Groothuis Jan T, Thijssen Dick H J, Kooijman Miriam, Paulus Rebecca, Hopman Maria T E
Department of Physiology, Institute for Fundamental and Clinical Human Movement Sciences, Radboud University Nijmegen Medical Centre, 6500 HB, Nijmegen, The Netherlands.
Age Ageing. 2008 Nov;37(6):680-4. doi: 10.1093/ageing/afn195. Epub 2008 Oct 1.
orthostatic hypotension is common in older men and associated with morbidity and mortality. During orthostatic challenges, older men maintain their blood pressure by an augmented increase in total peripheral resistance. Changes in the leg vascular bed contribute importantly to blood pressure regulation during orthostatic challenges, partly because of blood pooling in the legs. Little is known about the contribution of the leg vascular bed to the augmented increase in total peripheral resistance.
to examine tilt-induced peripheral vasoconstriction in the leg vascular bed of young and older men.
we measured forearm and calf blood flow in 12 young and 12 older men, using venous occlusion plethysmography during 30 degrees head-up tilt (HUT). Forearm and calf vascular resistance were calculated as mean arterial blood pressure divided by blood flow.
during HUT, calf and forearm vascular resistance increased in older and young men. The increase in forearm vascular resistance was similar between older (40 +/- 6%) and young men (51 +/- 12%). However, the increase in calf vascular resistance was lower in older (96 +/- 15%) than in young men (175 +/- 30%).
advancing age leads to an attenuated tilt-induced increase in calf vascular resistance, which may contribute to age-related orthostatic hypotension.
体位性低血压在老年男性中很常见，且与发病率和死亡率相关。在体位性应激期间，老年男性通过增加总外周阻力来维持血压。腿部血管床的变化在体位性应激期间对血压调节起着重要作用，部分原因是腿部血液淤积。关于腿部血管床对总外周阻力增加的贡献知之甚少。
研究年轻和老年男性腿部血管床中倾斜诱导的外周血管收缩情况。
我们使用静脉阻塞体积描记法，在12名年轻男性和12名老年男性进行30度头高位倾斜（HUT）期间测量前臂和小腿血流量。前臂和小腿血管阻力通过平均动脉血压除以血流量来计算。
在HUT期间，老年和年轻男性的小腿和前臂血管阻力均增加。老年男性（40±6%）和年轻男性（51±12%）的前臂血管阻力增加相似。然而，老年男性（96±15%）的小腿血管阻力增加低于年轻男性（175±30%）。
年龄增长导致倾斜诱导的小腿血管阻力增加减弱，这可能导致与年龄相关的体位性低血压。
