PHYSIOLOGICAL MODIFICATIONS INDUCED BY ACUTE AIRBORNE PARTICLE EXPOSURE DURING HIGH INTENSITY EXERCISE

Introduction In industrialized countries most common physical activities usually occurs in urban microenvironments with high levels of airborne particles (PM10) concentrations. Exercising in polluted urban areas increases particles inhaled amount as a result of the increased minute ventilation (Carlisle and Sharp, 2001). Since there is a lack of studies investigating acute physiological effects of high PM10 levels, this study aimed to assess physiological parameters during incremental maximal aerobic tests on a cycloergometer under low and high PM10 exposures. Methods Following informed consent, 9 male amateur cyclists performed 2 tests for each environmental condition: low and high PM10 concentration. Exposure scenarios were replicated using a fully controlled environmental chamber. Peak oxygen consumption (VO2peak), carbon dioxide production (VCO2peak), respiratory frequency (RFpeak), tidal volume (VTpeak), pulmonary ventilation (VEpeak), hearth rate (HRpeak) and mechanical power output (Ppeak) values were recorded for each trial. Gross efficiency (GE) was determined using the ratio between mechanical power output and metabolic power input. T-test was applied to evaluate differences (p<0.05) between physiological parameters. Results According to trial protocol, all subjects achieved equal mechanical power (Ppeak) in the 4 incremental tests. No significant differences in HRpeak, RFpeak and VEpeak were found. VTpeak increased (p<0.05) under high exposure (39.69 ± 8.12 ml•kg-1) compared to low exposure (38.16 ± 6.75 ml•kg-1). Differences (p<0.05) for VO2peak were found between low (38.39 ± 4.05 ml•kg-1•min-1) and high particles concentration conditions (41.68 ± 4.31 ml•kg-1•min-1). Since same mechanical work was expressed while significant VO2peak differences were recorded, GE reduced (p<0.02) during sustained exercise under high PM10 concentrations (21.47 ± 1.74 %) compared to low (23.24 ± 1.35 %) with a mean difference of 1.77%. Discussion The present findings indicate that during high intensity exercise GE is affected by high PM10 concentrations. As GE is defined one of the most important functional abilities of cyclists (Coyle, 1995), results suggest that cyclist’s athletic performances are impaired by polluted microenvironments. References Carlisle AJ, Sharp NC. (2001) Exercise and outdoor ambient air pollution. Br J Sports Med 35(4), 214–22. Coyle EF. (1995) Integration of the physiological factors determining endurance performance ability. Exerc Sports Sci Rev 23, 25-64.