HOW DO THE TIMING AND LENGTH OF A NIGHT-SHIFT NAP AFFECT SLEEP INERTIA?
HOW DO THE TIMING AND LENGTH OF A NIGHT-SHIFT NAP AFFECT SLEEP INERTIA?
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DOI：
10.3109/07420528.2010.489502
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发表时间：
2010-01-01
影响因子：
2.8
通讯作者：
Itani, Toru
中科院分区：
文献类型：
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作者：
Kubo, Tomohide;Takahashi, Masaya;Itani, Toru
午睡是帮助上夜班的人克服困倦和疲劳的一种策略。然而，午睡的一个潜在缺点是，从午睡中醒来会受到睡眠惰性的干扰，这也被发现会短暂地损害表现和/或情绪。作者在实验室环境中研究了夜班小睡的时间和时间对睡眠惯性的影响。12名男大学生(平均+/-SD：21.6+/-2.8岁)参加了为期3天的实验，包括模拟夜班(22：00-08：00h)和第二天(11：30-17：30h)和夜间睡眠(00：00-07：00h)。模拟夜班被设计为包括五种情况之一(四种午睡/一种不午睡)。打盹的时间和持续时间不同：00：00-01：00h(早60min；E60)、00：00-02：00h(早120min；E120)、04：00-05：00h(晚60min；L60)、04：00-06：00h(晚120min；1120)。参与者按平衡顺序完成所有实验条件。在模拟换班期间记录直肠温度(R(T))，并在午睡期间记录多导睡眠图(PSG)。在每次午睡之前和之后，参与者被要求完成视觉模拟量表(VAS)以评估困倦程度和视觉警觉性测试(VVT)。在模拟夜班期间，除午睡时间外，每小时重复一组任务(英语转录任务、性能测试电池和休息时间)。对每种午睡状态下的视觉模拟评分和视觉诱发电位结果进行双向重复测量方差分析(午睡与不午睡[午睡与不午睡]×时间点[午睡前与午睡后])。对PSG和RT数据进行单因素方差分析。在L60 NAP状态下，观察到RTS和VVT的轻微显著交互作用(分别为p=.071和p=.070)。然而，这些效应大小是中等的(偏等效应系数(2)分别为0.266、0.268)。事后分析显示，与不午睡相比，L60午睡后的RTS(p<；0.05)和更多的失误(p<；0.05)显著延长。相比之下，L60或任何其他午睡条件与不午睡条件之间的困倦程度没有显著差异。我们的发现表明，在L60状态下，睡眠惯性对VVT表现的影响是深远的，尽管VAS自我报告没有对困倦产生显著影响。表现和困倦之间的分离可能反映了一种不稳定的状态，参与者无法感知到他们表现的下降。目前的发现在职业安全方面具有重要意义；实际意义是，在夜班的04：00到05：00之间小睡一小时需要非常小心。(作者通讯：Kubo@h.jniosh.go.jp)
Napping is one strategy that may assist night shiftworkers to cope with sleepiness and fatigue. However, one potential disadvantage of napping is that awakening from naps is disturbed by sleep inertia, which has also been found to impair performance and/or mood, transiently. The authors examined the effects of the timing and length of a night-shift nap on sleep inertia in a laboratory setting. Twelve male university students (mean +/- SD: 21.6 +/- 2.8 yrs) participated in this 3-day experiment, during which included a simulated night shift (22:00-08:00 h) and subsequent day (11:30-17:30 h) and night sleep (00:00-07:00 h). The simulated night shift was designed to include one of five (four nap/one no-nap) conditions. The napping conditions differed by their timing and duration:00:00-01:00 h (Early 60 min; E60), 00:00-02:00 h (Early 120 min; E120), 04:00-05:00 h (Late 60 min; L60), 04:00-06:00 h (Late 120 min; L120). Participants completed all the experimental conditions in a counterbalanced order. Rectal temperature (R(T)) was recorded throughout the simulated shift and polysomnography (PSG) was recorded during the nap period. Immediately before and after each nap, participants were required to complete a visual analogue scale (VAS) to assess sleepiness and a visual vigilance test (VVT). During the simulated night shift, a set of tasks (an English transcription task, a performance test battery, and a break) was repeated hourly, except during the periods of napping. For each nap condition, the VAS and VVT (reaction time [RT]; lapses >5 s) results were analyzed by two-way, repeated-measures analysis of variance (ANOVA) (nap [nap versus no-nap] x time point [pre-nap versus post-nap]). PSG and RT data were analyzed with one-way repeated-measures ANOVA. Marginally significant interactions were observed for RTs and lapses in VVT for the L60 nap condition (p = .071 and p = .070, respectively). However, those effect sizes were moderate (partial eta(2) = 0.266, 0.268, respectively). Post hoc analyses showed significantly longer RTs (p < .05) and more lapses (p < .05) following the L60 nap compared with no nap. In contrast, there was no significant difference in sleepiness between the L60, or any of the other nap conditions, and the no-nap condition. Our findings suggest the effect of sleep inertia on VVT performance was profound in the L60 condition, although no significant effects on sleepiness were self-reported by VAS. The dissociation between performance and sleepiness might reflect an unstable state where participants cannot perceive decline in their performance. The present findings are significant in terms of occupational safety; the practical implication is that great care is needed when taking a 1-h nap between 04: 00 and 05: 00 h on the night shift. (Author correspondence: kubo@h.jniosh.go.jp)