Sleep and muscle recovery: endocrinological and molecular basis for a new and promising hypothesis

Prevalence of and risk factors for low back pain among professional drivers: a systematic review and meta-analysis

PURPOSE

A growing body of research indicates a correlation between occupational exposure, particularly among individuals in driving-related occupations, and the incidence of low back pain (LBP).

METHODS

Databases were systematically searched, including PubMed, Embase, Web of Science, Cochrane Library, and SinoMed, from their inception through December 2023 for relevant studies of the prevalence and risk factors of LBP among professional drivers. Subsequent meta-analyses were performed utilizing Stata 17.0 and RevMan 5.4 software, while risk factor indicators were assessed using the Grading of Recommendations, Assessment, Development and Evaluation evidence quality grading system.

RESULTS

A systematic review and meta-analysis comprising 19 studies involving 7,723 patients indicated that the incidence of LBP among drivers was 39% (95% confidence interval [CI] 0.20-0.57) in the past 7 days and 53% (95% CI 0.43-0.63) in the past 12 months. A subgroup analysis revealed a prevalence of 48% (95% CI 0.33-0.64) in 2005-2015 and 56% (95% CI 0.42-0.70) in 2016-2023. Among the identified factors, robust evidence highlighted age ≥ 41 years (odds ratio [OR] = 2.10; 95% CI 1.36-3.24; P = 0.0008), alcohol consumption (OR = 1.75; 95% CI 1.31-2.34; P = 0.0001), sleeping < 6 h/night (OR = 1.60; 95% CI 1.13-2.24; P = 0.007), uncomfortable seating (OR = 1.71; 95% CI 1.23-2.36; P = 0.001), improper driving posture (OR = 2.37; 95% CI 1.91-2.94; P < 0.00001), and manual handling (OR = 2.23; 95% CI 1.72-2.88; P < 0.00001) as significant risk factors for LBP. There was moderate evidence of a lack of exercise (OR = 1.78; 95% CI 1.37-2.31; P < 0.0001), working > 10 h/day (OR = 2.49; 95% CI 1.89-3.28; P < 0.00001), > 5 years' driving experience (OR = 2.12; 95% CI 1.66-2.69; P < 0.00001), a lack of back support (OR = 1.81; 95% CI 1.25-2.62; P = 0.002), high work-related pressure (OR = 2.04; 95% CI 1.59-2.61; P < 0.00001), and job dissatisfaction (OR = 1.57; 95% CI 1.23-2.01; P = 0.0003) as moderate risk factors. There was no evidence of body mass index or smoking as risk factors for LBP among professional drivers.

CONCLUSION

The current evidence indicates an increasing annual trend in the prevalence of LBP among professional drivers. Factors including age ≥ 41 years, alcohol consumption, and sleeping < 6 h/night were among the 12 influential factors contributing to LBP in professional drivers. Enhancing awareness of these factors and formulating targeted preventive strategies may be beneficial.

12-week melatonin supplementation improved dynamic postural stability and walking performance in persons living with multiple sclerosis: A randomized controlled trial

BACKGROUND

Persons with multiple sclerosis (PwMS) suffer from sleep disturbances, fatigue and pain, which can be due, at least in part, to decreased levels of endogenous melatonin. These alterations could exacerbate postural instability, gait disorders and fall risk. Acute effects of exogenous melatonin on physical disorders have been studied in PwMS but its long-term effects on these parameters have not been explored yet in this population. This study aimed to determine the impact of chronic melatonin intake on dynamic postural stability, walking performance and fall risk in PwMS.

METHODS

This randomized placebo-controlled study included 27 PwMS who were assigned to either melatonin group (MG, n=15) or placebo group (PG, n=12) (3 mg/night for 12 weeks). Dynamic postural balance (force platform), walking performance (locometer) and fall risk (Four Square Step Test) were evaluated pre (T0)- and post (T1)-intervention. Sleep quality (Pittsburgh Sleep Quality Index (PSQI)), fatigue perception (Fatigue Severity Scale (FSS)), neuropathic pain (Neuropathic Pain Questionnaire 4 (DN4)) and quality of life (International Multiple Sclerosis (MS) Quality of Life Questionnaire) were also assessed at T0 and T1.

RESULTS

The center of pressure mean velocity decreased in MG compared with PG in the frontal plane (22.98 %, p=0.028). Stride length and walking speed increased in MG comparatively with PG (18.09 %, p=0.036; 9.65 %, p=0.025, respectively). The PSQI (55.89 %, p<0.001), FSS (32.38 %, p=0.003) and DN4 (32.41 %, p=0.035) scores decreased in MG compared with PG.

CONCLUSION

12-week melatonin supplementation can be recommended for managing MS-related gait disorders and dynamic postural imbalance. This therapy may also be prescribed for PwMS due to its anti-fatigue and analgesic effects as well as its benefits on sleep quality.

CLINICAL REGISTRATION

This study was prospectively recorded in the Pan African Clinical Trial Registry database (PACTR202007465309582) (https://pactr.samrc.ac.za/.).

Association between sarcopenia and sleep disorders: a cross-sectional population based study

Objective

Sleep disorders is a worldwide public health problem. We sought to examine the association between sarcopenia, a decline in skeletal muscle mass and function, and sleep disorders within the adult demographic of the United States during the period spanning 2011 to 2018.

Methods

Diagnosis of sarcopenia and sleep disorders was ascertained through appropriate calculations and a structured questionnaire. The primary correlation analysis was conducted using a weighted multivariate logistic regression model. Furthermore, to confirm the presence of a potential non-linear association between sarcopenia and sleep disorders, additional analyses were performed using multivariate logistic regression and restricted cubic spline (RCS) regression with dose-response curve analysis. Subgroup analyses were also conducted to explore the influence of relevant socio-demographic factors and other covariates.

Results

The final analysis encompassed 5,616 participants. Model 4, inclusive of all pertinent covariates, revealed a positive correlation between sarcopenia and sleep disorders, yielding an odds ratio (OR) of 1.732 (95% CI: 1.182-2.547; P = 0.002). Further analysis, utilizing the restricted cubic spline model, indicated a decreasing trend in sleep disorders as sarcopenia indices rose. Stratified analyses across diverse variables underscored the significant impact of sarcopenia on sleep disorders prevalence in several subgroups. Specifically, males, individuals aged 40 and above, non-Hispanic whites, those with high school education or equivalent, unmarried individuals, obese individuals (BMI ≥ 30), alcohol drinkers, former smokers, diabetics, and those engaging in less rigorous recreational activities exhibited a more pronounced association between sarcopenia and sleep disorders. The incidence of sleep disorders exhibited an upward trend as the incidence of sarcopenia declined among study participants.

Conclusions

In summary, our study provides evidence of an association between sarcopenia and the prevalence of sleep disorders, with a negative correlation observed between the sarcopenia index and the odds ratio of sleep disorders. These findings suggest that maintaining optimal muscle mass may have a beneficial impact on sleep-related issues. In terms of exploring the mechanisms underlying the relationship between sarcopenia and sleep disorders, more in-depth research is warranted to ascertain the definitive causal relationship.

Current Aspects of Selected Factors to Modulate Brain Health and Sports Performance in Athletes

This review offers a comprehensive evaluation of current aspects related to nutritional strategies, brain modulation, and muscle recovery, focusing on their applications and the underlying mechanisms of physiological adaptation for promoting a healthy brain, not only in athletes but also for recreationally active and inactive individuals. We propose that applying the rule, among others, of good sleep, regular exercise, and a properly balanced diet, defined as "SPARKS", will have a beneficial effect on the function and regeneration processes of the gut-brain-muscle axis. However, adopting the formula, among others, of poor sleep, stress, overtraining, and dysbiosis, defined as "SMOULDER", will have a detrimental impact on the function of this axis and consequently on human health as well as on athletes. Understanding these dynamics is crucial for optimizing brain health and cognitive function. This review highlights the significance of these factors for overall well-being, suggesting that adopting the "SPARKS" approach may benefit not only athletes but also older adults and individuals with health conditions.

Stress systems exacerbate the inflammatory response after corneal abrasion in sleep-deprived mice via the IL-17 signaling pathway

Sleep deprivation (SD) has a wide range of adverse health effects. However, the mechanisms by which SD influences corneal pathophysiology and its post-wound healing remain unclear. This study aimed to examine the basic physiological characteristics of the cornea in mice subjected to SD and determine the pathophysiological response to injury after corneal abrasion. Using a multi-platform water environment method as an SD model, we found that SD leads to disturbances of corneal proliferative, sensory, and immune homeostasis as well as excessive inflammatory response and delayed repair after corneal abrasion by inducing hyperactivation of the sympathetic nervous system and hypothalamic-pituitary-adrenal axis. Pathophysiological changes in the cornea mainly occurred through the activation of the IL-17 signaling pathway. Blocking both adrenergic and glucocorticoid synthesis and locally neutralizing IL-17A significantly improved corneal homeostasis and the excessive inflammatory response and delay in wound repair following corneal injury in SD-treated mice. These results indicate that optimal sleep quality is essential for the physiological homeostasis of the cornea and its well-established repair process after injury. Additionally, these observations provide potential therapeutic targets to ameliorate SD-induced delays in corneal wound repair by inhibiting or blocking the activation of the stress system and its associated IL-17 signaling pathway.

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.

Sleep architecture of elite soccer players surrounding match days as measured by WHOOP straps

This study aimed to quantify and compare sleep architecture before and after home and away matches in elite soccer players from the English Premier League. Across two seasons, 6 male players (age 28 ± 5 y; body mass 85.1 ± 9.5 kg; height 1.86 ± 0.09 m) wore WHOOP straps to monitor sleep across 13 matches that kicked off before 17:00 h. For each, sleep was recorded the night before (MD-1), after (MD) and following the match (MD +1). Across these 3 days total sleep time (TST), sleep efficiency (SE), sleep disturbances, wake time, light sleep, deep sleep, REM sleep, sleep and wake onsets, alongside external load, were compared. TST was reduced after MD versus MD +1 (392.9 ± 76.4 vs 459.1 ± 66.7 min, p = 0.003) but no differences existed in any other sleep variables between days (p > 0.05). TST did not differ after home (386.9 ± 75.7 min) vs. away matches (401.0 ± 78.3 min) (p = 0.475), nor did other sleep variables (p > 0.05). GPS-derived external load peaked on MD (p < 0.05). In conclusion, despite reduced TST on MD, sleep architecture was unaffected after matches played before 17:00 h, suggesting sleep quality was not significantly compromised.

Sarcopenia risk, sarcopenia-related quality of life, and associated factors in people living with human immunodeficiency virus (HIV): A web-based survey

OBJECTIVES

We aimed to screen for the risk of sarcopenia and sarcopenia-related quality of life and associated factors of people living with HIV (PLWH).

RESEARCH METHODS AND PROCEDURES

This nonprobabilistic web-based survey evaluated PLWH. The participants were invited directly from a university-based inpatient clinic and responded to a web questionnaire that included the SARC-F and SarQoL to screen people at risk of sarcopenia and their quality of life. People at risk of sarcopenia were defined by the proposed cutoff points for SARC-F (≥ 4 points), and SarQoL overall score was categorized according to the median. Moreover, we performed a logistic regression to investigate associations between HIV-, lifestyle-, and health-associated factors (i.e., physical activity, dietary pattern, sleep quality, gastrointestinal symptoms, HIV diagnosis, type, combinations, and duration of ART, smoking, drinking, BMI, and weight loss), and outcomes (SARC-F and SarQoL).

RESULTS

The sample comprised 202 PLWH, mainly middle-aged (50.6-60.5 y; n = 101). Only 5.9% (n = 12) are at risk of sarcopenia according to SARC-F, and only 17.3% (n = 35) exhibited lower sarcopenia-related quality of life according to SarQoL. In the multiple models, only the gastrointestinal symptoms increased the odds of sarcopenia risk (OR: 1.058; P = 0.01) and poor sarcopenia-associated quality of life (OR: 1.041; P = 0.013).

CONCLUSIONS

We verified that only 5.9% and 17.3% of PLWH are at risk of sarcopenia and presented lower sarcopenia-related quality of life, respectively. Only the gastrointestinal symptoms were associated with a risk of sarcopenia and lower sarcopenia-related quality of life, without significant differences between age groups.

Longitudinal association of sleep duration with possible sarcopenia: evidence from CHARLS

OBJECTIVES

There are limited data on the relationship between sleep duration and possible sarcopenia. Hence, this study aimed to investigate the associations of sleep duration with possible sarcopenia and its defining components based on the China Health and Retirement Longitudinal Study (CHARLS).

DESIGN

A retrospective cohort study.

SETTING

This study was conducted on participants aged over 45 years applying the 2011 baseline and 2015 follow-up survey from CHARLS covering 450 villages, 150 counties and 28 provinces.

PARTICIPANTS

Data from 5036 individuals (2568 men and 2468 women) free of possible sarcopenia at baseline were analysed.

PRIMARY AND SECONDARY OUTCOME MEASURES

The dose-response relationship between sleep duration and possible sarcopenia.

RESULTS

During 4 years of follow-up, 964 (19.14%) participants developed possible sarcopenia. Compared with participants who slept 6-8 hours per night, those with shorter sleep duration (<6 hours per night) were independently associated with 22% (OR, 1.22; 95% CI, 1.04 to 1.44) increased risk of developing possible sarcopenia and 27% (OR, 1.27; 95% CI, 1.04 to 1.57) increased risk of developing low handgrip strength after controlling for potential confounders. Long sleep duration (>8 hours per night) was not significantly associated with incident possible sarcopenia. The plots of restricted cubic splines exhibited an atypical inverse J-shaped association between sleep duration and possible sarcopenia. Subgroup analysis showed a stronger association between sleep duration and possible sarcopenia in participants aged 45-59 years and composed of male populations.

CONCLUSIONS

Short sleep duration was a potential risk factor for possible sarcopenia and low handgrip strength. The improvement of sleep duration should be considered a target in early preventive and administrative strategies against the development of handgrip strength decline and further reduced the occurrence of sarcopenia.

Association of the Combination of Moderate-to-Vigorous Physical Activity and Sleep Quality with Physical Frailty

BACKGROUND

The association of the individual and combined effects of moderate-to-vigorous physical activity (MVPA) and sleep quality with physical frailty in community-dwelling older adults is still unknown.

SUBJECTS AND METHODS

A cross-sectional study was conducted with a sample of older adults who had not required nursing care or support services. Physical frailty was assessed using Liu's definition based on Fried's concept. MVPA was measured by a triaxial accelerometer, and individuals who met either moderate physical activity (MPA) for ≥300 min/week, vigorous physical activity (VPA) for ≥150 min/week, or both were defined as "MVA+". "SLP+" was defined as a Pittsburgh Sleep Quality Index score of <5.5 points.

RESULTS

A total of 811 participants were included in the final analysis. After adjusting for the multivariable confounding factors, the odds ratios (ORs) and 95% confidence intervals (CIs) for physical pre-frailty and frailty in the MVA-SLP+ (OR, 2.56; 95%CI, 1.80-3.62) and the MVA-SLP- group (OR, 3.97; 95%CI, 2.33-6.74) were significantly higher compared with the MVA+SLP+ group.

CONCLUSION

Community-dwelling older adults who did not meet the MVPA criteria, regardless of sleep quality, had a higher prevalence of physical frailty.

Effects of a nighttime melatonin ingestion on dynamic postural balance and muscle strength the following morning in people living with multiple sclerosis: A preliminary study

BACKGROUND

Decreased endogenous melatonin concentrations in people with multiple sclerosis (PwMS) are associated with fatigue and pain that impair postural balance and muscle strength. Melatonin ingestion had analgesic and anti-fatigue effects. However, the acute effect of exogenous melatonin on dynamic postural stability and muscle strength has not been studied yet in PwMS. This study aimed to investigate the safety and the efficacy of a nighttime melatonin intake on dynamic postural balance and lower-extremity muscle strength the following morning in PwMS.

METHODS

Fourteen PwMS (28.36 ± 6.81 years) were assessed (8 a.m.) pre- and post-acute intake of melatonin or placebo (6mg, 30 minutes before nocturnal bedtime). Evaluated parameters included dynamic postural balance (force platform), lower-extremity muscle strength [Five-Repetition Sit-To-Stand Test (5-STST)], hand dexterity (Nine-Hole Peg Test), nociceptive pain [Visual Analogue Scale (VAS)], neuropathic pain [Neuropathic Pain 4 Questions (DN4)], sleep quality and fatigue perception [Hooper Index (HI)].

RESULTS

In the frontal plane, melatonin reduced the center of pressure (CoP) path length (CoPL), CoPL in the anteroposterior axis (CoPLY) and CoP sway area (CoPAr) compared with placebo by 7.56% (p=0.02, Cohens'd (d)=1.24), 19.27% (p<0.001, d=2.60) and 13.82% (p<0.001, d=2.02), respectively. Melatonin induced a higher decrease in these posturographic parameters compared with placebo in the sagittal plane [CoPL: 9.10% (p=0.005, d=1.02), CoPLY: 4.29% (p=0.025, d=1.07) and CoPAr: 7.45% (p=0.038, d=0.74)]. Melatonin decreased 5-STST duration as well as VAS, DN4, HI-fatigue and HI-sleep scores compared with placebo by 8.19% (p=0.008, d=1.19), 5.74% (p=0.04, d=0.82), 27.30% (p=0.023, d=0.98), 40.15% (p=0.044, d=0.85) and 30.16% (p=0.012, d=1.10), respectively.

CONCLUSION

This preliminary study, among PwMS, showed that acute melatonin ingestion was safe and efficient for improving dynamic postural stability and lower-extremity muscle strength probably through its analgesic and anti-fatigue effects.

Association between poor sleep quality and locomotive syndrome in middle-aged and older women: A community-based, cross-sectional study

OBJECTIVE

Poor sleep quality, such as nocturnal arousal and sleep inefficiency, is associated with frailty and sarcopenia. Herein, we evaluated the relationship between poor sleep quality and locomotive syndrome (LS), a motor organ dysfunction common among community-dwelling middle-aged and older women.

METHODS

Participants comprised 2246 Japanese middle-aged and older women. LS was classified into stages LS-1, LS-2, and LS-3 (from least to most severe) according to the results of the stand-up test, two-step test, and 25-question Geriatric Locomotive Function Scale. Sleep quality was assessed using the Pittsburgh Sleep Quality Index.

RESULTS

The Pittsburgh Sleep Quality Index scores were significantly higher in the LS group than that in the non-LS group (P < .001). Multivariate logistic regression analyses adjusted for potential confounders identified poor sleep quality as an independent factor of LS (odds ratio 1.59 [95% confidence interval 1.30-1.93], P < .001). Similar results were observed in the sensitivity analysis in postmenopausal women. LS and trouble sleeping because of pain showed stepwise association in all LS stages.

CONCLUSIONS

Poor sleep quality was independently associated with LS among community-dwelling middle-aged and older women. As the stage of LS progressed, the proportion of women with poor sleep quality increased significantly.

Sedentary behaviour (especially accumulation pattern) has an independent negative impact on skeletal muscle size and architecture in community-dwelling older adults

Prolonged sedentary behaviour (SB) i.e. longer bouts, is suggested to have a range of negative health effects, independent of habitual light and medium-to-vigorous physical activity (LIPA or MVPA). Any effect on musculoskeletal size, architecture or morphology has seldom been reported in older adults. Moreover, no study has yet determined if any association would persist following adjustment for covariates. Therefore, the aim of the present study was to investigate the associations between SB, and properties of the Gastrocnemius Medialis (GM) muscle, in a cross-sectional sample of older adults using compositional data analysis. 105 healthy older adults (73±6y) wore a thigh mounted tri-axial accelerometer for seven consecutive days, and underwent ultrasound [e.g. muscle length (Lm), anatomical cross-sectional area (ACSA), muscle volume (VM), fascicle length (LF), & physiological cross-sectional area (PCSA)], body composition (e.g. DEXA) and health (e.g. medical history) assessments. In-unadjusted models, SB time was negatively associated with ACSA at 75% of Lm (R2adj = 0.085), VM (R2adj = 0.020), and PCSA (R2adj = 0.039). Standing was positively associated with pennation angle (R2adj = 0.110), which persisted following co-variate adjustment (R2adj = 0.296). In fully adjusted models, both SB & LIPA time were associated with ACSA at 75% of Lm (Both R2adj = 0.393). Standing and light activity time were also associated with LF, VM, & PCSA (R2adj 0.116-0.573). In fully adjusted models, SB pattern parameters (i.e. the manner in which sedentary behaviour is accumulated daily throughout waking hours such as the timing, duration and frequency of sedentary bouts), were associated with GM muscle properties (R2adj 0.156-0.564) including LM, LF, and VM. The pattern, rather than accumulated daily SB time, was associated with the size and architecture of the GM. Our results suggest that regardless of co-existing habitual physical activities, SB bouts should be kept short and frequently interrupted to offset some of the deleterious ageing-related muscle architecture characteristics changes.

Changing Sleep Architecture through Motor Learning: Influences of a Trampoline Session on REM Sleep Parameters

Previous research has shown that learning procedural tasks enhances REM sleep the following night. Here, we investigate whether complex motor learning affects sleep architecture. An experiment in which twenty-two subjects either learned a motor task (trampolining) or engaged in a control task (ergometer) was carried out in a balanced within-group design. After an initial laboratory adaptation night, two experimental nights were consecutive. The results indicate that learning a motor task had an effect on REM sleep parameters and, therefore, support the hypothesis that learning a procedural skill is related to an increase in REM sleep parameters. However, the statistical effect on REM sleep is smaller than found in previous studies. One might speculate that the motor learning was not intense enough compared to other studies. For sports practice, the results suggest that REM sleep, which is particularly rich in the morning, plays an important role in motor memory consolidation. Thus, this phase should not be interrupted after complex motor skill learning sessions. In future studies, other motor tasks should be applied.

Bidirectional Associations Between Sleep Quality and Grip Strength and the Mediating Role of Depression: Evidence From Two Nationally Representative Cohorts

BACKGROUND

Although studies have demonstrated associations between sleep quality (SQ) and grip strength (GS) in older adults, the direction and underlying mechanisms of this relationship are yet to be better delineated. We aimed to longitudinally investigate the bidirectional association between SQ and GS and the mediating role of depression in this association.

METHODS

Based on 2 nationally representative samples with people aged ≥50 years from the China Health and Retirement Longitudinal Study (CHARLS; 4 200 participants) and English Longitudinal Study of Ageing (ELSA; 5 922 participants), cross-lagged panel models were employed to examine the potential bidirectional relationships between objectively measured GS and self-reported SQ.

RESULTS

We observed a GS-SQ bidirectional association dominated by GS. After adjusting for potential confounders, a higher GS at T1 predicted better SQ at T2 (ELSA: β = 0.075; CHARLS: β = 0.104, p < .001) and vice versa (ELSA: β = 0.034; CHARLS: β = 0.030, p < .01). Moreover, depression partially mediated the impact of GS on subsequent SQ (ELSA, indirect effect: 0.0057, 95% confidence interval [CI]: 0.0035-0.0084; CHARLS, indirect effect: 0.0086, 95% CI: 0.0051, 0.0131), but not vice versa.

CONCLUSIONS

The results regarding data from both cohorts consistently supported a bidirectional association between GS and SQ and the mediating role of depression in the dominant pathway of this bidirectional relationship. Older adults with a low GS should be made aware of a potentially vicious cycle related to depression that can affect their sleep. Regular screening for depression may help to break this cycle.

Depressive symptoms and sleep duration in relation to chronic kidney disease: Evidence from the China health and retirement longitudinal study

OBJECTIVE

Nowadays, the joint effects of depressive symptoms and sleep duration on the risk of chronic kidney disease (CKD) are still unclear. We aimed to prospectively assess the combined effect of depressive symptoms and sleep duration on the incidence of CKD in middle-aged and elderly Chinese population.

METHODS

A total of 10,953 participants from the China Health and Retirement Longitudinal Study (CHARLS) were included. Depressive symptoms were measured using the 10-item Center for Epidemiological Studies Depression scale (CESD-10). Sleep duration was evaluated by self-reported. CKD events were based on self-reported physicians' diagnosis or personal estimate glomerular filtration rate level (eGFR <60 mL/min/1.73 m2). Cox regression models were established to analyze the correlation between depressive symptoms, sleep duration and the risk of CKD.

RESULTS

Over a mean follow-up time was 6.76 ± 0.98 years, 851 (7.8%) participants had reported CKD events during the follow-up. Elevated depressive symptoms (HR = 1.65, 95% CI = 1.43-1.90) and short sleep duration (HR = 1.48, 95% CI = 1.27-1.72) were independently associated with an increased CKD risk after adjusting for potential confounding factors. Participants with short sleep duration (< 6 h)/elevated depressive symptoms (HR = 2.24, 95% CI = 1.89-2.65) were associated with the highest risk of CKD than those with normal sleep duration/low depressive symptoms.

CONCLUSIONS

Elevated depressive symptoms and short sleep duration were independent risk factors for CKD. There was a combined effect between depressive symptoms and sleep duration in increasing the risk of CKD.

Effect of changes in sleeping behavior on skeletal muscle and fat mass: a retrospective cohort study

BACKGROUND

An association between sleep behaviors and muscle-fat mass is continuously interesting topic.

METHODS

Based on the survey on sleep behaviors (quality and duration), the poor quality of sleep was evaluated when the subject did not feel satisfied after sleep, while the good quality was evaluated as they feel refreshed. A total of 19,770 participants were divided into the four groups according to changes in sleep quality: Good-to-Good (those who continuously maintained good quality), Good-to-Poor (those who reported initial good quality but subsequently reported a poor quality), Poor-to-Poor (those who continuously maintained poor quality), and Poor-to-Good (those who reported improved quality of sleep). As changes in skeletal muscle and fat mass index [kg/m2] were estimated by a validated prediction equation, multiple linear regression was used to calculate adjusted mean (adMean) of muscle and fat mass according to changes in sleep behavior.

RESULTS

When sleep duration decreased and quality of sleep deteriorated (from good to poor), fat mass index significantly increased (adMean: 0.087 for the Good-to-Good group and 0.210 for the Good-to-Poor group; p-value = 0.006). On the other hand, as the quality of sleep deteriorated, skeletal muscle mass more decreased despite the maintained sleep duration (adMean: -0.024 for the Good-to-Good group and - 0.049 for the Good-to-Poor group; p-value = 0.009).

CONCLUSION

Our results showed that changes in sleep quality and duration affect changes in muscle and fat mass. Thus, we suggest maintaining a good quality of sleep, even if sleep duration is reduced, to preserve muscle mass and inhibit the accumulation of fat.

Acute sleep deprivation induces synaptic remodeling at the soleus muscle neuromuscular junction in rats

Sleep is important for cognitive and physical performance. Sleep deprivation not only affects neural functions but also results in muscular fatigue. A good night's sleep reverses these functional derangements caused by sleep deprivation. The role of sleep in brain function has been extensively studied. However, its role in neuromuscular junction (NMJ) or skeletal muscle morphology is sparsely addressed although skeletal muscle atonia and suspended thermoregulation during rapid eye movement sleep possibly provide a conducive environment for the muscle to rest and repair; somewhat similar to slow-wave sleep for synaptic downscaling. In the present study, we have investigated the effect of 24 h sleep deprivation on the NMJ morphology and neurochemistry using electron microscopy and immunohistochemistry in the rat soleus muscle. Acute sleep deprivation altered synaptic ultra-structure viz. mitochondria, synaptic vesicle, synaptic proteins, basal lamina, and junctional folds needed for neuromuscular transmission. Further acute sleep deprivation showed the depletion of the neurotransmitter acetylcholine and the overactivity of its degrading enzyme acetylcholine esterase at the NMJ. The impact of sleep deprivation on synaptic homeostasis in the brain has been extensively reported recently. The present evidence from our studies shows new information on the role of sleep on the NMJ homeostasis and its functioning.

Sleep quality is a predictor of muscle mass, strength, quality of life, anxiety and depression in older adults with obesity

We aimed to investigate associations between sleep quality with selected quantitative and qualitative parameters of health in older individuals with obesity. Cross-sectional assessment (n = 95 men/women; ≥ 65 years; BMI ≥ 30 kg/m²) of sleep quality, body composition, handgrip strength, quality-of-life, anxiety/depression. Mean PSQI score was 6.3. Poor sleepers (n = 49) presented lower appendicular lean mass (ALM) (16.2 vs 17.8 kg; p = 0.0273), ALM/BMI (0.47 vs 0.53 kg/BMI; p = 0.0085), fat mass (48.6 vs 46.6%; p = 0.0464), handgrip strength (19.7 vs 22.0 kgf; p = 0.0542) and handgrip/BMI (0.57 vs 0.66 kgf/BMI; p = 0.0242) than good sleepers. They also had higher anxiety (8.6 vs 5.6; p = 0.0100) and depression (4.8 vs 3.2; p = 0.0197) scores, worse health-related quality-of-life and lower scores in mental (62.8 vs 73.0; p = 0.0223) and physical (52.9 vs 67.3; p = 0.0015) domains. Adjusted models showed that PSQI was negatively associated with ALM (β = - 0.13, 95% CI - 0.25; - 0.01) and health-related quality of life on physical (β = - 2.76, 95% CI - 3.82; - 1.70) and mental (β = - 2.25, 95% CI - 3.38; - 1.12) domains, and positively associated with anxiety (β = 0.57; 95% CI 0.26; 0.87) and depression (β = 0.31; 95% CI 0.13; 0.49). Poor sleep quality associates with impaired selected quantitative and qualitative parameters of health. Additionally, sleep quality was shown as an independent predictor of ALM, health-related quality-of-life, anxiety and depression in older individuals with obesity.

Sleep and Sport Performance

SUMMARY

Elite athletes and coaches believe sleep is the most important recovery strategy and widely consider it critical to optimal performance. Despite this perceived importance, there are numerous circumstances that can reduce sleep quantity and quality in athletic populations. Because of the effects of sleep loss on various physical, neurophysiological, and cognitive parameters, such perturbations can have consequences for performance and recovery outcomes. Although peer-reviewed literature examining the interaction between sleep, performance, and recovery in athletes is increasing, understanding of these issues remains equivocal. Perhaps most pertinently, the effect of sleep on sport performance does not align with a one-size-fits-all approach and rather depends on numerous factors such as type of sport, scheduling, time of the season, and the intraindividual requirements for sleep. The relationship between brain plasticity and memory, which in turn can influence learning processes and long-term memory consolidation, suggests that sleep may play an important role in learning new skills and tactics for both elite and developing athletes. The aim of this special issue review was to analyze the evidence of sleep loss on sport performance and recovery, with a specific focus on elite athletes. An assessment of these sleep-compromising situations that elite athletes may face during a typical season and practical considerations for alleviating these issues is also provided to further the understanding for medical professionals, scientists, and applied sporting practitioners alike.

How do patients sleep after orthopaedic surgery? Changes in objective sleep parameters and pain in hospitalized patients undergoing hip and knee arthroplasty

PURPOSE

The aim of this observational cohort study was to assess actigraphy-based sleep characteristics and pain scores in patients undergoing knee or hip joint replacement and hospitalized for ten days after surgery.

METHODS

N=20 subjects (mean age: 64.0±10.39 years old) wore the Actiwatch 2 actigraph (Philips Respironics, USA) to record sleep parameters for 11 consecutive days. Subjective scores of pain, by a visual analog scale (VAS), were constantly monitored and the following evaluation time points were considered for the analysis: pre-surgery (PRE), the first (POST1), the fourth (POST4), and the tenth day (POST10) after surgery.

RESULTS

Sleep quantity and timing parameters did not differ from PRE to POST10, during the hospitalization whereas sleep efficiency and immobility time significantly decreased at POST1 compared to PRE by 10.8% (p=0.003; ES: 0.9, moderate) and 9.4% (p=0.005; ES: 0.86, moderate) respectively, and sleep latency increased by 18.7 min (+320%) at POST1 compared to PRE (p=0.046; ES: 0.70, moderate). Overall, all sleep quality parameters showed a trend of constant improvement from POST1 to POST10. VAS scores were higher in the first day post-surgery (4.58 ± 2.46; p=0.0011 and ES: 1.40, large) compared to POST10 (1.68 ± 1.58). During the time, mean VAS showed significant negative correlations with mean sleep efficiency (r = -0.71; p=0.021).

CONCLUSION

Sleep quantity and timing parameters were stable during the entire hospitalization whereas sleep quality parameters significantly worsened the first night after surgery compared to the pre-surgery night. High scores of pain were associated with lower overall sleep quality.

The Association between Sedentary Behavior, Physical Activity, and Physical Fitness with Body Mass Index and Sleep Time in Chilean Girls and Boys: A Cross-Sectional Study

BACKGROUND

In recent decades, the school population has undergone behavioral changes that have affected their health and adult life. The current educational scenario presents high levels of sedentary behavior, physical inactivity, low physical fitness, high levels of obesity, and non-compliance with sleep recommendations. In Chile, the scientific evidence on associations between these behaviors is incipient.

OBJECTIVE

To analyze the association between sedentary behavior, physical activity, and physical fitness with BMI and minutes of sleep in Chilean children aged 10 to 11 years.

METHODS

A non-probabilistic convenience sample of 222 schoolchildren aged 10 to 11 years. The variables measured were body composition (BMI), cardiorespiratory fitness (20 m shuttle run test), lower and upper muscular strength (long jump test and handgrip dynamometry), speed (4 × 10 m running), and flexibility (sit and reach test). Physical activity and sleep were measured by accelerometers.

RESULTS

Of the participants, 60.4% and 90.6% did not comply with sleep and physical activity recommendations, respectively. Physical fitness was higher in boys in all components. The results of the linear regression show that in girls, moderate-vigorous-intensity physical activity, lower- and upper-body muscular strength, and cardiorespiratory endurance were associated with BMI and sleep. In boys, light-intensity physical activity and upper-body muscular strength were associated with both variables.

CONCLUSIONS

Physical activity intensity, strength, and cardiorespiratory fitness were associated with BMI and sleep; however, physical activity intensity and associated physical fitness components differed by gender.

Chronotype and quality of sleep in alpine skiers

Alpine skiing is among the most demanding sporting activities in terms of physical effort and mental workload. The aim of the study was to compare sleep quality and chronotype distribution between 84 highly trained alpine skiers and a control sample of 84 non-athletes matched by age and sex ratio. Quality of sleep was assessed by the Pittsburgh Quality of Sleep Index (PSQI), and chronotype was assessed by the Morningness-Eveningness Questionnaire (MEQ). Additional questions assessed sleep management during training or competitions. The results showed a marked skewed chronotype distribution towards morningness in alpine skiers (52.4% morning type, 42.8% intermediate, and 4.8% evening type) in comparison to the control group. The midpoint of sleep was significantly anticipated among alpine skiers. Differently from the previous literature that showed poor sleep quality and quantity in competitive athletes, the quality and quantity of sleep in alpine skiers was within the normal range in all the PSQI subcomponents.

Associations of fat mass index with hot flashes and lean mass index with insomnia in middle-aged women

OBJECTIVE

This cross-sectional study examined the relationship between body composition and physical and mental symptom severity in middle-aged women.

METHODS

The first-visit records of 554 women aged 40-64 years were examined. The fat mass index (FMI) and lean mass index (LMI) were defined as fat mass and lean mass divided by the height squared, respectively. The participants were divided into two groups according to their median values.

RESULTS

The only menopausal symptom with significantly different severity between the high and low FMI groups was hot flashes (HF) on the Menopausal Health-Related Quality of Life Questionnaire. The factors associated with severe HF were investigated using multiple logistic regression analysis. After adjusting, the FMI (kg/m²) was independently positively associated with severe HF (odds ratio, 1.08; 95% confidence interval, 1.02-1.15). Insomnia was the only menopausal symptom with significantly different severity between the LMI groups (defined as Athens Insomnia Scale score ≥10 points). The factors associated with moderate-to-severe insomnia were investigated using multiple logistic regression analysis. After adjusting, the LMI (kg/m²) was independently negatively associated with moderate-to-severe insomnia (odds ratio, 0.72; 95% confidence interval, 0.55-0.94).

CONCLUSIONS

The FMI was positively associated with severe HF, whereas the LMI was negatively associated with moderate-to-severe insomnia in middle-aged women.

Is daytime napping an effective strategy to improve sport-related cognitive and physical performance and reduce fatigue? A systematic review and meta-analysis of randomised controlled trials

OBJECTIVE

To estimate the association between daytime napping and cognitive and physical sport performance and fatigue after normal sleep and partial sleep deprivation (less sleep duration than necessary).

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

The PubMed, Scopus, Web of Science, Cochrane Central, SportDiscus and PsycINFO databases.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Randomised controlled trials on the effect of daytime napping on sport performance and fatigue available from inception to 2 December 2022. Standardised mean differences (SMD) and their 95% compatibility intervals (CI) were estimated with the DerSimonian-Laird method through random effect models.

RESULTS

In the 22 included trials, 291 male participants (164 trained athletes and 127 physically active adults) aged between 18 and 35 years were studied. When performed after a normal night of sleep, napping from 12:30 hours to 16:50 hours (with 14:00 hours being the most frequent time) improved cognitive (SMD=0.69, 95% CI: 0.37 to 1.00; I²=71.5%) and physical performance (SMD=0.99, 95% CI: 0.67 to 1.31; I²=89.1%) and reduced the perception of fatigue (SMD=-0.76, 95% CI: -1.24 to -0.28; I²=89.5%). The positive effects of napping were also confirmed after partial sleep deprivation. Overall, the benefits were higher with a nap duration between 30 and <60 min and when the time from nap awakening to test was greater than 1 hour.

CONCLUSIONS

After a night of normal sleep or partial sleep deprivation, a daytime nap between 30 and <60 min has a moderate-to-high effect on the improvement of cognitive performance and physical performance and on the reduction of perceived fatigue.

PROSPERO REGISTRATION NUMBER

CRD42020212272.

Sleep duration, weekend catch-up sleep, and risk of obstructive sleep apnea in relation to handgrip strength

PURPOSE

This cross-sectional study aimed to evaluate whether weekday sleep duration, weekend catch-up sleep, and risk of obstructive sleep apnea are individually and in combination associated with handgrip strength.

METHODS

Data from the Korea National Health and Nutrition Examination Survey 2019, including weekday sleep duration, weekend catch-up sleep, STOP-BANG scores, relative handgrip strength (handgrip strength divided by body mass index), and confounding factors (sociodemographic factors, health behaviors, and health and nutritional status), were evaluated in 3678 Korean adults aged 40 to 80 years. Adequate (vs. inadequate) sleep parameters were defined as weekday sleep duration (6-7 vs. ≤ 5 or ≥ 8 h), weekend catch-up sleep (presence vs. absence), and risk of obstructive sleep apnea (low vs. high based on STOP-BANG scores). Sex-specific quintiles of relative handgrip strength were categorized as high (highest 5th quintile) or low (lower 1^st to 4^th quintiles). A complex-sample logistic regression analysis was performed.

RESULTS

After adjusting for other sleep parameters and confounding variables, each adequate sleep parameter individually and collectively was associated with high relative handgrip strength (adjusted odds ratios [95% confidence interval], 1.43 [1.09, 1.89] for 6-7 h weekday sleep duration; 1.44 [1.10, 1.90] for low risk of obstructive sleep apnea; 1.72 [1.23, 2.40] for any two parameters; 1.81 [1.18, 2.79] for all parameters). The combination of adequate weekend catch-up sleep and obstructive sleep apnea risk had the highest odds ratio for high relative handgrip strength (2.36 [1.45, 3.83]).

CONCLUSIONS

Adequate weekday sleep duration, weekend catch-up sleep, and low obstructive sleep apnea risk were individually and in combination associated with high handgrip strength.

Is There a Relationship Between Waking Up from Sleep and the Onset of Testicular Torsion?

Testicular torsion is a serious urologic emergency that can present with unusual or atypical history and examination. Classical pain from testicular torsion is of sudden onset, significantly severe, and is accompanied by nausea and vomiting. However, in some patients, the initial scrotal pain appears to considerably subside within the next few hours. In others, testicular torsion tends to occur while sleeping, and many patients recount a history of being woken up from sleep by intense pain. Furthermore, some patients in this subset can resume normal activities and even sleep through the night with little or no discomfort, without a perceived need for pain medications. Other patients initially experience mild pain, which worsens over time. Consequently, these patients are less likely to be evaluated immediately. In view of these atypical cases, the question remains unanswered regarding sleep as a predisposing factor for testicular torsion. This narrative review focuses on exploring the association between sleep and testicular torsion.

The Sleep Parameters of Paralympic Athletes: Characteristics and Assessment Instruments

CONTEXT

Sleep serves many important functions for athletes, particularly in the processes of learning, memory, recovery, and cognition.

OBJECTIVES

Define the sleep parameters of Paralympic athletes and identify the instruments used to assess and monitor sleep Paralympic athletes.

EVIDENCE ACQUISITION

This systematic review was carried out based on the PRISMA guidelines. The survey was conducted in April 2020, the searches were carried out again in September 2021 to check whether there were new scientific publications in the area of sleep and Paralympic sport, searches were performed in the following databases: PubMed, Web of Science, Scopus, SPORTDiscus, Virtual Health Library (BIREME), and SciELO. This systematic review has included studies that investigated at least one of the following sleep parameters: total sleep time, sleep latency, sleep efficiency, number of awakenings, quality of sleep, daytime sleepiness, and chronotype; the participants were comprised of athletes with disabilities. Studies published at any time in English, Portuguese, and Spanish, were included.

EVIDENCE SYNTHESIS

Data extraction and study selection were performed by 2 researchers independently, and a third author was consulted as necessary. The search returned a total of 407 studies. Following the screening based on exclusion and inclusion criteria, a total of 13 studies were considered. Paralympic athletes have a low amount (7.06 h) of sleep with poor quality and sleep latency (28.05 min), and 57.2% have daytime sleepiness, with the majority belonging to the indifferent chronotype (53, 5%). Moreover, 11 studies assess sleep using subjective instruments (questionnaires), and 2 studies used an objective instrument (actigraphy).

CONCLUSIONS

Sleep disorders are common among Paralympic athletes, poor sleep quality and quantity, and high rates of daytime sleepiness. Subjective methods are most commonly used to assess sleep.

The Influence of Different Training Load Magnitudes on Sleep Pattern, Perceived Recovery, and Stress Tolerance in Young Soccer Players

ABSTRACT

Ferreira, ABdM, Ribeiro, BLL, Batista, EdS, Dantas, MP, and Mortatti, AL. The influence of different training load magnitudes on sleep pattern, perceived recovery, and stress tolerance in young soccer players. J Strength Cond Res 37(2): 351-357, 2023-The aim of this study was to analyze the influence of 3 weeks on sleep parameters, perceived recovery, and stress tolerance in young soccer players using different training load magnitudes. A total of 13 young male soccer athletes (15.9 ± 0.5 years; 68.7 ± 6.1 kg; 170 ± 7 cm) who performed 3 typical training weeks with different workloads were analyzed. The external training load (ETL) was verified by the PlayerLoad method, and the internal training load (ITL) was determined using the session rating of perceived exertion method. Sleep was monitored using a wrist-actigraphy monitor. Sleep variables, including total time in bed (TTB), total sleep time (TST), sleep latency (SL), wake after sleep onset (WASO), and sleep efficiency (SE), were evaluated across all nights of sleep. The recovery status was assessed with the perceived recovery status (PRS) scale, and the stress tolerance was monitored using the "daily analysis of life demands of athletes" questionnaire. There was an increase in sleep time during the week with the highest training load (week 2) (TTB: +35 minutes, TST: +46 minutes, SL: -5 minutes, SE: +3%). There was no difference in the PRS or in the stress tolerance during the evaluation weeks. A very large within-individual correlation was observed between ITL and ETL ( r = 0.78) and moderate within-individual correlation between ETL and TST ( r = 0.34), between ITL and TST ( r = 0.45), and between ITL and SE ( r = 0.359). These results showed that there was an increase in TST during a microcycle with intensified loads, without impairing bedtime and resulting in maintenance of the perceived recovery or stress tolerance values.

Less daytime sleepiness and slow wave activity during sleep predict better physical readiness in military personnel

BACKGROUND

Military personnel must maintain physical performance despite exposure to operational stressors such as sleep loss, caloric restriction and high cognitive load. Habitual sleep and specific sleep features are positively associated with fitness and may contribute to physical performance in operational settings. Further, by affecting muscle recovery, sleep may contribute to the ability to maintain performance across multiple days of exposure to operational stressors.

OBJECTIVES

We examined the role of individual differences in baseline sleep on baseline physical performance and on change in physical performance throughout exposure to simulated military operational stress (SMOS).

METHODS

Military personnel (36 male, 9 female, 26.3 ± 5.3 years) completed a 5-day SMOS protocol during which they completed a tactical mobility test daily. Sleep questionnaires were administered at intake and sleep was monitored each night with polysomnography. Lasso regressions were used to identify meaningful predictors of physical performance at baseline and of change in physical performance across SMOS.

RESULTS

Better aerobic fitness, lower daytime sleepiness (Epworth Sleepiness Scale), and lower absolute slow wave activity (0.5-4 Hz) predicted better physical performance at baseline (66.1% of variance explained), but did not relate to changes in performance.

CONCLUSIONS

Collectively, higher daytime sleepiness and slow wave activity may reflect more chronic exposure to insufficient sleep and higher baseline sleep drive, which in turn led to compromised physical performance. The findings suggest that low self-report sleepiness and low objective slow wave activity may reflect two quantifiable markers of healthy sleep behaviors that have implications for operational performance.

The association between sleep parameters and sarcopenia in Japanese community-dwelling older adults

PURPOSE

This study aimed to examine the association between sleep duration and quality and sarcopenia, assessed by factors such as low muscle mass (LMM), low muscle strength (LMS), and low physical performance (LPP) among older community-dwellers in Japan.

METHODS

In this cross-sectional study, a total of 2,069 (men, 902; women, 1,167) participants aged 65 to 80 years were included. Sarcopenia and each low physical function were defined using the definitions of the Asian Working Groups of Sarcopenia 2019. Sleep duration was stratified into three categories: short sleep (<6 h), normal sleep (6-8 h), and long sleep (>8 h). Sleep quality was classified into two groups based on 8-item Athens Insomnia Scale score: insomnia (≥6), and non-insomnia (<6). We analyzed the association between sleep parameters and sarcopenia, including low physical functions, by logistic regression analysis.

RESULTS

Compared to normal sleepers, long sleepers had a positive association with sarcopenia (odds ratio [OR] 2.11, 95% confidence interval [CI] 1.25-3.58). In particular, long sleep was strongly associated with LMS (OR 1.77, 95%CI 1.07-2.94) and LPP (OR 1.90, 95%CI 1.25-2.88). On the other hand, poor sleep quality was not associated with sarcopenia in long sleepers, but in normal sleepers.

CONCLUSIONS

Long sleep was associated with sarcopenia, including LMS and LPP. However, in long sleepers, insomnia was not associated with sarcopenia or any of its components.

Shorter sleep time relates to lower human defensin 5 secretion and compositional disturbance of the intestinal microbiota accompanied by decreased short-chain fatty acid production

Sleep is essential for our health. Short sleep is known to increase disease risks via imbalance of intestinal microbiota, dysbiosis. However, mechanisms by which short sleep induces dysbiosis remain unknown. Small intestinal Paneth cell regulates the intestinal microbiota by secreting antimicrobial peptides including α-defensin, human defensin 5 (HD5). Disruption of circadian rhythm mediating sleep-wake cycle induces Paneth cell failure. We aim to clarify effects of short sleep on HD5 secretion and the intestinal microbiota. Fecal samples and self-reported sleep time were obtained from 35 healthy middle-aged Japanese (41 to 60-year-old). Shorter sleep time was associated with lower fecal HD5 concentration (r = 0.354, p = 0.037), lower centered log ratio (CLR)-transformed abundance of short-chain fatty acid (SCFA) producers in the intestinal microbiota such as [Ruminococcus] gnavus group (r = 0.504, p = 0.002) and Butyricicoccus (r = 0.484, p = 0.003), and lower fecal SCFA concentration. Furthermore, fecal HD5 positively correlated with the abundance of these genera and SCFA concentration. These findings suggest that short sleep relates to disturbance of the intestinal microbiota via decreased HD5 secretion.

Changes in Sleep Problems in Patients Who Underwent Surgical Treatment for Degenerative Spinal Disease with a Concurrent Sleep Disorder: A Nationwide Cohort Study in 3183 Patients during a Two-Year Perioperative Period

Sleep disturbance is prevalent in patients with degenerative spinal disease, and recent studies have reported that surgical treatment is more effective for improving sleep quality than conservative treatment. We aimed to investigate the perioperative changes of sleep problems in patients who underwent surgical treatment for degenerative spinal disease with a concurrent sleep disorder, and presented them according to various clinical profiles possibly associated with sleep disturbance. In addition, we identified factors associated with poor sleep improvement after surgery. This study used data from the Korea Health Insurance Review and Assessment Service database from 2016 to 2018. We included 3183 patients aged ≥19 years who underwent surgery for degenerative spinal disease and had a concurrent sleep disorder. Perioperative changes in the two target outcomes, including the use of sleep medication and hospital visits owing to sleep disorders, were precisely investigated according to factors known to be associated with sleep disturbance, including demographics, comorbidities, and spinal regions. Logistic regression analysis was performed to identify factors associated with poor improvement in terms of sleep medication after surgery. All estimates were validated using bootstrap sampling. During the 1-year preoperative period, the use of sleep medications and hospital visits owing to sleep disorder increased continuously. However, they abruptly decreased shortly after surgical treatment, and throughout the 1-year postoperative period, they remained lower than those in the late preoperative period. At the 1-year follow-up, 75.6% (2407 of 3183) of our cohort showed improvement in sleep medication after surgery. Multivariable analysis identified only two variables as significant factors associated with non-improvement in sleep medication after surgery: depressive disorder (odds ratio (OR) = 1.25 [1.06-1.48]; p = 0.008), and migraine (OR = 1.42 [1.04-1.94]; p = 0.028). We could not investigate the actual sleep quality and resultant quality of life; however, our results justify the necessity for further high-quality studies that include such information and would arouse clinicians' attention to the importance of sleep disturbance in patients with degenerative spinal disease.

Primum non nocere; It's time to consider altitude training as the medical intervention it actually is!

Sleep is one of the most important aspects of recovery, and is known to be severely affected by hypoxia. The present position paper focuses on sleep as a strong moderator of the altitude training-response. Indeed, the response to altitude training is highly variable, it is not a fixed and classifiable trait, rather it is a state that is determined by multiple factors (e.g., iron status, altitude dose, pre-intervention hemoglobin mass, training load, and recovery). We present an overview of evidence showing that sleep, and more specifically the prolonged negative impact of altitude on the nocturnal breathing pattern, affecting mainly deep sleep and thus the core of physiological recovery during sleep, could play an important role in intra- and interindividual variability in the altitude training-associated responses in professional and recreational athletes. We conclude our paper with a set of suggested recommendations to customize the application of altitude training to the specific needs and vulnerabilities of each athlete (i.e., primum non nocere). Several factors have been identified (e.g., sex, polymorphisms in the TASK2/KCNK5, NOTCH4 and CAT genes and pre-term birth) to predict individual vulnerabilities to hypoxia-related sleep-disordered breathing. Currently, polysomnography should be the first choice to evaluate an individual's predisposition to a decrease in deep sleep related to hypoxia. Further interventions, both pharmacological and non-pharmacological, might alleviate the effects of nocturnal hypoxia in those athletes that show most vulnerable.

Resistance Training Improves Sleep and Anti-Inflammatory Parameters in Sarcopenic Older Adults: A Randomized Controlled Trial

Sleep and exercise have an important role in the development of several inflammation-related diseases, including sarcopenia. Objective: To investigate the effects of 12 weeks of resistance exercise training on sleep and inflammatory status in sarcopenic patients. Methods: A randomized controlled trial comparing resistance exercise training (RET) with a control (CTL) was conducted. Outcomes were obtained by physical tests, polysomnography, questionnaires, isokinetic/isometric dynamometry tests, and biochemical analysis. Results: Time to sleep onset (sleep latency) was reduced in the RET group compared to the CTL group (16.09 ± 15.21 vs. 29.98 ± 16.09 min; p = 0.04) after the intervention. The percentage of slow-wave sleep (N3 sleep) was increased in the RET group (0.70%, CI: 7.27−16.16 vs. −4.90%, CI: 7.06−16.70; p = 0.04) in an intention to treat analysis. Apnea/hour was reduced in the RET group (16.82 ± 14.11 vs. 7.37 ± 7.55; p = 0.001) and subjective sleep quality was improved compared to the CTL (−1.50; CI: 2.76−6.14 vs. 0.00; CI: 1.67−3.84 p = 0.02) in an intention-to-treat analysis. Levels of interleukin-10 (IL-10) (2.13 ± 0.80 vs. 2.51 ± 0.99; p < 0.03) and interleukin-1 receptor antagonist (IL-1ra) (0.99 ± 0.10 vs. 0.99 ± 0.10 ng/mL; p < 0.04; delta variation) were increased in the RET group. Conclusions: RET improves sleep parameters linked to muscle performance, possibly due to an increase in anti-inflammatory markers in older sarcopenic patients.

Anxiety state impact on recovery of runners with lower extremity injuries

This prospective cohort study examined the impact of high anxiety levels on psychological state and gait performance during recovery in runners with lower body injuries. Recreational runners diagnosed with lower body injuries who had reduced running volume (N = 41) were stratified into groups using State Trait Anxiety Inventory (STAI) scores: high anxiety (H-Anx; STAI ≥40 points) and low anxiety (L-Anx; STAI <40 points). Runners were followed through rehabilitation to return-to-run using monthly surveys. Main outcome measures included kinesiophobia (Tampa Scale of Kinesiophobia, TSK-11), Positive and Negative Affect Schedule (PANAS; Positive and negative scores), Lower Extremity Function Scale (LEFS), running recovery (University of Wisconsin Running Injury and Recovery Index [UWRI]) and CDC Healthy Days modules for general health, days of anxiety/tension, disrupted sleep and work/usual activities. Running biomechanics were assessed at baseline and the final visit using 3D motion capture and a force-plated treadmill. The time to return-to-running for was 5.0±3.1 and 7.9±4.1 months for L-Anx and H-Anx, respectively and participants who withdrew (n = 15) did so at 7.7±6.2 months. L-Anx maintained low anxiety and H-Anx reduced anxiety from baseline to final visit (STAI = 31.5 to 28.4 points, 50.4 to 37.8 points, respectively), whereas the withdrawn runners remained clinically anxious at their final survey (41.5 to 40.3 points; p < .05). Group by time interactions were found for PANAS positive, LEFS UWRI, general health scores, and days feeling worry, tension and anxiety (all p < .05). Final running performance in L-Anx compared to H-Anx was most improved with cadence (8.6% vs 3.5%; p = .044), impact loading rate [-1.9% vs +8.9%] and lower body stiffness [+14.1% vs +3.2%; all p < .05). High anxiety may identify runners who will experience a longer recovery process, health-related functional disruptions, and less optimization of gait biomechanics during rehabilitation after a lower extremity injury.

Sleep, circadian biology and skeletal muscle interactions: Implications for metabolic health

There currently exists a modern epidemic of sleep loss, triggered by the changing demands of our 21st century lifestyle that embrace 'round-the-clock' remote working hours, access to energy-dense food, prolonged periods of inactivity, and on-line social activities. Disturbances to sleep patterns impart widespread and adverse effects on numerous cells, tissues, and organs. Insufficient sleep causes circadian misalignment in humans, including perturbed peripheral clocks, leading to disrupted skeletal muscle and liver metabolism, and whole-body energy homeostasis. Fragmented or insufficient sleep also perturbs the hormonal milieu, shifting it towards a catabolic state, resulting in reduced rates of skeletal muscle protein synthesis. The interaction between disrupted sleep and skeletal muscle metabolic health is complex, with the mechanisms underpinning sleep-related disturbances on this tissue often multifaceted. Strategies to promote sufficient sleep duration combined with the appropriate timing of meals and physical activity to maintain circadian rhythmicity are important to mitigate the adverse effects of inadequate sleep on whole-body and skeletal muscle metabolic health. This review summarises the complex relationship between sleep, circadian biology, and skeletal muscle, and discusses the effectiveness of several strategies to mitigate the negative effects of disturbed sleep or circadian rhythms on skeletal muscle health.

Prevalence of Sleep Disturbance and Its Risk Factors in Patients who Undergo Surgical Treatment for Degenerative Spinal Disease: A Nationwide Study of 106,837 Patients

Spinal surgeons have not yet considered sleep disturbance an area of concern; thus, a comprehensive study investigating the epidemiology of sleep disturbance in patients with degenerative spinal disease is yet to be conducted. This study aimed to fill this research gap by investigating the epidemiology of sleep disturbance in patients who underwent spinal surgery for degenerative spinal disease and identifying the associated risk factors. This nationwide, population-based, cohort study, used data from January 2016 and December 2018 from the Korea Health Insurance Review and Assessment Service database. This study included 106,837 patients older than 19 years who underwent surgery for degenerative spinal disease. Sleep disorder was initially defined as a diagnosis of a sleep disorder made within one year before the index surgery and identified using the International Classification of Diseases, 10th revision, codes F51 and G47 (main analysis). We also investigated the use of sleep medication within 90 days prior to the index surgery, which was the target outcome of the sensitivity analysis. The prevalence of sleep disturbance was precisely investigated according to various factors, including demographics, comorbidities, and spinal region. Logistic regression analysis was performed to identify the independent factors associated with sleep disturbance. The results of the statistical analysis were validated using sensitivity analysis and bootstrap sampling. The prevalence of sleep disorder was 5.5% (n = 5847) in our cohort. During the 90 days before spinal surgery, sleep medication was used for over four weeks in 5.5% (n = 5864) and over eight weeks in 3.8% (n = 4009) of the cohort. Although the prevalence of sleep disturbance differed according to the spinal region, the spinal region was not a significant risk factor for sleep disorder in multivariable analysis. We also identified four groups of independent risk factors: (1) Age, (2) other demographic factors and general comorbidities, (3) neuropsychiatric disorders, and (4) osteoarthritis of the extremities. Our results, including the prevalence rates of sleep disturbance in the entire patient population and the identified risk factors, provide clinicians with a reasonable reference for evaluating sleep disturbance in patients with degenerative spinal disease and future research.

A Mask-Shaped Respiration Sensor Using Triboelectricity and a Machine Learning Approach toward Smart Sleep Monitoring Systems

Daily sleep monitoring is limited by the needs for specialized equipment and experts. This study combines a mask-shaped triboelectric nanogenerator (M-TENG) and machine learning for facile daily sleep monitoring without the specialized equipment or experts. The fabricated M-TENG demonstrates its excellent ability to detect respiration, even distinguishing oral and nasal breath. To increase the pressure sensitivity of the M-TENG, the reactive ion etching is conducted with different tilted angles. By investigating each surface morphology of the polytetrafluoroethylene films according to the reactive ion etching with different tilted angles, the tilted angle is optimized with the angle of 60° and the pressure sensitivity is increased by 5.8 times. The M-TENG can also detect changes in the angle of head and snoring. Various sleep stages can be classified by their distinctive electrical outputs, with the aid of a machine learning approach. As a result, a high averaged-classification accuracy of 87.17% is achieved for each sleep stage. Experimental results demonstrate that the proposed combination can be utilized to monitor the sleep stage in order to provide an aid for self-awareness of sleep disorders. Considering these results, the M-TENG and machine learning approach is expected to be utilized as a smart sleep monitoring system in near future.

The effect of acute sleep extension vs active recovery on post exercise recovery kinetics in rugby union players

Background

Elite rugby players experience poor sleep quality and quantity. This lack of sleep could compromise post-exercise recovery. Therefore, it appears central to encourage sleep in order to improve recovery kinetics. However, the effectiveness of an acute ergogenic strategy such as sleep extension on recovery has yet to be investigated among athletes.

Aim

To compare the effects of a single night of sleep extension to an active recovery session (CON) on post-exercise recovery kinetics.

Methods

In a randomised cross-over design, 10 male rugby union players participated in two evening training sessions (19:30) involving collision activity, 7-days apart. After each session, participants either extended their sleep to 10 hours or attended an early morning recovery session (07:30). Prior to (PRE), immediately after (POST 0 hour [h]), 14h (POST 14) and 36h (POST 36) post training, neuromuscular, perceptual and cognitive measures of fatigue were assessed. Objective sleep parameters were monitored two days before the training session and over the two-day recovery period.

Results

The training session induced substantial decreases in countermovement jump mean power and wellness across all time points, while heart rate recovery decreased at POST 0 in both conditions. Sleep extension resulted in greater total sleep time (effect size [90% confidence interval]: 5.35 [4.56 to 6.14]) but greater sleep fragmentation than CON (2.85 [2.00 to 3.70]). Between group differences highlight a faster recovery of cognitive performance following sleep extension (-1.53 [-2.33 to -0.74]) at POST 14, while autonomic function (-1.00 [-1.85 to -0.16]) and upper-body neuromuscular function (-0.78 [-1.65 to 0.08]) were better in CON. However, no difference in recovery status between groups was observed at POST 36.

Conclusion

The main finding of this study suggests that sleep extension could affect cognitive function positively but did not improve neuromuscular function the day after a late exercise bout.

Sleep regularity in athletes: Comparing sex, competitive level and sport type

This study aims to describe the athletes' sleep regularity using the Sleep Regularity Index (SRI) and determine whether factors, such as sex, competitive level and sport type, could affect the sleep/wake rhythm. It is a descriptive, cross-sectional study consisting of 172 athletes (25 ± 7 y old; 45 women). Seventy-three competed in team sports and 99 in individual sports. Furthermore, 56 competed in the international level, 95 in the national and 21 in the regional. We recorded the SRI values for at least 5 d via continuous actigraphy. We recorded a mean SRI value of 73 ± 12. We found no significant differences between athletes' sleep parameters in relation to sleep regularity. Furthermore, SRI data showed no correlations (Spearman's ρ) with sleep parameters, bed time and wake time. Female athletes (p = 0.001) and individual sport athletes (p = 0.001) reported better sleep regularity than their counterparts. International-level athletes reported better sleep regularity than those in other competitive levels (national: p = 0.001; regional: p = 0.024). Our study showed that international level athletes, female athletes and individual sport athletes reported better sleep regularity. Additionally, SRI data showed no correlation with athletes' sleep parameters, bed and wake time.

Sleep duration and sarcopenia in adults aged ≥ 65 years from low and middle-income countries

BACKGROUND

Sleep duration may influence risk for sarcopenia but studies on this topic are scarce, especially from low and- middle-income countries (LMICs). Thus, the aim of the present study was to investigate the association between sleep duration and sarcopenia among adults aged ≥ 65 years from five LMICs (China, Ghana, India, Russia, South Africa).

METHODS

Cross-sectional, community-based data from the WHO study on global ageing and adult health (SAGE) were analysed. Sarcopenia was defined as having low skeletal muscle mass (SMM) and weak handgrip strength, while severe sarcopenia was defined as having low SMM, weak handgrip strength, and slow gait speed. Self-reported sleep duration in the past two nights were averaged and classified as ≤ 6, > 6 to ≤ 9, and ≥ 9 h/day. Multivariable logistic regression analysis was conducted.

RESULTS

Data on 13,210 adults aged ≥ 65 years [mean (SD) age 72.6 (11.3) years; 55.0% females] were analyzed. In the overall sample, compared to > 6 to ≤ 9 h/day of sleep duration, > 9 h/day was associated with 1.70 (95% CI 1.15-2.51) and 1.75 (95% CI 1.08-2.84) times higher odds for sarcopenia and severe sarcopenia, respectively. No significant associations were observed among males, but associations were particularly pronounced among females [i.e., OR = 2.19 (95% CI 1.26-3.81) for sarcopenia, and OR = 2.26 (95% CI 1.20-4.23) for severe sarcopenia].

CONCLUSIONS

Long sleep duration was associated with an increased odds of sarcopenia and severe sarcopenia in LMICs, particularly in females. Future studies should investigate whether addressing long sleep duration among females can lead to lower risk for sarcopenia onset in LMICs.

Sex differences among endurance athletes in the pre-race relationships between sleep, and perceived stress and recovery

This study examined sex differences among endurance athletes in pre-race relationships between sleep, and perceived stress and recovery. Thirty-six athletes completed the Short Recovery and Stress Scale, and had sleep monitored via actigraphy, over four consecutive days prior to an ultra-marathon. Overall, compared with males, females had shorter wake after sleep onset (mean ± SD, 50 ± 23 vs 65 ± 23 min, p = .04) and lower emotional balance (3.9 ± 1.1 vs 4.8 ± 1.1 arbitrary units, p = .001). The day before the race, females scored higher for all stress-related items (p < 0.05). Among females, higher scores for emotional balance (β = -31 min, p = .01) and negative emotional state (β = -21 min, p < .001) were associated with reduced sleep duration. Among males, higher scores for overall stress were associated with increased sleep duration (β = 22 min, p = .01). Across all athletes, longer sleep duration was associated with improved overall recovery (β = 0.003 arbitrary units, p = .02). Females experienced greater pre-race stress than males, and their sleep duration was associated with emotional factors. The SRSS may help identify female athletes at risk of sleep difficulties prior to competition.

Study of factors leading to poor sleep among management students

Sleep is the most important but often neglected element of an individual’s overall health and well-being. Lack of sleep or poor sleep can adversely affect health in an individual and lead to various diseases. At the same time, sleep problems are not uncommon among students. The factors leading to poor sleep among management students who have a comparatively tight schedule are still unclear. The paper aims to understand the factors leading to poor sleep among management students. The study has been focused on the management students (MBA’s) studying in the different management colleges of the state of Maharashtra. A total of 297 management students were surveyed. Apart from factor analysis, the Kessler distress scale was used for Measuring Psychological distress.52% of the respondents fell in the category of likely to have a mental disorder. Managements can draw inference from this and implement strategies to make sure this number reduces.

Sleep Quality and Well-Being in Junior Elite Athletes

Abstract. Little cross-sectional and even less longitudinal research has been conducted on sleep quality and well-being in junior elite athletes. This study analyzed the relationship between subjective sleep quality and both psychological and physiological well-being in junior elite athletes using both a cross-sectional ( N = 625 athletes; 49.9 % = female; M = 16.4 years, SD = 3.5 years) and a longitudinal approach ( n = 79; 44.3 % = female; M = 16.4 years, SD = 3.5 years) over a period of M = 1.66 years ( SD = 0.87 years). The results demonstrated that both samples showed that subjective sleep quality is correlated with well-being in junior elite athletes. In addition, the results showed that athletes of prepuberty age reported significantly better sleep quality than athletes during and after puberty, and that the relationship between sleep quality and psychological well-being is stronger in female junior athletes than in male athletes. This study emphasizes the need to ensure quality sleep in junior elite athletes.

The Effect of Rugby Union Match Play on Sleep Patterns and Subsequent Impact on Postmatch Fatigue Responses

PURPOSE

Sleep is recognized as an important recovery strategy, yet little is known regarding its impact on postmatch fatigue. The aims of this study were to (1) describe sleep and postmatch fatigue, (2) understand how sleep is affected by contextual and match factors, and (3) assess how changes in sleep can affect postmatch fatigue.

METHODS

Twenty-three male rugby union players were monitored across 1 season (N = 71 player-match observations). Actigraphy was used during preseason to establish baseline sleep quality and quantity. Sleep was then measured 1 and 2 days after each match day (MD + 1 and MD + 2). Global positioning systems, notational analysis, and rating of perceived exertion represented external and internal load from matches. Subjective wellness and a standardized run were used to characterize postmatch fatigue 2 days prior (baseline) and at MD + 1 and MD + 2. Linear mixed models established the magnitude of change (effect size [ES]) between baseline, MD + 1, and MD + 2 for sleep and postmatch fatigue. Stepwise forward selection analysis ascertained the effect of match load on sleep and the effect of sleep on postmatch fatigue. Each analysis was combined with magnitude-based decisions.

RESULTS

Sleep characteristics and neuromuscular and perceptual postmatch fatigue were negatively affected at MD + 1 and MD + 2 (ES = small to very large). Kickoff and travel time had the greatest effect on sleep (ES = small). Wellness and soreness were influenced by sleep (fall-asleep time and fragmentation index) and collisions, respectively (ES = small).

CONCLUSION

Sleep quality and quantity were affected independently of the match load (ie, running activity) sustained, and changes in sleep marginally affected postmatch fatigue.

Sleep of recruits throughout basic military training and its relationships with stress, recovery, and fatigue

Objective

Studies in basic military training (BMT) examining sleep are largely cross-sectional, and do not investigate relationships between sleep, stress, recovery and fatigue. The aims of this study were to (1a) quantify changes in recruits’ sleep quantity and quality over 12 weeks of BMT; (1b) quantify changes in recruits’ perceptions of stress, fatigue and recovery over BMT; and (2) explore relationships between sleep, and perceptions of stress, fatigue and recovery.

Methods

45 recruits (37 male; 8 female, age: 25.2 ± 7.2 years, height: 176.2 ± 10.0 cm, mass: 76.8 ± 15.0 kg) wore ActiGraph GT9X’s for 12 weeks of BMT, collecting sleep duration, efficiency and awakenings. Subjective sleep quality, fatigue were measured daily, with stress and recovery measured weekly. Multi-level models assessed relationships between sleep, and stress, recovery, and fatigue.

Results

Objective daily means for sleep duration were 6.3 h (± 1.2 h) and 85.6% (± 5.5%) for sleep efficiency. Main effects were detected for all mean weekly values (p < 0.05). Sleep quality showed the strongest relationships with stress, recovery and fatigue. The best model to explain relationships between, stress, recovery and fatigue, included sleep quality, sleep duration, sleep efficiency and awakenings.

Conclusions

The reported mean sleep duration of 6.3 h per night may negatively impact training outcomes across BMT. Combining both subjective and objective measures of sleep best explained relationships between sleep metrics stress, fatigue and recovery. Perceived sleep quality was most strongly related to change in stress, recovery, or post-sleep fatigue.

Sleep and psychological factors are associated with meeting discharge criteria to return to sport following ACL reconstruction in athletes

This study aimed to determine if sleep quality and psychological factors were associated with time to meet the discharge criteria to return to sport (RTS) following anterior cruciate ligament reconstruction (ACL-R) among athletes. A cohort-study design included 89 athletes following ACL-R. Each participant completed a battery of questionnaires at 6 different time points: within 3 days of injury occurrence and at post-surgery (1.5 m, 3 m, 4.5 m, 6 m and when discharge criteria were met). Assessment included sleep quality and quantity, symptoms of depression, anxiety, stress, psychological readiness to RTS and fear of re-injury. The primary outcome was the time needed to meet all discharge criteria to RTS. Sleep parameters and psychological factors were not associated with time to meet the discharge criteria to RTS. However, athletes that had lower scores of anxiety (OR 1.2 (95% CI 1.0, 1.3) and insomnia (OR 1.2 (95% CI 1.0, 1.3) at baseline were more likely to meet the RTS discharge criteria. Athletes with better sleep quality at 3m, 4.5m and 6m were more likely to meet the RTS discharge criteria OR 1.3 (95% CI 1.1, 1.7), 2.0 (95% CI 1.1-3.4) and 1.4 (95% CI 1.0, 1.9) respectively. Sleep quality and psychological factors were not associated with time to meet the discharge criteria to RTS but impacted whether athletes adhered and completed their rehabilitation program or not. Monitoring sleep quality and psychological factors of athletes before and following ACL-R surgery is important to identify athletes who could have difficulties in adhering to and completing their rehabilitation program to RTS.