Sleep Length and Circadian Regulation in Humans

描述(申请人提供)：数以百万计的美国人患有昼夜节律睡眠障碍，包括轮班工作睡眠障碍、时差、睡眠相延迟综合症，可能还有冬季抑郁症。这些情况的典型特征是持续失眠和/或白天过度嗜睡，表现不佳，以及胃肠道不适。这些负面症状是由于外部社会世界的时间与体内生物钟的时间不一致造成的。强光可以有效地治疗昼夜节律睡眠障碍，它会使生物钟发生相移，从而使其与外部社交世界的时间重新调整。人们普遍认为，社会影响导致了现代社会中越来越普遍的睡眠限制。我们最近首次证明，与长睡眠相比，短睡眠显著地减少了向明亮光线的相位推进。因此，当人们缩短睡眠时间时，他们会无意中降低他们对明亮光线的昼夜反应。这些减少到光的相移背后的机制(S)尚不清楚。然而，至少有两个方面的短时睡眠可能会导致这种效果。首先，短时睡眠与部分睡眠不足有关。其次，由于人类睡觉时眼睛是闭着的，醒着时通常会暴露在阳光下，所以短时间的睡眠也与短时间的黑暗有关。我们的总体目标是确定生物行为机制，通过这些机制，短暂的睡眠会损害从相变到明亮光线的转变。具体目标1是确定部分睡眠剥夺对向光明阶段推进的影响，同时控制黑暗的长度。具体目标2是确定在最大限度地减少睡眠剥夺的同时，较短的黑暗长度对向光明阶段推进的影响。我们将通过测量唾液褪黑素(一种从松果体释放的神经内分泌激素)来估计人类生物钟的时间，并通过活动记录仪收集睡眠指标，通过计算机评估收集睡眠、情绪、胃肠道不适和认知表现。表征睡眠剥夺和黑暗长度对人类昼夜相移到光的单独影响对于理解人类在日常生活活动中如何对光做出反应至关重要。此外，这项研究的结果将为避免减少到相移到光，从而优化昼夜节律睡眠障碍的强光治疗，从而改善公共健康和安全，幸福感，情绪，认知功能和生活质量提供重要而实用的建议。

DESCRIPTION (provided by applicant): Millions of Americans suffer from circadian rhythm sleep disorders, which include shift work sleep disorder, jet lag, delayed sleep phase syndrome and possibly winter depression. These conditions are typically characterized by persistent insomnia and/or excessive daytime sleepiness, impaired performance, and gastrointestinal distress. These negative symptoms result from a misalignment between the timing of the external social world and the timing of the internal circadian (body) clock. Circadian rhythm sleep disorders are effectively treated with bright light, which phase shifts the circadian clock, thereby realigning it with the timing of the external social world. It is widely recognized that social influences have led to an increasing prevalence of sleep restriction in modern society. We recently demonstrated for the first time that short sleep episodes, when compared to long sleep episodes, markedly reduce phase advances to bright light. Thus when people cut their sleep short, they inadvertently reduce their circadian responsiveness to bright light. The mechanism(s) behind these reduced phase shifts to light are unknown. However, there are at least two aspects of short sleep episodes that could be responsible for this effect. First, short sleep episodes are associated with partial sleep deprivation. Second, as humans sleep with their eyes closed and are usually exposed to light when awake, short sleep episodes are also associated with short dark lengths. Our overall goal is to determine the biobehavioral mechanisms by which short sleep episodes impair phase shifts to bright light. Specific Aim 1 is to determine the effect of partial sleep deprivation on phase advances to light, while controlling for dark length. Specific Aim 2 is to determine the effect of short dark lengths on phase advances to light while minimizing sleep deprivation. We will estimate the timing of the human circadian clock by measuring salivary melatonin, a neuroendocrine hormone released from the pineal gland, and collecting measures of sleep via actigraphy, and sleepiness, mood, gastrointestinal distress and cognitive performance via computerized assessment. Characterization of the separate effects of sleep deprivation and dark length on circadian phase shifts to light in humans is critical to understanding how humans respond to light during their daily life activities. Furthermore, the findings of this research will produce important and practical recommendations for avoiding decrements to phase shifts to light, thereby optimizing the bright light treatment of circadian rhythm sleep disorders, and thus improving public health and safety, well-being, mood, cognitive function, and quality of life.