Age, aerobic fitness, and cerebral perfusion during exercise: role of carbon dioxide.

摘要: Middle cerebral artery mean velocity (MCAvmean) is attenuated with increasing age both at rest and during exercise. The aim of this study was to determine the influence age-dependent reduction in arterial Pco2 (PaCO2) physical fitness herein. We administered supplemental CO2 (CO2 trial) or no additional gas (control inspired air a blinded randomized manner, assessed middle flow graded exercise 1) 21 young [Y; 24 ± 3 yr (±SD)] volunteers whom 11 were trained (YT) 10 considered untrained (YUT), 2) 17 old (O; 66 4 yr) 8 9 (OT) (OUT), respectively. A resting hypercapnic reactivity test also performed. MCAvmean PaCO2 lower O [44.9 3.1 cm/s 30 1 mmHg (±SE)] compared Y (59.3 2.3 34 mmHg, P < 0.01) rest, independent aerobic level. age-related decreases persisted Supplemental reduced age-associated decline by 50%, suggesting that major component decline. On other hand, relative neither influenced (P = 0.46) nor 0.36). Although exercise-induced oxygenation (near-infrared spectroscopy), did not performance. In conclusion, contributes exercise; however capacity diminish effect.