Monk Timothy H, Buysse Daniel J, Begley Amy E, Billy Bart D, Fletcher Mary E
Neuroscience Clinical and Translational Research Center, Western Psychiatric Institute and Clinic, University of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA.
Chronobiol Int. 2009 Apr;26(3):526-43. doi: 10.1080/07420520902821119.
Some of the sleep disruption seen in seniors (>65 yrs) may be due to alteration of the circadian pacemaker phase and/or its phase angle with bedtime. The purpose of this study was to determine the effects of 2 h changes in the timing of bedtime (both earlier and later) on the sleep of seniors. Ten healthy seniors (9 F, 1 M, age 70-82 yrs) were each studied individually during three 120 h sessions (each separated by >2 weeks) in a time-isolation laboratory. On nights 1 and 2, bedtime and rise-time occurred at the subjects' habitual times; on nights 3-5, bedtime was specified by the experiment, but rise-time was at the subjects' discretion (without knowledge of clock time). Under the control condition, subjects went to bed at their habitual bedtime (HBT), under the earlier bedtime condition at (HBT-2 h), and under the later bedtime condition at (HBT+2 h). Sleep was polysomnnographically recorded and rectal temperature continuously monitored. Although total sleep time increased in the earlier compared to the later condition (p<0.01), sleep efficiency decreased and wake after sleep onset increased (p<0.01). Subjective ratings of sleep were also worse under the earlier (HBT-2 h) than under later (HBT+ 2 h) condition (p<0.05). Performance did not differ between the earlier and later conditions. The larger the phase angle between actual bedtime and circadian temperature minimum (Tmin), the longer the time spent in bed and total sleep time, and the worse the sleep efficiency and subjective sleep ratings. There were no effects related to the phase angle between Tmin and rise-time. The relative benefits of longer vs. more efficient sleep in the elderly require further investigation.
在老年人（>65岁）中观察到的一些睡眠中断可能是由于昼夜节律起搏器相位的改变和/或其与就寝时间的相位角变化。本研究的目的是确定就寝时间提前或推迟2小时对老年人睡眠的影响。10名健康老年人（9名女性，1名男性，年龄70 - 82岁）在时间隔离实验室中，分别在三个120小时的时间段（每个时间段间隔>2周）内进行单独研究。在第1和第2晚，就寝时间和起床时间按照受试者的习惯时间；在第3 - 5晚，就寝时间由实验指定，但起床时间由受试者自行决定（受试者不知道时钟时间）。在对照条件下，受试者在其习惯就寝时间（HBT）上床睡觉，在提前就寝条件下在（HBT - 2小时）上床睡觉，在推迟就寝条件下在（HBT + 2小时）上床睡觉。通过多导睡眠图记录睡眠情况，并持续监测直肠温度。与推迟就寝条件相比，提前就寝条件下总睡眠时间增加（p<0.01），但睡眠效率降低，睡眠开始后的觉醒时间增加（p<0.01）。提前（HBT - 2小时）条件下的睡眠主观评分也比推迟（HBT + 2小时）条件下更差（p<0.05）。提前和推迟条件下的表现没有差异。实际就寝时间与昼夜节律体温最低点（Tmin）之间的相位角越大，在床上花费的时间和总睡眠时间越长，睡眠效率和睡眠主观评分越差。Tmin与起床时间之间相位角没有影响。老年人中较长睡眠时间与较高睡眠效率的相对益处需要进一步研究。
