Cerebral oxygenation declines in healthy elderly subjects in response to assuming the upright position.

Abstract

Background and Purpose —With increasing age, assuming the upright position is more often accompanied by symptoms such as dizziness and lightheadedness, possibly as a result of a diminished oxygen supply to the brain due to impaired cerebral autoregulation. We aimed to quantify postural changes in cerebral oxygenation and systemic hemodynamics in healthy elderly and young subjects. Methods —In 18 healthy elderly subjects (aged 70 to 83 years) and 10 healthy young subjects (aged 22 to 45 years), frontal cortical oxygenation and hemodynamic responses were continuously monitored by near infrared spectroscopy and Finapres, respectively, before and during 10 minutes of active standing. Results —Cortical oxyhemoglobin concentration [O ₂ Hb] decreased by −4.6±2.2 μmol/L ( P P 2 Hb] decreases (r =0.53, P Conclusions —Assuming the upright position evokes an asymptomatic decrease in frontal cortical oxygenation in healthy elderly subjects but not in healthy young subjects. Cortical [O ₂ Hb] changes are affected by diastolic BP changes. These findings may indicate that regulation of cerebral oxygenation alters with increasing age.