Lane J D, Adcock R A, Burnett R E
Department of Psychiatry, Duke University Medical Center, Durham, NC 27710.
Psychophysiology. 1992 Jul;29(4):461-70. doi: 10.1111/j.1469-8986.1992.tb01720.x.
The parasympathetic nervous system provides mechanisms that could attenuate sympathetically mediated heart rate stress responses and might have even more general antagonistic actions on stress reactivity. Individuals characterized by higher levels of parasympathetic tone might, through such mechanisms, be less reactive when stimuli elicit sympathetically mediated responses. Respiratory sinus arrhythmia (RSA) is considered to be a noninvasive index of cardiac parasympathetic (vagal) tone. The present study investigated whether individual differences in RSA level at rest could predict variations among individuals in the magnitude of cardiovascular responses to psychological stress. None of the measures of resting respiratory sinus arrhythmia, derived from spectral analysis of beat-to-beat changes in resting heart rate, predicted the observed variations in cardiovascular task reactivity. However, scores reflecting respiratory sinus arrhythmia as the percentage of total heart rate variability (RSAnorm) were negatively correlated with blood pressure levels, both at rest and during the task. Furthermore, subjects with higher scores for RSAnorm demonstrated a faster adaptation of heart rate responses during stress, which suggests the development of parasympathetic antagonism to ongoing sympathetic arousal. Although a simple relationship between respiratory sinus arrhythmia and reactivity was not observed, these results encourage further investigation of RSA measures as psychophysiological indices of individual differences in parasympathetic (vagal) cardiac tone, or perhaps of general parasympathetic/sympathetic balance, which could modulate the expression of potentially pathogenic stress responses.
副交感神经系统提供了一些机制，这些机制可以减弱交感神经介导的心率应激反应，并且可能对应激反应性具有更广泛的拮抗作用。具有较高副交感神经张力水平的个体，可能通过这些机制，在刺激引发交感神经介导的反应时反应性较低。呼吸性窦性心律不齐（RSA）被认为是心脏副交感神经（迷走神经）张力的一种非侵入性指标。本研究调查了静息时RSA水平的个体差异是否能够预测个体对心理应激的心血管反应强度的变化。从静息心率逐搏变化的频谱分析得出的静息呼吸性窦性心律不齐的各项测量指标，均无法预测所观察到的心血管任务反应性的变化。然而，反映呼吸性窦性心律不齐占总心率变异性百分比的分数（RSAnorm），在静息和任务期间均与血压水平呈负相关。此外，RSAnorm得分较高的受试者在应激期间心率反应的适应速度更快，这表明副交感神经对持续的交感神经兴奋产生了拮抗作用。尽管未观察到呼吸性窦性心律不齐与反应性之间存在简单的关系，但这些结果鼓励进一步研究将RSA测量作为副交感神经（迷走神经）心脏张力个体差异的心理生理指标，或者可能作为一般副交感神经/交感神经平衡的指标，这可能会调节潜在致病性应激反应的表达。
