Chronic low blood pressure (hypotension) is accompanied by symptoms such as fatigue, reduced drive, faintness, dizziness, cold limbs, and concentration difficulties. The study explored the involvement of aberrances in autonomic cardiovascular control in the origin of this condition. In 40 hypotensive and 40 normotensive subjects, impedance cardiography, electrocardiography, and continuous blood pressure recordings were performed at rest and during stress induced by mental calculation. Parameters of cardiac sympathetic control (i.e., stroke volume, cardiac output, pre-ejection period, total peripheral resistance), parasympathetic control (i.e., heart rate variability), and baroreflex function (i.e., baroreflex sensitivity) were obtained. The hypotensive group exhibited markedly lower stroke volume, heart rate, and cardiac output, as well as higher pre-ejection period and baroreflex sensitivity than the control group. Hypotension was furthermore associated with a smaller blood pressure response during stress. No group differences arose in total peripheral resistance and heart rate variability. While reduced beta-adrenergic myocardial drive seems to constitute the principal feature of the autonomic impairment that characterizes chronic hypotension, baroreflex-related mechanisms may also contribute to this state. Insufficient organ perfusion due to reduced cardiac output and deficient cardiovascular adjustment to situational requirements may be involved in the manifestation of bodily and mental symptoms.

中文翻译：

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慢性低血压下静息时和压力时的自主性心血管失调

慢性低血压（低血压）伴有疲劳，驱动力下降，晕厥，头晕，四肢发冷和注意力不集中等症状。该研究探讨了这种疾病起源中异常与自主性心血管控制的关系。在40名血压正常的受试者和40名血压正常的受试者中，在静息时以及在精神计算引起的压力下进行了阻抗心动图，心电图和连续血压记录。获得了心脏交感神经控制参数（即中风量，心输出量，射血前期，总外周阻力），副交感神经控制参数（即心率变异性）和压力反射功能（即压力反射敏感性）。降压组的中风量，心率和心输出量明显降低，以及射血前期和压力反射敏感性高于对照组。低血压还与压力期间较小的血压反应有关。总外周阻力和心率变异性未出现组差异。虽然减少的β-肾上腺素能心肌驱动似乎构成了以慢性低血压为特征的自主神经功能障碍的主要特征，但压力反射相关的机制也可能导致这种状态。心脏和精神症状的表现可能归因于心排血量减少和对情况的适应性心血管调节不足引起的器官灌注不足。总外周阻力和心率变异性未出现组差异。虽然减少的β-肾上腺素能心肌驱动似乎构成了以慢性低血压为特征的自主神经功能障碍的主要特征，但压力反射相关的机制也可能导致这种状态。心脏和精神症状的表现可能归因于心排血量减少和对情况的适应性心血管调节不足引起的器官灌注不足。总外周阻力和心率变异性未出现组差异。虽然减少的β-肾上腺素能心肌驱动似乎构成了以慢性低血压为特征的自主神经功能障碍的主要特征，但压力反射相关的机制也可能导致这种状态。心脏和精神症状的表现可能归因于心排血量减少和对情况的适应性心血管调节不足引起的器官灌注不足。