Youngstedt Shawn D, Kripke Daniel F, Elliott Jeffrey A, Rex Katharine M
Department of Exercise Science, Norman J. Arnold School of Public Health, University of South Carolina, Columbia, SC 29208, USA.
J Circadian Rhythms. 2005 Sep 9;3:11. doi: 10.1186/1740-3391-3-11.
Our aims were to examine the influence of different bright light schedules on mood, sleep, and circadian organization in older adults (n = 60, ages 60-79 years) with insomnia and/or depression, contrasting with responses of young, healthy controls (n = 30, ages 20-40 years).
Volunteers were assessed for one week in their home environments. Urine was collected over two 24-hour periods to establish baseline acrophase of 6-sulphatoxymelatonin (aMT6s) excretion. Immediately following home recording, volunteers spent five nights and four days in the laboratory. Sleep periods were fixed at eight hours in darkness, consistent with the volunteers' usual sleep periods. Volunteers were randomly assigned to one of three light treatments (four hours per day) within the wake period: (A) two hours of 3,000 lux at 1-3 hours and 13-15 hours after arising; (B) four hours of 3,000 lux at 6-10 hours after arising; (C) four hours of dim placebo light at 6-10 hours after arising. Lighting was 50 lux during the remainder of wakefulness. The resulting aMT6s acrophase was determined during the final 30 hours in the laboratory.
Neither mood nor total melatonin excretion differed significantly by treatment. For the three light treatments, significant and similar phase-response plots were found, indicating that the shift in aMT6s acrophase was dependent upon the circadian time of treatment. The changes in circadian timing were not significantly correlated to changes in sleep or mood.
The trial failed to demonstrate photoperiodic effects. The results suggest that even low levels of illumination and/or fixed timing of behavior had significant phase-shifting effects.
我们的目的是研究不同的强光照射时间表对患有失眠和/或抑郁症的老年人（n = 60，年龄60 - 79岁）的情绪、睡眠和昼夜节律组织的影响，并与年轻健康对照组（n = 30，年龄20 - 40岁）的反应进行对比。
志愿者在其家庭环境中接受为期一周的评估。在两个24小时时间段内收集尿液，以确定6 - 硫酸氧褪黑素（aMT6s）排泄的基线峰值相位。在家中记录之后，志愿者在实验室度过五个晚上和四天。睡眠时间固定为黑暗环境下的八小时，与志愿者通常的睡眠时间一致。志愿者在清醒期被随机分配到三种光照治疗之一（每天四小时）：（A）起床后1 - 3小时和13 - 15小时接受两小时3000勒克斯光照；（B）起床后6 - 10小时接受四小时3000勒克斯光照；（C）起床后6 - 10小时接受四小时昏暗的安慰剂光照。其余清醒时间的光照强度为50勒克斯。在实验室的最后30小时内确定最终的aMT6s峰值相位。
不同治疗组之间的情绪和总褪黑素排泄均无显著差异。对于三种光照治疗，发现了显著且相似的相位反应图，表明aMT6s峰值相位的变化取决于治疗的昼夜时间。昼夜节律时间的变化与睡眠或情绪的变化无显著相关性。
该试验未能证明光周期效应。结果表明，即使是低水平的光照和/或固定的行为时间也具有显著的相位转移效应。
