Vascular effects of physical activity are not modified by short-term inhaled diesel exhaust: Results of a controlled human exposure study

The combined effects of physical activity and air pollution exposure on vascular function are insufficiently understood, particularly after the inhalation of a β2-agonist, a vasodilating agent. To assess the micro- and macrovascular response to physical activity after β2-agonist use while breathing diesel exhaust (DE) in individuals with exercise-induced bronchoconstriction. On four exposure visits, eighteen adults inhaled either 400 μg of the β2-agonist salbutamol or placebo before resting for 60 min, followed by a 30-min cycling bout. During rest and cycling, participants inhaled filtered air (FA) or DE (300 μg/m3 of PM2.5). Microvascular (central retinal arteriolar and venular equivalents, CRAE and CRVE, respectively) and macrovascular parameters (blood pressure (BP)) and heart rate (HR)) were assessed at baseline (T1), 10 min (T2) and 70 min (T3) after cycling. The cycling bout increased CRAE (T2-T1 difference (95th % confidence interval): 4.88 μm (4.73, 5.00 μm), p