Research on the relationship between the structural properties of bedding layer in spring mattress and sleep quality

Mattress, as a sleep platform, its types and physical properties has an important effect on sleep quality and rest efficiency. In this paper, by subjective evaluations, analysis of sleeping behaviors and tests of depth of sleep, the relationship between characteristics of the bedding materials, the structure of mattress, sleep quality and sleep behaviors were studied. The results showed that: (1) Characteristics of the bedding materials and structure of spring mattress had a remarkable effect on sleep behaviors and sleep quality. An optimum combination of the bedding materials, the structure of mattress and its core could improve the overall comfort of mattress, thereby improving the depth of sleep and sleep quality. (2) Sleep behaviors had a close relationship with sleeping postures and sleep habits. The characteristics of sleep behaviors vary from person to person.     

Modeling human-bed interaction: the predictive value of anthropometric models in choosing the correct bed support

The sleep system (i.e. the combination of mattress and bed base) is an important factor of the sleep environment since it allows physical recuperation during sleep by providing proper body support. However, various factors influence the interaction between the human body and the sleep system. Contributing factors include body dimensions, distribution of body weight and stiffness of the sleep system across the mattress surface. During the past decade, the rise of several new bedding technologies has made it increasingly difficult for the consumer to select a proper sleep system. Therefore, this study presents a method to model human-bed interaction in order to objectively predict the ideal sleep system for a particular individual. The proposed method combines a personalized anthropometric model with standardized load-deflection characteristics of mattress and bed base. Results for lateral sleep positions show a root mean square deviation of 11.9 ± 6.1 mm between modeled spine shapes and validation shapes, derived from 3D surface scans of the back surface. The method showed to be a reliable tool to individually identify the sleep system providing superior support from a variety of possible mattress-bed base combinations.     

Early to bed and earlier to rise: school,maternal employment,and children’s sleep

School-age children need 10–11 h of sleep per night. It has been well-documented that lack of sleep leads to diminished cognitive performance and that people who sleep less are more likely to be overweight or obese. I use data from the American Time Use Survey to examine two factors that can potentially influence the amount of time children sleep: school and maternal employment. I find that school-age children sleep less when school is in session than during the summer, and that they get less sleep on school nights than on non-school nights. Children go to bed about 38 min earlier on school nights, but wake up about 72 min earlier on school days. This translates into about 34 min less sleep on school nights compared with non-school nights, and implies that these children have a cumulative sleep deficit of over two-and-a-half hours by the time they arrive at school Friday morning. In addition to the lost sleep time, the earlier wake-up times on school days appear to disrupt children’s natural sleep cycles. Maternal employment affects children’s sleep time in the summer, because children wake up earlier on days that their mothers work. But during the school year, maternal employment effects are dominated by school effects.     

Minor psychiatric disorders among nursing workers--is there an association with current or former night work?

We aimed at analyzing whether Minor Psychiatric Disorders (MPD) is associated to night work either currently or in the past. A cross-sectional study was conducted at three public hospitals in Brazil, with female nursing workers. Data collection (N=1,134) was based on a comprehensive questionnaire that included the self-reported questionnaire (SRQ-20) for screening of MPD. Former night workers were subdivided into three groups according to their reasons for leaving night work: (i) directly related to work, (ii) related to better reconcile with studies or another job, and (iii) related to health, sleep, fatigue or stress. Binomial logistic regression was performed, with adjustment for potential confounders. A dose response gradient was observed between current night work and MPD (OR=1.5; 95% CI: 1.1-2.2 and OR=2.1; 95%CI: 1.5-3.1 for those who worked up to five nights and six or more nights per 2-week span, respectively). Potential detrimental effects of night work were confirmed. The association between working at night and MPD was not restricted to current night workers as workers who left night work for health/fatigue/sleep/strain also showed higher chances of reporting MPD (OR=1.8;95%CI:1.14-2.90). Results contribute to the scientific debate on the impact of night work on health and wellbeing.     

Automatic sleep stage classification based on easy to register signals as a validation tool for ergonomic steering in smart bedding systems

Ergonomic sleep studies benefit from long-term monitoring in the home environment to cope with daily variations and habituation effects. Polysomnography allows to asses sleep accurately, but is costly, time-consuming and possibly disturbing for the sleeper. Actigraphy is cheap and user friendly, but for many studies lacks accuracy and detailed information. This proof-of-concept study investigates Least-Squares Support Vector Machines as a tool for automatic sleep stage classification (Wake-N1-Rem to N2-N3 separation), using automatic trainingset-specific filtered features as derived from three easy to register signals, namely heart rate, breathing rate and movement. The algorithms are trained and validated using 20 nights out of a 600 night database from over 100 different healthy persons. Different training and test set strategies were analyzed leading to different results. The more person-specific the training nights to the test nights, the better the classification accuracy as validated against the hypnograms scored by experts from the full polysomnograms. In the limit of complete person-specific training, the accuracy of the algorithm on the test set reached 94%. This means that this algorithm could serve its use in long-term monitoring sleep studies in the home environment, especially when prior person-specific polysomnographic training is performed.     

Infant motor development predicts the dynamics of movement during sleep

The characteristics of infant sleep change over the first year. Generally, infants wake and move less at night as they grow older. However, acquisition of new motor skills leads to temporary increases in night waking and movement at night. Indeed, sleep-dependent movement at night is important for sensorimotor development. Nevertheless, little is known about how movement during sleep changes as infants accrue locomotor experience. The current study investigated whether infant sleep and movement during sleep were predicted by infants' walking experience. Seventy-eight infants wore an actigraph to measure physical activity during sleep. Parents reported when their infants first walked across a room >10 feet without stopping or falling. Infants in the midst of walking skill acquisition had worse sleep than an age-group estimate. Infants with more walk experience had more temporally sporadic movement during sleep and a steeper hourly increase in physical activity over the course of the night. Ongoing motor skill consolidation changes the characteristics of movement during sleep and may alter sleep state-dependent memory consolidation. We propose a model whereby changes in gross motor activity during night sleep reflect movement-dependent consolidation.     

Caregiving at night: Understanding the impact on carers

Caregiving research has rarely examined the nature and impact of care provision at night. This paper analyses indepth interviews with 24 older people in England whose sleep had been adversely affected by providing care at night. A framework is proposed that illustrates how six aspects of caregiving can disrupt carers' sleep quality: first, attending to the night-time physical needs of the care recipient; second, anticipation of their night-time care needs; third, ‘monitoring’ their relative at night; fourth, disruption from relatives who are awake for long periods at night, wandering or shouting; fifth, undertaking emotional support, and worries or anxieties related to their relative; and finally, the legacy of caregiving may continue to disrupt sleep after caring ceases, because of painful images of their relative's suffering or feelings of guilt. Adverse effects on carers' sleep are greatest for co-resident carers, especially when caring for a spouse or relative with a life-limiting illness or dementia.     

Analysis of ergonomics conditions of a brand of mattress and pillows. University-industry project, Medellín-Colombia

This project presents an analysis of the ergonomic conditions of three types of mattress and three types of pillow. The products are manufactured by a Colombian company which specializes in flexible polyurethane foam and other products designed for rest and relaxation. The project was developed through the University - Industry relationship: a strategic partnership based on the knowledge and strengths of each component. The conceptual theories that underpin the Ergonomics Research Division of the Design Studies Research Group (GED) provided the methodological approach for the project: the characteristics, the requirements and the relationships that are established between the components that constitute the User - Product - Context system (basic principles of the Ergonomics - Design relationship). An important factor in the project was the conception and measurement of comfort. Comfort can be measured on an objective level (quantitative measurement), and on a subjective level (a user's particular perceptions and tastes). What constitutes 'comfort' can vary from person to person, thus making the identification of criteria for the standardization of consumer products problematic. This project enabled design recommendations to be made to the Company vis-à-vis future proposals for mattress and pillow products. This experience of applied research was carried out by professors and students from the Faculty of Industrial Design at the UPB in Medellín, Colombia.     

Leisure-time physical activity and health-care utilization in older adults

This study examined whether leisure-time physical activity (LTPA) was associated with health-care utilization in a racially diverse sample of rural and urban older adults. Community-dwelling adults (N = 1,000, 75.32 +/- 6.72 years old) self-reported participating in LTPA and their use of the health-care system (physician visits, number and length of hospitalizations, and emergency-room visits). After controlling for variables associated with health and health-care utilization, older adults who reported lower levels of LTPA also reported a greater number of nights in the hospital in the preceding year. There was no support, however, for a relationship between LTPA and the other indicators of health-care utilization. Our findings suggest that being physically active might translate to a quicker recovery for older adults who are hospitalized. Being physically active might not only have health benefits for older persons but also lead to lower health-care costs.     

Daily Variation in Adolescents' Sleep,Activities, and Psychological Well‐Being

The daily diary method was used to examine the daily dynamics of adolescent sleep time, activities, and psychological well‐being among an ethnically diverse sample of over 750 adolescents approximately 14–15 years of age. Studying and stressful demands during the day were modestly but consistently associated with less sleep that evening. Receiving less sleep at night, in turn, was modestly but consistently related to higher levels of anxiety, depressive feelings, and fatigue during the following day. In addition, the daily variability in adolescents' sleep time was notable and just as important for the youths' average levels of daily psychological well‐being as was the average amount of time spent sleeping each night. A small number of ethnic and gender differences emerged in the dynamics of adolescent sleep, activities, and well‐being. Discussion focuses on the importance of examining variability in adolescents' sleep behaviors in order to better understand the implications of sleep for adolescent well‐being and development.     

Daily rhythm of salivary IL-1ß, cortisol and melatonin in day and night workers

Shiftwork-induced sleep deprivation and circadian disruption probably leads to an increase in the production of cytokines and dysregulation of innate immune system, respectively. This project aims evaluating changes in salivary IL-1 beta, cortisol, and melatonin in night workers. Method. Two day and three night healthy workers participated in this study. Sleep was evaluated by actimetry and activity protocols. Saliva was collected at waking and bedtime the last workday and the following two days-off and was analyzed by ELISA. Results. Neither sleep duration nor efficiency showed any association with salivary IL-1beta. IL-1beta levels were higher at waking than at bedtime during working days for all workers, but only one day and one night-worker maintained this pattern and hormone rhythms during days off. For this night worker, melatonin levels were shifted to daytime. A second one presented clear alterations in IL-1beta and hormone rhythms on days-off. Conclusions. Our preliminary results suggest that night work can disturb the variation pattern of salivary IL-1beta. No association of this variation with sleep was observed. It seems that disruption in hormone rhythms interfere with salivary IL-1beta production. IL- 1beta production pattern seems to be maintained when rhythms are present, in spite of a shift in melatonin secretion.     

Sleep patterns of college students at a public university

OBJECTIVE: The authors' purpose in this study was to determine the sleep patterns of college students to identify problem areas and potential solutions. PARTICIPANTS: A total of 313 students returned completed surveys. METHODS: A sleep survey was e-mailed to a random sample of students at a North Central university. Questions included individual sleep patterns, problems, and possible influencing factors. RESULTS: Most students reported later bedtimes and rise times on weekends than they did on weekdays. More than 33% of the students took longer than 30 minutes to fall asleep, and 43% woke more than once nightly. More than 33% reported being tired during the day. The authors found no differences between freshmen, sophomores, juniors, seniors, and graduate students for time to fall asleep, number of night wakings, or total time slept each night. CONCLUSIONS: Many students have sleep problems that may interfere with daily performance, such as driving and academics. Circadian rhythm management, sleep hygiene, and white noise could ameliorate sleep difficulties.     

The relationship between social media use and sleep quality among undergraduate students

Insufficient sleep is a growing health problem among university students, especially for freshmen during their first quarter/semester of college. Little research has studied how social media technologies impact sleep quality among college students. This study aims to determine the relationship between social media use and sleep quality among freshman undergraduates during their first quarter in college. Specifically, we explored whether variations in Twitter use across the time of day and day of the week would be associated with self-reported sleep quality. We conducted a study of freshman Twitter-using students (N?=?197) over their first quarter of college, between October and December of 2015. We collected students’ tweets, labeled the content of the tweets according to different emotional states, and gave theme weekly surveys on sleep quality. Tweeting more frequently on weekday late nights was associated with lower sleep quality (β?=??0.937, SE?=?0.352); tweeting more frequently on weekday evenings was associated with better quality sleep (β?=?0.189, SE?=?0.097). Tweets during the weekday that were labeled related to the emotion of fear were associated with lower sleep quality (β?=??0.302, SE?=?0.131). Results suggest that social media use is associated with sleep quality among students. Results provided can be used to inform future interventions to improve sleep quality among college students.     

Preparing,Working, Recovering: Gendered Experiences of Night Work among Women and their Families

The negative physiological consequences of night work are well evidenced, but there has been limited research on the gendered consequences of night work for partnered women with children. This paper examines women's experiences of night work by drawing on qualitative interview and audio sleep diary data with 20 UK female nurses working non‐regular rotating shifts, together with interview and diary data from their male partners and children. The analysis shows how the lived experience of women's night work is characterized by three phases, which we discuss within a timescape perspective. Alongside changes to paid work and sleep during the period of night shifts, the ‘preparation’ and ‘recovery’ phases of women's night work involve intense periods of considerable additional unpaid and unrecognized work and anxiety. Gendered expectations for household management and family wellbeing mean that women night workers undertake considerable responsibility for complex planning before night shifts begin, and re‐enter established domestic routines within hours after night shifts end. Women maintain continuity for their families by actively managing the impacts of night work. This enables the fulfilment and ‘display’ of successful and normative gendered patterns of domestic responsibility, which appears to be central to women's own coping with night shifts.     

Nonstandard Work Schedules and Marital Instability

Based on subsample of 3,476 married couples drawn from two waves of the National Survey of Families and Household, this study examines the extent to which working evening, night, or rotating schedules and weekends affects the likelihood of marriages ending in separation or divorce within approximately 5 years. Logistic regression analysis revealed that this relationship depends on the presence of children and is specific to the type of nonstandard schedule, the gender of the spouse, and the duration of marriage. Among men with children, married less than 5 years at Wave 1, working fixed nights made separation or divorce some six times more likely relative to working days. Among women with children, married more than 5 years at Wave 1, working fixed nights increased the odds by three times, and might have had an effect during the earlier years of marriage as well (although not statistically significant). These findings are evident when controlling for the number of hours worked as well as for demographic variables, and when considering, in addition, the husband's and wife's gender ideologies and the extent to which couples spent time alone together. The question of whether spouses in troubled marriages are more likely to move into night or rotating shifts was explored, but this did not seem to be the case.     

Sleep Patterns of College Students at a Public University

Objective: The authors' purpose in this study was to determine the sleep patterns of college students to identify problem areas and potential solutions. Participants: A total of 313 students returned completed surveys. Methods: A sleep survey was e-mailed to a random sample of students at a North Central university. Questions included individual sleep patterns, problems, and possible influencing factors. Results: Most students reported later bedtimes and rise times on weekends than they did on weekdays. More than 33% of the students took longer than 30 minutes to fall asleep, and 43% woke more than once nightly. More than 33% reported being tired during the day. The authors found no differences between freshmen, sophomores, juniors, seniors, and graduate students for time to fall asleep, number of night wakings, or total time slept each night. Conclusions: Many students have sleep problems that may interfere with daily performance, such as driving and academics. Circadian rhythm management, sleep hygiene, and white noise could ameliorate sleep difficulties.     

Behavior of Infant Chimpanzees During the Night in the First 4 Months of Life: Smiling and Suckling in Relation to Behavioral State

This article reports the behavior of 3 newborn chimpanzees in the first 4 months of life, reared by their mothers and living in a community of 14 chimpanzees in a semi‐natural enriched environment. We focused on spontaneous activity during the night partly because sleeping behavior constitutes an essential part of the infants' activity. Observation during the night also had the advantage of keeping the influence of the mothers' activity as well as the environmental stimulation constant throughout the observation period. We report several interesting findings. Behavioral states defined through overt features such as open or closed eyes were variable during the night, with the rapid eye movement (REM) and non‐REM sleep patterns alternating much as they do in human infants. Although crying is one of the distinctive behavioral states in the case of human infants, the chimpanzee infants did not cry like humans. Suckling behavior was often accompanied by open eyes until the end of the first 2 months. Thereafter, suckling with the eyes closed became more prominent. Although there were no explicit stimuli, the newborns showed neonatal smiling with the eyes closed during REM sleep periods. However, neonatal smiling disappeared within the first 2 months and was replaced by social smiling with open eyes. Taken together, the results suggest a strong similarity between human infants and chimpanzee infants in terms of developmental changes in spontaneous activities at around 2 months of age.     

Losing Sleep Over It: Daily Variation in Sleep Quantity and Quality in Canadian Students' First Semester of University

Daily covariation of sleep quantity and quality with affective, stressful, academic, and social experiences were observed in a sample of Canadian 17–19‐year‐olds in their first year of university. Participants (N=191) completed web‐based checklists for 14 consecutive days during their first semester. Multilevel models predicting sleep quantity and quality from daily experiences indicated that more time on schoolwork, expecting a test, and alcohol use predicted less sleep whereas socializing predicted more sleep. More positive affect and no alcohol use predicted better sleep quality. Models predicting daily experiences from sleep the night before indicated that less sleep preceded increases in negative affect, decreases in schoolwork time, and a higher likelihood of socializing. Better sleep quality preceded increased positive affect, decreased negative affect and stress, and less time on schoolwork. These data are informative for understanding relations between sleep and daily experiences as they occur naturally in first‐year university students.     

MORNING AND NIGHT COUPLES: THE EFFECT OF WAKE AND SLEEP PATTERNS ON MARITAL ADJUSTMENT*

This study explored the effects of spouses' wake and sleep patterns on marital adjustment. A total of 150 couples from three states completed questions on wake/sleep patterns, marital interaction, marital adjustment, and problem solving. Couples whose wake and sleep patterns were mismatched (e.g., an evening person married to a morning person) reported significantly less marital adjustment, more marital conflict, less time spent in serious conversation, less time spent in shared activities and less frequent sexual intercourse than matched couples. Contrary to expectations for matched couples, night couples did not report more involvement in extra-familial social activities than morning couples. Morning couples engaged in sexual intercourse more frequently in the morning than night couples; night couples had sex more often in the evening than morning couples. There were no significant differences in the intercourse rates for morning couples and night couples. Compared to matched couples, mismatched couples with high marital adjustment reported more flexibility and adaptability in their marital problem solving. The implications of these findings for premarital counseling and marital therapy are discussed.