To investigate the effects of combinations of brief naps (a 90- followed by a 30-min nap vs. a 30- followed by a 90-min nap) on sleep inertia, reducing sleepiness and fatigue, and maintaining performance during night hours. This randomized, comparative, repeated-measure, cross-over study investigated subjective and cognitive performance in 12 healthy females, evaluated in three experimental nap conditions: 1) from 22:30 to 00:00 and 02:30 to 03:00 (Pre90-NAP group), 2) from 23:30 to 00:00 and 02:30 to 04:00 (Pre30-NAP) group, and 3) no naps (NO-NAP group). Participants’ body temperature, psychomotor vigilance task (PVT) and Uchida-Kraepelin test (UKT) scores, and subjective feelings of drowsiness and fatigue were evaluated. Sleep state was determined by an actigraphy monitoring device worn by participants. Regardless of timing, both 90-min naps were associated with sleep inertia, and both 30-min naps with minimal sleep inertia. Reaction times were shorter and fewer errors were committed at 2 h post-nap in the Pre30-NAP and Pre90-NAP groups compared with those at the same time in the NO-NAP group. Adding a 90-min nap to a 30-min nap reduced subjective fatigue and shortened reaction times, and adding a 30-min nap to a 90-min nap was effective in maintaining performance, suggesting a synergistic effect. Taking two naps during a night work can mitigate sleepiness and fatigue, and maintain performance. A 90- followed by a 30-min nap reduced fatigue and reaction time, and a 30- followed by a 90-min nap maintained cognitive performance in the early morning.

中文翻译：

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90 分钟小睡后 30 分钟可减轻疲劳，而小睡 30 分钟后小睡 90 分钟可维持夜间工作中的认知表现：一项随机交叉试点研究

旨在研究短暂小睡组合（90 分钟后小睡 30 分钟与 30 分钟后小睡 90 分钟）对睡眠惰性、减少困倦和疲劳以及保持夜间表现的影响。这项随机、比较、重复测量、交叉研究调查了 12 名健康女性的主观和认知表现，并在三种实验性午睡条件下进行评估：1) 22:30 至 00:00 和 02:30 至 03:00（Pre90） -NAP 组），2）23:30 至 00:00 和 02:30 至 04:00（Pre30-NAP）组，以及 3）不午睡（NO-NAP 组）。评估参与者的体温、精神运动警戒任务（PVT）和内田-克雷佩林测试（UKT）分数以及嗜睡和疲劳的主观感觉。睡眠状态是通过参与者佩戴的体动监测设备来确定的。无论时间如何，这两种 90 分钟的小睡都与睡眠惰性有关，而两种 30 分钟的小睡都与睡眠惰性最小相关。与 NO-NAP 组相比，Pre30-NAP 和 Pre90-NAP 组在午睡后 2 小时的反应时间更短，错误更少。在 30 分钟小睡中增加 90 分钟小睡可减少主观疲劳并缩短反应时间，在 90 分钟小睡中增加 30 分钟小睡可有效保持表现，这表明存在协同效应。夜间工作期间小睡两次可以减轻困倦和疲劳，并保持工作表现。 90 分钟小睡后 30 分钟可减少疲劳和反应时间，而 30 分钟小睡后 90 分钟可维持清晨的认知能力。