Effects of aging on the cerebrovascular orthostatic response

When healthy subjects stand up, it is associated with a reduction in cerebral blood velocity and oxygenation although cerebral autoregulation would be considered to prevent a decrease in cerebral perfusion. Aging is associated with a higher incidence of falls, and in the elderly falls may occur particularly during the adaptation to postural change. This study evaluated the cerebrovascular adaptation to postural change in 15 healthy younger (YNG) vs. 15 older (OLD) subjects by recordings of the near-infrared spectroscopy-determined cerebral oxygenation (cO2Hb) and the transcranial Doppler-determined mean middle cerebral artery blood velocity (MCA Vmean). In OLD (59 (52-65) years) vs. YNG (29 (27-33) years), the initial postural decline in mean arterial pressure (−52 ± 3% vs. −67 ± 3%), cO2Hb (−3.4 ± 2.5 μmol l−1 vs. −5.3 ± 1.7 μmol l−1) and MCA Vmean (−16 ± 4% vs. −29 ± 3%) was smaller. The decline in MCA Vmean was related to the reduction in MAP. During prolonged orthostatic stress, the decline in MCA Vmeanand cO2Hb in OLD remained smaller. We conclude that with healthy aging the postural reduction in cerebral perfusion becomes less prominent.