Variability of Sleep Duration Is Related to Subjective Sleep Quality and Subjective Well-Being: An Actigraphy Study

While there is a large body of evidence that poor subjective sleep quality is related to lower subjective well-being, studies on the relation of objective sleep measures and subjective well-being are fewer in number and less consistent in their findings. Using data of the Survey of Mid-Life in the United States (MIDUS), we investigated whether duration and quality of sleep, assessed by actigraphy, were related to subjective well-being and whether this relationship was mediated by subjective sleep quality. Three hundred and thirteen mainly white American individuals from the general population and 128 urban-dwelling African American individuals between 35 and 85 years of age were studied cross-sectionally. Sleep duration, variability of sleep duration, sleep onset latency, and time awake after sleep onset were assessed by actigraphy over a period of 7 days. Subjective sleep quality was assessed with the Pittsburgh Sleep Quality Index, positive psychological well-being and symptoms of psychological distress were assessed with the Satisfaction with Life Scale and the Mood and Anxiety Symptom Questionnaire. In both white and African Americans high day-to-day variability in sleep duration was related to lower levels of subjective well-being controlling age, gender, educational and marital status, and BMI. By contrast, sleep duration, sleep onset latency, and time awake after sleep onset were not related to subjective well-being controlling covariates and other sleep variables. Moreover, the relationship between variability in sleep duration and well-being was partially mediated by subjective sleep quality. The findings show that great day-to-day variability in sleep duration – more than average sleep duration – is related to poor subjective sleep quality and poor subjective well-being.     

Relationship of chronotype to sleep, light exposure, and work-related fatigue in student workers

Students who work during the school year face the potential of sleep deprivation and its effects, since they have to juggle between school and work responsibilities along with social life. This may leave them with less time left for sleep than their nonworking counterparts. Chronotype is a factor that may exert an influence on the sleep of student workers. Also, light and social zeitgebers may have an impact on the sleep-related problems of this population. This study aimed to document sleep, light exposure patterns, social rhythms, and work-related fatigue of student workers aged 19-21 yrs and explore possible associations with chronotype. A total of 88 student workers (mean ± SD: 20.18 ± .44 yrs of age; 36 males/52 females) wore an actigraph (Actiwatch-L; Mini-Mitter/Respironics,Bend, OR) and filled out the Social Rhythm Metric for two consecutive weeks during the school year. Also, they completed the Morningness-Eveningness Questionnaire (MEQ), Epworth Sleepiness Scale (ESS), Pittsburgh Sleep Quality Index (PSQI), and Occupational Fatigue Exhaustion/Recovery Scale (OFER). Repeated and one-way analyses of variance (ANOVAs), Pearson's chi-square tests, and correlation coefficients were used for statistical comparisons. Subjects slept an average of 06:28 h/night. Actigraphic sleep parameters, such as sleep duration, sleep efficiency, wake after sleep onset, and sleep latency, did not differ between chronotypes. Results also show that evening types (n = 17) presented lower subjective sleep quality than intermediate types (n = 58) and morning types (n = 13). Moreover, evening types reported higher levels of chronic work-related fatigue, exhibited less regular social rhythms, and were exposed to lower levels of light during their waking hours (between 2 and 11 h after wake time) as compared to intermediate types and morning types. In addition, exposure to light intensities between 100 and 500 lux was lower in evening types than in intermediate types and morning types. However, bright light exposure (≥ 1000 lux) did not differ between chronotypes. In conclusion, results suggest that student workers may constitute a high-risk population for sleep deprivation. Evening types seemed to cope less well with sleep deprivation, reporting poorer sleep quality and higher levels of work-related fatigue than intermediate types and morning types. The higher chronic work-related fatigue of evening types may be linked to their attenuated level of light exposure and weaker social zeitgebers. These results add credence to the hypothesis that eveningness entails a higher risk of health-impairing behaviors.     

Relationship of Chronotype to Sleep,Light Exposure,and Work-Related Fatigue in Student Workers

Students who work during the school year face the potential of sleep deprivation and its effects, since they have to juggle between school and work responsibilities along with social life. This may leave them with less time left for sleep than their nonworking counterparts. Chronotype is a factor that may exert an influence on the sleep of student workers. Also, light and social zeitgebers may have an impact on the sleep-related problems of this population. This study aimed to document sleep, light exposure patterns, social rhythms, and work-related fatigue of student workers aged 19–21 yrs and explore possible associations with chronotype. A total of 88 student workers (mean?±?SD: 20.18?±?.44 yrs of age; 36 males/52 females) wore an actigraph (Actiwatch-L; Mini-Mitter/Respironics,Bend, OR) and filled out the Social Rhythm Metric for two consecutive weeks during the school year. Also, they completed the Morningness-Eveningness Questionnaire (MEQ), Epworth Sleepiness Scale (ESS), Pittsburgh Sleep Quality Index (PSQI), and Occupational Fatigue Exhaustion/Recovery Scale (OFER). Repeated and one-way analyses of variance (ANOVAs), Pearson's chi-square tests, and correlation coefficients were used for statistical comparisons. Subjects slept an average of 06:28?h/night. Actigraphic sleep parameters, such as sleep duration, sleep efficiency, wake after sleep onset, and sleep latency, did not differ between chronotypes. Results also show that evening types (n?=?17) presented lower subjective sleep quality than intermediate types (n?=?58) and morning types (n?=?13). Moreover, evening types reported higher levels of chronic work-related fatigue, exhibited less regular social rhythms, and were exposed to lower levels of light during their waking hours (between 2 and 11 h after wake time) as compared to intermediate types and morning types. In addition, exposure to light intensities between 100 and 500 lux was lower in evening types than in intermediate types and morning types. However, bright light exposure (≥1000 lux) did not differ between chronotypes. In conclusion, results suggest that student workers may constitute a high-risk population for sleep deprivation. Evening types seemed to cope less well with sleep deprivation, reporting poorer sleep quality and higher levels of work-related fatigue than intermediate types and morning types. The higher chronic work-related fatigue of evening types may be linked to their attenuated level of light exposure and weaker social zeitgebers. These results add credence to the hypothesis that eveningness entails a higher risk of health-impairing behaviors. (Author correspondence: luc.laberge@uqac.ca)     

Morningness–eveningness interferes with perceived health,physical activity,diet and stress levels in working women: A cross-sectional study

Sleep and health are closely interrelated and sleep quality is a well-known contributor to perceived health. However, effects of sleep-timing preference i.e. morningness–eveningness on health has yet to be revealed. In this study, we explored the relationship between morningness–eveningness and perceived health in a sample of female working professionals (N?=?202). Sleep-timing preference was measured using the Composite Scale of Morningness. Perceived health was characterized by Center for Epidemiologic Studies Depression Scale, WHO Well-Being Scale-5 and Patient Health Questionnaire-15 scores. We also investigated possible mechanisms, including stress and health-impairing behaviours. In accordance with previous data, we found more depressive mood, lower well-being and poorer perceived health among evening types. To assess health-impairing behaviours we collected data on smoking habits, alcohol consumption, physical activity and diet. Among the possible mechanism variables, greater stress, less frequent physical activity and less healthy diet were associated with eveningness. Furthermore, stress diminished the strength of the association between morningness–eveningness and depressed mood. Physical activity attenuated the strength of the association between morningness–eveningness and well-being. No effects of alcohol consumption could be identified. Our data show that evening preference behaves as a health risk in terms of associating with poor perceived health. Our findings also suggest that this effect might be mediated by health behaviours and stress.     

Subjective sleep quality exclusively mediates the relationship between morningness-eveningness preference and self-perceived stress response

Eveningness preference has been associated with lower sleep quality and higher stress response compared with morningness preference. In the current study, female morning (n = 27) and evening (n = 28) types completed the Pittsburgh Sleep Quality Index (PSQI) and were additionally challenged with an arithmetic stress-induction task. Evening types reported lower subjective sleep quality and longer sleep latency than morning types. Furthermore, evening types reported higher self-perceived stress after the task than morning types. Subjective sleep quality fully mediated the relationship between morningness-eveningness preference and stress response. Poor sleep quality may, therefore, contribute to the elevated health risk in evening types.     

Association between morningness and resilience in Korean college students

Circadian typology and sleep quality may be essential factors associated with the promotion of resilience. However, previous studies investigating the association between circadian typology and resilience did not analyze the effects of sleep quality on resilience. Thus, the present study evaluated the association between circadian typology and resilience in Korean college students after controlling for sleep quality. Additionally, this study investigated several sleep-related variables, including sleep duration, social jetlag and sunlight exposure during the daytime, to examine the modifiable behavioral features of morningness and also investigated whether the findings regarding morningness-related modifiable habits were associated with resilience. This study included 1094 participants (947 males and 147 females) between 19 and 29 years of age (22.8 ± 1.9 years) who completed the 10-item Korean version of the Connor–Davidson Resilience Scale (CD-RISC-10), the Korean version of the Morningness–Eveningness Questionnaire (MEQ), the Pittsburgh Sleep Quality Index (PSQI), the Korean version of the Hospital Anxiety and Depression Scale (HADS) and a survey about social jetlag that determined misalignments between weekday and weekend times of awakening and activity duration under conditions of sunlight between 10:00 and 15:00. A multiple linear regression analysis revealed that sleep duration, mean daily sunlight exposure between 10:00 and 15:00 and age were positive predictors of morningness, whereas social jetlag was a negative predictor of morningness. Of these morningness-related modifiable behavioral features, mean daily sunlight exposure between 10:00 and 15:00 significantly predicted greater resilience. An additional multiple linear regression analysis revealed that morningness was a positive predictor of resilience after controlling for age, sex, depression, anxiety and sleep quality. These results support the idea that morningness and better sleep quality are associated with greater resilience. Morningness was also associated with longer sleep duration, longer sunlight exposure during the daytime and less social jetlag, whereas longer daily sunlight exposure between 10:00 and 15:00 was associated with greater resilience. Future longitudinal studies are needed to examine whether manipulations of morningness-related modifiable behavioral features can rearrange chronotype and promote resilience.     

Validity of the Morningness‐Eveningness Scale for Children among Spanish Adolescents

Adolescents tend to be much later chronotypes than other age groups. This circadian phase delay is attributed as much to biological as psychosocial factors. Because the consequences of this change on performance and health have been documented, questionnaires to identify morning and evening‐type adolescents are necessary. The aim of the present study was to validate a Spanish version of the Morningness‐Eveningness Scale for Children (MESC) by means of several relevant psychological variables as external criteria. A sample of 623 urban high school students completed the MESC and self‐reported measures of sleep behaviors, subjective alertness, physical performance, and mood. On the whole, results indicate a good validity of MESC. Significant differences in the self‐reported ratings between morning and evening types were obtained by time‐of‐day. These results provide preliminary support for the Spanish version of MESC.     

Subjective Sleep Quality Exclusively Mediates the Relationship Between Morningness-Eveningness Preference and Self-Perceived Stress Response

Eveningness preference has been associated with lower sleep quality and higher stress response compared with morningness preference. In the current study, female morning (n?=?27) and evening (n?=?28) types completed the Pittsburgh Sleep Quality Index (PSQI) and were additionally challenged with an arithmetic stress-induction task. Evening types reported lower subjective sleep quality and longer sleep latency than morning types. Furthermore, evening types reported higher self-perceived stress after the task than morning types. Subjective sleep quality fully mediated the relationship between morningness-eveningness preference and stress response. Poor sleep quality may, therefore, contribute to the elevated health risk in evening types. (Author correspondence: karolin.roeser@uni-wuerzburg.de)     

The relationship between chronotype,sleep disturbance,severity of fibromyalgia,and quality of life in patients with fibromyalgia

ABSTRACT

Patients with fibromyalgia (FM) report high levels of sleep disturbance and chronic diffuse musculoskeletal pain. These patients experience diminished quality of life (QoL) due to pain and other comorbidities. Chronotype preferences have been suggested as a potential factor connecting increased severity of FM, sleep disturbances, and poor overall QoL. The present study is the first study examining the possible association between chronotype preferences, sleep disturbance, severity of FM, and QoL in patients with FM.

One hundred drug-free patients diagnosed with FM participated in this cross-sectional study. Of them, 79 (79%) were females and 21 (21%) were males. The mean age was 41.65 ± 9.17 years (range: 21–62 years). The severity of FM symptoms, chronotype preferences, and QoL was evaluated using the Fibromyalgia Impact Questionnaire (FIQ), Morningness-Eveningness Questionnaire (MEQ), and World Health Organization Questionnaire on Quality of Life: Short Form (WHOQOL-BREF). The participants’ anxiety/depressive symptoms and sleep problems were assessed using the Hospital Anxiety and Depression Scale (HADS) and Pittsburgh Sleep Quality Index (PSQI).

The participants were classified according to their MEQ scores as evening type (score: 16–41), neither type (score: 42–58), and morning type (score: 59–86). It was found that there were significant differences in the FIQ score between the three groups (p < .001). It was determined that the total PSQI score was significantly higher in the evening type than the other two types (p < .05). It was found that there were significant differences in the general health, physical health, psychological, and environmental domain scores of the WHOQOL-BREF between the three groups (p < .05). It was detected that there were significant correlations between MEQ scores, WHOQOL-BREF subscale scores, FIQ scores, HADS-A and HADS-D scores, and PSQI scores. According to hierarchical regression analysis, eveningness preference explained an additional 21.9% of the variation in FM severity, thereby causing a statistically significant change in R-squared.

Our results indicated that eveningness preference was directly related to increased FM symptom severity and poorer QoL. Based on these findings, neglecting to take chronotype preference into account may not result in optimal response to standard treatment for some patients with FM.     

Cyberbullying perpetration among undergraduates: evidence of the roles of chronotype and sleep quality

Cyberbullying is one of the important negative issues among adolescents and youngsters. Victims of cyberbullying perpetration have been reported to suffer many psychological and emotional problems that can lead them as far to suicide. The purpose of the present study was to investigate the associations of cyberbullying perpetration with gender, personality traits, chronotype, and sleep quality. Three hundred and fifty-three freshman and sophomore university students from Turkey (45.9% (n = 162) female and 54.1% (n = 191) male) completed a questionnaire that included Cyberbullying Scale, Big-5 Inventory, Composite Scale of Morningness, and Sleep Quality Scale. The most conspicuous result of the study was that chronotype and sleep quality were significant predictors of cyberbullying perpetration. Evening-type students had significantly higher scores on cyberbullying scale than neither-type students and morning-type students, and also neither-type students had higher scores on cyberbullying scale than morning-type students. Further, poorer sleep quality, being male, higher extraversion, higher neuroticism, and lower conscientiousness were related to higher cyberbullying perpetration.     

A prospective study of seasonal variation in shift-work tolerance

Seasonal effects on shift-work tolerance were assessed using the Standardized Shiftwork Index and the 21-item Hamilton Depression Scale. Participants (N=88) mainly worked a two-day, two-night, four-off rotation with 12 h shifts changing at 06:00 and 18:00 h in Vancouver, Canada. At this latitude (approximately 49 degrees N), daylength varies seasonally from approximately 16 to approximately 8 h, and both daily commutes occur in the dark in mid-winter and in sunlight in mid-summer. Questionnaires were completed twice, near the summer and winter solstices (order counterbalanced). Outcome variables were mood, general psychological health, sleep quality, chronic fatigue, physical health, job satisfaction, and social and domestic disruption. Of these, general psychological health and mood were significantly worse in winter, while sleep was more disturbed in summer. In winter, 31% exceeded the cutoff for psychological distress, and >70% scored in the higher than normal range for depressive symptoms. In summer, the proportions dropped to 19% and 53%, respectively. Measures of physical health and psychosocial well-being showed no seasonal effects. Relationships among explanatory and outcome variables, assessed by linear regression and canonical correlations, were also stable across season. Neuroticism was the strongest predictor of tolerance to shift work. Age was predictive only of sleep disturbance in both summer and winter. These results indicate that time of year can affect important outcome measures in shift-work assessment and intervention studies. The high average scores on measures of psychological distress and depression in winter suggest that at northern latitudes, some shift schedules may increase the risk of seasonal-type depression.     

Associations between chronotype,sleep disturbances and seasonality with fatigue and inflammatory bowel disease symptoms

Growing number of studies suggests link between circadian rhythms and inflammatory bowel diseases (IBD) manifestation. We hypothesize that: 1) IBD are associated with increased eveningness and sleep disturbances; 2) eveningness and sleep disturbances are related to more severe IBD symptoms. In total, 129 participants were enrolled to this study, divided into three groups: 34 Crohn’s disease (CD) patients, 38 ulcerative colitis (UC) patients and 57 healthy controls (HC) group. They all fulfilled a questionnaire, consisting of the Composite Scale of Morningness (CSM), Seasonal Pattern Assessment Questionnaire (SPAQ), Pittsburgh Sleep Quality Index, Inflammatory Bowel Disease Questionnaire (IBDQ) and Multidimensional Fatigue Inventory (MFI). Multiple regression models controlled for age and sex revealed that in CD group higher eveningness measured with CSM was associated with higher general fatigue, physical fatigue, mental fatigue and reduced motivation measured by MFI. Lower CSM morning affect is associated with greater general fatigue, physical fatigue and more reduced activity. Greater seasonality scores are associated with increased physical fatigue and more reduced activity and motivation. Lower sleep quality measured with PSQI is associated with higher physical fatigue and more reduced activity. Correlational analysis revealed that higher seasonality and lower sleep quality are associated with increased systemic and bowel symptoms and decreased emotional and social functions measured with IBDQ. In UC group, eveningness is associated with greater general fatigue, physical fatigue and more reduced activity. Higher CSM morning affect is associated with decreased general fatigue, physical fatigue and less reduced activity. Higher CSM circadian preference scores are associated with decreased general and physical fatigue, and less reduced activity. Increased seasonality is associated with more physical fatigue. Lower sleep quality is associated with greater general and physical fatigue. To our best knowledge this is the first study evaluating associations between chronotype and sleep disturbances with IBD symptoms. We have found that chronotype preferences, whose role in IBD has been until now overlooked, may be one of the important factors contributing to fatigue in this clinical group.     

Changes in growth and sleep across school nights,weekends and a winter holiday period in two Australian schools

Studies suggest that there may be an association between sleep and growth; however, the relationship is not well understood. Changes in biology and external factors such as school schedule heavily impact the sleep of adolescents, during a critical phase for growth. This study assessed the changes in sleep across school days, weekends and school holidays, while also measuring height and weight changes, and self-reported alterations in food intake and physical activity. The impact of morningness–eveningness (M-E) on height change and weight gain was also investigated. In a sample of 63 adolescents (mean age = 13.13, SD = 0.33, 31 males) from two independent schools in South Australia, height and weight were measured weekly for 4 weeks prior to the school holidays and 4 weeks after the school holidays. Participants also completed a Morningness/Eveningness Scale and 7-day sleep, diet and physical activity diaries prior to, during and after the school holidays. Participants at one school had earlier wake times during the weekends than participants attending the other school, leading to a significantly shorter sleep duration on weekends for those participants. Regardless of school, sleep was significantly later and longer during the holidays (p < 0.001) and those with a stronger morning preference fell asleep (F_18,36 = 3.4, p = 0.001) and woke (F_18,44 = 2.0, p = 0.027) earlier than evening types. Growth rate was lower during the holiday weeks. For those attending the school with limited sleep in opportunities, growth after the holidays was lower for those with greater evening preference, whereas for those at the other school, growth was greater for those with greater evening preference. The increase in average weight from pre- to post-holidays was greater for those attending the school with limited opportunities to sleep longer. Participants reported greater food intake during the holidays compared to school days and greater physical activity levels on weekends compared to school days, and school days compared to holidays. Results suggest that time of day preference may impact growth, with evening types who cannot sleep in growing at a slower rate than evening types who can or morning types. This may be related to sleep restriction. Despite sleep being both later and longer during the school holidays, participants’ growth slowed during the holiday period. It is possible that this may be a reflection of other behavioural changes in the holidays (increased food intake and reduced physical activity), as sleep timing during the school period was related to growth.     

The self-morningness/eveningness (Self-ME): An extremely concise and totally subjective assessment of diurnal preference

The assessment of diurnal preference, or the preferred timing of sleep and activity, is generally based on comprehensive questionnaires such as the Horne–Östberg (HÖ). The aim of the present study was to assess the reliability of a subject’s self-classification as extremely morning (Self-MM), more morning than evening (Self-M), more evening than morning (Self-E) or extremely evening (Self-EE) type, based on the last question of the HÖ (Self-ME). A convenience sample of 461 subjects [23.8?±?4.7 years; 322 females] completed a full sleep–wake assessment, including diurnal preference (HÖ), night sleep quality (Pittsburgh Sleep Quality Index, PSQI), daytime sleepiness (Karolinska Sleepiness Scale, KSS), and habitual sleep–wake timing (12?d sleep diaries; n?=?296). Significant differences in HÖ total score were observed between Self-ME classes, with each class being significantly different from neighboring classes (p?<?0.0001). Significant differences in sleep–wake timing (bed time, try to sleep and sleep onset, wake up, and get up time) were observed between Self-ME classes. Such differences were maintained when sleep–wake habits were analysed separately on work and free days, and also in a smaller group of 67 subjects who completed the Self-ME as a stand-alone rather than as part of the original questionnaire. Significant differences were observed in the time-course of subjective sleepiness by Self-ME class in both the large and the small group, with Self-MM and Self-M subjects being significantly more alert in the morning and sleepier in the evening hours compared with their Self-E and Self-EE counterparts. Finally, significant differences were observed in night sleep quality between Self-ME classes, with Self-EE/Self-E subjects sleeping worse than their Self-MM/Self-M counterparts, and averaging just over the abnormality PSQI threshold of 5. In conclusion, young, healthy adults can define their diurnal preference based on a single question (Self-ME) in a way that reflects their sleep–wake timing, their sleepiness levels over the daytime hours, and their night sleep quality. Validation of the Self-ME across the decades and in diseased populations seems worthy.     

Sleep quality,chronotype and metabolic syndrome components in bipolar disorders during the remission period: Results from the FACE-BD cohort

Data on sleep or circadian abnormalities and metabolic disturbances in euthymic bipolar disorders are scarce and based on small sample sizes. The aim of this study was to explore the associations between sleep disturbances, chronotype and metabolic components in a large sample of euthymic patients with bipolar disorders (BD). From 2009 to 2015, 752 individuals with bipolar disorders from the FACE-BD cohort were included and assessed for sleep quality, chronotype and metabolic components. The Structured Clinical Interview for DSM-IV Axis I Disorders (SCID) was used to confirm the diagnosis of BD. Subjective sleep quality was measured with the Pittsburgh Sleep Quality Index and chronotype with the Composite Scale of Morningness. Sociodemographic and clinical characteristics, psychotropic treatment, psychiatric comorbidities and blood samples were collected. In our sample, 22.4% of individuals with BD presented with a metabolic syndrome, 53.7% had sleep disturbances, 25.4% were considered as having an evening chronotype and 12.6% as having a morning chronotype. Independently of potential confounders, euthymic patients with sleep disturbances had a higher abdominal circumference, and patients with evening chronotype had a significantly higher level of triglycerides. There was an association between evening chronotype and an increased atherogenic index of plasma (OR = 4.8, 95%CI = 1.6–14.7). Our findings contribute the scant literature on the relationship between sleep quality, chronotype and cardiometabolic components in euthymic individuals with BD and highlight the need to improve quality of sleep and patient education about healthier sleep-hygiene practices.     

An in-depth look into the association between morningness–eveningness and well-being: evidence for mediating and moderating effects of personality

Morningness–eveningness and standard personality traits are associated with well-being but few studies have directly compared the two types of construct as correlates of life satisfaction. Influences on well-being common to both chronotype and personality may include shared biological bases for depression and sleep disturbance, tendencies toward social jetlag, and emotion-regulation mechanisms. The current study tested mediation and moderation hypotheses in a sample of 379 Polish adults. The first hypothesis was that conscientiousness and emotional stability traits would mediate the relationship between morningness and life satisfaction. Consistent with previous results, morningness, the two personality traits, and satisfaction tended to be mutually positively correlated. A multiple mediation analysis showed that both traits partially mediated the morningness–satisfaction association. Data are compatible with morningness influencing personality development adaptively, although other causal hypotheses could be advanced. The second hypothesis was that extraversion would moderate the association between chronotype and satisfaction. This hypothesis was supported, with extraverted evening types showing disproportionately high life satisfaction, whereas introverted evening types showed the lowest levels of satisfaction. Level of extraversion may influence whether or not evening types choose to engage in adaptive social activities that boost well-being during the evening hours. Results demonstrate the importance of investigating both chronotype and personality in studies of well-being.     

Building-site camps and extended work hours: A two-week monitoring of self-reported physical exertion, fatigue, and daytime sleepiness

Large-scale construction work often requires people to work longer daily hours and more than the ordinary five days in a row. In order to minimize transportation times and optimize the use of personnel, workers are sometimes asked to live in temporary building-site camps in the proximity of the work site. However, little is known about the biological and psychological effects of this experience. The objective of the present study was to investigate whether exposure to long work hours and extended workweeks while living in building-site camps in between work shifts was associated with a build-up of increased complaints of poor sleep, daytime sleepiness, physical exertion, and fatigue across a two-week work cycle. Two groups of construction workers were examined. The camp group of 13 participants (mean age: 42+/-11 S.D. yrs) lived in building-site camps and worked extended hours (between 07:00 and 18:00 h) and extended workweeks (six days in a row, one day off, five days in a row, nine days off). The home group of 16 participants (mean age 40+/-9 yrs) worked ordinary hours between 07:00 and 15:00 h and returned home after each workday. Self-ratings of daytime sleepiness (Karolinska Sleepiness Scale), physical exertion (Borg CR-10), and mood were obtained six or seven times daily during two workweeks. Fatigue ratings were obtained once daily in the evening, and ratings of sleep disturbances were obtained once daily in the morning with the Karolinska Sleep Diary. Data were evaluated in a repeated measures design. The results showed that both groups reported a similar level of daytime sleepiness, physical exertion, and mood across workdays and time points within a workday (all three-way interactions had p>0.898). Although the home group reported earlier wake-up times, the pattern of sleep disturbance ratings across the workdays did not differ between the groups. Both groups reported few sleep disturbances and good mood. However, the camp group reported higher physical exertion already at the start of work and showed a more gentle increase in ratings during the work shift and a smaller decline between the end of work and bedtime. The camp group also reported higher fatigue scores than the home group. However, none of the groups showed signs of increasing ratings in the progress of the two workweeks. For both groups, the ratings of daytime sleepiness formed a U-shaped pattern, with the highest scores at awakening and at bedtime. Yet, the camp group reported higher daytime sleepiness than the home group at lunch break and at the second break in the afternoon. In conclusion, there were no signs of fatigue build-up or accumulation of daytime sleepiness, physical exertion, or sleep disturbances in either group. Despite the fact that the camp group showed some signs of having trouble in recuperating in between work shifts, as indicated by the higher physical exertion ratings at the start of work, higher fatigue scores, and higher daytime sleepiness, the results constitute no real foundation for altering the camp group's current work schedule and living arrangements.     

Evening preference is related to the incidence of depressive states independent of sleep-wake conditions

Although evening preference has recently been identified as a risk factor for depression, it has not been substantiated whether evening preference is a direct risk factor for depressive states, or if it is associated secondarily through other factors, such as delayed sleep timing and shortened sleep duration. The objective of this study is to investigate associations in Japanese adult subjects between evening preference and incidence of depressive states, adjusting for various sleep parameters related to depressive states. The Morningness-Eveningness Questionnaire (MEQ), the Pittsburgh Sleep Quality Index (PSQI), and the Center for Epidemiologic Studies Depression Scale (CES-D) were administered to 1170 individuals (493 males/677 females; mean and range 38.5 and 20-59 yrs) to assess their diurnal preferences, sleeping states, and presence of depression symptoms. Subjects were classified into five chronotypes based on MEQ scores. Evening preference was associated with delayed sleep timing, shortened sleep duration, deteriorated subjective sleep quality, and worsened daytime sleepiness. Logistic regression analysis demonstrated that the extreme evening type (odds ratio [OR]?=?1.926, p?=?.018) was associated with increased incidence of depressive states and that the extreme morning type (OR?=?0.342, p?=?.038) was associated with the decreased incidence of depressive states, independent of sleep parameters, such as nocturnal awakening (OR?=?1.844, p?相似文献   

Shift work tolerance and the importance of sleep quality: a study of police officers

The aim of this study was to examine how subjective shift work tolerance was related to general health variables, with the expectation of inter-individual differences in the nature of this relation. A total of 740 employees of the Dutch Police force completed a questionnaire, covering seven health-related domains: sleep quality, sleep duration, need for recovery, fatigue, physical health, mental health, and work–life balance. Based on subjective reports of shift work tolerance, participants were classified as intolerant, medium-tolerant, or tolerant workers. Analysis involved group comparisons, regression, and cluster analysis. Eighteen percentage of the shift workers were classified as intolerant. The intolerant and medium-tolerant workers expressed more severe complaints than the tolerant workers, for all seven health-related domains. Shift work tolerance was primarily related to sleep quality and subsequently to need for recovery, fatigue, and work–life balance. No indications were found for systematic inter-individual differences in the nature of this relationship. For all participants equally, the degree of shift work tolerance was related to the severity of health-related complaints. This study highlights the central role of sleep for tolerance to shift work and underlines the need for occupational medicine to take explicit account of sleep.     

Eveningness, sleep patterns, daytime functioning, and quality of life in Israeli adolescents

The purpose of the study was to assess the relationships between eveningness, sleep patterns, measures of daytime functioning, i.e., sleepiness, sleep problem behaviors, and depressed mood, and quality of life (QOL) in young Israeli adolescents. A cross-sectional survey was performed in urban and rural middle schools in Northern Israel. Participants were 470 eighth and ninth grade middle school students (14?±?0.8 yrs of age) in the normative school system. Students completed the modified School Sleep Habits Survey (SSHS) and Pediatric Quality of Life Inventory Short Form, assessing six subscales of physical, emotional, social, school performance, and psychosocial functioning, plus an addition generated total score. During weekdays and weekends, evening types went to bed later, their sleep latency was longer, their wake-up time was later, and their sleep duration was shorter than intermediate and morning types. Evening types exhibited more sleep problem behaviors, sleepiness, depressed mood, and lower QOL compared to intermediate and morning types. Based on the regression model, sleepiness, sleep-problem behaviors, and depressed mood were the variables most strongly associated with QOL, followed by morning-evening preference, weekday sleep duration, and weekend sleep latency. This study is the first to assess QOL in normative, healthy adolescents and to demonstrate strong associations between morning-evening preference and QOL. These findings enhance the need to identify young individuals with an evening preference, and to be aware of the characteristics and manifestations of the evening chronotype on daytime and nighttime behaviors in adolescence.