下体负压对脑认知工效及心率、血压的影响

目的　探讨坐位下体负压暴露对脑认知工效及心血管功能的影响 .方法　 1 3名健康青年男性被试者在坐位下体负压 - 4 .0 k Pa,- 6.67k Pa条件下 ,分别测试暴露前、暴露时和卸压后的脑事件相关电位 P3 0 0 、反应时、跟踪误差等工效学指标和心率、血压等生理指标 .结果　在 - 4 .0 k Pa下体负压作用时 ,P3 0 0 波幅、潜时 ,反应时、跟踪误差 ,血压与负压前对照无明显差别 ;心率在下体负压作用 3 min,5 min时 ,显著增快(P<0 .0 1 ) .在 - 6.67k Pa下体负压作用时 ,P3 0 0 波幅降低 (P<0 .0 1 ) ,P3 0 0 潜时延长 (P<0 .0 1 ) ;反应时延长 (P<0 .0 5) ,跟踪误差增大 (P<0 .0 5) ;心率在负压作用 1 ,3和 5min时与负压作用前比较均显著增快 (P<0 .0 1 ) ;收缩压与负压前对照无显著改变 ,舒张压显著升高 (P<0 .0 1 ) .不论是 - 4 .0k Pa还是 - 6.67k Pa下体负压卸压后 ,心率和血压均迅速恢复 ,与负压前对照无明显差异 .结论　坐位下体负压造成血液在下肢积聚 ,引起大脑供血量减少 ,从而引起大脑对外界刺激的反应减慢 ,脑认知工效下降 ,同时心血管部分代偿功能加强 ,心率加快 ,血压升高

Effects of lower body negative pressure on human brain cognitive ergonomics hear t rate and blood pressure

AIM To investigate the effects of different lower body negative pressure (LBNP) in upright seated position on human brain cognitive ergonomics and cardiovascular function. METHODS Thirteen young men were selected as subjects. P 300 amplitude and latency, reaction time (RT) , tracking error (TrE), heart rate (HR) and blood pressure (BP) were measured during LBNP of -4.0 kPa and -6.67 kPa in upright seated position. RESULTS Under -4.0 kPa LBNP, P 300 amplitude and latency, RT, TrE and blood pressure had no significant differences compared with control. Whereas HR increased at 3, 5 min during LBNP ( P <0.01). Under -6.67 kPa LBNP, P 300 amplitude decreased ( P <0.01). P 300 latency and RT delayed ( P <0.01, P <0.05). TrE increased ( P <0.05). HR increased ( P <0.01). Diastolic pressure rose ( P <0.01), but systolic pressure had no significant changes. After LBNP of -4.0 or -6.67 kPa was released, HR and BP recovered rapidly. CONCLUSION LBNP can cause blood pooling in lower body so that brain blood supply decreases. Then brain reaction to ambient stimuli becomes slow and brain cognitive ergonomics decreases. Meanwhile cardiovascular compensation function enhances, HR increases and BP rises.