.5 concentrations in Heart Rate Variability (HRV) in young healthy non-smokers. Methods: 33 regular street runners age 19±1 years old, entered into the study and performed morning running (8-9 A.M.) of 7.5 km of distance, one week in a circuit on a Park (Pk) and another in a circuit on Public Roads (PR). We recorded HRV before (15 minutes at rest) and during running (45 minutes) on Mondays and Fridays, with a Heart Rate (HR) monitor, Polar RS800. During races individual monitoring of PM 2.5 concentrations and environmental temperature were carried out. Descriptive, univariate and multivariate analyzes using mixed effects model were performed. Results: The concentration of PM 2.5 on Pk and PR circuits were 24.0µg/m³ (IQR:11-39) and 53.0µg/m³ (IQR:37-82), respectively (p Conclusions: The exercises at different environmental PM 2.5 concentrations exert different significant effects on HRV, with small magnitude, that is not likely to have clinical implications in young healthy population.