The impact of pulmonary and peripheral vascular change from fine and ultrafine particulate matter inhalation on exercise performance

Introduction: Particulate matter (PM) inhalation has been associated with increased morbidity and mortality among susceptible populations, however, only recently has athletic performance among healthy subjects been investigated. PM inhalation has been shown to result in vasoconstriction of both the pulmonary and peripheral vasculature, yet no present study has investigated both the effects of PM inhalation on performance and its effect on the vasculature. The purpose of this study was to determine if the inhalation fine and ultrafine particulate matter (PM1) would result in decreased athletic performance and what the effects would be on the pulmonary and peripheral vasculature. Methods: Sixteen volunteer participants were randomly assigned to two consecutive workouts (separated by 24 hr) in either high PM (HPM) or low PM (LPM) conditions. HPM conditions were created through freshly generated PM from a 4-cycle gasoline engine. Following a seven day washout period, subjects returned to complete a second set of exercise bouts in a different condition. The participants' pulmonary pressures and flow-mediated vasodilation (FMD) were assessed before and after each exercise bout. Results: Exercise performance in HPM conditions was significantly lower than that in LPM conditions (p = 0.019). Pulmonary pressure was significantly increased (p = 0.043) after a single bout of exercise in HPM conditions among participants with baseline pressures exceeding 16.00 mmHg, while pressures were significantly greater (p < 0.001) among all participants after the second bout of exercise in HPM compared to their initial baseline measurement taken approximately 24 hr prior. FMD measurements also taken after the second bout of exercise in HPM were significantly decreased (p = 0.023) compared to the initial baseline. Conclusion: Exercise performance was significantly lower under HPM conditions, even during the initial exercise bout after a brief 20 min exposure. It appears as though both increased PP and impaired vasodilation contributed to the decreased performance observed during the HPM exposures. The impact of HPM inhalation appeared to have an immediate impact on the pulmonary vasculature, while a response in the peripheral vasculature was more delayed. The changes in PP and FMD are consistent with a progressive, dose-dependent inflammatory process.