Impact of nap length, nap timing and sleep quality on sustaining early morning performance

The study examined how nap length, nap timing and sleep quality affect early morning performance (6:00 to 8:00). Twelve students participated in a simulated nightshift schedule (22:00 to 8:00) where the length and timing of nocturnal naps were manipulated (0:00-1:00, 0:00-2:00, 4:00-5:00 and 4:00-6:00). A performance test battery was administered consisting of a psychomotor vigilance test, a logical reasoning test, and a visual analogue scale for subjective fatigue and sleepiness. The results showed that a 120-min nap sustained early morning performance better than a 60-min nap. Taking a nap earlier or later did not affect the neurobehavioral performance tests, although participants slept more efficiently during naps later in the night shift. A negative effect of a nocturnal nap during the night shift on subsequent daytime and nocturnal sleep was not observed in the sleep architecture. It still remains unclear whether slow wave sleep plays an important role in sustaining early morning performance. In terms of work safety and sleep health, the results suggest that a longer and later nap is beneficial during night shifts.     

The nighttime nap strategies for improving night shift work in workplace

Nighttime napping is an effective measure to prevent adverse effects due to night shift work. A characteristic of nighttime nap is that it can result in considerably deeper sleep. Several studies have shown that taking nighttime naps suppressed increasing sleepiness, decreasing alertness during the period following awaking from a nap, and prevented disturbance of circadian rhythm ("anchor sleep"). The length of daytime sleep after night shift, when combined with a nighttime nap, is shorter than that without nap. This finding might be interpreted as a beneficial effect rather than a negative feature because workers can then spend time engaged in other activities rather than sleeping. Nevertheless, the introduction of nighttime sleep break in the workplace has not been widely accepted. To promote nighttime napping strategy in the workplace, consensus building while acting on conflicting interest is essential. Recently, participatory method for improvement of working condition has expanded worldwide. A characteristic of the activity is using action checklist and group work, and heightening motivation to improvement working condition between worker and manager. Through the activities, nighttime napping strategy would be spread more in the workplaces and play a role as one of the effective tools for improving working conditions, work performance and safety in the future.     

Daytime napping and its effects on alertness and short-term memory performance in shiftworkers

Summary Daytime napping and its effects on 145 female shiftworkers were studied by comparing the individual characteristics, alertness, and short-term memory performance of subjects who took or did not take naps. Of the subjects 56% (n = 82) took a nap before a night shift and 21% (n = 30) after a morning shift. After a morning shift, napping was more frequent among evening types and subjects living alone (not married). Before a night shift, daytime napping was not connected to individual characteristics, but the total sleep time of nappers during the preceding night was shorter than that of non-nappers. At 10.00 and at 04.00–08.00, at the end of the night shift, nappers were significantly more alert than subjects who had not taken naps. The length and timing of the daytime nap did not correlate to either alertness or performance during the following night. In a questionnaire, nappers before a night shift had less sleep disturbances than non-nappers.     

Penile tumescence monitoring during morning naps to assess male erectile functioning: An initial study of healthy men of varied ages

Whether sleep erections occurred during morning naps (preceded by modest sleep deprivation) in healthy men whose ages were representative of clients in sexual health clinics was assessed. Subjects (N = 30) reduced their normal sleep time to increase the likelihood that they would experience rapid eye movement (REM) sleep [closely associated with nocturnal penile tumescence (NPT)]. They then reported to an outpatient psychophysiological laboratory for an early morning nap, during which sleep and penile tumescence measures were recorded continuously. All subjects were able to sleep during at least 1 of their 2 recording sessions, 24 (80%) experienced REM sleep, and 22 (73%) experienced tumescence episodes consistent with previous NPT studies. The magnitude of these erections could reduce concerns about the presence of organic pathology, and obviate the need for an NPT study. Results suggest that monitoring tumescence during naps may be useful as an inexpensive and convenient screening approach in the assessment of male erectile functioning.Supported in part by grants from Syracuse University to Christopher M. Gordon, and from the National Institute of Mental Health Grant 1-K21-MH01101 to Michael P. Carey.     

Self-report naps in irregular work schedules

Few studies have examined napping in irregular work schedules such as those experienced by freight locomotive engineers. The current study examined the effect of napping in irregular work schedules on sleep length and three subjective measures: ability to go to sleep, ability to stay asleep, and a feeling of being well-rested upon awakening. One hundred and seventy-nine freight engineers completed a 14-d activity log, providing information on sleep times and subjective evaluations of sleep. The results indicated that days with naps resulted in significantly more total sleep but less sleep in the main sleep period of the day. The days with naps also resulted in somewhat more difficulty with going to sleep, staying asleep and with feeling well-rested upon awakening. It is important to note, however, that when examining the days with naps, nap length was not significantly correlated with main sleep time, ability to go to sleep, ability to stay asleep, or feeling well-rested upon awakening. These results suggest that napping may be useful when working irregular work schedules if the engineer is willing to accept a slight decrease in ability to go to sleep, stay asleep, and feeling rested.     

A community-based study of sleep and behaviour problems in 12- to 36-month-old children

Background While evidence suggests sleep problems are common in young children and linked to behavioural problems, studies of toddlers are rare. This community‐based cross‐sectional study examined associations between sleep problems and daytime behaviour among 58 children aged 1 to 3 years who attended daycare centres. Methods Mothers and daycare providers completed four and three questionnaires, respectively, about children's sleep patterns and behaviour. Two hypotheses were tested: (1) children with higher sleep problem scores would have more behavioural problems by parental and daycare provider report; (2) problematic napping behaviours would be associated with night sleep problems. Results Mothers' reports of sleep problems were positively associated with children's behavioural problems at home and daycare providers' reports of nap problems were positively correlated with children's behavioural problems at daycare. Daycare providers' reports of children's behavioural problems at daycare were associated with maternal reports of behavioural problems. Older children in the sleep problem group had maternal reports of more behavioural problems. Daycare providers reported that children with sleep problems were less happy at daycare. Children who were happier following naps had less reported night settling difficulties. Children with difficulty settling for naps at daycare had maternal reports of more behavioural problems. Conclusions Napping in daycare settings is an important component of toddlers' sleep. Crossover effects between children's sleep and behaviour at daycare and home indicate similarities in mothers' and daycare providers' perceptions. Findings suggest parent and daycare provider interactions include discussions about sleep problems and settling at home and in daycares. Parents and daycare providers would benefit from education about relationships between sleep and behavioural problems.     

Sleep and wakefulness in a group of shift workers

Tune, G. S. (1969).Brit. J. industr. Med.,26, 54-58. Sleep and wakefulness in a group of shift workers. Fifty-two shift workers recorded their hours of sleep and wakefulness for a period of 10 weeks. Compared with matched non-shift-working control subjects it was found that they took a higher average duration of sleep per 24 hours and more and longer naps outside the major sleep period. A comparison of the on and off duty records from the shift workers showed that a sleep debt was incurred during the former which was largely paid off by taking long naps in the latter. It is suggested that the longer sleep taken by shift workers may be necessary in order to pay off specific kinds of sleep debt.     

Sleep strategies of 12-hour shift nurses with emphasis on night sleep episodes

OBJECTIVES: Episodes of sleep during a nightshift are frequently reported in various types of jobs. This phenomenon has been seldom documented so far. This field study investigated individual differences in the sleep-wake behavior of nurses. METHODS: A group of eight nurses working in an intensive care unit on a two 12-hour shift system kept a "sleep diary" for 1 month, recording main sleep periods and naps. They subjectively assessed sleepiness, sleep quality, and the need for sleep at various times of the day and night. Continuous actimetric measurements provided an evaluation of the rest-activity patterns and of the sleep parameters. RESULTS: Half of the nurses chose to take naps in 75% of their nightshifts. No differences between the night-nappers and nonnight-nappers were found for either total sleep length or the temporal patterns of subjective sleepiness at night but, during nightwork, night-nappers needed sleep earlier than nonnight-nappers. They had long naps during a worknight and short daytime sleep, sometimes followed by a late afternoon nap. This strategy probably favored the maintenance of a diurnal orientation. Nonnight-nappers had long daytime sleep and took preventive naps to anticipate sleepiness during nightwork. However, their readjustment to diurnal life seemed more difficult than that of night-nappers. CONCLUSIONS: Nurses use different sleep-wake strategies to cope with nightwork. These different strategies may be due to circadian influence although social factors cannot be totally excluded.     

Sleep and Academic Performance in Hong Kong Adolescents

BACKGROUND: Sleep problems may have different influences on students' academic performance. We investigated the prevalence of sleep patterns, naps, and sleep disorders, and their associations with academic performance in Hong Kong adolescents. METHODS: In 2007‐2008, 22,678 students aged 12‐18 (41.6% boys) completed a questionnaire on sociodemographic characteristics, sleep patterns and problems, and lifestyle factors including exercise, smoking, alcohol drinking, and academic performance. RESULTS: The prevalence of having >8 hours of sleep was higher on holiday nights (86.4%) than on school‐day nights (27.4%). Sleeping after midnight was more common before holidays (49.3%) than before school days (19.9%). Symptoms of insomnia and obstructive sleep apnea (OSA) were reported by 21.5% and 34.4% of students. Having >2 hours of weekend sleep delay was associated with poor academic performance with an odds ratio (OR) (95% confidence interval) of 1.46 (1.29‐1.65). However, having 1‐2 hours and >2 hours of weekend wake‐up delay were both associated with less likelihood of poor academic performance with ORs of 0.64 (0.56‐0.73) and 0.69 (0.59‐0.80). Other factors associated with poor academic performance included >2 hours of sleep debt, OR of 1.17 (1.03‐1.33); having any insomnia symptoms in the past 30 days, OR of 1.27 (1.17‐1.37); and having any OSA symptoms at least weekly, OR of 1.23 (1.14‐1.32). Napping in the past 5 school days was only marginally associated with poor school performance with an OR of 1.08 (1.00‐1.16). CONCLUSION: Poorer academic performance was associated with sleep debt, and symptoms of insomnia and OSA. Sleep compensation but not naps may be a protective factor of poor academic performance.     

孕前午睡与目前夜眠时长对孕晚期疲劳的相关性研究

目的 讨论孕前午睡与目前夜眠时长对孕晚期正常孕妇疲劳程度的影响。方法 收集2020年1～12月于厦门大学医学院第二附属医院就诊的正常孕晚期(孕28周～分娩)孕妇490例,收集其一般人口学信息与临床资料,记录孕前午睡与目前夜眠有效睡眠时长,排除3例缺失夜眠时长样本,有效样本487例。按孕前是否午睡分为午睡(n=332)和无午睡(n=141),依据美国国家睡眠基金会建议,以7 h为界点,结合目前夜眠有效睡眠时长≤7 h(n=165)和>7 h(n=308)进行分组。对各组样本进行一般资料调查,采用FS-14量表量化孕晚期妇女疲劳程度,将得分整理为总分、躯体疲劳得分、脑力疲劳得分三个项目,分析午睡、夜眠时长效应的交互作用、不同主效应的差异及夜眠时长与FS-14得分相关性。结果 FS-14总分、FS-14躯体疲劳得分组间差异有统计学意义,FS-14脑力疲劳得分组间差异无统计学意义。无午睡且夜眠≤7 h组孕妇FS-14总分、躯体疲劳得分、脑力疲劳得分均最高,无午睡且夜眠>7 h的孕妇三项得分均值为最低分。不论孕前是否午睡,夜眠时长>7 h,其疲劳总分、躯体疲劳得分均较低。结论 ...     

Beyond Access and Exposure: Implications of Sneaky Media Use for Preschoolers’ Sleep Behavior

ABSTRACT

Greater consumption of and access to screen media are known correlates of unhealthy sleep behavior in preschoolers. What remains unknown, however, is the role a child’s media use plays in this association. Parents and guardians of U.S. preschoolers (N = 278, average child age 56 months) provided information about their child’s nightly duration of sleep, daily duration of nap, quantity of screen media use, sneaky media use, and the presence of a screen media device in the bedroom. We assessed four media: television, DVD/VCRs, video games, and computer/Internet. Based on rationales of sleep displacement, the forbidden fruit hypothesis, and social cognitive theory, we predicted that increased consumption of and access to media, along with sneaky media use, would predict a shorter duration of nightly sleep and longer duration of daily nap across the four screen media. In correlational analyses, a clear pattern emerged with quantity of media use, screen media in the bedroom, and sneaky media use associated with shorter nightly duration of sleep and longer duration of daily nap. In regression analyses, only weekday evening television viewing and sneaky media use predicted shorter nightly sleep duration; weekend morning and evening DVD use predicted longer naps.     

睡眠不足对大学生中枢神经系统功能的影响

「目的」研究睡眠不足对大学生中枢神经系统功能造成的影响。「方法」对不同程度睡眠不足大学生进行了上肢短潜伏期躯体感觉诱发电位、脑干听觉诱发电位和视觉诱发电位的测试。「结果」与睡眠不足前比较,睡眠不足后上肢短潜伏期躯体感觉诱发电位无显著变化,脑干吸觉诱发电位和视觉诱发电位各波潜伏期较对照组有延长趋势,彻夜不眠者显著延长（Ｐ〈０．０５）。「结论」睡眠不足降低了中枢神经系统对外在刺激的应激能力。     

睡眠状况与儿童青少年心理行为问题关联研究

目的 分析儿童青少年睡眠不足、周末睡眠社会时差等睡眠问题与心理行为问题之间的相关性,为预防和改善儿童青少年心理行为问题提供参考依据。方法 2019年4-5月采用立意抽样按照街道—学校类型—学校3个阶段在深圳市宝安区辖区内6个街道选取14所学校,对30 188名1~12年级儿童青少年进行问卷调查。心理行为问题评定采用父母版与学生版困难与长处问卷进行,夜间睡眠时间、周末上床和起床推迟时间、午睡情况等采用自编的《中小学生成长轨迹及健康指数调查问卷》。调整性别、年龄、父母文化程度、学习成绩、学习负担和噪声等混杂因素,采用多因素logistic回归分析睡眠问题与心理行为问题之间的关联强度（OR值）及其95％CI。结果 小学低年级、小学高年级、初中和高中学生睡眠不足分别占90.4％、90.1％、98.2％和98.4％,有19.9％的学生不午睡,19.6％的学生周末推迟起床时间≥2 h,35.1％的学生晚上不固定时间睡觉,15.5％的学生每天不固定时间起床。与夜间睡眠时长8~9 h相比,小学低年级学生夜间睡眠时长≤7 h、7~8 h增加心理行为问题发生风险,睡眠时间>9 h与心理行为问题呈负向关联;小学高年级学生夜间睡眠时长≤7 h增加心理行为问题发生风险;初、高中生夜间睡眠≤6 h者心理行为问题增加,OR值（95％CI）分别为2.53（1.85~3.47）、2.41（1.11~5.25）,而夜间睡眠>9 h者心理行为问题也增加,OR值（95％CI）分别为2.37（1.40~4.01）、5.38（1.79~16.1）。与午睡时间0.5~1 h相比,不午睡及午睡时间<0.5 h都是中小学生出现心理行为问题的危险因素,午睡时间1~2 h还是高中生出现心理行为问题的危险因素。早上不固定时间起床、晚上不固定时间睡觉、周末推迟起床≥2 h是中小学生出现心理行为问题的危险因素。周末夜间推迟入睡≥2 h,小学低年级和高年级、初中、高中学生出现心理行为问题的OR值（95％CI）分别为2.07（1.45~2.97）、1.57（1.09~2.26）、2.66（2.06~3.44）、2.48（1.96~3.15）。结论 儿童青少年夜间睡眠不足、不午睡以及睡觉与起床时间不固定与心理行为问题呈正向关联,但夜间睡眠长也是中学生心理行为问题的危险因素。同时,睡眠的社会时差增加了儿童青少年心理行为问题发生风险,小学低年级学生周末入睡推迟0.5 h即与不良心理行为增加有关联。     

The effects of the number of consecutive night shifts on sleep duration and quality

Objectives:The organization of night shift work affects sleep duration and quality. The aim of this study was to investigate the effects of the number of consecutive night shifts on sleep duration and quality among police officers with night shift work as part of their normal schedule.Methods:This quasi-experimental, within-subject crossover study included 73 police officers. All participants performed three work schedules: two, four and seven consecutive night shifts followed by the same number of recovery days, ie, day work or days off (2+2, 4+4, and 7+7). Sleep assessed through sleep diaries and actigraphy after all night shifts and recovery days (totaling 26 days) was compared by use of repeated measures analysis.Results:Participants experienced shorter sleep duration (with and without naps), more premature awakening, less difficulty falling asleep, and more non-refreshing sleep after night shifts compared with recovery days. Sleep duration and quality did not change with increasing number of consecutive night shifts. Sleep was shorter and of poorer quality after the last night shift in the 2+2 and 4+4 work schedule compared with the second and fourth night shift, respectively, in the 7+7 schedule.Conclusion:Sleep duration was reduced after night shift work and did not increase with more consecutive night shifts, which leads to accumulated sleep debt. Sleep duration was shortest and sleep quality was poorest after the last night shift in a series of night shifts.     

Effects of consecutive night shifts with prolonged on-duty and overtime work on various sleep

The purpose of this research was to investigate the effect of consecutive night shifts upon various types of sleep. The subjects studied were 9 guards who usually worked on an alternate-day shift system. The nighttime nap EEG (3:00-6:30) during the 24-hr on-duty period was recorded, and then the subsequent day sleep EEG (11:00 to spontaneous awakening) and recovery night sleep (23:00 to spontaneous awakening) were also measured. These records were made for the nap, day sleep and recovery night under two different sets of conditions. The first was for the usual shift cycle (U), i.e. 24 hr duty (10:00-10:00)----off duty----24 hr duty----off duty. The other was for consecutive night shifts (CN) with overtime work (18:00-10:00) performed on the normal off day, i.e. 24 hr duty----8 hr off duty----40 hr duty----off duty. The results were as follows: There was no difference between U and CN conditions concerning time in bed and total sleep time in the nighttime nap, day sleep and recovery night. However, the total time of daytime sleep was significantly shortened under both U and CN conditions, as compared with the control night. The amount of REM sleep in the CN condition for both the nighttime nap and day sleep was significantly greater than in the U condition. In the recovery night, REM sleep continued to be slightly greater for the CN condition than for the U condition. Slow wave sleep (SWS) in the CN condition was slightly greater than in the U condition for the nighttime nap and day sleep, but in the recovery night, no difference was observed between the two conditions. In the U condition, the sleep onset REM period (SOREMP) was observed in 2 of the 9 cases, but only during the day sleep. In the CN condition, however, it occurred in 5 subjects during the nighttime nap, in 4 during the day sleep, and in 2 during the recovery night. The REM sleep latency in the CN condition thus tended to be diminished in each type of sleep compared with that in the U condition, but a significant difference between the two conditions was observed only in the nighttime nap. It is believed that the increase in the amount of REM sleep and in the frequency of SOREMP might be due to the repeated pattern of sleep loss and shortened periods of sleep during consecutive night shifts of prolonged duty, with partial sleep deprivation resulting from lack of REM sleep.     

Seasonal hazards and health risks in lower-income countries: field testing a multi-disciplinary approach

Understanding how risks to human health change as a result of seasonal variations in environmental conditions is likely to become of increasing importance in the context of climatic change, especially in lower-income countries. A multi-disciplinary approach can be a useful tool for improving understanding, particularly in situations where existing data resources are limited but the environmental health implications of seasonal hazards may be high. This short article describes a multi-disciplinary approach combining analysis of changes in levels of environmental contamination, seasonal variations in disease incidence and a social scientific analysis of health behaviour. The methodology was field-tested in a peri-urban environment in the Mekong Delta, Vietnam, where poor households face alternate seasonal extremes in the local environment as the water level in the Delta changes from flood to dry season. Low-income households in the research sites rely on river water for domestic uses, including provision of drinking water, and it is commonly perceived that the seasonal changes alter risk from diarrhoeal diseases and other diseases associated with contamination of water. The discussion focuses on the implementation of the methodology in the field, and draws lessons from the research process that can help in refining and developing the approach for application in other locations where seasonal dynamics of disease risk may have important consequences for public health.     

The competition between SWS and REM sleep as index of maladaptation to shift work.

Polysomnographic and questionnaire investigation was performed in 22 train dispatchers and in 15 employees of post transportation during one work-rest cycle. In the group of subjects well adapted to the shift work, the slow-wave-sleep reached its peak duration in the day sleep and in the first recovery night, while REM rebound took place only on the second night. In maladapted subjects, REM sleep prevailed in the day sleep as well as in the first recovery night. The alteration of sleep structure can be thus used as a sign of adaptation vs maladaptation to shift work. Sleep structure of the recovery day sleep after single night sleep deprivation may be used as a prediction of adaptation to the shift work.     

Actual conditions of work, fatigue and sleep in non-employed, home-based female information technology workers with preschool children

We conducted a study on time budget and fatigue feelings over a two-month period of 12 non-employed, home-based female workers using computers (mean age 35.2 yr). All of them had at least one preschool child. The actual amount of work done by these women and the related effects on the fatigue feelings and sleep were investigated. The results showed that the work done was characterized by involving many night hours, irrespective of the day of the week. The degree of subjective fatigue was not dependent on the number of hours worked, but affected by the time at which the work of the day was completed. This tendency was notable after one o'clock in the morning when the work was completed. Those who followed such a work pattern took daytime naps, although a quality of the subsequent nighttime sleep taken might be poor. They took a nap around 14:00 but not around 19:00. The sleep strategies were thus shown to be affected by home-based work. A need is suggested to support these workers in adjusting work time distribution and taking sleep patterns adapted to individual conditions.     

包头市大学生睡眠卫生知信行对睡眠质量的影响

目的了解大学生睡眠卫生知识、信念、行为与睡眠质量的关系。方法采用整群随机抽样选取773名在校大学生为测试对象,以中文版匹兹堡睡眠质量指数问卷(Pittsburgh Sleep Quality Index,PSQI)和大学生睡眠卫生知识、信念、行为问卷为工具,调查大学生的睡眠卫生知、信、行与睡眠质量的关系。结果大学生睡眠卫生知识、信念、行为得分依次为(16.30±2.79)、(40.61±7.46)、(49.65±8.61);不同性别在睡眠卫生信念得分上的差异有统计学意义(P<0.01);睡眠卫生信念及行为与PSQI总分呈负相关(P<0.01);睡眠卫生信念和行为与PSQI总分的标准回归系数分别为-0.164和-0.177(P<0.01)。结论睡眠卫生信念和行为对睡眠质量有预测作用。睡眠卫生信念与睡眠卫生行为是影响大学生睡眠质量的主要因素之一,开展大学生睡眠卫生健康教育是非常必要的。