Department of General Psychology, University of Padova, Italy.
J Sleep Res. 2011 Jun;20(2):318-25. doi: 10.1111/j.1365-2869.2010.00871.x.
The transition from wakefulness to sleep is characterized typically by a shift from sympathetic to parasympathetic regulation. Physiological functions, depending on the neurovegetative system, decrease overall. Previous studies have shown cardiovascular and electroencephalographic hyperactivity during wakefulness and sleep in insomniacs compared with normal sleepers, but there is very little evidence of this in the process of sleep onset. The purpose of this study was to compare cardiovascular and autonomic responses before and after falling asleep in eight insomniacs (who met DSM-IV criteria for primary insomnia) and eight normal sleepers. Non-invasive measures of heart rate (HR), stroke volume (SV), cardiac output (CO) and pre-ejection period (PEP) were collected by impedance cardiography during a night of polysomnographic recording. Frequency domain measures [low-frequency (LF), high-frequency (HF)] of heart rate variability (HRV) were also estimated. Decrements in HR and CO and increases in SV and HF normalized units (n.u.) were found in both groups after sleep onset compared with wakefulness. Conversely, PEP (related inversely to sympathetic β-adrenergic activity) showed increases after sleep onset in controls, but remained unchanged in insomniacs. PEP was also significantly lower in insomniacs than in normal sleepers in both conditions. These data suggest that, whereas normal sleepers follow the expected progressive autonomic drop, constant sympathetic hyperactivation is detected in insomniacs. These results support the aetiological hypothesis of physiological hyperarousal underlying primary insomnia.
从觉醒到睡眠的过渡通常表现为从交感神经调节向副交感神经调节的转变。依赖于自主神经系统的生理功能总体上会下降。先前的研究表明，与正常睡眠者相比，失眠症患者在觉醒和睡眠期间心血管和脑电图活动会增加，但在睡眠开始过程中，这方面的证据非常少。本研究旨在比较 8 名失眠症患者（符合 DSM-IV 原发性失眠标准）和 8 名正常睡眠者在入睡前后的心血管和自主神经反应。通过阻抗心动描记术在一整夜的多导睡眠记录期间收集心率（HR）、每搏量（SV）、心输出量（CO）和射血前期（PEP）的非侵入性测量值。还估计了心率变异性（HRV）的频域测量值[低频（LF）、高频（HF）]。与觉醒相比，两组在入睡后 HR 和 CO 均降低，SV 和 HF 归一化单位（n.u.）增加。相反，PEP（与交感β-肾上腺素能活性呈反比）在对照组中入睡后增加，但在失眠症患者中保持不变。在两种情况下，失眠症患者的 PEP 也明显低于正常睡眠者。这些数据表明，尽管正常睡眠者遵循预期的自主神经逐渐下降，但在失眠症患者中检测到持续的交感神经兴奋。这些结果支持原发性失眠症生理唤醒过度的病因假说。
