Inhaled whole exhaust and its effect on exercise performance and vascular function.

Internal combustion engines are a major source of particulate matter (PM) which has been shown to result in vasoconstriction, yet no present study to our knowledge has investigated the effect of exhaust emissions on both exercise performance and the vasculature. To examine the effect of freshly generated whole exhaust on exercise performance, pulmonary arterial pressure (PP), and flow-mediated vasodilation (FMD) of the brachial artery. Sixteen male, collegiate athletes (age: 20.8±1.28 years) were randomly assigned to submaximal exercise for 20min followed by a 6min maximal work accumulation exercise test in either high PM (HPM) or low PM (LPM) conditions on two consecutive days. After a 7-day washout period, subjects completed identical exercise trials in the alternate condition. HPM conditions were generated from a 4-cycle gasoline engine. The participants' PP and FMD were assessed before and after each exercise trial by tricuspid regurgitant velocity and brachial artery imaging, respectively. Total work (LPM: 108.0±14.8 kJ; HPM: 104.9±15.2 kJ, p=0.019) and FMD (LPM: 8.17±6.41%; HPM: 6.59±2.53%; p=0.034) significantly decreased in HPM while PP was significantly increased (LPM: 16.9±1.13 mmHg; HPM: 17.9±1.70 mmHg; p=0.004). A significant correlation was identified between the change in exercise performance and the change in FMD (r=0.494; p=0.026) after the first HPM trial. Exercise performance declined in HPM conditions in part due to impaired vasodilation in the peripheral vasculature.