The Potential Role of Sleep in Promoting a Healthy Body Composition: Underlying Mechanisms Determining Muscle, Fat, and Bone Mass and Their Association with Sleep

Sleep Characteristics, Magnetic Resonance Imaging- and Dual-Energy X-Ray Absorptiometry-Based Morphological Parameters, Muscle Strength, and Risk of Falls in Sedentary Older Subjects

BACKGROUND

The aims of this cross-sectional study were to (a) assess actigraphy-based sleep parameters (total sample and gender differences), (b) assess differences in morphological parameters and physical function between short- versus normal-sleepers and poor- versus good-sleepers, and (c) assess the possible correlations between sleep variables and morphological and physical function parameters in older subjects.

METHODS

This study enrolled 42 healthy older participants (60-80 years). Participants completed the following clinical evaluations: (1) whole-body dual-energy X-ray absorptiometry to assess the appendicular skeletal muscle mass index; (2) magnetic resonance imaging acquisition to determine the cross-sectional muscle area of thigh muscles and intermuscular adipose tissue; (3) risk of fall assessment through the mini-Balance Evaluation Systems Test; (4) strength assessment: (a) chair stand test and (b) handgrip strength test; (5) sleep monitoring by actigraphy to assess total sleep time, sleep efficiency, wake after sleep onset, sleep latency, fragmentation index, mobile time, and subjective sleep quality.

RESULTS

31.0% of subjects were short-sleepers (total sleep time < 6 hr), 19.1% were poor-sleepers (sleep efficiency < 85%), and gender differences were detected in mobile time (males: 15.8 ± 6.0 and females: 13.4 ± 6.8; p < .001) and fragmentation index (males: 35.3 ± 14.3 and females: 29.6 ± 14.6; p < .001); no significant differences were observed between groups (short- vs. normal-sleepers and poor- vs. good-sleepers) in morphological and physical function variables; correlation analysis showed that sleep latency negatively correlated with Mini-Balance Evaluation Systems Test (r = -.352; p = .022) and a positive correlation was detected between cross-sectional muscle area and mobile time (r = .349, p = .023).

CONCLUSION

No differences were observed in morphological and function parameters between good- versus poor-sleepers, those subjects with worse sleep onset latency (i.e., longer time to fall asleep) registered higher for risk of fall. The potential role of sleep in the physiological mechanisms of muscular aging must be explored through cross-sectional cohort studies with a larger population.

Gender differences in body composition, dietary patterns, and physical activity: insights from a cross-sectional study

Introduction

This study investigates the interplay between body composition, dietary patterns, and physical activity across genders, focusing on gender-specific differences in food preferences and eating behaviors. Understanding these interactions is crucial for developing targeted nutritional and lifestyle interventions.

Methods

A cross-sectional study was conducted with 1,333 participants (58.7% female, 41.3% male), aged 18-65 years. Participants were categorized into tertiles based on their fat mass to fat-free mass (FM-to-FFM) ratio. Data on dietary choices, eating behaviors, and physical activity were collected and analyzed to identify gender-specific trends.

Results

Significant gender-specific differences were observed in food preferences and eating behaviors. Males experienced greater hunger in the late afternoon, while females felt more hunger in the morning. Males showed a preference for processed and red meats, whereas females preferred cooked vegetables. Eating behaviors such as meal skipping, uncontrolled eating, nocturnal eating, and taste preferences (sweet or salty) varied distinctly between FM-to-FFM tertiles and genders. Higher FM-to-FFM ratios correlated with lower physical activity levels, particularly in strength training and general sports engagement.

Discussion

These findings highlight the complex interactions between body composition, dietary habits, and lifestyle factors, emphasizing gender-specific differences. The results suggest that body composition and BMI significantly impact health-related behaviors, necessitating tailored interventions to address these differences and promote healthier lifestyles.

Association Between Changes in Sleep, Nap Duration and Bone Mineral Density in Mexican Adults

Studies have found associations between sleep, nap duration, and bone mineral density (BMD). However, the longitudinal relationship between sleep, nap duration, and BMD has not been explored. We evaluated the association between the change in sleep and nap duration and BMD in Mexican adults. Data come from 1,337 adult participants of the Health Workers Cohort Study (341 were men and 996 were women, including 450 women < 45 years old and 546 ≥ 45 years old), with two study waves. At each wave, sleep and nap duration was assessed using self-administered questionnaires and BMD in g/cm2 was determined by dual X-ray absorptiometry. We used fixed-effect regression models stratified by sex and adjusted for BMI, diet, physical activity, vitamin supplements, and hormone replacement therapy. Women who changed from < 7 to ≥ 7 h/day of sleep from baseline to follow-up were associated with increases in the total hip (β = 0.012 g/cm2; 95% CI: 0.002, 0.022) and lumbar spine BMD (β = 0.024 g/cm2; 95% CI: 0.009, 0.039). Furthermore, most of these associations were observed in women ≥ 45 years. For women, a changing from 0 to > 60 min/day of napping was associated with a significant increase in total hip BMD of 0.012 g/cm2 (95% CI: 0.004, 0.024) and lumbar spine BMD of 0.027 g/cm2 (95% CI: 0.009, 0.045). No significant associations were observed for men. Our results suggest that increased sleep and nap duration are associated with gains in BMD in Mexican women, emphasizing sleep's role in promoting bone health and supporting established recommendations.

Gastrodin prevents myocardial injury in sleep-deprived mice by suppressing ferroptosis through SIRT6

Gastrodin (GAS), a bioactive compound derived from the orchid plant Gastrodia elata, exhibits numerous pharmacological effects. However, its effect on sleep deprivation (SD)-induced cardiac injury and the mechanisms are unknown. This study established SD mice model using a modified multiple platform water method and induced ferroptosis model in H9c2 cells using Erastin. The heart rate of mice was measured, and myocardial and mitochondrial structures were visualized using hematoxylin and eosin (H&E) staining and transmission electron microscopy (TEM). Myocardial injury, oxidative stress indicators, and Fe2+ levels were detected by the kit method. The reactive oxygen species (ROS) levels were detected by immunofluorescence, and SIRT6 and ferroptosis-associated protein expression levels were detected by Western blot. Reduced heart rate and abnormalities in myocardial tissue and mitochondrial structure were ameliorated in the SD group of mice after GAS treatment. GAS treatment reduced ROS levels in Erastin-induced H9c2 cells. GAS treatment reduced atrial natriuretic peptide (ANP), creatine kinase (CK), lactate dehydrogenase (LDH), malondialdehyde (MAD), and Fe2+ levels, and increased superoxide dismutase (SOD) and glutathione (GSH) levels in the SD and Erastin groups. Western blot showed that GAS treatment increased the expression of sirtuin 6 (SIRT6), solute carrier family 7 member 11 (SLC7A11), and glutathione peroxidase 4 (GPX4) and decreased the expression of P53 in SD and Erastin groups. The SIRT6 inhibitor OSS_128167 (OSS) reversed GAS treatment of Erastin-induced ferroptosis in H9c2 cells. These observations propose that GAS prevents myocardial injury in sleep-deprived mice by suppressing ferroptosis through SIRT6.

Exploring the Role of Circadian Rhythms in Sleep and Recovery: A Review Article

Sleep is essential for every living organism. Humans spend about one-third of their lives sleeping. Sleep has been studied extensively, and the role of sleep in psychological, mental, and physical well-being is established to be the best. The rhythm of the brain between wakefulness and sleep is called the circadian rhythm, which is mainly controlled by melatonin and the pineal gland. The imbalance of this rhythm can lead to devastating effects on health. Vigorous workouts close to bedtime can interfere with falling asleep. Meal timing and composition can significantly affect sleep quality. It is advised to avoid large meals, caffeine, and alcohol before bedtime. Heavy meals close to bedtime can lead to poor sleep and hormone disruption. By following these guidelines enumerated in the article, individuals can improve sleep quality and overall health. Sleep cycles, especially rapid eye movement sleep, have a profound influence on mental and physical health. Adhering to recommended sleep practices enhances bodily restoration, fortifies the immune system, and upholds metabolic equilibrium. Sleep hygiene aligned with circadian rhythms is crucial for disease prevention and well-being. Healthcare professionals should prioritize sleep optimization strategies for patient care and public health.

Short sleep duration is associated with higher risk of central obesity in adults: A systematic review and meta-analysis of prospective cohort studies

Background and Objective

The relationship between sleep duration and obesity has been the focus of numerous investigations. This systematic review and meta-analysis of prospective cohort studies aimed to assess the relationship between sleep duration, abdominal obesity, and body composition.

Methods

PubMed, Scopus, and Web of Science were searched until February 2024. Cohort studies that assessed the relationship between sleep duration at night and central obesity measures or body composition indices in adults were included. The quality of studies was assessed using the Newcastle-Ottawa scale. Random-effects meta-analysis was conducted on studies that reported risk ratio (RR) and 95% confidence intervals (CIs).

Results

Eighteen studies were eligible to be included. Eleven out of the 18 studies were not included in the analysis as 10 studies did not report RR, and in one study, the definition of short and normal sleep duration was different from others. The results of the meta-analysis indicated that short sleep duration was significantly associated with abdominal obesity (RR = 1.08; 95% CI: 1.04-1.12; I 2 = 49.1%, n = 7), but long sleep duration was not (RR = 1.02; 95% CI: 0.83-1.24; I 2 = 98.2%, n = 6).

Conclusions

Short sleep duration was associated with a slightly higher risk of central obesity, while long sleep duration was not.

A comprehensive review and advanced biomolecule-based therapies for osteoporosis

BACKGROUND

The prevalence of osteoporosis (OP) on a global scale is significantly elevated that causes life threatening issues. The potential of groundbreaking biomolecular therapeutics in the field of OP is highly encouraging. The administration of biomolecular agents has the potential to mitigate the process of bone demineralization while concurrently augmenting the regenerative capacity of bone tissue, thereby facilitating a personalized therapeutic approach. Biomolecules-based therapies showed promising results in term of bone mass protection and restoration in OP.

AIM OF REVIEW

We summarized the recent biomolecular therapies with notable progress in clinical, demonstrating the potential to transform illness management. These treatments frequently utilize different biomolecule based strategies. Biomolecular therapeutics has a targeted character, which results in heightened specificity and less off-target effects, ultimately leading to increased patient outcomes. These aspects have the capacity to greatly enhance the management of OP, thus resulting in a major enhancement in the quality of life encountered by individuals affected by this condition.

Association of fat-to-muscle mass ratio with physical activity and dietary protein, carbohydrate, sodium, and fiber intake in a cross-sectional study

Higher fat-to-muscle mass ratio (FMR) is reported to be a risk factor for various diseases, including type 2 diabetes and cardiovascular diseases, and mortality. Although this association suggests that reducing FMR may help to prevent certain diseases and mortality, the relationship between FMR and lifestyle factors is unclear. Therefore, we performed a cross-sectional study with the aim to elucidate this relationship. This cross-sectional study included 1518 healthy Japanese adults aged 30 to 64 years. We measured FMR in the whole body, arms, legs, and trunk and assessed various lifestyle factors. Then, we performed forced entry multiple regression analyses for FMR with the following variables: sex, age, physical activity, dietary intake, sleep quality, cigarette smoking, stress levels, and body mass index. As a result, whole-body and regional FMRs were correlated with female sex (β = 0.71); age (β = 0.06); physical activity (β = - 0.07); dietary intake of protein (β = - 0.12), carbohydrate (β = 0.04), sodium (β = 0.13), and fiber (β = - 0.16); and body mass index (β = 0.70). The results suggest that in the Japanese middle-aged population, low FMR is associated with certain lifestyle factors, i.e. higher physical activity and a diet with higher protein and fiber and lower carbohydrate and sodium, independent of age, sex, and body mass index.

Sleeping more than 8 h: a silent factor contributing to decreased muscle mass in Chinese community-dwelling older adults

BACKGROUND

Muscle mass loss is an age-related process that can be exacerbated by lifestyle, environmental and other factors, but can be mitigated by good sleep. The objective of this study was to investigate the correlation between varying time lags of sleep duration and the decline in muscle mass among individuals aged 60 years or older by using real-world health monitoring data obtained from wearable devices and smart home health monitoring devices.

METHODS

This study included 86,037 observations from 2,869 participants in the Mobile Support System database. Missing data were supplemented by multiple imputation. The investigation utilized generalized estimating equations and restricted cubic spline curve to examine the relationship between sleep duration and low muscle mass. Various lag structures, including 0, 1, 2, 0-1, 0-2, and 1-2 months, were fitted, and the interaction effect of observation time with sleep duration was estimated for each lag structure. Additionally, subgroup analyses were conducted. The models were adjusted for various covariates, including gender, age, body mass index, footsteps, smoking status, drinking status, marital status, number of chronic diseases, number of medications, diabetes mellitus, hyperlipidemia, coronary artery disease, respiratory disease, and musculoskeletal disease and an interaction term between time and sleep duration.

RESULTS

The results of the generalized estimating equation showed a significant correlation (p < 0.001) between sleep duration of 8 h or more and low muscle mass in older adults, using 6-7 h of sleep as a reference. This effect was seen over time and prolonged sleep accumulated over multiple months had a greater effect on muscle mass loss than a single month. The effect of long sleep duration on muscle mass loss was significantly greater in females than in males and greater in the over-75 than in the under-75 age group. Restricted cubic spline plots showed a non-linear relationship between sleep duration and low muscle mass (p < 0.001).

CONCLUSIONS

This study found an association between sustained nighttime sleep of more than eight hours and decreased muscle mass in older adults, especially older women.

Discriminating factors of body composition characteristics for academic performance in nursing college students: a cross-sectional study

BACKGROUND

Poor body composition may affect health status, and better body composition is often associated with better academic performance. Nursing students face heavy academic and practical pressures, and the relationship between body composition and academic performance in this group is not fully understood.

METHODS

This cross-sectional observational study used de-identified student data from a university of technology in southern Taiwan to analyze the correlation between body composition characteristics and academic performance using regression models.

RESULTS

A total of 275 nursing college students were divided into four groups according to academic performance. The group with the lowest academic performance had a lower percentage of body fat (P < 0.05) but a higher percentage of muscle mass (P < 0.05) than the other three groups. Academic performance was positively correlated with percentage of body fat (R = 0.16, P < 0.01) and body age (R = 0.41, P < 0.01), but was negatively correlated with percentage of muscle mass (R = - 0.16, P < 0.01). Percentage of body fat, visceral fat area, and body age were significant discriminators of academic performance (P < 0.05).

CONCLUSIONS

The relationship between academic performance and body composition among nursing college students is not straightforward. Contrary to our initial hypothesis, students with higher academic performance tended to have a higher percentage of body fat and a lower percentage of muscle mass. Percentage of body fat, visceral fat area, and body age were significant discriminators of academic performance, indicating that body composition should be considered an important factor in nursing education and practice.

Exploring the Dynamics of Sleep Deprivation: Insights into Complete Blood Count and Coagulation Parameters in a Case-Control Study

Background

The lack of preceding research in Sudan emphasizes the importance of this study, which contributes critical data to the global understanding of sleep-related health effects. This study investigates the complex relationship between sleep deprivation and blood-related factors, particularly focusing on full blood count and coagulation parameters.

Methods

From January to March 2022, a case-control study was conducted in Kosti, Sudan. A control group of 11 healthy 23-33-year-olds (6 men and 5 women) had regular sleep patterns. Six men and five women ages 23-33 were chosen for this sleep-deprived case study. The case group was deprived of sleep from 7:00 p.m. to 7:00 a.m. for three days and allowed to sleep normally during the day. Daily at 7:00 a.m., antecubital vein blood was drawn. The ACL 7000 coagulation analyzer and Sysmex fully automated hematology analyzers were used for coagulation and whole blood count analysis. Data analysis included descriptive and inferential approaches like the Mann-Whitney U test for group comparisons.

Results

The study found no significant differences in total white blood cell counts reported between case and control groups (p=0.898). The case group had a substantial drop in lymphocyte counts on day 3 (p=0.016). The third day showed significant differences in neutrophil and eosinophil levels (p=0.003 and 0.000, respectively). The difference in hemoglobin and hematocrit on day 3 was statistically significant (p=0.023). Platelet counts were stable. Both groups' prothrombin times were unaffected. On all three days, groups had significant differences in activated partial thromboplastin time (APTT) (p=0.004). Therefore, the intrinsic coagulation system may have changed.

Conclusion

This study demonstrates the complex link between sleep deprivation, coagulation indicators, and complete blood count. Monitoring blood indicators in poor sleep helps explain fundamental mechanisms and medicinal implications.

Gender-specific link between sleep quality and body composition components: a cross-sectional study on the elderly

Sleep duration has been associated with overweight/obesity. Since sleep quality and body composition alter during aging, we conducted this study to determine if sleep quality is linked to body composition components in elderly people. This is a cross-sectional study conducted on 305 Iranian community-dwelling elderly aged ≥ 65 years. Sleep quality and body composition components were evaluated using Pittsburgh sleep quality index and bioelectric impedance analysis, respectively. The association of sleep quality and body composition components was examined using linear regression analysis. The prevalence of poor sleep quality and overweight/obesity was 48.9% and 54.4% in men and 77.0% and 79.3% in women, respectively. Women had significantly higher scores in most PSQI items than men, indicating their worse sleep quality compared to men. Women also had significantly higher body mass index (BMI), body fat percentage, and visceral adipose tissue and lower skeletal muscle and fat-free mass percentages than men. In the adjusted regression model, men showed positive associations between the third tertile of poor sleep quality and BMI (B = 1.35; 95% CI 0.08-2.61) and waist circumference (B = 4.14; 95% CI 0.39-7.89), but they did not demonstrate an association between sleep quality and body composition components. In the adjusted regression model for women, there were positive associations for BMI (B = 1.21; 95% CI 0.34-2.07), waist circumference (B = 2.95; 95% CI 0.99-4.91), body fat percentage (B = 2.75; 95% CI 1.06-4.45), and visceral adipose tissue (B = 7.80; 95% CI 1.73-13.87); also there were negative associations for skeletal muscle (B =  - 1.40; 95% CI - 2.39 - - 0.41) and fat-free mass (B =  - 2.76; 95% CI - 4.46 - -1.07) percentages. Except for waist circumference, other variables differed between men and women (P < 0.001). Weight management, prevention of muscle wasting, and improvement of sleep quality should be considered in a consortium when designing healthcare strategies for the elderly.

Phenotyping obesity: A focus on metabolically healthy obesity and metabolically unhealthy normal weight

Over the past 4 decades, research has shown that having a normal body weight does not automatically imply preserved metabolic health and a considerable number of lean individuals harbour metabolic abnormalities typically associated with obesity. Conversely, excess adiposity does not always equate with an abnormal metabolic profile. In fact, evidence exists for the presence of a metabolically unhealthy normal weight (MUHNW) and a metabolically healthy obese (MHO) phenotype. It has become increasingly recognised that different fat depots exert different effects on the metabolic profile of each individual by virtue of their location, structure and function, giving rise to these different body composition phenotypes. Furthermore, other factors have been implicated in the aetiopathogenesis of the body composition phenotypes, including genetics, ethnicity, age and lifestyle/behavioural factors. Even though to date both MHO and MUHNW have been widely investigated and documented in the literature, studies report different outcomes on long-term cardiometabolic morbidity and mortality. Future large-scale, observational and population-based studies are required for better profiling of these phenotypes as well as to further elucidate the pathophysiological role of the adipocyte in the onset of metabolic disorders to allow for better risk stratification and a personalised treatment paradigm.

Complex relationship between growth hormone and sleep in children: insights, discrepancies, and implications

Growth hormone (GH) is crucial to growth and development. GH secretion is regulated by a complex feedback system involving the pituitary gland, hypothalamus, and other organs, and predominantly occurs during deep sleep. Isolated and idiopathic growth hormone deficiency (GHD) is a condition characterized by GHD without any other signs or symptoms associated with a specific syndrome or disease. The aim of this narrative review was to evaluate the relationship between GH and sleep in children using published data. Various databases (Medline/PubMed, Scopus, and Web of Science) were systematically searched for relevant English language articles published up to April 2023. Search strategies included the terms 'children/pediatric', 'growth hormone', 'growth hormone deficiency' and 'sleep'. Data were extracted by two independent reviewers; 185 papers were identified of which 58 were duplicates and 118 were excluded (unrelated n=83, syndromic/genetic GHD n=17, non-English n=13, abstract n=1, case report n=1). Overall, nine studies (six clinical studies, two case series, and one survey) were included. GHD appears to have an adverse effect on sleep in children, and GH therapy has only been shown to have a beneficial effect on sleep parameters in some individuals. Notably, identified data were limited, old/poor quality, and heterogenous/inconsistent. Further research of GHD in pediatric populations is necessary to improve the understanding of GHD impact on sleep and its underlying mechanisms, and to determine the specific impacts of GH therapy on sleep in children.

Sleep Quality and Cognitive Abilities in the Greek Cohort of Epirus Health Study

Purpose

Sleep is essential to all human body functions as well as brain functions. Inadequate sleep quantity and poor sleep quality have been shown to directly affect cognitive functioning and especially memory. The primary aim of the present study was to investigate the association of sleep quality with cognitive abilities cross-sectionally in a middle-aged Greek population and secondarily to examine this association prospectively in a smaller group of these participants.

Patients and Methods

A total of 2112 healthy adults aged 25-70 years (mean: 46.7±11.5) from the Epirus Health Study cohort were included in the analysis and 312 of them participated in secondary prospective analysis. Sleep quality was measured by the Pittsburgh Sleep Quality Index (PSQI) scale and cognition was assessed in primary cross-sectional analyses with three neuropsychological tests, namely the Verbal Fluency test, the Logical Memory test and the Trail Making test, and in secondary prospective analyses with online versions of Posner cueing task, an emotional recognition task, the Corsi block-tapping task and the Stroop task. Statistical analysis was performed using multivariable linear regression models adjusted for age, sex, education, body mass index and alcohol consumption.

Results

Attention/processing speed was the only cognitive domain associated cross-sectionally with PSQI score. Specifically, participants with better self-reported sleep quality performed faster on the Trail Making Test - Part A (β= 0.272 seconds, 95% CI 0.052, 0.493).

Conclusion

Further studies are needed to clarify the association of sleep quality with cognition, especially in middle-aged people that are still in productive working years.

The Function of Sleep and the Treatment of Primary Insomnia

BACKGROUND

Approximately 21 900 women and 35 300 men developed lung cancer in Germany in 2018, and 16 999 women and 27 882 men died of it. The outcome mainly depends on the tumor stage. In early stages (stage I or II), treatment can be curative; unfortunately, because early-stage lung cancers are generally asymptom - atic, 74% of women and 77% of men already have advanced-stage disease (stage III or IV) at the time of diagnosis. Screening with low-dose computed tomography is an option enabling early diagnosis and curative treatment.

METHODS

This review is based on pertinent articles retrieved by a selective search of the literature on screening for lung cancer.

RESULTS

In the studies of lung cancer screening that have been published to date, sensitivity ranged from 68.5% to 93.8%, and specificity from 73.4% to 99.2%. A meta-analysis by the German Federal Office for Radiation Protection revealed a 15% reduction in lung cancer mortality when low-dose computed tomography was used in persons who were judged to be at high risk for lung cancer (risk ratio [RR] 0.85, 95% confidence interval [0.77; 0.95]). 1.9% of subjects died in the screening arm of the meta-analysis, and 2.2% in the control group. The observation periods ranged from 6.6 to 10 years; false-positive rates ranged from 84.9% to 96.4%. Malignant findings were confirmed in 45% to 70% of the biopsies or resective procedures that were performed.

CONCLUSION

Systematic lung cancer screening with low-dose CT lowers mortality from lung cancer in (current or former) heavy smokers. This benefit must be weighed against the high rate of false-positive findings and overdiagnoses.

The Effect of Sleep on Metabolism, Musculoskeletal Disease, and Mortality in the General US Population: Analysis of Results From the National Health and Nutrition Examination Survey

BACKGROUND

Sleep is an important physiological behavior in humans that is associated with the occurrence and development of various diseases. However, the association of sleep duration with health-related outcomes, including obesity-related factors, musculoskeletal diseases, and mortality because of different causes, has not been systematically reported.

OBJECTIVE

This study aims to systematically investigate the effect of sleep duration on health-related outcomes.

METHODS

Overall, 54,664 participants with sleep information from 8 survey cycles of the National Health and Nutrition Examination Survey (2005-2020) were included in the analysis. Health-related outcomes comprised obesity-related outcomes (ie, BMI, obesity, waist circumference, and abdominal obesity), metabolism-related outcomes (ie, uric acid, hyperuricemia, and bone mineral density [BMD]), musculoskeletal diseases (ie, osteoarthritis [OA] and rheumatoid arthritis [RA]), and mortality because of different causes. The baseline information of participants including age, sex, race, educational level, marital status, total energy intake, physical activity, alcohol consumption, smoking, hypertension, and diabetes was also collected as covariates. Information about the metabolism index, disease status, and covariates was acquired from the laboratory, examination, and questionnaire data. Survival information, including survival status, duration, and cause of death, was obtained from the National Death Index records. Quantile regression models and Cox regression models were used for association analysis between sleep duration and health-related outcomes. In addition, the threshold effect analysis, along with smooth curve fitting method, was applied for the nonlinear association analysis.

RESULTS

Participants were divided into 4 groups with different sleep durations. The 4 groups showed significant differences in terms of baseline data (P<.001). The quantile regression analysis indicated that participants with increased sleep duration showed decreased BMI (β=-.176, 95% CI -.220 to -.133; P<.001), obesity (odds ratio [OR] 0.964, 95% CI 0.950-0.977; P<.001), waist circumference (β=-.219, 95% CI -.320 to -.117; P<.001), abdominal obesity (OR 0.975, 95% CI 0.960-0.990; P<.001), OA (OR 0.965, 95% CI 0.942-0.990; P=.005), and RA (OR 0.940, 95% CI 0.912-0.968; P<.001). Participants with increased sleep duration also showed increased BMD (β=.002, 95% CI .001-.003; P=.005), as compared with participants who slept <5.5 hours. A significant saturation effect of sleep duration on obesity, abdominal obesity, and hyperuricemia was detected through smooth curve fitting and threshold effect analysis (sleep duration>inflection point). In addition, a significant threshold effect of sleep duration on BMD (P<.001); OA (P<.001); RA (P<.001); and all-cause (P<.001), cardiovascular disease-cause (P<.001), cancer-cause (P=.005), and diabetes-cause mortality (P<.001) was found. The inflection point was between 6.5 hours and 9 hours.

CONCLUSIONS

The double-edged sword effect of sleep duration on obesity-related outcomes, embolism-related diseases, musculoskeletal diseases, and mortality because of different causes was detected in this study. These findings provided epidemiological evidence that proper sleep duration may be an important factor in the prevention of multisystem diseases.

Sleep deprivation in development of obesity, effects on appetite regulation, energy metabolism, and dietary choices

Sleep deprivation, which is a decrease in duration and quality of sleep, is a common problem in today's life. Epidemiological and interventional investigations have suggested a link between sleep deprivation and overweight/obesity. Sleep deprivation affects homeostatic and non-homoeostatic regulation of appetite, with the food reward system playing a dominant role. Factors such as sex and weight status affect this regulation; men and individuals with excess weight seem to be more sensitive to reward-driven and hedonistic regulation of food intake. Sleep deprivation may also affect weight through affecting physical activity and energy expenditure. In addition, sleep deprivation influences food selection and eating behaviours, which are mainly managed by the food reward system. Sleep-deprived individuals mostly crave for palatable energy-dense foods and have low desire for fruit and vegetables. Consumption of meals may not change but energy intake from snacks increases. The individuals have more desire for snacks with high sugar and saturated fat content. The relationship between sleep and the diet is mutual, implying that diet and eating behaviours also affect sleep duration and quality. Consuming healthy diets containing fruit and vegetables and food sources of protein and unsaturated fats and low quantities of saturated fat and sugar may be used as a diet strategy to improve sleep. Since the effects of sleep deficiency differ between animals and humans, only evidence from human subject studies has been included, controversies are discussed and the need for future investigations is highlighted.

Sleep-Body Composition Relationship: Roles of Sleep Behaviors in General and Abdominal Obesity in Chinese Adolescents Aged 17-22 Years

This study aimed to investigate the association between sleep behaviors and body composition, which was measured by bioelectrical impedance analysis (BIA) among Chinese adolescents. Overall, 444 students (65.3% females, 19.12 ± 1.177 years) completed questionnaires describing sleep characteristics. Sleep characteristics were derived from subjective means. Body composition was obtained from BIA by InBody 720 (Biospace Co. Ltd., Seoul, Republic of Korea). Regression models tested relationships between sleep and body composition after adjustment for covariates. Students with weekday nap duration (>30 min/d) exerted higher waist-height ratio (WHtR) (B = 0.013, FDR-corrected p = 0.080). Average sleep duration (≤7 h/d) was linked to more WHtR (B = 0.016, FDR-corrected p = 0.080). People with high social jetlag showed gained visceral fat area (B = 7.475), WHtR (B = 0.015), waist to hip ratio (B = 0.012), fat mass index (B = 0.663) and body fat percentage (B = 1.703) (all FDR-corrected p < 0.1). Individuals with screen time before sleep (>0.5 h) exhibited higher visceral fat area (B = 7.934, FDR-corrected p = 0.064), WHtR (B = 0.017, FDR-corrected p = 0.080), waist to hip ratio (B = 0.016, FDR-corrected p = 0.090), fat mass index (B = 0.902, FDR-corrected p = 0.069) and body fat percentage (B = 2.892, FDR-corrected p = 0.018). We found poor sleep characteristics were closely related to general and abdominal obesity.

Association of 24-h movement behaviors with phase angle in community-dwelling older adults: a compositional data analysis

BACKGROUND

Phase angle (PhA) is an indicator of cellular conditions. Recent studies have suggested that PhA supports healthy aging. Identifying modifiable lifestyle factors for PhA is important. The associations of PhA in 24-h movement behaviors, including physical activity (PA), sedentary behavior (SB), and sleep, have not been studied in older adults.

OBJECTIVES

We investigated the cross-sectional associations between 24-h movement behaviors and PhA in community-dwelling older adults while appropriately considering the co-dependent nature of daily time use using compositional data analysis.

METHODS

The participants were 113 healthy older adults. PhA was measured using a bioelectrical impedance device. Time spent in light-intensity PA (LPA), moderate- to vigorous-intensity PA (MVPA), and SB was measured using a tri-axial accelerometer. Sleep duration information was self-reported in a questionnaire. Compositional multiple linear regression and compositional isotemporal substitution were performed to examine the associations of 24-h movement behaviors with PhA and hypothetical time reallocation in movement behaviors with PhA, respectively.

RESULTS

Even after adjusting for potential confounders, relative to other behaviors more time spent in MVPA was significantly associated with higher PhA (p < 0.001). The 30 min/day of time reallocation from the other behaviors (SB, LPA, and sleep) to MVPA was predicted to be 0.12 higher PhA (corresponding to 2.3% increase; 95% CI 0.01, 0.24).

CONCLUSIONS

Our results suggest that increasing or maintaining the daily time spent in MVPA is important for managing PhA in older adults, regardless of the other behaviors time consumed instead.

The Effects of Different Modalities of an Acute Energy Deficit on Sleep and Next Morning Appetitive and Compensatory Behavior in Healthy Young Adults: The EDIES Protocol

Sleep is bi-directionally linked to energy balance. This crossover study design will evaluate the acute effect of a moderate energy deficit (500 kcal) induced by diet, exercise, or mixed (-250 kcal by diet and 250 kcal by exercise) on sleep and the next morning's appetitive responses. The study sample comprises 24 healthy young adults. The experimental measurements will be conducted in a naturalistic, momentary manner and partly assessed by the participants. The participants will undergo a run-in period in order to stabilize their sleep schedules and provide them with training on the study protocol and measurements. Indirect calorimetry will be used to determine their resting metabolic rate and peak oxygen consumption (VO₂ peak). Then, they will take part in a control session (CTL), followed by three energy deficit sessions in random order: a diet-induced energy deficit session (DED), an exercise-induced energy deficit session (EED), and a mixed energy deficit session (MED). All experimental sessions will be separated by a one-week washout. The participants' sleep will be monitored by ambulatory polysomnography, and the next morning's appetitive response will be evaluated via ad libitum food intake, appetite sensations, and food reward, measured by a food liking and wanting computerized test.

Method to quantify the impact of sleep on cardiac neuroautonomic functionality: application to the prediction of cardiovascular events in the Multi-Ethnic Study of Atherosclerosis

We introduce the concept of cardiac neuroautonomic renewability and a method for its quantification. This concept refers to the involuntary nervous system's capacity to improve cardiac control in response to restorative interventions, such as sleep. We used the change in heart rate fragmentation (ΔHRF), before sleep onset compared with after sleep termination, to quantify the restorative effects of sleep. We hypothesized that the ability to improve cardiac neuroautonomic functionality would diminish with age and be associated with lower risk of major adverse cardiovascular events (MACE). We analyzed the ECG channel of polysomnographic recordings from an ancillary investigation of the Multi-Ethnic Study of Atherosclerosis (MESA). In a cohort of 659 participants (mean ± SD age, 69.7 ± 8.8; 42% male), HRF was significantly (P < 0.001) lower after sleep (before: 74 ± 12%, after: 67 ± 13%). Furthermore, the magnitude of the decrease significantly (P < 0.001) diminished with cross-sectional age. In addition, a larger reduction in HRF following sleep (i.e., higher ΔHRF) was associated with lower risk of MACE, independent of traditional cardiovascular risk factors and current measures of sleep quality. Specifically, over a mean follow-up period of 6.4 ± 1.6 yr, in which 60 participants had their first MACE, a one-SD (12%) increase in ΔHRF was associated with a 36% (95% CI: 12%-53%) decrease in the risk of MACE. The results demonstrate the restorative impact of sleep on heart rate control. As such they support the concept of cardiac neuroautonomic renewability and the utility of ΔHRF for its quantification.

Effects of auditory sleep modulation approaches on brain oscillatory and cardiovascular dynamics

Slow waves, the hallmark feature of deep nonrapid eye movement sleep, do potentially drive restorative effects of sleep on brain and body functions. Sleep modulation techniques to elucidate the functional role of slow waves thus have gained large interest. Auditory slow wave stimulation is a promising tool; however, directly comparing auditory stimulation approaches within a night and analyzing induced dynamic brain and cardiovascular effects are yet missing. Here, we tested various auditory stimulation approaches in a windowed, 10 s ON (stimulations) followed by 10 s OFF (no stimulations), within-night stimulation design and compared them to a SHAM control condition. We report the results of three studies and a total of 51 included nights and found a large and global increase in slow-wave activity (SWA) in the stimulation window compared to SHAM. Furthermore, slow-wave dynamics were most pronouncedly increased at the start of the stimulation and declined across the stimulation window. Beyond the changes in brain oscillations, we observed, for some conditions, a significant increase in the mean interval between two heartbeats within a stimulation window, indicating a slowing of the heart rate, and increased heart rate variability derived parasympathetic activity. Those cardiovascular changes were positively correlated with the change in SWA, and thus, our findings provide insight into the potential of auditory slow wave enhancement to modulate cardiovascular restorative conditions during sleep. However, future studies need to investigate whether the potentially increased restorative capacity through slow-wave enhancements translates into a more rested cardiovascular system on a subsequent day.

Chronic Sleep Deprivation Impaired Bone Formation in Growing Rats and Down-Regulated PI3K/AKT Signaling in Bone Tissues

BACKGROUND

This study aimed to assess the effects of chronic sleep deprivation (CSD) on bone metabolism in growing rats and the likely underlying mechanism.

METHODS

Twenty 5-week-old male Wistar rats and randomly divided into the CSD and normal control (NC) groups after one-week acclimatization. After a 6-week intervention of sleep deprivation, the distal femurs of both groups were harvested for micro-computed tomography scans and histological analysis. Meanwhile, the femur tissues were measured the mRNA and protein expression via RNA sequencing and immunohistochemical analysis. Serum bone turnover markers were evaluated at 0, 2, 4, and 6 weeks.

RESULTS

CSD impaired the bone growth, showing an imbalance of bone turnover status, dysphasia in the metaphysis growth plate, and deterioration of bone microarchitecture. Further, CSD suppressed bone formation, showing that the expression of osteogenesis-related proteins (col1α1 and osteocalcin) and mRNA (igf1, bglap, runx2, col1α1, pth1r) are down-regulated. Differentially expressed genes were detected, and functional enrichment analyses revealed that the PI3K/AKT pathway was significantly down-regulated in the CSD group.

CONCLUSION

These results suggest that CSD can significantly impaire bone health, and it may exert these effects in part by suppressing bone formation and osteoblast differentiation, and inactivating the PI3K/AKT signaling pathway.