Article

The influence of bed firmness on sleep quality

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Abstract

We studied the relationship between sleep quality and bed surface firmness. Nine men were investigated, sleeping in their homes for at least 5 consecutive nights on a soft and a more firm mattress using a sensor pad placed under the mattress and a solid-state recording device. The subjective feeling of sleep quality did not always agree with the recorded sleep data. The difference was most marked when changing from the subject's own to one of the test mattresses. For the same subject the results were reproducible between nights provided there were no external disturbing factors. Four of the 9 subjects slept significantly better on the softer of the two mattresses and 2 on the hard mattress. The difference in sleep quality observed among the subjects tested makes it necessary to relate the results to the same person rather than considering a whole group as an entity. The adaptation period for a new sleep surface extended to many days.

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... Some studies evaluate the association between sleep surface, sleep quality and pain (back and shoulder) [8,9]. Bader et al. [10] concluded that mattress differences did not significantly affect sleep quality, whereas others consider that those with different firmness or construction can affect quality of sleep [11]. ...
... The influence of the hardness of a mattress in sleep quality and low back pain is subject of controversy, Bader et al. [10] found no difference in subjective sleep quality between two mattresses, commercially sold as smooth and hard. In the same way, in the present study there was no change in the sleep quality, measured by PSQI. ...
... In our study, P-VAS was steeply reduced over the duration of the study. It has been described that new mattresses require time to deliver full benefit [10], nevertheless there is no agreement of the amount of break-in time. Rosekind [33] suggested 15 nights long and others just 5 or 6 nights long [6]; moreover Scharf et al. [34] consider that only one night could be enough to adapt. ...
Article
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We aimed to evaluate the impact in sleep quality and musculoskeletal pain of a Medium-Firm Mattress (MFM), and their relationship with objective sleep parameters in a group of institutionalized elders. The sample size included forty older adults with musculoskeletal pain. We did a clinical assessment at baseline and weekly trough the study period of four weeks. We employed the Pittsburgh Sleep Quality Index (PSQI) and Pain Visual Analog Scale (P-VAS). Additionally a sub-group of good sleepers, selected from PSQI baseline evaluation, were studied with actigraphy and randomized to MFM or High Firm Mattress (HFM), in two consecutive nights. We found a significant reduction of cervical, dorsal and lumbar pain. PSQI results did not change. The actigraphy evaluation found a significant shorter sleep onset latency with MFM, and a slightly better, but not statistically significant, sleep efficiency. The medium firmness mattress improved musculoskeletal pain and modified the sleep latency.
... To improve sleep quality, various mattresses have been designed in existing studies [25][26][27]. In a few studies, a thermal controlling device was applied to the developed mattress to improve the sleep quality of the users [28][29][30][31]; others studies have determined the relation between sleep quality and the rigidity of a mattress [27,32,33]. Furthermore, several studies have varied the materials used to design the mattress and have modified its structure [34][35][36]. ...
... The study showed a discrepancy between the subjective and objective sleep evaluations. Bader et al. conducted an objective sleep evaluation using sleep parameters obtained from BCG signals and a subjective sleep evaluation obtained from self-made questionnaires on soft and hard mattresses [32]. In that study, there was also a discrepancy between the subjective and the objective sleep evaluation. ...
Article
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Several studies, wherein the structure or rigidity of a mattress was varied, have been conducted to improve sleep quality. These studies investigated the effect of variation in the surface characteristics of mattresses on sleep quality. The present study developed a mattress whose rigidity can be varied by controlling the amount of air in its air cells. To investigate the effect of the variable rigidity of the air mattress on sleep quality, participants (Male, Age: 23.9 ± 2.74, BMI: 23.3 ± 1.60) were instructed to sleep on the air mattress under different conditions, and their sleep quality was subjectively and objectively investigated. Subjectively, sleep quality is assessed based on the participants’ evaluations of the depth and length of their sleep. Objectively, sleep is estimated using the sleep stage information obtained by analysing the movements and brain waves of the participants during their sleep. A subjective assessment of the sleep quality demonstrates that the participants’ sleep was worse with the adjustment of the air mattress than that without; however, the objective sleep quality results demonstrates an improvement in the sleep quality when the rigidity of the air mattress is varied based on the participant’s preference. This paper proposes a design for mattresses that can result in more efficient sleep than that provided by traditional mattresses.
... Previous studies suggest that sleeping device has an important role on sleep quality and health. 14,15 Our results suggest that subjective sleep quality perception is independent of sleeping device, but objective sleep quality measures (actigraphy) show differences between users of the hammock or bed. However, sex and BMI were better predictors of sleep actigraphy parameters than sleeping device. ...
... Nonetheless, since the subjects slept either in bed or hammock, but not in both, it was not possible to establish whether their subjective perception of sleep quality was different according to the sleeping device. On the other hand, besides the sleeping device itself, other factors associated with its use could condition the perception of sleep quality, such as (1) the perception of comfort, as suggested by studies performed in comfortable and uncomfortable beds 14,15 and (2), the usual sleeping device, since previous investigations indicate that the change from hammock to bed alters the perception of sleep quality in hospital conditions. 4 On the other hand, objective data indicate that hammock users have a higher ACTX and shorter MSEP. ...
Article
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Objectives To compare and predict sleep quality between bed and hammock users . Design Cross-sectional pilot study. Setting Habitual hammock and bed users of southern Mexico. Participants Sixty-eight college students (53% female, mean age 21 ± 1.6 years); 33 usually sleep in bed and 35 in hammock. Intervention Not applicable. Measurements Objective sleep measures were obtained using an actigraphy device on 7 consecutive days. Questionnaires about sleep habits and sleepiness (Epworth scale) were completed. Body mass index (BMI) was obtained with a weighing machine and altimeter. Results Subjective sleep measures between habitual hammock and bed users were not significant (P > .05). Differences were found on 2 objective sleep measures: (1) activity index, on which hammock users obtained 7.62 minutes more than bed users (M = 36.72, standard deviation [SD] = 10.86 vs M = 44.34, SD = 13.08, P = .018) and (2) mean sleep episodes, on which hammock users had 19.67 minutes less than bed users (M = 71.52, SD = 34.37 vs M = 51.85, SD = 24.29, P = .014). Hammock users had a higher BMI than bed users (M = 23.38, SD = 3.45 vs M = 26.20, SD = 4.86, P = .010). Sex and BMI were included in the predictive model of linear regression (P < .05) of the sleep actigraphy parameters, the sleeping device was excluded of final model. Conclusions Hammock users show increased BMI, higher activity index and shorter mean sleep episodes than bed users. However, sex and BMI were stronger predictors of actigraphy parameters than bed type.
... Many previous studies that evaluated the effects of mattresses on sleep among healthy participants have lacked clarity in their descriptions of the nature of interventions performed and the methods used to evaluate sleep. Ambiguous terms, such as "soft, " "firm, " "comfort, " and "dis- comfort" have been used to describe the different types of mattresses used [8][9][10], while some studies provided no detailed information about their mattresses [11,12], making experiments difficult to repeat. Other studies evaluated the effects of mattresses on pressure distribution and spinal distortion but did not measure sleep quality [13][14][15][16]. ...
... The following reasons can be cited as no difference in the major PSG parameters between the mattresses. Firstly, the participants of the present study were young healthy men and their sleep efficiency (approximately 97% for both mattresses) was higher in the present study than the 80-93% efficiency reported in previous studies [9,12,18], suggesting the ceiling effect. Secondly, intervention using a mattress was too subtle and did not change the whole night sleep dramatically. ...
Article
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Background and Objective This study evaluated the effects of a mattress with better body pressure dispersal in comparison to a control mattress on sleep quality. Methods In this randomized crossover study, 10 healthy young men slept in an experimental sleep room on either a functional mattress made from polyurethane, with a special four-layer three-dimensional structure, or a control mattress made from solid polyester wadding, which is a mattress commercially available in Japan. Polysomnography recordings were used to characterize sleep architecture, and the length of slow wave sleep (SWS) episodes and delta power density were calculated from the electroencephalography data and subjective sleep quality was evaluated by questionnaire they answered after waking. Results There were no significant differences in sleep latency, the total duration of each sleep stages, total sleep time, or sleep efficiency. Although the difference was subtle, delta power density significantly increased with the functional mattress. There was no difference in the total duration of SWS, but there were significantly fewer SWS episodes with the functional mattress (10.3 ± 1.8) than with the control mattress (16.9 ± 1.2) and longer SWS episode duration (10.9 ± 1.7 min) with the functional mattress than with the control mattress (5.6 ± 0.5 min). Conclusions It was suggested that the functional mattress lengthened SWS episode duration, and its fragmentation was effective in evaluating the sleep quality of healthy young individuals.
... 33 Other factors such as environmental noise and bed firmness were also associated with sleep quality and/or OSA. 34,35 As considering those who experienced sleep deprivation showed decreased vigilance and increased response times even when they did not complain of severe sleepiness, 36,37 decreased sleep quality associated with sleeping environments could results in disastrous result. It has also been studied that decreased sleep quality is associated with occupational accidents. ...
... Sleeping environments at home were not associated with human errors and near-miss events in our study. However, considering previous studies that suggested sleeping environments including thermal environment, noise and bed firmness be associated with sleep quality and/or OSA, [33][34][35]43 the results of our study could not be interpreted as sleeping environments at works are only important for sleep quality of train workers. Jay et al reviewed articles related to sleeping at work and concluded that sleep at home tends to be longer and more efficient and is the familial environment for workers. ...
Article
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Objectives Reducing human errors caused by daytime sleepiness among train drivers is important to prevent train accidents. Our purpose of the study was to investigate the association among sleep, workplace sleeping environments, and human errors. Methods We recruited 144 South Korean train drivers belongs to the Korean Railroad Corporation. This cross‐sectional data was analyzed to investigate the association of insomnia (insomnia severity index), sleep quality (Pittsburgh sleep quality index), obstructive sleep apnea (Berlin questionnaire), and daytime sleepiness (Epworth scale) with human error and near‐miss experiences. We examined whether human error and near‐miss events were associated with various sleeping environments at work and at home after adjusting for the sleep indices. Results The experience of human errors was associated with insomnia and daytime sleepiness, and near‐miss events were associated with insomnia among South Korean drivers. Sleeping environments including cold temperature and odor were related to both human errors and near‐miss events among South Korean train drivers, after adjusted for age, working years, shiftwork, obesity, smoking, binge drinking, regular exercise, caffeine consumption, sleep quality, severity of insomnia, obstructive sleep apnea, and daytime sleepiness. Conclusions The train drivers’ workplace sleeping environment is significantly associated with human error events and near‐miss events after adjusting for sleep quality, insomnia, obstructive sleep apnea, and daytime sleepiness. To prevent train accidents caused by human errors, more attention is necessary for improving workplace sleeping environments.
... (Kovacs et al. 2003). Nonetheless, the influence of the hardness of a mattress in sleep quality is subject of controversy (Bader and Engdal 2000). Moreover, to the best of our knowledge, no previous study examined the effect of a mattress on sleep, pain, and recovery in toplevel athletes. ...
... Even if it is commonly believed that changing sleep surfaces could improve sleep, the scientific literature in this research field is extremely scarce and the impact of mattress on sleep quality is still controversial (Radwan et al. 2015). Previous studies reported that unsuitable and low-quality mattress could determine insomnia complaints and lower sleep quality in non-athlete populations (Addison et al. 1986;Enck et al. 1999) while, Bader and Engdal (2000) did not observe a clear preference in healthy active middle-aged men for any one of the mattresses used in their study, neither firm nor soft. In general, the use of firm or medium-firm new mattress was associated with lower drug treatment and relevant improvements in pain and sleep quality (Kovacs et al. 2003;Tonetti et al. 2011a, 2011b); whereas, on the contrary, foam-made and soft mattress designs can actually create symptoms of pain in individuals with back problems (Jacobson et al. 2010). ...
Article
This study aimed to evaluate the effect of a new mattress on sleep quality, perceived pain and recovery, and physical performance in top-level athletes. Twenty-five volleyball players were randomized to either an intervention group (INT, n = 13) or a control group (CON, n = 12). Sleep data were collected by actigraphy and Pittsburgh Sleep Quality Index (PSQI), perceived pain was evaluated by the Numeric Rating Scale (NRS), perceived recovery with the Total Quality Recovery scale (TQR), and physical performance with the Counter Movement Jump (CMJ) and Reaction Time (RT) tests. All evaluations were carried out during the competitive season at baseline condition (PRE) and four weeks later (POST). All actigraph parameters, PSQI, and NRS values improved for INT but not for CON while no differences were observed in CMJ and RT for both groups. TQR was higher for INT at POST compared to CON. A 4-weeks use of high-quality mattress could be beneficial for players’ sleep, pain, and recovery.
... 47,48 With age, the number of position shifts decrease from 27 to 16 per night, with an average of 20 position shifts per night. [47][48][49][50] Consequently, the time spent in each position increases with age. The lateral sleep position is most common in all studies averaging 65% lateral, 30% supine, and 5% prone. ...
... It can take up to 4 weeks to accommodate to a change in bedding system. 47,49,58 As plastic surgeons, we advise our patients to control the variables that influence aging based on current understanding. We advise our patients use sunscreen to minimize photoaging, quit smoking, optimize nutrition, and maximize topical skin care. ...
Article
Wrinkles are just one indicator of facial aging, but an indicator that is of prime importance in our world of facial aesthetics. Wrinkles occur where fault lines develop in aging skin. Those fault lines may be due to skin distortion resulting from facial expression or may be due to skin distortion from mechanical compression during sleep. Expression wrinkles and sleep wrinkles differ in etiology, location, and anatomical pattern. Compression, shear, and stress forces act on the face in lateral or prone sleep positions. We review the literature relating to the development of wrinkles and the biomechanical changes that occur in response to intrinsic and extrinsic influences. We explore the possibility that compression during sleep not only results in wrinkles but may also contribute to facial skin expansion.
... Looking at preceding studies from an ergonomic aspect, the measurement of peak human body pressure distribution and user's subjective questionnaire evaluation were used in the studies on mattresses (Parson, 1972). In particular, peak body pressure distribution was described as one of the important variables (Bader and Engdal, 2000). Kovacs et al. (2003) reported spinal part is not heavily bent or does not become gentle, only if peak body pressure is evenly distributed on the main parts of human body (head, body, waist and leg). ...
... This study proposed a mathematical model equation using bio signals, and this model equation has meaning in that it can discern wrong selection of a mattress unsuitable for oneself. However, Defloor (2000) said discomfort becomes different, according to sleeping posture, and Bader (2000) said the strength of a mattress affects the quality of sleep. Kawabata and Tokura (1995) asserted the effects on the ratio of deep sleep are different, according to bed type in a sleep experiment using a water bed and a spring bed. ...
Article
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Objective: The purpose of this study is to find the level of physical relaxation of individual subject by monitoring psychophysiological biofeedback to different types of mattresses. And, the study also aims to find a protocol to make a selection of the best mattress based on the measured information. Background: In Korea, there are an increasing number of people using western style bed. However, they are often fastidious in choosing the right mattress for them. In fact, people use their past experience with their old mattress as well as the spontaneous experience they encounter in a show room to finally decide to buy a bed. Method: Total five mattresses were tested in this study. After measuring the elasticity of the mattresses, they were sorted into five different classes. Physiological and psychological variables including Electromyography (EMG), heart rates (HR), oxygen saturations (SaO2) were used. In addition, the peak body pressure concentration rate was used to find uncomfortably pressured body part. Finally, the personal factors and subjective satisfaction were also examined. A protocol was made to select the best mattress for individual subject. The selection rule for the protocol considered all the variables tested in this study. Results: The result revealing psychological comfort range of 0.68 to 0.95, dermal comfort range of 3.15 to 6.07, back muscle relaxation range of 0.25 to 1.64 and personal habit range of 2.0 to 3.4 was drawn in this study. Also a regression model was developed to predict biofeedback with the minimal use of biofeedback devices. Moreover results from the proposed protocol with the regression equation and subjective satisfaction were compared with each other for validation. Ten out of twenty subjects recorded the same level of relaxation, and eight subjects showed one-level difference while two subjects showed two-levels difference. Conclusion: The psychophysiological variables and suitability selection process used in this study seem to be used for selecting and assessing ergonomic products mechanically or emotionally. Application: This regression model can be applied to the mattress industry to estimate back muscle relaxation using dermal, psychophysiology and personal habit values.
... The current research was based on previous protocols in which no sham beds were used [19,38,39], but rather compared firmness of separate beds or adjustable beds. One study [40] did compare new beds to beds 8-yrs old and found significantly greater sleep quality in the newer beds. ...
... It is likely that once the "new" wears off, the efficacy of the intervention diminishes. Additionally, the sample size may be considered small, however; similar studies [39,40] involved fewer participants. ...
Article
Background: It has been long assumed that stress interferes with sleep, but less has been attributed to the converse of poor sleep contributing to stress. Study question: Can an older sleep surface contribute to poor sleep and thus, stress and will a new sleep surface provide better sleep, thus less stress. Methods: Forty-six participants rated physical and psychological signs of stress and sleep efficiency for three weeks while sleeping in their own beds. Following baseline measures participants’ beds were replaced by new, unmarked beds and they again rated their stress and sleep efficiency. Results: Average age of participants’ bed was 11.27 yrs. Physical and psychological signs of stress were reduced significantly (p<0.01) from pre- to post-assessments. Similarly, sleep efficiency improved significantly (p<0.01) between pre- and post-assessments. Conclusions: Replacing an older mattress that may have lost adequate support and comfort may result in a better night’s sleep thereby reducing stress brought on by a lack of sleep. It was suggested that a simple principal step in acquiring better sleep is to consider a new sleep surface rather than to opt for pharmaceuticals to achieve better sleep.
... There are lots of environmental factors affects sleep quality including light, humidity, temperature, noise, smell, and sleeping system. We become more sensitive to the influences of sleeping environment and mattress quality (Bader and Engdal, 2000). It was highlighted that 7 % of sleep problems were related to an uncomfortable mattress (Addison et al., 1987). ...
... It was highlighted that 7 % of sleep problems were related to an uncomfortable mattress (Addison et al., 1987). Few studies disclosed that the mattress could not affect sleep quality (Okamoto et al., 1997;Scharf et al., 1997;Okamoto et al., 1998;Bader and Engdal, 2000;Tonettik et al., 2011). However, a few recent studies have highlighted the fact that mattress could improve sleep quality in healthy people (Jacobson et al., 2006;Lee and Park, 2006;Jacobson et al., 2008). ...
Conference Paper
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Sleeping environment can have a significant influence on sleep quality. Sleeping on the incorrect mattress can cause lot of health problems and affects comfort. The mattress with extra firmness or softness does not allow the sleepers muscle to rest. This study developed a methodology to evaluate compatibility between human and mattress firmness using an electromyogram (EMG). Two mattresses were considered (spring and tempur mattress) with different firmness. Ten healthy participants were tested (age: 31.70 ± 2.19 years; height: 170.90 ± 7.90 cm; weight: 70.60 ± 13.95 kg) on each mattress when lying supine and turning to their right for ten times. The EMG activities (RMS) were measured from eight different muscles (right side cervical paraspinal, right and left side upper trapezius, right and left side latissimus dorsi, right and left side lumbar erector spinae, and right side gastrocnemius lateral). Subjective rating was also collected from the participants. The RMS results showed significantly lower muscle activities when subject tossing and turning to their right on the spring mattress than tempur mattress. Spring mattress provided significantly greater relaxation on subjective rating. This methodology can be used to evaluate different mattress compatibility with various material properties.
... The firmness of a mattress can significantly impact sleep quality, with some individuals reporting better sleep on softer mattresses and others reporting better sleep on firmer ones [23]. The choice of mattress hardness coupled with optimal sleeping position plays an important role in determining sleep quality and overall health outcomes. ...
Article
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Mattress comfort, often associated with firmness, is a complex construct influenced by factors such as material composition, construction, and personal preference. In this short communication paper, we indirectly investigated the effects of long-term mattress use on its hardness and sleep quality by observing the changes in the mattress. A mechanical durability test was performed on two structurally different mattress samples (with polyurethane core and pocket spring core) using a modified method based on the EN 1957 standard, aiming to understand the long-term effects of mattress characteristics on sleep quality. Preliminary results confirm that the mattress samples can maintain firmness and support during long-term use. The polyurethane foam mattress experienced initial compression but quickly stabilized, while the pocket spring mattress showed slight softening, maintaining overall firmness. For the polyurethane mattress, after the initial drop, the hardness value stabilized, varying between 7.53 and 9.03 N/mm, and at the end of the test, it stopped at 8.60 N/mm. The firmness rating stabilized at 4.3, showing minimal fluctuation between 4.0 and 4.6 throughout the process, while the total height loss was 3.79 mm. The hardness value of pocket spring mattresses generally decreased with increasing test cycles (it started at 5.86 N/mm and ended at 5.21 N/mm). The firmness remained relatively stable, varying between 7.3 and 7.1, and the total height loss was only 2.86 mm. The findings suggest that the firmness of a mattress can be changed with its use, highlighting the need for further research on a larger number of samples in the direction of the long-term implications of these changes on sleep comfort.
... It has been claimed that 7% of sleep difficulties are attributable to uncomfortable mattresses that put stress on the spine during sleep (2). Previous research has suggested that the type of mattress can alter sleep quality (3,4). In another study, participants who slept on air mattresses had a higher body temperature than those who slept on futons (5). ...
Article
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Purpose: Numerous mattress manufacturers market their products as "orthopedic" with therapeutic capabilities, claiming that the right mattress can improve an individual's sleep and quality of life. In this qualitative focus group study, we aimed to investigate how customers see the mattress brand that provides physiotherapist support services and their experiences with mattress companies with different characteristics. Methods: Fifty participants were selected from women between the ages of 20 and 60 who were married or in preparation for marriage, and who had purchased a mattress or were in the research phase. The group discussion rules were determined and shared separately in all five groups. The data were thematically analyzed using the framework analysis approach. Results: Customers' perceptions about mattress brands and their thoughts on physiotherapist consultancy are understood by questions such as "what do you think about mattress brands?" and "what does physiotherapist consultancy for mattress selection mean to you?" These two themes will be presented and discussed. Conclusion: The physiotherapist consultancy was a service to satisfy consumer needs in terms of trust. An innovative service has been offered that can persuade the consumer to switch to the new and unknown New Brand. However, it is also possible that advertisements with health content, as previously experienced with other brands, have a negative effect on brand perception. For this reason, it may be more beneficial for the brand if physiotherapists who will work in the field act as life coaches rather than health professionals.
... Many authors and researchers have devoted considerable research efforts to predict sleep comfort and contact pressure between the human body and a mattress cushion. Some of these are limited by the mechanical geometry of the model, whereas others are limited by the material models used [2,4,[14][15][16][17][18][19][20][21][22]. ...
Article
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Body pressure dispersion mattresses are useful tools for preventing pressure ulcers in patients with limited mobility who experience prolonged body weight-related compression loads at their body contact areas over time. The objective of this study is to propose and optimize a multicell finite element (FE) model of foam mattress to prevent patients from developing pressure ulcers (bed sores), by improving the contact pressure distribution on the upper mattress surface and immersion in the mattress. The NSGA-II multi-objective genetic algorithm was used to predict different configurations of cell materials to provide a more comfortable sleep. Our mattress model contains many cells (50 × 50 × 50), each of which can contain one of the nine different foam firmnesses. The NSGA-II algorithm attempts to combine the properties of soft and firm foams into a single mattress. however, the complexity and intersection of the fitness function objectives and the high number of possible chances forced the optimal solutions set to extend into the area under the result of foams that have a compressive strength between soft and firm. Based on the overall optimization results, the standard deviation ranged from 0.00325 to 0.00175 MPa and the maximum mattress immersion ranged from 50 mm to less than 20 mm. Mattresses with optimal configurations disperse body pressure smoothly to fit the patient's body shape.
... Um bom sistema de apoio deve respeitar o ponto de equilíbrio onde haja baixa pressão com bom alinhamento corporal. Esta seria a melhor situação, porque superfícies que promovessem pressões mais baixas ainda tenderiam a prejudicar o alinhamento 16 . ...
Article
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Atualmente, não são encontráveis referências na literatura em saúde sobre critérios objetivos e práticos para a prescrição e adequação de colchões. Objetivo: propor um método quantitativo de avaliação da postura deitada baseado em fotografia digital e validá-lo. Métodos: Foram avaliados 25 voluntários normais. Os voluntários receberam marcadores adesivos, e colocaram-se em decúbito dorsal e lateral sobre 2 colchões de diferentes densidades. Foram feitas fotografias digitais, que foram analisadas em um programa de computador. Dois observadores obtiveram o valor das inclinações dos segmentos corporais, e estes valores foram comparados aos valores fornecidos por um padrão ouro. Resultados: A análise dos dados mostrou que a validade, a reprodutibilidade intra-observador, a reprodutibilidade inter-observadores e a responsividade do método proposto foram estatisticamente significantes, com excelentes valores de concordância (acima de 0,9). Houve duas excessões, em situações específicas, que não invalidam o método como um todo. Conclusão: O método proposto tem caracterísitcas metodológicas adequadas para ser usado clinicamente e em pesquisa. Relevância: O sistema descrito pode ser usado em pesquisas futuras sobre o alinhamento da postura deitada a fim de orientar grupos populacionais sobre qual tipo de colchão lhes é mais adequado.
... Literature indicates that sleep adaptations to a new mattress take time. It has been reported that adaptation to mattress firmness may take about five nights (Bader and Engdal 2000). The measurement period of three days in our study is short, and it is recommended in future studies to extend the period for adaptation to at least five days. ...
Article
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Purpose To determine the efficacy of decreasing spinal curvature – when sleeping laterally – in reducing low-back pain (LBP) and improving sleep quality in people with chronic LBP. Secondly, to investigate whether sleeping positions, nocturnal movements, and skin temperature are related to pain in people with chronic LBP. Methods Sixteen subjects with chronic LBP (50% female, mean age 45.6 ± 13.1 years) slept for one night on their own mattress, followed by three nights on an experimental mattress – designed to reduce spinal curvature in lateral sleeping positions – and then a final night again on their own mattress. Sleep positions, nocturnal movements, skin temperature, and room temperature were measured throughout the five nights. Numerical pain ratings for pain while lying, pain on rising, stiffness on rising, sleep quality, and mattress comfort were recorded for both mattresses. Results The experimental mattress was associated with 18% (p<.05) lower pain scores while lying and a 25% (p<.01) higher comfort rating. Pain on rising, stiffness on rising, and sleep quality were not different between own and experimental mattress. The relationship between sleep positions and pain scores was non-significant, but pain when rising was positively correlated with nocturnal movement (p<.05) and skin temperature was negatively correlated with pain while lying (p<0.05). Conclusion Pain while lying in bed decreased and comfort was higher for the experimental mattress compared to the participants’ own mattresses.
... Sleep quality is also influenced by the contact pressure distribution. 14,15 It has been known that a mattress with insufficient force dispersion could not improve poor sleep quality. 16 Previous study indicated that the cardboard bed with a blanket could not improve sleep EEG indexes in two-hour nap compared to the blanket on the floor. ...
Article
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Objective This study aimed to describe and evaluate the dispersion of body-mattress contact pressure on a cardboard bed and investigate whether the cardboard bed has a positive effect on evacuees’ musculoskeletal burden. Materials and Methods A high-performance nursing simulator was used to measure the contact pressure and the body surface contour area of the bed, and these values were collected with the patient in the supine position using the Body Pressure Measurement System. Data of each test were acquired 10 times and were compared among 4 conditions (plastic sheet, cardboard bed, cardboard bed with a blanket, and cardboard bed with a mattress-topper). The data analysis for body-mattress contacts pressure and the surface contour area of the whole body, head, chest, and buttocks were conducted by one-way repeated analysis of variance and Bonferroni post-hoc test. Results The average body-contact pressure on the cardboard bed did not decrease compared with that on the floor with plastic sheets. In contrast, the body surface contour area was significantly different among any other conditions, but the gap was only approximately 16%. However, the body-contact pressure and the body surface contour area were improved when a mattress-topper was added on the cardboard bed. When a blanket was laid on the cardboard bed, the contact area was increased. Conclusion Our results indicate that the pressure dispersion ability of the cardboard bed was not sufficient; however, adding the mattress-topper or the blanket could contribute to an improvement in the evacuees’ musculoskeletal burden. Many evacuees lay a mattress topper or futon on a cardboard bed after installing cardboard beds. Our findings may also support the scientific validity of the evacuees’ actual sleeping style in Japan. This preliminary study provides the basis for future research on exploring an appropriate sleeping bed condition in evacuee shelters.
... Spinal and capsular ligaments are highly innervated [48] and have been shown to produce pro-inflammatory cytokines following sustained or repeated loading in feline studies [18]. Pain free adults of mixed age and gender have been noted to change posture approximately 12 to 20 times per night [49][50][51]. This frequency of posture shifts is reported to double in those describing themselves as poor sleepers [22]. ...
Article
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Introduction Research with a focus on sleep posture has been conducted in association with sleep pathologies such as insomnia and positional obstructive sleep apnoea. Research examining the potential role sleep posture may have on waking spinal symptoms and quality of sleep is however limited. The aims of this research were to compare sleep posture and sleep quality in participants with and without waking spinal symptoms. Methods Fifty-three participants (36 female) were, based on symptoms, allocated to one of three groups; Control (n = 20, 16 female), Cervical (n = 13, 10 female) and Lumbar (n = 20, 10 female). Participants completed an online survey to collect general information and patient reported outcomes and were videoed over two consecutive nights to determine sleep posture using a validated classification system including intermediate sleep postures. Results Participants in the symptomatic groups also reported a lower sleep quality than the Control group. Compared to Control group participants, those in the Cervical group had more frequent posture changes (mean (SD); 18.3(6.5) versus 23.6(6.6)), spent more time in undesirable/provocative sleep postures (median IQR; 83.8(16.4,105.2) versus 185.1(118.0,251.8)) minutes and had more long periods of immobility in a provocative posture, (median IQR: 0.5(0.0,1.5) versus 2.0 (1.5,4.0)). There were no significant differences between the Control and Lumbar groups in the number of posture changes (18.3(6.5) versus 22.9(9.1)) or the time spent in provocative sleep postures (0.5(0.0,1.5) versus 1.5(1.5,3.4)) minutes. Discussion This is the first study using a validated objective measure of sleep posture to compare symptomatic and Control group participants sleeping in their home environment. In general, participants with waking spinal symptoms spent more time in provocative sleep postures, and experienced poorer sleep quality.
... 10 Recent studies have revealed that the mattress should remain flat or have a good spring action which should support body curvature, 13 providing increased bed mobility, comfortable sleep and not exerting unwanted compressive forces. 14 The lumbar support distributes the force of gravity more over the pelvic, lumbar and thoracic area while maintaining the lumbar lordosis in supine position, suggesting that uniform body support reduces muscular activity during sleep. 15 Other than the mattresses, sleeping positions also contribute significantly to the initiation of LBP. ...
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Objective: To find out the frequency of low back pain in young adults and its relationship with the mattresses being used. Methods: The cross-sectional study was conducted from September 2019 to February 2020 in Rawalpindi and Islamabad, Pakistan, and comprised young adults aged 18-35 years who were using the same kind of mattress for more than 3 months. Data was collected using a self-structured questionnaire along with the Modified Oswestry Scale and the Numeric Pain Rating Scale. Data was analysed using SPSS 24. Results: Of the 366 subjects, 266(72.7%) were women and 100(27.3%) were men. The overall mean age was 22.06±3.74 years. Of the total, 208(56.4%) participants were feeling low back pain, and, of them, pain was most prevalent in 30(14.4%) who were using firm mattress, and by 128(61.5%) who were using foam mattress. The pain was more frequent in those not having changed their mattresses for more than three years 105(50.4%). Conclusions: Low back pain was found to be a frequent occurrence in young adults and it was more prevalent in those using firm or foam mattresses for more than three years.
... Although a higher pressure was observed in harder mattresses, elderly people subjectively felt the harder mattresses as more comfortable. Bader and Engdal (2000) examined the relationship between sleep quality and mattress hardness (hard vs. soft) and indicated that sleep quality had a high correlation with personal characteristics rather than the hardness of the mattress. ...
Article
Placing a topper on a sleeping system is common practice to enhance sleeping comfort. The aim of this study was to determine the thickness and hardness effect of a mattress topper by measuring the four physiological measurements from 40 healthy males. The results showed that the use of a thin mattress topper (30 mm) significantly induced lower body pressure and temperature, higher muscle activities in the biceps femoris, and a straighter spinal alignment in the T12–L4 vertebrae. The use of a hard mattress topper significantly induced a higher body pressure, a lower body temperature in the lower extremities, a higher EMG (%MVC) in the trapezius, but a lower EMG (%MVC) in the biceps femoris, and a straighter spinal alignment at T1–T4, T4–T6, and T6–T8. Overall, a soft topper of 30-mm thickness was suggested as the best combination. The findings can provide very useful information for topper design and selection.
... Individuals who are 'natural long sleepers', needing 9 h or more of sleep each night, may not be able to achieve sufficient sleep during the working week, and it remains unclear whether these individuals might benefit from oversleeping on free days. A good mattress, pillows and bedding make intuitive sense for good sleep, but surprisingly, strong empirical evidence for mattress quality is lacking [180]. Bedside lights should be bright enough for reading, but kept as low as possible to reduce alertness. ...
Article
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At the core of human thought, for the majority of individuals in the developed nations at least, there is the tacit assumption that as a species we are unfettered by the demands imposed by our biology and that we can do what we want, at whatever time we choose, whereas in reality every aspect of our physiology and behaviour is constrained by a 24 h beat arising from deep within our evolution. Our daily circadian rhythms and sleep/wake cycle allow us to function optimally in a dynamic world, adjusting our biology to the demands imposed by the day/night cycle. The themes developed in this review focus upon the growing realization that we ignore the circadian and sleep systems at our peril, and this paper considers the mechanisms that generate and regulate circadian and sleep systems; what happens mechanistically when these systems collapse as a result of societal pressures and disease; how sleep disruption and stress are linked; why sleep disruption and mental illness invariably occur together; and how individuals and employers can attempt to mitigate some of the problems associated with working against our internal temporal biology. While some of the health costs of sleep disruption can be reduced, in the short-term at least, there will always be significant negative consequences associated with shift work and sleep loss. With this in mind, society needs to address this issue and decide when the consequences of sleep disruption are justified in the workplace.
... It was essential to obtain the most natural sleep environment and reduce external disturbing factors. Th erefore, Bader and Engdal (2000) investigated the subjects in their own bedroom and instead of using electrodes fi xed on the body they used sensor pads. Following a control of the methodology, they have studied the sleep quality of subjects sleeping in their own beds. ...
Conference Paper
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A person with his thermo-physiological characteristics directly infl uence the mattress by changing his properties and a healthy bed climate. In this paper, the heat conductivity and moisture permeability through the mattress with the pocket spring core during the sleep were studied. Each of four subjects slept for seven nights on the same mattress in their own bedroom. Seven sensors measured the heat and moisture content released by the subject to the mattress and the environmental conditions. Th e results have shown that during fi rst 180 minutes of lying, the temperature increases on all sensors and starts to decrease aft er that time. It has been observed that the moisture in most cases increases in the direction from the top layer of mattress towards the centre, and that the moisture above the coconut coir layer does not stay much longer than in the other mattress layers and can be relatively quick to dry out.
... In addition, popular contour pillows are ineffective in the management of chronic neck pain (Helewa et al., 2007). Furthermore, mattress type and hardness are closely related to sleep quality (Bader and Engdal, 2000;Marin et al., 2006) and increase the possibility of a guest suffering back pain and sleep problems (Enck et al., 1999;Marin et al., 2006). It shows that the sleep amenities are closely related to sleep quality. ...
... The pressures recorded on air-filled mattresses are typically between 1.5 and 3.5 kPa and are dependent on the inflation pressure [16,17]. There is also a substantial degree of variability in the preferred firmness of the sleeping surface between individuals [18,19]. For example, 4 "The value below which the absolute difference between two test results obtained under reproducibility conditions may be expected to occur with a probability of approximately 0.95 (95 %)" [2]. ...
Article
There is no standardized test method specifically for determining the thermal resistance (R-value) of air-filled mattresses. Unacceptable inter-and intra-laboratory variations in round-robin testing have been attributed to differences in the test apparatus and test parameters used. To identify relevant sources of variation, the repeatability of the guarded hotplate apparatus (in a double plate configuration) was first characterized, and then the effect of modifying selected test parameters on mattress thickness and thermal resistance was investigated. Two mattress types, in two different sizes, were examined: one contained air only while the other contained air plus a nonwoven polyester fill. It was found that repeatable outcomes could be attained when using the guarded hotplate apparatus (95 % repeatability limit of less than 0.08 m 2 K/W for all mattresses tested). The modification of test parameters had significant effects on mattress thickness or R-value, or both. External pressure, the temperature difference across the specimen, supplementary insulation, mattress size, and environmental conditions affected both the thickness and R-value of the test mattresses. Inflation pressure, over the range tested, did not have a significant effect on the R-value but did influence mattress thickness. This work highlights the need for the standardization of the test apparatus and test parameters and will aid in the development of a standardized test method.
... In addition to thermal comfort, the sensorial comfort of a pillow is also important. In terms of pillow filling, sensorial comfort is linked to a firm or soft surface, 8 pillow dimensions and form stability. 2,[9][10][11][12][13][14][15][16][17][18] These properties are affected significantly by the nature of the filling material used. ...
Article
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The choice of a comfortable pillow is essential for good sleep. The filling material for pillows should be bulky, resilient and comfortable. For reasons of price, availability and resilience, polyester is the most commonly used filling material. Its drawbacks, however, lie in poor moisture management and a lack of biodegradability. This is the first study of the physical and microclimate properties of pillows with carded filling containing lyocell fiber. Pillow samples were manufactured on an industrial production line. Their carded fillings were rolled and comprised either 30% or 50% lyocell, blended with polyester (virgin and recycled), high elastic triexta and biodegradable polylactide fibers. In simulated sleeping conditions, using a thermal sweating manikin, it was proven that pillows with fillings made of 50% lyocell blended with polyester demonstrated an enhanced microclimate through much better moisture management than pillows with fillings made from pure polyester. It was also found, under use and care conditions, that lyocell affected the sensorial properties of pillows. Pillow form stability and height regain correlated with lyocell’s linear density. A higher lyocell content (50%) improved the form-keeping characteristics of pillows after repeated washing and drying. The type of lyocell used had only a minor effect on the compression resilience of the filling and perception of pillow firmness. The evaluators perceived higher pillows as firmer. The developed new methods for the evaluation of pillow quality and the results of this study can be of practical relevance in the bedding industry, where the reduction of non-biodegradable raw material is strategically important.
... In addition, variations in weight and height can affect perceptions of comfort [28]. However, the current state of knowledge does not allow specifying the mattress characteristics that are likely to promote sleep in the elderly [29][30][31]. ...
Article
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The aim of this study was to draw a portrait of the sleep environment of elderly persons living in private households and to determine its relationship with the presence of insomnia. A sample of 599 individuals aged 70 years and older responded to questions about the comfort of their pillow and mattress and the noise level and brightness of their bedroom at night and in the morning. They were also asked whether or not they shared their bed or bedroom with a sleep partner. The Insomnia Severity Index was used to assess insomnia severity. Over 40% of the study participants were using a pillow that was not very comfortable, and almost 30% said that their bedroom was not completely quiet. Binomial logistic regression results revealed that two variables were significantly associated with insomnia symptoms: a pillow rated as moderately comfortable to very uncomfortable and a bedroom that was not completely quiet. No other sleep environment characteristics considered in this study were associated with the risk of insomnia. These results indicate that a nonnegligible proportion of the elderly population endures a suboptimal sleep environment. Although it is difficult to predict the real impact of changes to the sleep environment, this study supports the proposal that simple, minor changes to the bedroom can promote sleep in the elderly.
... Mattress' personalisation can maximise ergonomy maintaining physiological positions of the spine [32]. Comfort implies objective and subjective components [53]: changing mattress effects are not immediately perceived, since it requires some adaptation [54]. ...
Article
Introduction: Sleep surfaces must adapt to individual somatotypic features to maintain a comfortable, convenient and healthy sleep, preventing diseases and injuries. Individually determining the most adequate rest surface can often be a complex and subjective question. Objectives: To design and validate an automatic multimodal somatotype determination model to automatically recommend an individually designed mattress-topper-pillow combination. Methods: Design and validation of an automated prescription model for an individualised sleep system is performed through a single-image 2 D–3 D analysis and body pressure distribution, to objectively determine optimal individual sleep surfaces combining five different mattress densities, three different toppers and three cervical pillows. Results: A final study (n = 151) and re-analysis (n = 117) defined and validated the model, showing high correlations between calculated and real data (>85% in height and body circumferences, 89.9% in weight, 80.4% in body mass index and more than 70% in morphotype categorisation). Conclusions: Somatotype determination model can accurately prescribe an individualised sleep solution. This can be useful for healthy people and for health centres that need to adapt sleep surfaces to people with special needs. Next steps will increase model’s accuracy and analise, if this prescribed individualised sleep solution can improve sleep quantity and quality; additionally, future studies will adapt the model to mattresses with technological improvements, tailor-made production and will define interfaces for people with special needs.
... 4 Several previous studies have suggested that mattress material can affect sleep quality. [8][9][10] Dickson 11 noted increased sleep quality of human participants sleeping on natural wool. Okamoto et al 12 further reported that body temperature was higher in participants sleeping on an air mattress than on a futon mattress. ...
Article
Objectives: This study compared the body contact pressure profiles of 2 types of mattresses: latex and polyurethane. Methods: Twenty participants were required to lie down on the different mattresses in 3 different postures for 6 minutes, and their body contact pressure profiles were recorded with a pressure mat sensor. Results: The data indicated that the latex mattress was able to reduce the peak body pressure on the torso and buttocks and achieve a higher proportion of low-pressure regions compared with the polyurethane mattress. Conclusions: Latex mattress reduced peak body pressure and achieved a more even distribution of pressure compared with polyurethane mattress across different sleeping postures.
... (5) Analysis: Prior research on sleep surfaces had suggested that a time frame of up to 4 nights or more may be required before a sleeper accommodates to a new sleeping surface in their home (Jacobson et al. 2008;Bader and Engdal 2000;Scharf et al. 1997). Therefore, data for VAS, sleep diary, sleep structure and movement parameters were analyzed from the fourth day to the seventh day of sleeping on one mattress, the first three night's record were not used. ...
Chapter
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Mattress, as a sleep platform, its types and physical properties have important effects on sleep quality and rest efficiency. In this paper, by subjective evaluations, analysis of sleeping behaviors, the relationship between the sleep postures, change postures and sleep quality were studied. The results showed that: (1) the mattress properties had a remarkable effect on sleep behaviors 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; (3) Chinese people had tended to prefer supine posture, and the number of turns during night was less in supine position than in the lateral position.
... Bekannt ist, dass die Qualität der Matratze oder des Kopfkissens für Patienten, die z. B. an Wirbelsäulenproblemen oder anderen Gelenkschmerzen leiden, eine besondere Rolle spielt [6,7,8,9,10,11,12,13]. Zusätzlich führt guter Schlaf zu einer Minderung der Schmerzwahrnehmung am Tag. ...
Article
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It’s well known that sleep structure and sleep quality can strongly be influenced by environmental factors. Changes and benefit in sleep comfort is one of those components. We tested whether the use of a newly developed mattress could improve subjective and objective parameters of sleep. By applying a randomized cross-over design, 30 healthy volunteers were investigated on two subsequent nights in a sleep lab under polysomnographic surveillance. Volunteers slept one night on the newly developed mattress Menschmodell (test mattress) and the second night on a standard mattress. In addition to the polysomnography actigraphic recorders, standardized and study-specific questionnaires on sleep quality were given to the volunteers. Analysis of data revealed that patients sleeping on the test mattress had a significant increase of slow wave sleep and rapid-eye-movement sleep and a significant decrease of light sleep. In the morning after sleeping on the test mattress, tiredness was found to be reduced and scales of mood were increased. Differences in sleep structure with respect to the mattress used could be demonstrated using polysomnography. These methods allow advantages of a newly developed mattress for the sleep structure and sleeping quality at night to be verified.
... It is well known that people that sit or lie down for prolonged periods change their posture on a regular basis. Even when people are asleep on average 20-40 postural can be observed during an 8 hours period of night rest [1,2]. ...
Article
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It is well known that people that sit or lie down for prolonged periods change their posture on a regular basis. Even when people are asleep on average 20-40 postural can be observed during an 8 hours period of night rest. One of the reasons that can be found in literature for this 'urge to move' is that these movements are necessary to persevere the blood flow in the tissue. The aim of this paper is to study the relation between tissue perfusion and pressure on the tissue and frequency of the load cycle. Each subject is subjected to a treatment scheme that varies in pressure and frequency of the load on the tissue. The pressure levels that are used are 2.7 kPa, 4.0 kPa and 5.3 kPa and the frequency levels that are used are loading/unloading at intervals of 5 min., 10 min., 15 min. Statistics shows that for 2.7 kPa there is a significant reduction of blood flow between time intervals of 5 min. and 10 min. (P=0.028), and 5 min. and 15 min. (p=0.009). Statistics also shows that there is no significant reduction in blood flow at the time interval of 10 minutes, for every level of pressure. This series of measurements seems to suggest that at the time interval of 10 minutes for every level of pressure the blood flow does not decrease compared to the start situation.
... Porównując komfort snu na miękkim materacu do wypoczynku na twardym materacu wykazano, że większość osób preferuje miękki. Podkreśla się iż okres adaptacji do nowych warunków snu może trwać wiele dni [11], a na jakość snu wpływa także pozycja śpiącego [12]. Obecnie nie istnieje żadna reguła pozwalająca na dostosowanie materacu do potrzeb danej osoby. ...
Article
Background US military service members have characteristically poor sleep, even when ‘ in garrison ’ or at one’s home base. The physical sleeping environment, which is often poor in military-provided housing or barracks, may contribute to poor sleep quality in soldiers. The current study aimed to assess whether the sleeping environment in garrison is related to sleep quality, insomnia risk and military readiness. Methods Seventy-four US army special operations soldiers participated in a cross-sectional study. Soldiers were queried on their sleeping surface comfort and the frequency of being awakened at night by excess light, abnormal temperatures and noise. Subjective sleep quality and insomnia symptoms were also queried, via the Pittsburgh Sleep Quality Index and Insomnia Severity Index, respectively. Lastly, measures of soldier readiness, including morale, motivation, fatigue, mood and bodily pain, were assessed. Results Soldiers reporting temperature-related and light-related awakenings had poorer sleep quality higher fatigue and higher bodily pain than soldiers without those disturbances. Lower ratings of sleeping surface comfort were associated with poorer sleep quality and lower motivation, lower morale, higher fatigue and higher bodily pain. Each 1-point increase in sleeping surface comfort decreased the risk for a positive insomnia screen by 38.3%, and the presence of temperature-related awakenings increased risk for a positive insomnia screen by 78.4%. Those living on base had a poorer sleeping environment than those living off base. Conclusion Optimising the sleep environment—particularly in on-base, military-provided housing—may improve soldier sleep quality, and readiness metrics. Providers treating insomnia in soldiers should rule out environment-related sleep disturbances prior to beginning more resource-intensive treatment.
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Sound sleep aids sound health and good ageing, unfortunately, people still wake up in the morning feeling tired, sleep at work, and sometimes unnecessarily aggressive. It is normal to experience sleeplessness once in a while, but it is not normal to regularly have problems getting to sleep at night and to wake up feeling exhausted. Poverty, socioeconomic instability, inadequate medicare etc. have continued to hamper the quality of sleep for the majority of the populace. Sleep helps the brain to function properly and not getting enough sleep or poor quality sleep has many consequences: behavioural problems in children, hypertension, fatigue, cardiovascular diseases, mental health problems etc. in adults. This study evaluated subjective sleep qualities (timing of sleep, environmental factors, health status, and socioeconomic status) on the sleep status of an average Nigerian adult in selected areas of South-West Nigeria. A descriptive analysis was used for the study as contained in the SPSS version 15.0 software on a total population of 207 adults. A self-developed questionnaire validated by experts in the field producing an Alpha reliability co-efficient of 0.735 was used for the study analysis. Findings from the study revealed no significant relationship between gender, religious affiliations and sleep quality, whereas, age, nature of work, health status, body height, marriage, the timing of sleep and hobbies have critical negative and positive significances with sleep qualities respectively. In all, the subjective sleep factors as indicated in the study could be depended upon in rating the sleep quality of an average Nigerian adult.
Article
Purpose The purpose of the present study was to evaluate the effect of air mattress pressure on sleep quality. Design/methodology/approach Ten young healthy males participated in all hard surface [AH], shoulder soft [SS] and shoulder and hip soft mattress [SHS] conditions. The surface pressure for SS and SHS were set at their preferred levels. Findings The results showed that sleep efficiencies were over 95% for all the three conditions; there were no significant differences in individual sleep variables among the three conditions, but overall sleep quality was better for SS than AH ( p = 0.065); heart rates during sleep was greater for AH than the other two conditions ( p < 0.1); and a stronger relationship between clothing and bed microclimate humidity were found for SS and SHS than that for AH. Research limitations/implications These results indicated that the both pressure relief air mattresses that were set at their own preferred levels provided high quality sleep with no marked differences. Practical implications Air pressure relief mattresses can improve sleep quality of healthy individuals during sleep at night. The results can be used to understand appropriate pressure distribution on surface mattress according to body region, and also to develop algorithms to provide optimum sleep using mattresses with surface pressure control by body region. Originality/value The present study found that the shoulder and/or hip pressure relief air mattresses that were set at their own preferred levels provided high quality sleep with no marked differences.
Article
Infancy is a developmental stage in an individual's life. As an important part of infant development, sleep greatly influences the physiological and mental development of infants, and the health and comfort of infant sleep is a major public concern. From the viewpoint of ergonomics, this study investigated the effects of mattress firmness on the body pressure distribution of infants aged 0–3 years in the supine posture. Six types of mattresses with different firmness values were tested and 11 healthy infant subjects participated in the experiment. A Tekscan body pressure measurement system was used to record data. The body pressure distribution of infants was analysed using six pressure distribution indices including the maximum pressure, average pressure, contact area, maximum pressure gradient, average pressure gradient, and longitudinal pressure distribution curve. The results revealed that, in the supine posture, there is significant correlation between the body pressure indices and the mattress firmness. The average pressure has the strongest correlation with mattress firmness. The infants' buttocks zone had the highest pressure, while the pressure on the head and leg zones was relatively low. The recommended K value, which represents the mattress firmness, ranges from 267 to 669 mm².
Chapter
This paper studied the relationship between the characteristic of mattress materials and sleeping comfort with supine and lateral sleeping of different age groups. The test adopted the pressure distribution system, subjective evaluation and the subjective and objective analysis of correlation on ergonomics methods. The results showed that, as the subjects’ age increasing, the subjects’ sensitivity of mattress materials increased and had partiality for harder material. The elder subjects had the highest sensitivity on different mattress materials. The young and middle-aged subjects had high evaluation on memory foam, and latex mattress in supine and lateral position. The young-elder subjects had higher evaluation on memory foam, and coir mattress in supine and lateral position. And the elder subjects preferred coir and cotton mattress in supine position and preferred memory foam and coir mattress in lateral position. The subjects lay on back preferred softer material than subjects lay on side.
Article
This study aimed to identify the motion sequences and time-flow of roll-overs during sleep in women to develop a self-helped roll-over maneuver for elderly patients. Shifts from deeper sleep stages to lighter stages leading to arousal occur at roll-over-onset. Quick re-falling-asleep after completion may aid peaceful sleep continuation. Motion sequences of six women aged 43-65 years were examined at a sleep laboratory using polysomnography and infrared video. Relationships among phase I (before roll-over onset), II (roll-over movements), and III (roll-over end to re-falling-asleep onset) were determined. Mean total sleep time was 6.72±0.77 h, with over 80% sleep efficiency. Among 12 patterns examined, only supine-to-left and supine-to-right lateral roll-overs were classified: type A, sliding waist with pause (n=11, sleep); B, sliding waist without pause (n=56, sleep and arousal); and C, without sliding waist or pause (n=1, arousal). Time spent in phase I and III in type A were correlated (r=0.78, p=0.005), and were the shortest among the types. Discriminant analysis for type A (n=11) and B (n=20, sleep) showed 80.6% correct classification. In conclusion, type A roll-overs, involving efficient motion with quick re-falling-asleep, may be a useful foundation to develop self-helped roll-over maneuvers.
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Introduction Sleep loss is ubiquitous in military settings, and it can be deleterious to cognitive, physiological, and operational functioning. This is especially true in the military operational context (e.g., training, garrison, combat) where continuous operations prevent adequate time for rest and recuperation. Furthermore, even when servicemembers do have opportunities for sleep, environmental disruptors in the military operational context make it difficult to obtain restorative sleep. Such environmental disruptors are potentially preventable or reversible, yet there is little public awareness of how to minimize or eliminate these sleep disruptors. Therefore, the goal of this review was to outline prominent environmental sleep disruptors, describe how they occur in the military operational context, and also discuss feasible strategies to mitigate these disruptors. Materials and Methods We discuss four factors – light, noise, temperature, and air pollution – that have previously been identified as prominent sleep disruptors in non-military settings. Additionally, we extracted publicly-available yearly temperature and pollution data, from the National Oceanic and Atmospheric Association and the Environmental Protection Agency, respectively, for major prominent military installations in the continental US in order to identify the sites at which servicemembers are at the greatest risk for environmental sleep disruptions. Results Based on previous literature, we concluded light and noise are the most easily mitigatable sleep-disrupting environmental factors. Air pollution and temperature, on the other hand, are more difficult to mitigate. We also propose that harsh/uncomfortable sleeping surface is a fifth critical, previously unexplored sleep disruptor in the military operational context. Furthermore, we identified several problematic military sites for air pollution for temperature. Specifically, each branch has major installations located in regions with extreme heat (especially the Army), and each branch has at least one major installation in a high air pollution region. These findings show that even when in training or garrison in the US, military servicemembers are at risk for having sleep disruption due to environmental factors. Conclusions Environmental disruptors, such as light, noise, temperature, and air pollution, can negatively impact sleep in the military operational context. Simple, feasible steps can be taken to reduce sleep disruptions that are caused by light and noise. Yet there is a need for research and development on tools to mitigate air pollution, extreme temperatures, and inhospitable sleeping surfaces. Leadership at the discussed military bases and training facilities should focus on improving the sleep environment for individuals under their command. Such interventions could ultimately improve warfighter health, wellness, and operational performance, leading to greater warfighter readiness and lethality.
Conference Paper
Sleep is separated into several stages, and in the stage of deep sleep, body and mind could recover because of the secreting of neurotransmitters. However, stimulation when sleeping would stop the mechanism and cause arousal. Pressure paralysis is a kind of stimulation, and that would be caused by long-time pressure on nerve. To avoid pressure paralysis, with morphological analysis, there would be a three-layer mattress design in this study based on pressure and temperature distribution.
Article
Objectives: We aimed to evaluate the effects of mattress type on both objective and subjective sleep quality in healthy good sleepers. Methods: Fifteen healthy good sleepers with a mean age of 30.8 years participated in this study. A randomized crossover trial was carried out using two different mattress types: a standard mattress and a contour coil mattress. After a night of adaptation, all participants were randomized to either a standard mattress or a contour coil mattress. Then, nocturnal polysomnography was conducted for two consecutive nights. Subjective evaluations were obtained using a self-report questionnaire before and after the polysomnographic recording sessions. Results: The polysomnographic showed no differences in total sleep time, sleep stage, or wake time after sleep onset between the two mattress conditions. Of the polysomnographic variables, only sleep onset latency was significantly reduced for the contour coil mattress. Additionally, participants reported better subjective sleep quality when sleeping on the contour coil mattress, according to the questionnaires. Conclusion: The type of mattress might affect not only subjective, but also objective sleep quality, including sleep onset latency.
Article
Objective To investigate the various effects of the mattresses with different firmness on sleep quality. Method: Thirty healthy subjects (17 men, 13 women, 28 to 52 years old) volunteered for the experiment spending three consecutive nights in the same bedroom. Each subject was asked to sleep in turn on three mattresses with different firmness with one type for one night, including innerspring mattress, wooden board mattress and sponge mattress. Ergocheck Measuring System and Infrared Video Camera were used to detect the body movement, body mattress interface pressure and body mattress interface area during sleep. For every test session, each subject accepted sleep quality evaluation with Sleep Quality Questionnaire(SQQ) and Self-feeling Scale of Sleep(SFSS) next morning. Result: 1 When using innerspring mattress the scores of SQQ and SFSS of the subjects were superior to those when using board mattress or sponge mattress(P<0.05).2 The amount of body movement of the subjects were less when using innerspring mattress than that when using board mattress or sponge mattress (P<0.05). 3 The pressure and support of the buttocks, scapular and low back of the subjects to the mattress showed more desirable when using innerspring mattress than those when using board mattress or sponge mattress. 4 No matter lying on the back or on the side, the body mattress interface area on the innerspring mattress showed more acceptable, which was between the values on the board mattress and on the sponge mattress. Conclusion: The firmness of a mattress may affect the quality of sleep directly. An innerspring mattress with medium firmness could help the sleeper enjoy a better sleep than the hard board mattress and the soft sponge mattress.
Article
Background and aim: Ergonomic factors in sleep designing system will have direct effects on maintaining the spinal alignment during sleep. Studies show that a mattress with uniform stiffness cannot preserve the spine's natural posture. Using a mattress made of components with different stiffness can be considered as a solution for this problem. In this study, male spinal alignment has been assessed and compared on the hard and soft mattress along with a new type of mattress with different stiffness. The aim of this study was to evaluate the performance of this new type of mattress and determination of specific layout for each volunteer. Materials and Methods: After obtaining the dimensional survey data, 25 male volunteers were asked to take the side sleeping position on soft and very firm surfaces, with specific stiffness based on a predetermined protocol. The location coordinates of markers installed on the spinous process by optical detection methods were obtained in frontal plane. In the next step, spring-foam elements were arranged in a frame for each volunteer so that their spinal frontal plane can be close to their natural alignment. Results: In side sleeping posture a c formed curvature appeared along the spinal frontal plane on stiff surface due to lack of support of the spine, and on the soft mattress, softness caused further sinking in the area of pelvis and loss of natural posture. But the arrangement of elements with different stiffness (custom made mattresses) maintained the natural posture of spine. The specific layouts for each volunteer were extracted. Conclusion: The results of this study showed that use of mattresses with custom arrangement is an appropriate way for maintaining optimum spinal alignment during sleep. Common mattresses with uniform stiffness do not have the ability to maintain the spine in a natural position during sleep. Determination of specific arrangements for side sleeping posture can help predict layout required for every individual in the future studies without performing a test.
Article
Bed interface material can affect the person's temperature characteristics. This article is based on ergonomics principle and method, paralyzedgroup for the audience to carry the mattress temperature sensation characteristic experiments. Through the subjective survey, found that paralyzed sponge mattress material local temperature influence the human body, through the objective experiment, it is pointed out that different sponge mattress different effects on human body temperature; correlation between subjective and objective analysis found: Waist temperature on the maximum total thermal comfort; the best waves sponge thermal comfort; consistent with the results of subjective and objective analysis.
Article
A significant number of US citizens lack appropriate sleep for several reasons. Back pain has been identified as possible cause for inappropriate sleep in adults. Previously, the quality of mattresses and bedding systems has been correlated to the pain perceived by individuals. However, there is controversy in the literature regarding the type and characteristics of a mattress that best serve the purpose of decreasing spinal pain, and improving spinal alignment and quality of sleep. This study gathered the best available evidence in the literature related to this matter through conducting a systematic review of controlled trials that were published since the year of 2000. In those trials, mattresses were subjectively identified as soft, medium firm, firm, or custom inflated. Articles examining the effect of temperature alterations of mattresses on promoting sleep quality and reducing pain were included as well. Twenty-four articles qualified for inclusion into this systematic review. The methodological quality of the reviewed clinical trials was deemed moderate to high according to the PEDro scale. Results of this systematic review show that a mattress that is subjectively identified as a medium-firm mattress and is custom inflated (self-adjusted) is optimal for promoting sleep comfort, quality, and spinal alignment. Evidence is not sufficient yet regarding the appropriate temperature of the optimum mattress; however, warm temperature has been recommended by authors.
Article
Aim: This is the fourth and last part of a series of literature reviews, which seek to find out whether different types of sleep disturbance can be caused by different sorts of back pain. Here in Part 4 we show how researchers have assumed, speculated, or theorized upon the mechanisms whereby back problems can cause sleep disturbance. Methods: The same search of Medline, Embase, Psycinfo, and the OVID journals databases using the keywords ‘low back pain’ and ‘sleep’ was used as in the previous reviews. Results: It was difficult to synthesize a unified theory of back pain insomnia from the available literature. This was mainly because few researchers have tried to distinguish different sorts of back pain. This has resulted in an inability to compare for their different response to banishing the vertical gravitational forces on adopting the horizontal posture and the other phenomena associated with quiet repose. Though the introduction or discussion section of published articles might have permitted more speculation on relevant mechanisms, most authors have limited their propositions to the data collected. Discussion: Some of the more interesting observations on the matter of back pain insomnia found in the literature are presented.
Article
The purpose of this study is to find out the relations between the characteristic of mattress, anthropometric features, body pressure distribution, and spinal curvature and to examine the overall relations between the comfort and the features of mattress. In order to evaluate mattress comfort, subjective ratings were performed. For an objective evaluation, anthropometric features, plaster cast, spinal curvature and body contact pressure distribution were used. The spinal curvatures were compared using the plaster cast and 3D measurement. The individually favored mattresses were found by figuring out the spinal curvature most similar to the spinal curvature when standing by comparing with the spinal curvature on bed with the difference of firmness. Also, by the analysis of body contact pressure, there were significant differences between body pressure and comfort ratings. As the result of this research, we could found out the comfort mattress by spinal curvature and body pressure.
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In the final article of this series, patient turning, the place of risk assessment and ‘stepping down’ are considered. A warning note is sounded in that comfort does not necessarily equate with safety.
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Aim This is part of a literature review series and a data analysis study, which seek to find out whether different types of sleep disturbance can be caused by different sorts of back pain. Here, in Part 1, we examine the systems described as an insomnia or sleep disturbance questionnaire, diary, index, item, or scale. Those used in back pain studies were of particular interest. Methods A search of Medline, Embase, Psycinfo, and the OVID journals databases was made using the keywords ‘low back pain’ and ‘sleep’. Results Forty-four sleep enquiry systems were traced. Their similarities and differences were displayed in tables. Discussion Creating the main display table helped us to sort out the considerable variation in questionnaire content. It was important to distinguish the elements of impairment, disability, and handicap and further consequences. It also helped us to rigidly define the 24-hour time sequence. First, there were the evening difficulties getting off to sleep. Then, nighttime awakenings and other disturbances were listed along with total night scores. Then, the morning waking process and conditions were distinguished. Lastly, the daytime fallout was noted. Further clarity was sought for the wording of questions by recognizing the many synonyms for tiredness and somnolence, which seemed to imply there were far more sleep items than really exist. It was noted that the results of using these subjective opinions obtained from patients often varied considerably with the objective measures recorded using actigraphy and polysomnography. Little is known as to why there is such divergence.
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In an attempt to characterize the development of sleep positions and position shifts in the human, 10 subjects (5 males and 5 females) in each of the following five age groups were studied: 3-5, 8-12, 18-24, 35-45 and 65-80 years old. Subjects slept for four consecutive nights (except the 3-5 year olds who slept two nights) in the laboratory where standard polysomnography was recorded. On nights 3 and 4, sleep positions were recorded with a Super 8 Camera taking one frame every 8 seconds and were scored using four dimensions (head, trunk, legs and arms) each consisting of four categories. The results revealed a significant ontogenetic decrease in the number of position shifts with averages of 4.4, 4.7, 3.6, 2.7 and 2.1 changes per hour, respectively. There was a corresponding progressive increase in the duration of positions and in the number of periods of more than 30 minutes of postural immobility. Whereas in children, prone, supine and lateral positions were assumed to occupy an equal proportion of sleep time, trend analyses revealed a significant progressive ontogenetic disappearance of prone positions and a progressive preference, very marked in the elderly, for right-side positions.
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PHYSIOLOGICAL, PERSONALITY, AND EEG SLEEP PATTERNS OF 16 POOR-SLEEP GROUP (PSG) SS WERE COMPARED WITH 16 GOOD-SLEEP GROUP (GSG) SS. COMPARED WITH GOOD SLEEPERS, POOR SLEEPERS HAD LESS SLEEP TIME, A HIGHER PROPORTION OF STAGE 2 SLEEP, MARKEDLY LESS REM SLEEP DESPITE A SIMILAR NUMBER OF REM PERIODS, MORE AWAKENINGS, AND REQUIRED MORE TIME TO FALL ASLEEP. SIGNIFICANT PHYSIOLOGICAL DIFFERENCES BETWEEN THE GROUPS WERE OBSERVED DURING ALL STAGES OF SLEEP AND DURING A PRESLEEP PERIOD. PERSONALITY TEST RESULTS CLEARLY INDICATED A MUCH HIGHER PROBABILITY OF SYMPTOMATIC COMPLAINTS AMONG POOR SLEEPERS AS WELL AS A STRONG POTITIVE RELATIONSHIP BETWEEN DREAMING AND INDEXES OF PSYCHOPATHOLOGY. THIS STUDY DID NOT RESOLVE CAUSE AND EFFECT RELATIONSHIPS AMONG PHYSIOLOGICAL VARIABLES, PERSONALITY MEASURES, AMOUNT OF DREAMING, AND GOOD AND POOR SLEEP; HOWEVER, SIGNIFICANT EEG, PHYSIOLOGICAL, AND PSYCHOLOGICAL DIFFERENCES WERE DEMONSTRATED. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
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Numerous medical authors have discussed the effects that are supposed to be exerted on the functioning of bodily organs by the postures that are assumed and maintained for long periods during sleep. Most of them agree that the effects are genuine, and also important. They intimate that some postures tend to produce deformities, while other postures tend to correct them. They say that some postures interfere with the action of such organs as the heart, the stomach, and the mechanisms involved in breathing, while other postures render such action easier. They do not agree at all well, however, in assigning any particular effect to any specific posture. Some of the points on which they disagree most widely are interesting.Some of these writers advise sleeping on the back, while about as many other writers, of equal professional standing, advise against it. Some recommend that people sleep lying on the abdomen;
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In 33 adults, discrete periods of rapid eye movement potentials were recorded without exception during each of 126 nights of undisturbed sleep. These periods were invariably concomitant with a characteristic EEG pattern, stage 1.Composite histograms revealed that the mean EEG, eye movement incidence, and body movement incidence underwent regular cyclic variations throughout the night with the peaks of eye and body movement coinciding with the lightest phase of the EEG cycles. A further analysis indicated that body movement, after rising to a peak, dropped sharply at the onset of rapid eye movements and rebounded abruptly as the eye movements ceased.Records from a large number of nights in single individuals indicated that some could maintain a very striking regularity in their sleep pattern from night to night.The stage 1 EEG at the onset of sleep was never associated with rapid eye movements and was also characterized by a lower auditory threshold than the later periods of stage 1. No dreams were recalled after awakenings during the sleep onset stage 1, only hypnagogic reveries.
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The principle of 'a static charge sensitive bed' method for recording body movements during sleep is described. We made records during 30 nights and the measured total number of movements per night (80-200) is in agreement with the findings of studies based on a combination of direct observation, EMG and videotape. The method is simple, inexpensive and very sensitive to all kinds of movement.
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Nocturnal respiration, the ballistocardiogram, and body movement activity were studied with the static charge-sensitive bed (SCSB) in snorers who represented a wide range of severity of sleep-related upper airway obstruction. The emphasis was to evaluate the performance of the SCSB as a noninvasive tool for assessing nocturnal breathing disturbances. The results show that periodic episodes of obstructive apnea or hypopnea can reliably be monitored with the method. Additional breathing abnormalities suggesting the presence of increased respiratory resistance and increased body motility were frequently observed not only in OSAS patients but also in snorers without apnea. Permanent morphological abnormalities of the upper airways were observed in pharyngeal CT in patients with OSAS but also in subjects with severe partial obstruction without apnea. The findings in the SCSB recordings clearly illustrate that there is a functional continuum from partial to complete upper airway obstruction during sleep. However, the structural differences of the upper airways observed between subjects with partial airway obstruction and with OSAS suggest that partial obstruction without apnea cannot always be considered as heralding the development of the OSAS, but rather as a separate entity, which may produce the same clinical signs and symptoms as in the OSAS. The SCSB turned out to be a simple but sensitive method to detect complete and partial upper airway obstruction during sleep. The SCSB may optimally yield information beyond reach of more complex recording systems. Nonapneic SCSB findings may have particular significance for the evaluation of preclinical stages of sleep-related upper airway obstruction.
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Amounts of slow wave sleep (SWS) in men exposed to either thermoneutral (29 degrees C) or cool (21 degrees C) ambient temperatures were positively correlated with tympanic and rectal temperatures at SWS onset. Decreases in each temperature measure between sleep onset and the nightly termination of SWS were negatively correlated with oxygen consumption during SWS.
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Nocturnal motor activity of 67 poor sleepers referred to the Rehabilitation Research Centre (RRC) and of 16 healthy subjects were recorded to distinguish poor sleepers without affective disorders from those with affective disorders. All subjects slept on the static charge sensitive bed (SCSB) in a single room of the patient dormitory. All subjects filled out a sleep questionnaire about their subjective sleep quality. After comprehensive rehabilitation consultations the poor sleepers were divided into two subgroups: those with and those without affective disorders. Complaints about insomnia and sleep disorders distinguished poor sleepers from healthy controls but the subgroups of poor sleepers did not differ in the estimation of the quality of sleep. However, when the distribution of body movements through the night was considered, the dynamic of nocturnal motor activity typified poor sleepers with affective symptoms.
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A new wrist actometer was used to obtain ambulatory activity-rest recordings in 18 patients with sleep apnea syndrome (SAS) and in 22 control subjects. A movement index (MI) and a fragmentation index (FI) during sleep time were computed, giving an estimate of the stability of sleep. In control subjects, we observed a clear differentiation between night and day activity levels. The distribution of MI and FI was very narrow, with a mean +/- SD of 13.9 +/- 5.4 and 16.1 +/- 5.8%. No correlation of MI and FI with body mass index, even in heavily obese subjects, was found; MI and FI decrease significantly with age. A diagnosis of SAS was made by standard all-night polysomnography. Patients with SAS had a significantly higher MI and FI than did control subjects (p less than 0.001). With respect to polysomnographic diagnosis of SAS, the sensitivity of activity recordings was 89%, whereas the specificity was 95%. Five patients were studied after treatment, and decreases in MI and FI at home were in good agreement with the improvement in their sleep as assessed clinically and by polysomnography. We conclude that this technique is useful for an objective measurement of sleep restlessness and fragmentation, and for a simple evaluation of therapeutic effects under real life conditions in SAS.
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All-night polygraphic recordings were made on five normal human male subjects for two nights to study body motility quantitatively in relation to the sleep electroencephalogram. Body movements were significantly related temporally to preceding K-complexes during stage 2 sleep with a mean latency of 2.52 sec for 396 movements scored. This relationship was consistent for both nights one and two. The rate of body movements per minute was significantly lower in slow-wave sleep than in any other stage and was not different in stages 2 and REM. Movements in slow-wave sleep were more extensive and usually occurred at the end of periods, often heralding a change of stage. Brief isolated twitches of extremities were predominantly observed in stage REM. In all stages, movements of the face and mouth alone were frequent. An attempt was made to unify the known relations of K-complexes, body movements and autonomic activity and to organize them with respect to subcortical origins and electrophysiologic mechanisms.
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The reliability of sleep measures was calculated over two nights (and within the nights) for 20 young adult males. Percent time in stages 1, 2, 3, and 4, percent movement time, number of movements, and number of stage changes were significantly correlated between Ss over nights. The percent REM time and REM cycle duration were not significantly correlated over nights. Within Ss, the length of the REM period had a significant negative correlation with the length of the preceding NREM period but not with the following NREM period. These data raise questions as to the use of the standard sleep measures as reliable human traits in young male adults.
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Thirty male patients evaluated sequentially for sleep apnea syndrome by all-night clinical polysomnography were compared for apnea plus hypopnea index (A + HI) during the time in the side versus time in the back sleep posture. For 24 subjects of this sample, who occupied both major body positions during the evaluation night, the apnea index was found to be twice as high during the time spent sleeping on their backs as it was when they slept in the side position. This difference is reliable and inversely related to obesity. Five patients meeting diagnostic criteria for sleep apnea on an all-night basis fell within normal limits while in the side sleep position. This suggests sleep position adjustment may be a viable treatment for some nonobese sleep apnea patients.
Article
The principle of the static charge-sensitive-bed (SCSB) method is described. The method is simple and inexpensive. From the SCSB recording the ballistocardiogram (BCG) and respiratory movement can be simultaneously recorded by selective filtering of the original signal. The SCSB recording thus enables continuous long-term monitoring of the BCG, heart rate, respiratory rate, respiratory amplitude, and body movements. There are no electrodes or cables connected to the subject. The SCSB-BCG signal was studied by comparing the SCSB method with the conventional ultralow-frequency (ULF) acceleration BCG. The wave forms at rest and the amplitude responses to physical exercise were studied by both methods. Multiple recordings of the BCG, heart rate, respiratory movement, respiratory rate, and body movements after exercise and during sleep using the SCSB method are presented. The SCSB method opens new approaches to long-term studies of the regulation of myocardial performance, heart rate, and respiration. Applications of the SCSB method for clinical sleep studies, patient monitoring and cardiovascular screening examinations are discussed.
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The comparative effects of sleep patterns and rates of cyclic alternating patterns (CAP rate) in a high quality innerspring mattress were compared to those on a unique foam support mattress in 10 normal subjects. Results showed no differences in sleep stages, number of wakes, or total sleep time between the two conditions. CAP rates were significantly reduced on the foam surface. CAP rate was sensitive to the first-night effect on both surfaces, but was blunted on the foam mattress.
Transient insomnias and insomnias associated with circadian rhythm disorders
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E!ects of water bed surface on sleep: a pilot study Body motility during sleep and its relation to the K-complex
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Sleep movements and poor sleep in patients with non-speci"c somatic complaints * II. A!ective dis-orders and sleep quality Autonomic quanti"cation of body movements and autonomic ner-vous system variability during sleep in healthy young adults (Ab-stract)
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Transient insomnias and insomnias associated with circadian rhythm disorders
  • Roehrs
A simple and inexpensive technique to record sleep positions
  • De Koninck