Airborne Ultrafine Particle and Acute Physiological Effects during Maximal Aerobic Power Test

BACKGROUND: The practice of physical exercise in polluted areas could lead to adverse health effects that may contribute to the incidence and/or worsening of respiratory and cardiovascular diseases and some types of cancer. METHODS: Male recreational cyclists performed tests in a manner randomized crossover in two environmental conditions: low (environmental noise exposure) and high ultrafine particle concentration. For each trial, oxygen consumption (VO� 2), carbon dioxide production (VĊO2), respiratory frequency (Rf), tidal volume (Vt), pulmonary ventilation (VE�), and mechanical workload (WL) were measured. Gross efficiency (GE) was determined using the ratio between mechanical power output and metabolic power input. Repeated-measures ANOVA was applied to evaluate differences (P < 0.05) between physiological and mechanical parameters and compare oxygen consumption trends in the two scenarios. RESULTS: HR, Rf, and VE values do not show any significant difference. On the contrary, VO� 2peak increased (P < 0.05) under high exposure (41.6 ± 4.31 mL kg–1 min–1 ), during high-intensity exercise, compared to a low exposure (38.4 ± 4.05 mL kg–1 min–1 ). VO� 2 and GE show differences (p < 0.05) between low and high ultrafine particle concentration conditions during exercise above 80% WLpeak. CONCLUSIONS: Present data suggest that high airborne UFPs levels impair recreational cyclists' gross efficiency