反复体位改变训练可提高人体头低位耐力

REPEATED BODY POSITION CHANGE TRAINING CAN IMPROVE HUMAN HEAD-DOWN TILT TOLERANCE

目的:检验反复体位改变训练可提高人体头低位耐力的假设是否正确。方法:6名青年男性被试者经受了为期11 d、共9次反复体位改变训练。在训练前、后分别评价被试者对-30°/30 min头低位倾斜(head-down tilt,HDT)的反应,记录症状、心率、血压、颈部血流等主客观指标。结果:①训练后,被试者在HDT中的反应得到了改善,表现为与训练前相比,HDT中的不良症状明显减轻(症状得分1.00±0.63vs6.00±3.79,P<0.05),心率降低的幅度明显增加(-4.4±3.6vs-0.6±2.5,P<0.01);②训练前,被试者在HDT中,颈内静脉血流与仰卧位比较明显减少(P<0.01),初期颈内动脉血流明显增加(P<0.01),颈总动脉血流呈现增加的趋势;训练后,被试者在HDT中,颈内静脉血流与仰卧位比较无显著差别,颈内动脉血流呈现先升后降的趋势,颈总动脉血流呈现降低的趋势。结论:反复体位改变训练可提高人体头低位耐力;血液头向转移得到抑制是反复体位改变训练提高头低位耐力的主要机制。

Aim： To verify the hypothesis that repeated body position change training can improve human head-down tilt （HDT） tolerance. Methods： Six young healthy subjects were trained with repeated position change for 9 times and 11 days according to protocol of alternative head-down and head-up tilts, each time of training lasted for about 35 min. Their HDT tolerance （ - 30＊/30 min） were determined before and after training. Results： （1）Compared with the data before training, subjects＇ symptom scores during HDT test after training decreased significantly（6.00 ± 3.79 vs 1.00 ± 0.63, P 〈 0.05）, magnitude of the decreased heart rate increased significantly（ - 0.6 ± 2.5 vs - 4.4 ± 3.6, P〈 0.01 ）. （2）Before training, blood flow volume of internal jugular vein（IJV） during HDT decreased significantly and that of internal carotid artery（ICA） increased significantly at the beginning period of HDT compared with pre-HDT（P〈0.01）, while blood flow volume of the common carotid artery（CCA） presented increasing trend. After training, there was no significant difference in blood flow volume of IJV between during HDT and pre-UDT, that of ICA and CCA presented decreasing trend in the final period of HDT compared with Pre-HDT.Concusion： Repeated body position change training can improvehuman head-down tilt tolerance. And its main causation is that headward shift of blood volume is restrained to some extend during HDT after training.