65岁以上的老人,每4个人中就可有1个人发生体位性低血压。通常当人的体位从卧位变为立位时,有300～800ml 血液郁积在躯干和两下肢而导致心输出量减少和动脉压的下降。位于颈动脉窦和主动脉弓的压力感受器感受了这些变化,并起动代偿机制以保持血压的稳定:如心肌收缩增强、心率加快、小动脉和静脉收缩,随之高血压蛋白原酶、血管紧张素和醛固酮开始分泌。随着年龄的增长,压力感受器的敏感性下降,代偿机能减弱。 People over the age of 65 can have one person with orthostatic hypotension in every 4 people. Often when a person’s position changes from supine position to standing position, 300-800 ml of blood is accumulated on the trunk and both lower limbs resulting in decreased cardiac output and decreased arterial pressure. The baroreceptor located in the carotid sinus and the aortic arch senses these changes and initiates a compensatory mechanism to maintain blood pressure stability: increased myocardial contractions, accelerated heart rate, arteriolar and venous contractions followed by hypertensive proteinase, angiotensin And aldosterone began to excrete. With age, baroreceptor sensitivity decreased, the compensatory function weakened.