The siesta culture concept is not supported by the sleep habits of urban Mexican students

The contribution of self-concept to sleep quality in adolescents: A cross-sectional study

Self-concept has been associated with health-related behaviors and emotional self-regulation, which can improve sleep. However, its involvement in sleep quality in a healthy adolescent population has been little studied. This study evaluated the association between self-concept and sleep quality in adolescents adjusting for sleep/wake habits. The cross-sectional study included 1,751 adolescents, 54% females, with an age of M = 16.76 ± 1.04 years. The information was collected through an electronic survey that contained the Patient Health Questionnaire, Sleep Habits Questionnaire, Pittsburgh Sleep Quality Index, and Self-Concept Scale. A significant association between self-concept, adjustment for adolescents´ characteristics and sleep/wake habits was observed (R² = .17, F = 26.61, p < .001). That is, in addition to the adolescent habits, self-concept also contributed to the explanation of sleep/wake habits. These results reinforce the idea that the self-concept can be an essential factor that contributes to better sleep quality, despite the habits of adolescents.

Duration of Daytime Napping Is Related to Physical Fitness among Chinese University Students

Reportedly, daytime napping affects the physical fitness of athletes. However, results of these studies are conflicting, and may not be generalizable to all populations. Early adulthood is an important period linking adolescents and adults, during which building good physical fitness is crucial for their remaining lives. Thus, we investigated whether daytime napping duration is associated with physical fitness among Chinese university students. This study was based on an annual physical health examination for all university students and included 11,199 participants (6690 males; 4509 females). The daytime napping duration was assessed using a self-report questionnaire. Physical fitness was measured with a 50 m sprint; 1000 m (for males) and 800 m (for females) runs; standing long jump, sit-and-reach, pull-up (for males), and sit-up (for females) tests; and vital capacity. The adjusted association was evaluated using analysis of covariance. Of the participants, 86% napped regularly. After covariate adjustment was performed, significant V-shaped associations were observed between the daytime napping duration and the 50 m sprint and 800 m run results in males and females. Inverted V-shaped associations were observed between the daytime napping duration and the sit-and-reach, standing long jump, and pull-up test performances and vital capacity in males and between the daytime napping duration and the standing long jump test performance in females. Daytime napping for <30 min may have beneficial effects on physical fitness among university students.

Associations between sleep duration and Mediterranean diet score in Costa Rican adults

Both insufficient and excessive sleep duration have been associated with lower-quality diets in adult populations. However, investigations in Latin America, where different sleep norms may exist (e.g., daily napping), are scarce. Therefore, we examined whether weekday sleep duration and inconsistencies between weekday and weekend sleep duration were related to adherence to the Mediterranean diet among Costa Rican adults. The study population included 2169 controls (74% men) from a population-based case-control study. Usual sleep duration (weekday versus weekend) was self-reported and defined as short, recommended, and long (<7 h, 7-9 h, >9 h, respectively). Inconsistent weekday-weekend sleep duration was defined as >1-h difference. Diet was assessed with a food frequency questionnaire, and adherence to the Mediterranean diet was calculated with the Alternative Mediterranean Diet Score (AMED). Sex-stratified linear regression models were conducted with AMED score as a continuous outcome and sleep variables as categorical or dichotomous exposures (in separate models). Models were adjusted for age, area of residence, education, napping, caffeine intake, smoking status, type 2 diabetes mellitus, hypertension, and physical activity. Average (SD) hours of sleep per night reported were 7.0 (1.4) on weekdays and 7.3 (1.6) on weekends for men, and 7.0 (1.5) on weekdays and 7.2 (1.6) on weekends for women. Among women, sleep duration <7-h per night was associated with a lower AMED score compared to those with recommended sleep duration (β: -0.35, CI: -0.63 to -0.07). Unstratified models showed a suggestive association between inconsistent weekday-weekend sleep and lower AMED scores that did not vary by sex (β: -0.08, CI: -0.16, 0.006; P, interaction with sex = 0.93). Lastly, the napping frequency was not associated with AMED scores in any model. In conclusion, short and inconsistent sleep duration may affect the dietary patterns of Costa Ricans.

The Interactive Effect of Positive Mental Health and Subjective Sleep Quality on Depressive Symptoms in High School Students

Objective/Background: The objective of this study was to observe the effect of positive mental health (PMH) and subjective sleep quality (SQ) on depressive symptoms in high school students. Participants: This cross-sectional study evaluated 2,186 students (55% female and 45% male) with a mean age of 16.8 years (SD ± 0.7) at 20 private high schools in Mexico City. Methods: An electronic survey was used, which included a questionnaire on sleep habits that is a Spanish-language adaptation of Rosenthal's Sleep-Wake Activity Inventory, the Pittsburgh Sleep Quality Index (PSQI), the Morningness-Eveningness Scale for Children and Adolescents (MESC), the combined scales to evaluate positive aspects of mental health, and the Patient Health Questionnaire (PHQ-9). Results: Main and interaction effects of PMH and SQ were observed, demonstrating that students with high-PMH (p ≤ .0001) or good-SQ (p ≤ .0001) had fewer depressive symptoms. Thus, the students with both high-PMH and good-SQ had the lowest depressive symptomatology (p ≤ .01). Conclusion: Depressive symptoms are associated with a combination of sleep quality and positive mental health.

Social Jet-Lag in Tertiary Students Following a Modern Curriculum with Few Time-Tabled Contact Hours: A Pilot Study

Social jet-lag (SJL) impairs academic performance, specifically for late chronotypes faced with early start times. Most modern tertiary educational systems have fewer time-tabled contact hours and consequently fewer early starts, which may limit SJL. We performed a pilot study of SJL in a convenience sample of students from Maastricht University, where problem-based learning (PBL) is implemented throughout the curricula. PBL is a modern curriculum, with only few contact hours and student-driven learning, comprising substantial amounts of self-study. Fifty-two students kept a detailed sleep diary for one week, and completed the Pittsburgh Sleep Quality Index (PSQI) and the Epworth Sleepiness Scale (ESS). Participants were divided into early and late sleepers based on a ranking of their reported sleeping times, combined with a single question on their self-reported chronotype. Late sleepers (for brevity: “Owls”; n = 22) had later midpoint-sleep (5:14 ± 0:11 on weekdays; 5:50 ± 0:07 on weekend days) than early sleepers (for brevity: “Larks”; n = 11, 3:21 ± 0:05 on weekdays; 3:41 ± 0:06 on weekend days, F = 10.8, p = 0.003). The difference between the midpoint of sleep on weekdays and weekend days was comparable for Larks and Owls (F = 1.5; p = 0.22). SJL (0:53 ± 0:06, T = 1.4; p = 0.16), total sleep duration (7:58 ± 0:08; p = 0.07), and PSQI score (4.7 ± 0.3, U = 137; p = 0.56) were comparable for Larks and Owls. Average ESS score was higher in Larks (10.7 ± 0.96) than in Owls (7.0 ± 0.72; U = 52; p = 0.007). Within this pilot study of students engaged in a problem-based learning curriculum, Owls have no selective disadvantage compared to Larks concerning sleep.

Napping: A public health issue. From epidemiological to laboratory studies

Sleep specialists have proposed measures to counteract the negative short- and long-term consequences of sleep debt, and some have suggested the nap as a potential and powerful "public health tool". Here, we address this countermeasure aspect of napping viewed as an action against sleep deprivation rather than an action associated with poor health. We review the physiological functions that have been associated positively with napping in both public health and clinical settings (sleep-related accidents, work and school, and cardiovascular risk) and in laboratory-based studies with potential public health issues (cognitive performance, stress, immune function and pain sensitivity). We also discuss the circumstances in which napping-depending on several factors, including nap duration, frequency, and age-could be a potential public health tool and a countermeasure for sleep loss in terms of reducing accidents and cardiovascular events and improving sleep-restriction-sensitive working performance. However, the impact of napping and the nature of the sleep stage(s) involved still need to be evaluated, especially from the perspective of coping strategies in populations with chronic sleep debt, such as night and shift workers.

Intermittent hypoxemia and sleep fragmentation: associations with daytime alertness in obese sleep apnea patients living at moderate altitude

BACKGROUND

Although obstructive sleep apnea (OSA) has long been associated with daytime sleepiness, far less is known about its association with the ability to remain awake. The aim of this study was to examine the relative importance of inter-correlated measures of OSA severity (eg, various indices of oxygen saturation and sleep fragmentation) in the ability to stay alert as measured objectively by the Maintenance of Wakefulness Test (MWT), defined by a mean sleep latency of ≥12 min.

METHODS

Seventy-eight obese women and men of similar age and body mass index living at altitude (Mexico City) underwent standard polysomnography, MWT, and completed validated sleep-related questionnaires.

RESULTS

Men had more severe sleep apnea than women (p = 0.002) and were also less alert on MWT (p = 0.022). Logistic regression models indicated that measures of desaturation consistently predicted MWT-defined alertness, whereas varied measures of sleep fragmentation did not. Nearly a third of the variance (r(2) = 0.304) in MWT-defined alertness was accounted for by the number of desaturations per hour of sleep (p = 0.003), which is considerably higher than other studies have reported in different populations.

CONCLUSION

The ability to remain awake in obese patients is best accounted for by hypoxemia rather than sleep fragmentation. Whether the size of this effect reflects differences in the population under study (eg, extent of obesity, racial background, residence at moderate altitude) and/or is a function of the measurement of alertness with the MWT remains uncertain.

Is the siesta an adaptation to disease? : A cross-cultural examination

Why does the practice of the siesta vary across human cultures? One explanation is that it is a form of energy conservation in environments with high temperatures and/or agricultural labor. Disease palliation and prevention represents another area where the siesta might be beneficial. A preliminary study used the Human Relations Area Files (HRAF) to examine the characteristics associated with siesta occurrence. Siestas were not statistically associated with high temperatures or agricultural labor (p>.05). They were, however, statistically associated with the occurrence of malaria (p<.05) and marginally associated with parasitic and chronic infectious disease. Preliminary results suggest that siestas could be adaptive in environments with chronic infectious disease.

Predictors of poor sleep quality among Lebanese university students: association between evening typology, lifestyle behaviors, and sleep habits

Adequate, good night sleep is fundamental to well-being and is known to be influenced by myriad biological and environmental factors. Given the unavailability of sleep data about Lebanon, the cultural shifts and socioeconomic pressures that have affected many aspects of society, particularly for students and working adults, as well as our understanding of sleep in university students in other countries, we conducted a national study to assess sleep quality and factors contributing to sleep and general health in a culture-specific context. A self-filled questionnaire, inquiring about sociodemographics, health-risk behaviors, personal health, and evaluating sleep quality and chronotype using standard scales was completed by 540 students at private and public universities in Lebanon. Overall, they reported sleeping 7.95±1.34 hours per night, although 12.3% reported sleeping <6.5 hours and more than half scored in the poor-sleeper category on the Pittsburgh Sleep Quality Index (PSQI). Sleep timing differed markedly between weekdays and weekends, with bedtimes and wake-up times delayed by 1.51 and 2.43 hours, respectively, on weekends. While most scored in the "neither type" category on the Morningness-Eveningness Questionnaire (MEQ), 24.5% were evening types and 7.3% were morning types. MEQ score was significantly correlated with smoking behavior and daily study onset, as well as with PSQI score, with eveningness associated with greater number of cigarettes, later study times, and poor sleep. We conclude that the prevalence of poor sleep quality among Lebanese university students is associated with reduced sleep duration and shifts in sleep timing between weekdays and weekends, especially among evening types. While chronotype and certain behavioral choices interact to affect sleep dimensions and quality, raising awareness about the importance of obtaining adequate nighttime sleep on daily performance and avoiding risky behaviors may help Lebanese students make better choices in school and work schedules.

Sleep duration, quality, and timing and their associations with age in a community without electricity in Haiti

OBJECTIVES

Sleep comprises one-third of one's life, yet little is known about sleep in developing countries. Furthermore, many studies in industrialized countries have reported that sleep duration and quality decline with aging, but whether this association persists globally is unknown. This study's objectives were to characterize sleep in a community without electricity in Haiti and to examine associations between measures of sleep and age.

METHODS

Fifty-eight Haiti residents (50% women) in four age groups, 18-30, 31-50, 51-64, and ≥ 65 years participated. Three days of wrist actigraphy were used to estimate sleep patterns.

RESULTS

Mean (standard deviation) values of sleep measures were: 20:57 (0:40) for sleep onset, 4:54 (0:43) for sleep end, 9.3 (1.2) h for time in bed, 7.0 (1.0) h for sleep duration, 54 (24) min awake after sleep onset, and 88.7 (5.4)% for sleep maintenance (percentage of sleep period actually spent sleeping). There were no significant differences in the sleep measures between men and women. Regression analyses adjusting for sex, household size, and number of people sleeping in the same room indicated that only sleep fragmentation differed by age group. Specifically, mean fragmentation was higher in the youngest age group than all other age groups, which did not differ from one another.

CONCLUSIONS

Average time in bed in this Haitian sample was greater than previously reported for industrialized countries like the United States (9.3 versus. 7-8 h);, however, actual sleep duration averaged only 7 h. No age-related decline in sleep duration or quality was observed in Haiti.

Sociodemographic and cultural determinants of sleep deficiency: implications for cardiometabolic disease risk

Sleep is a biological imperative associated with cardiometabolic disease risk. As such, a thorough discussion of the sociocultural and demographic determinants of sleep is warranted, if not overdue. This paper begins with a brief review of the laboratory and epidemiologic evidence linking sleep deficiency, which includes insufficient sleep and poor sleep quality, with increased risk of chronic cardiometabolic diseases such as obesity, diabetes and hypertension. Identification of the determinants of sleep deficiency is the critical next step to understanding the role sleep plays in human variation in health and disease. Therefore, the majority of this paper describes the different biopsychosocial determinants of sleep, including age, gender, psychosocial factors (depression, stress and loneliness), socioeconomic position and race/ethnicity. In addition, because sleep duration is partly determined by behavior, it will be shaped by cultural values, beliefs and practices. Therefore, possible cultural differences that may impact sleep are discussed. If certain cultural, ethnic or social groups are more likely to experience sleep deficiency, then these differences in sleep could increase their risk of cardiometabolic diseases. Furthermore, if the mechanisms underlying the increased risk of sleep deficiency in certain populations can be identified, interventions could be developed to target these mechanisms, reduce sleep differences and potentially reduce cardiometabolic disease risk.

Sleep and sleepiness during an ultra long-range flight operation between the Middle East and United States

This study provides a practical example of fatigue risk management in aviation. The sleep and sleepiness of 44 pilots (11 trips × 4 pilot crew) working an ultra long-range (ULR; flight time >16 h) round-trip operation between Doha and Houston was assessed. Sleep was assessed using activity monitors and self-reported sleep diaries. Mean Karolinska Sleepiness Scores (KSS) for climb and descent did not exceed 5 ("neither alert nor sleepy"). Mean daily sleep duration was maintained above 6.3h throughout the operation. During in-flight rest periods, 98% of pilots obtained sleep and sleepiness was subsequently reduced. On layover (49.5h) crew were advised to sleep on Doha or Universal Co-ordinated Time (UTC), but 64% slept during the local (social) night time. Pilots originating from regions with a siesta culture were more likely to nap and made particularly effective use of their daytime in-flight rest periods. The results indicate that the operation is well designed from a fatigue management perspective.

Sleep characteristics of young children in Japan: internet study and comparison with other Asian countries

BACKGROUND

A recent international Internet-based study of young children (birth to 36 months) found that total sleep duration in Japan was the shortest among 17 countries/regions. The present study compared features of children's sleep in Japan relative to those in other Asian countries/regions.

METHODS

Parents of 872 infants and toddlers in Japan (48.6% boys), and parents of 20 455 infants and toddlers in 11 other Asian countries/regions (48.1% boys; China, Hong Kong, India, Indonesia, Korea, Malaysia, Philippines, Singapore, Taiwan, Thailand, and Vietnam) completed an Internet-based expanded version of the Brief Infant Sleep Questionnaire.

RESULTS

Young children in Japan exhibited significantly fewer nocturnal wakings and shorter daytime sleep in comparison with other Asian countries/regions. Although the former finding was apparent in all age groups, the reduced duration of daytime sleep in Japan was not present until after 3 months of age. Interestingly, sleep problems were reported by significantly fewer parents in Japan compared with those in other Asian countries/regions, although parents in Japan reported significantly more difficulty at bedtime.

CONCLUSIONS

The short sleep duration of young children in Japan is largely due to a relatively short duration of daytime sleep. Significant differences in sleep characteristics in Japan relative to other Asian regions were found primarily after 3 months of age. Future studies should further explore the underlying causes and the potential impacts of these sleep differences.

Sleep Patterns of Day-Working, Evening High-Schooled Adolescents of São Paulo, Brazil

Children who grow up in developing countries of the world must work to help financially support their families, and they must also attend school. We investigated the impact of work on the sleep of working vs. nonworking high school students. Twenty-seven São Paulo, Brazil, public high school students (eight male and eight female working students plus six nonworking female and five nonworking male students) 14-18 yrs of age who attended school Monday-Friday between 19:00 to 22:30h participated. A comprehensive questionnaire about work and living conditions, health status, and diseases and their symptoms was also answered. The activity level and rest pattern (sleep at night and napping during the day) were continuously assessed by wrist actigraphy (Ambulatory Monitoring, USA). The main variables were analyzed by a two-factor ANOVA with application of the Tukey HSD test for multiple comparisons, and the length of sleep during weekdays vs. weekends was compared by Student t-test. Working students went to sleep earlier weekends [F(1,23)=6.1; p=0.02] and woke up earlier work days than nonworking students [F(1,23) = 17.3; p = 0.001]. The length of nighttime sleep during weekdays was shorter among all the working [F(1,23)= 16.7; p <0.001] than all the nonworking students. The sleep duration of boys was shorter than of girls during weekends [F(1,23)= 10.8; p <0.001]. During weekdays, the duration of napping by working and nonworking male students was shorter than nonworking female students. During weekdays working girls took the shortest naps [F(1,23)= 5.6; p = 0.03]. The most commonly reported sleep complaint during weekdays was difficulty waking up in the morning [F(1,23) = 6.5; p = 0.02]. During weekdays, the self-perceived sleep quality of working students was worse than nonworking students [F(1,23) = 6.2; p = 0.02]. The findings of this study show that work has negative effects on the sleep of adolescents, with the possible build-up of a chronic sleep debt with potential consequent impact on quality of life and school learning.

Invited commentary: cross-cultural influences on sleep--broadening the environmental landscape

Recognition among epidemiologists of the adverse health consequences of sleep habits and sleep disorders has flourished in recent years. Identifying and understanding the cross-sectionally defined environmental factors that are associated with individual differences in habitual sleep duration represents an important line of inquiry. Because of the complexity of sleep as a behavior, traditional measures such as socioeconomic and marital status, health habits, and education may require supplementation with types of data that are both novel and less conventional. Studies across cultures offer one such possibility, although it may be necessary to broaden the view of the environment at both the macro level (e.g., seasonal, geographic, and climatic variation) and the micro level (the bedroom milieu and factors that affect it) in order to fully understand the scope of such influences.

Siesta and sleep patterns in a sample of adolescents in Greece

BACKGROUND

Sleep behaviors and disturbances in adolescence are being increasingly investigated. The aim of the present study was to investigate the sleep habits of adolescents living in provincial Greece.

METHODS

Responses to pre-constructed questionnaires on sleep habits and disturbances from 471 high-school students (259 boys; 212 girls), aged 14-18 years, attending four high schools of rural and semi-urban areas in north-western Greece, were analyzed.

RESULTS

The median nocturnal and total sleep duration was 7.5 h (range, 2.5-11 h) and 8.5 h (range, 2.5-14 h), respectively, and the average bedtime was 23.55 hours. Male students, older adolescents and residents of towns went to bed later than female students, younger adolescents and residents of villages (P = 0.039, P = 0.0003 and P = 0.056, respectively). Siesta on a regular basis was reported by 43% and on an occasional basis by 46% of the students. Siesta median duration was 1.5 h (range 0.5-4.5 h). Daytime sleepiness, difficulties in morning awakening and in falling asleep, and night awakenings were reported by 26.3%, 17.4%, 17.2% and 11.2%, respectively. Students who had siestas reported less daytime sleepiness (P < 0.0001). Significant differences were observed between boys and girls regarding sleep disturbances.

CONCLUSION

Adolescents in provincial Greece present with a different sleep pattern as compared to their northern European peers, characterized by late bedtime and midday siesta. Similarly to their peers in other countries, considerable rates of sleep disturbances were reported.

Sleep and behavioral correlates of napping among young adults: a survey of first-year university students in Madrid, Spain

OBJECTIVE

Between November 2002 and March 2003, the authors assessed the prevalence and correlates of napping among Spanish university students.

PARTICIPANTS

The sample comprised 1,276 first-year university students; the mean age was 18.74 +/- 1.24 years, and 35.45% were men.

METHODS

The study was cross-sectional, and the students completed self-report, anonymous questionnaires provided during an in-class survey.

RESULTS

Almost half (44%) of the sample reported napping (90% did so after lunch for longer than 1 hour). Multiple logistic regression analysis showed that experiencing an irregular sleep-wakefulness pattern, having a morning school schedule, and being male were significant predictor variables of napping. Further significant outcome variables related to napping were having excessive daytime sleepiness, missing classes because of tiredness, better ability to concentrate later in the afternoon, and a perception of deeper nighttime sleep.

CONCLUSIONS

Habitual napping is common among Spanish university students and associated with an irregular sleep-wakefulness pattern. Taking long postlunch naps seems to be used by students to cope with insufficient sleep and daytime sleepiness.

From wakefulness to excessive sleepiness: what we know and still need to know

The epidemiological study of hypersomnia symptoms is still in its infancy; most epidemiological surveys on this topic were published in the last decade. More than two dozen representative community studies can be found. These studies assessed two aspects of hypersomnia: excessive quantity of sleep and sleep propensity during wakefulness excessive daytime sleepiness. The prevalence of excessive quantity of sleep when referring to the subjective evaluation of sleep duration is around 4% of the population. Excessive daytime sleepiness has been mostly investigated in terms of frequency or severity; duration of the symptom has rarely been investigated. Excessive daytime sleepiness occurring at least 3 days per week has been reported in between 4% and 20.6% of the population, while severe excessive daytime sleepiness was reported at 5%. In most studies, men and women are equally affected. In the International Classification of Sleep Disorders, hypersomnia symptoms are the essential feature of three disorders: insufficient sleep syndrome, hypersomnia (idiopathic, recurrent or posttraumatic) and narcolepsy. Insufficient sleep syndrome and hypersomnia diagnoses are poorly documented. The co-occurrence of insufficient sleep and excessive daytime sleepiness has been explored in some studies and prevalence has been found in around 8% of the general population. However, these subjects often have other conditions such as insomnia, depression or sleep apnea. Therefore, the prevalence of insufficient sleep syndrome is more likely to be between 1% and 4% of the population. Idiopathic hypersomnia would be rare in the general population with prevalence, around 0.3%. Narcolepsy has been more extensively studied, with a prevalence around 0.045% in the general population. Genetic epidemiological studies of narcolepsy have shown that between 1.5% and 20.8% of narcoleptic individuals have at least one family member with the disease. The large variation is mostly due to the method used to collect the information on the family members; systematic investigation of all family members provided higher results. There is still a lot to be done in the epidemiological field of hypersomnia. Inconsistencies in its definition and measurement limit the generalization of the results. The use of a single question fails to capture the complexity of the symptom. The natural evolution of hypersomnia remains to be documented.

Circadian rhythms and sleep patterns in urban Greek couples

A convenience sample of 14 adults (seven couples) who intentionally nap regularly was recruited to describe circadian rhythms and sleep patterns in a culture in which afternoon naps are routine. Participants wore a wrist actigraph for 48 hr during May to obtain two peaks and troughs of activity data. Peak activity, estimated by cosinor analysis (acrophase), occurred at 1542 hours for men and at 1600 hours for women. Compared to their male partners, women had a later acrophase and a significantly stronger 24-hr rhythm, despite similar nap and nighttime sleep schedules. Men had more awakenings during the night and slightly shorter naps than did women. For the 24-hr period, men averaged 6.8 +/- 1.0 hr of sleep and women averaged 7.4 +/- 1.1 hr. Results indicate that Greek adults delay sleep onset at night and awaken early in the morning. Among this small group, naps are an accepted cultural behavior.

Sleep and sleepiness among working and non-working high school evening students

The aim of this study was to evaluate patterns of sleepiness, comparing working and non-working students. The study was conducted on high school students attending evening classes (19:00-22:30 h) at a public school in São Paulo, Brazil. The study group consisted of working (n=51) and non-working (n=41) students, aged 14-21 yrs. The students answered a questionnaire about working and living conditions and reported health symptoms and diseases. For seven consecutive days, actigraphy measurements were recorded, and the students also filled in a sleep diary. Sleepiness ratings were given six times per day, including upon waking and at bedtime, using the Karolinska Sleepiness Scale. Statistical analyses included three-way ANOVA and t-test. The mean sleep duration during weekdays was shorter among workers (7.2 h) than non-workers (8.8 h) (t=4.34; p<.01). The mean duration of night awakenings was longer among workers on Tuesdays and Wednesdays (28.2 min) and shorter on Mondays (24.2 min) (t=2.57; p=.03). Among workers, mean napping duration was longer on Mondays and Tuesdays (89.9 min) (t=2.27; p=.03) but shorter on Fridays and Sundays (31.4 min) (t=3.13; p=.03). Sleep efficiency was lower on Fridays among non-workers. Working students were moderately sleepier than non-workers during the week and also during class on specific days: Mondays (13:00-15:00 h), Wednesdays (19:00-22:00 h), and Fridays (22:00-00:59 h). The study found that daytime sleepiness of workers is moderately higher in the evening. This might be due to a work effect, reducing the available time for sleep and shortening the sleep duration. Sleepiness and shorter sleep duration can have a negative impact on the quality of life and school development of high school students.

Teen at work: the burden of a double shift on daily activities

The purpose of this study was to the evaluate time spent by working and nonworking adolescents on daily activities (work, home duties, school, transportation, other activities, leisure, sleep, and naps). Twenty-seven students, 8 male workers, 8 female workers, 5 male nonworkers, and 6 female nonworkers, ages 14-18 yrs participated in the study. They attended evening classes Monday-Friday (19:00-22:30h) in a public school in the city of São Paulo, Brazil. The students answered a comprehensive questionnaire on the characterization of their life, work, and health conditions. Simultaneously, they wore actigraphs (Ambulatory Monitoring, Inc.) and completed a diary of their daily activities (time spent at work, on home duties, commuting, leisure, other activities) for a minimum of 10 to a maximum of 17 consecutive days. The means of the variables were tested for differences by a two-factor (work and sex) ANOVA and Student-t test applied to pair-wise samples (weekdays and weekends). The average duration during weekdays of working time was 7 h 09 min and home duties 0 h 48 min. As for commuting time, there was a work effect [F(1,23) = 4.9; p = 0.04]; mean commuting time was 2 h 22 min for workers (males and females) and 1 h 25 min for nonworkers. There was a significant difference between workers and nonworkers [F(1,23) = 4.6; p = 0.04] regarding extra-cirricular class activities; workers spent a mean of 3 min/day on them as opposed to 1 h 14 min by nonworkers. The average daily time spent on leisure activities by workers was 6h 31 min; whereas, for nonworkers it was 7h 38min. Time spent in school amounted to 2h 47min for workers in comparison to 3h 22min by nonworkers. There was a significant work effect upon sleep [F(1,23)= 10.0; p <0.01]. The work effect upon nighttime sleep duration was significant [F(1,23)= 16.7; p <0.01]. Male workers showed a mean night sleep of 6 h 57 min and female workers 07h 15min. The average nighttime sleep duration for nonworkers was 9 h 06 min. There was a significant interactive effect between work and sex [F(1,23)= 5.6; p=0.03] for naps. Female workers showed took shortest nap on average (36 min; SD = 26 min), and female nonworkers the longest naps (1 h 45min; SD= 35min). Study and employment exert significant impact on the life and activities of high school students. Work affects sleep and nap duration plus the amount of time spent in school and other extra-curricular activities.

Ethnocultural differences in sleep complaints among adolescents

Data from a school survey (N = 5423) were used to examine differences in sleep complaints among adolescents from nine ethnocultural groups. Compared with Anglo youths, Chinese American youths were at significantly lower risk for insomnia, whereas Mexican American youths had an elevated risk, adjusting for the effects of age, gender, and socioeconomic status. Adjusting for the same three covariates, African, Mexican and Central American youths were at elevated risk for hypersomnia. No group was at lower risk for hypersomnia than the Anglos. The results suggest minority status may affect risk for sleep problems but that the direction and the magnitude of the effects vary depending on the outcome examined, severity of the problem, and the ethnic group studied. Given the paucity of data on culture and risk for disturbed sleep among adolescents, more research is needed on the role of ethnocultural background on sleep.

Siestas among Brazilian Native Terena adults : a study of daytime napping

Regular daytime napping behavior, also known as siesta culture, is influenced by circadian, cultural and environmental factors. This research analyzes characteristics of regular daytime napping in Brazilian Native Terenas. We evaluated 65 adults ( 32 M; 33 F ) from 18 to 75 years, with a mean age of 37.2, from the Indian Reservation village Córrego do Meio, in the central region of Mato Grosso do Sul. Daytime napping characteristics were evaluated by means of a standard questionnaire applied to each individual. It was observed that weekly daytime napping (at least once a week) was present in 72. 3% of the population. There was a tendency to occur in males. The effects of weekends was mild. Mean onset time of daytime sleep was 12.2 h, remarkably earlier than usually described in urban populations. This data stresses the need to consider ethnic influences in order to understand sleep habits.