Dickinson David L, Drummond Sean P A, McElroy Todd
Department of Economics & Center for Economic Research and Policy Analysis, Appalachian State University, Boone, North Carolina, United States of America.
IZA (Institute for the Study of Labor), Bonn, Germany.
PLoS One. 2017 Mar 20;12(3):e0174367. doi: 10.1371/journal.pone.0174367. eCollection 2017.
Chronic sleep restriction (SR) increases sleepiness, negatively impacts mood, and impairs a variety of cognitive performance measures. The vast majority of work establishing these effects are tightly controlled in-lab experimental studies. Examining commonly-experienced levels of SR in naturalistic settings is more difficult and generally involves observational methods, rather than active manipulations of sleep. The same is true for analyzing behavioral and cognitive outcomes at circadian unfavorable times. The current study tested the ability of an at-home protocol to manipulate sleep schedules (i.e., impose SR), as well as create a mismatch between a subject's circadian preference and time of testing. Viability of the protocol was assessed via completion, compliance with the SR, and success at manipulating sleepiness and mood. An online survey was completed by 3630 individuals to assess initial eligibility, 256 agreed via email response to participate in the 3-week study, 221 showed for the initial in-person session, and 184 completed the protocol (175 with complete data). The protocol consisted of 1 week at-home SR (5-6 hours in bed/night), 1 week wash-out, and 1 week well-rested (WR: 8-9 hours in bed/night). Sleep was monitored with actigraphy, diary, and call-ins. Risk management strategies were implemented for subject safety. At the end of each experimental week, subjects reported sleepiness and mood ratings. Protocol completion was 83%, with lower depression scores, higher anxiety scores, and morning session assignment predicting completion. Compliance with the sleep schedule was also very good. Subjects spent approximately 2 hours less time in bed/night and obtained an average of 1.5 hours less nightly sleep during SR, relative to WR, with 82% of subjects obtaining at least 60 minutes less average nightly sleep. Sleepiness and mood were impacted as expected by SR. These findings show the viability of studying experimental chronic sleep restriction outside the laboratory, assuming appropriate safety precautions are taken, thus allowing investigators to significantly increase ecological validity over strictly controlled in-lab studies.
长期睡眠限制（SR）会增加嗜睡感，对情绪产生负面影响，并损害多种认知表现指标。绝大多数证实这些影响的研究都是在实验室中进行的严格对照实验研究。在自然环境中研究常见的睡眠限制水平更加困难，通常涉及观察方法，而非主动控制睡眠。在昼夜节律不利的时间分析行为和认知结果也是如此。本研究测试了一种居家方案对睡眠时间表进行控制（即实施睡眠限制）的能力，以及制造受试者昼夜偏好与测试时间之间不匹配的能力。通过方案的完成情况、对睡眠限制的依从性以及对嗜睡感和情绪的调控成功与否来评估该方案的可行性。3630名个体完成了一项在线调查以评估初始资格，256人通过电子邮件回复同意参与为期3周的研究，221人参加了初始的面对面会议，184人完成了该方案（175人有完整数据）。该方案包括1周的居家睡眠限制（每晚卧床5 - 6小时）、1周的洗脱期和1周的充足休息期（WR：每晚卧床8 - 9小时）。通过活动记录仪、日记记录和电话汇报来监测睡眠情况。为了受试者的安全实施了风险管理策略。在每个实验周结束时，受试者报告嗜睡感和情绪评分。方案完成率为83%，抑郁得分较低、焦虑得分较高以及上午时段的安排可预测完成情况。对睡眠时间表的依从性也非常好。与充足休息期相比，受试者在睡眠限制期每晚卧床时间减少约2小时，平均每晚睡眠时间减少1.5小时，82%的受试者平均每晚睡眠时间减少至少60分钟。如预期的那样，睡眠限制对嗜睡感和情绪产生了影响。这些发现表明，在采取适当安全措施的情况下，在实验室外研究实验性长期睡眠限制是可行的，从而使研究人员能够比严格控制的实验室研究显著提高生态效度。
