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1.
Optimising sleep and performance during night float: A systematic review of evidence and implications for graduate medical education trainees.
Sholtes, D, Kravitz, HM, Deka, A, Westrick, J, Fogg, LF, Gottlieb, M
Journal of sleep research. 2021;(4):e13212
Abstract
Graduate medical education (GME) training commonly requires residents and fellows to engage in night float shift work. This review aims to assess the effectiveness of interventions for trainees when preparing for, completing, and recovering from working night float shifts. We reviewed all available studies published prior to September 2019 using PubMed, Scopus, CINAHL, the Cochrane library, PsycINFO, and Google Scholar databases. We included all original, primary research articles assessing either non-pharmacological or pharmacological interventions on the chronobiological and physiological effects of night float shift work among GME trainees. Five studies (n = 179 patients) met inclusion criteria. Interventions included melatonin in the morning before sleep after night float shifts, napping during night float shifts, modafinil after a night of sleep deprivation, and caffeinated energy drinks after 6 consecutive night float shifts. Melatonin improved one measure of attention. A 2-hr nap was associated with improved speed related to task switching. Modafinil improved performance in tests of cognition. Caffeinated energy drinks led to improvement in select driving performance variables and reaction time. Effect sizes for outcome variables were calculated. Heterogeneity among the studies precluded combining the data in a meta-analysis. According to GRADE criteria, the quality of the evidence in these studies was low or very low. Our findings suggest GME trainees may benefit from utilising a limited number of interventions when preparing for or recovering from night float shift work. More investigation is needed to identify interventions that could help GME trainees adapt to and recover from working night float shifts.
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2.
Impairments in glycaemic control do not increase linearly with repeated nights of sleep restriction in healthy adults: a randomised controlled trial.
Sweeney, EL, Peart, DJ, Ellis, JG, Walshe, IH
Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme. 2021;(9):1091-1096
Abstract
Evidence suggests reduced glycaemic control following sleep restriction in healthy individuals. However, it remains unknown if impairments in glycaemic control increase with each additional night of sleep restriction in a linear manner. This randomised crossover study aimed to determine if the impairment in glycaemic control increases with each additional night of sleep restriction. Ten healthy individuals underwent 4 nights of control sleep (8 hours in bed) and 4 nights of sleep restriction (4 hours in bed) in a sleep laboratory. An oral glucose tolerance test was conducted each morning. Serum glucose and insulin were measured. Glucose and insulin area under the curve were higher overall in the sleep restriction trial compared with control (p < 0.001 and p = 0.033); however, no effect of day (p = 0.620 and p = 0.863) or interaction effect (p = 0.152 and p = 0.285) were observed. This supports previous literature showing a detrimental impact of sleep restriction on glucose regulation. The present findings, however, suggest the impairment in glycaemic control does not increase in a linear manner with an increasing number of nights of sleep restriction. This may have implications for the design of future studies examining sleep restriction and glycaemic control. Novelty: Four nights of sleep restriction impaired glycaemic control in healthy individuals, but did not do so in a linear manner. No effect of number of nights of restriction was found for glucose or insulin, which may have implications for future studies.
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Physical activity, screen exposure and sleep among students during the pandemic of COVID-19.
Guo, YF, Liao, MQ, Cai, WL, Yu, XX, Li, SN, Ke, XY, Tan, SX, Luo, ZY, Cui, YF, Wang, Q, et al
Scientific reports. 2021;(1):8529
Abstract
This study aimed to determine the levels of health-related behaviours (physical activity, screen exposure and sleep status) among Chinese students from primary, secondary and high schools during the pandemic of COVID-19, as well as their changes compared with their status before the pandemic. A cross-sectional online survey of 10,933 students was conducted among 10 schools in Guangzhou, China, between 8th and 15th March, 2020. After getting the informed consent from student's caregivers, an online questionnaire was designed and used to obtain time spending on health-related behaviours during the pandemic of COVID-19, as well as the changes compared with 3 months before the pandemic, which was completed by students themselves or their caregivers. Students were stratified by regions (urban, suburban, exurban), gender (boys and girls), and grades (lower grades of primary school, higher grades of primary schools, secondary schools and high schools). Data were expressed as number and percentages and Chi-square test was used to analyse difference between groups. Overall, the response rate of questionnaire was 95.3% (10,416/10,933). The median age of included students was 13.0 (10.0, 16.0) years and 50.1% (n = 5,219) were boys. 41.4%, 53.6% and 53.7% of total students reported less than 15 min per day in light, moderate and vigorous activities and 58.7% (n = 6,113) reported decreased participation in physical activity compared with the time before pandemic. Over 5 h of screen time spending on online study was reported by 44.6% (n = 4,649) of respondents, particular among high school students (81.0%). 76.9% of students reported increased screen time compared with the time before pandemic. Inadequate sleep was identified among 38.5% of students and the proportion was highest in high school students (56.9%). Our study indicated that, during the COVID-19 pandemic, the school closure exerted tremendous negative effects on school-aged children's health habits, including less physical activity, longer screen exposure and irregular sleeping pattern.
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4.
Obesity and Sleep.
Primack, C
The Nursing clinics of North America. 2021;(4):565-572
Abstract
Sleep is often misunderstood in its impact on many chronic diseases including obesity. Obesity and restorative sleep are intertwined processes. Poor sleep negatively affects the key hormones of weight and appetite regulation, thereby potentially increasing weight via mechanisms that increase hunger and lower metabolism, thereby making the successful treatment of obesity more difficult. Clinicians should consider a comprehensive sleep history and proper treatment or referral to a sleep specialist in conjunction with obesity treatment. Adequate restorative sleep is integral to a comprehensive obesity treatment program.
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5.
Genetic Determinants of Neurobehavioral Responses to Caffeine Administration during Sleep Deprivation: A Randomized, Cross Over Study (NCT03859882).
Erblang, M, Sauvet, F, Drogou, C, Quiquempoix, M, Van Beers, P, Guillard, M, Rabat, A, Trignol, A, Bourrilhon, C, Erkel, MC, et al
Genes. 2021;(4)
Abstract
This study investigated whether four single nucleotide polymorphisms (SNPs) moderated caffeine effects on vigilance and performance in a double-blind and crossover total sleep deprivation (TSD) protocol in 37 subjects. In caffeine (2 × 2.5 mg/kg/24 h) or placebo-controlled condition, subjects performed a psychomotor vigilance test (PVT) and reported sleepiness every six hours (Karolinska sleepiness scale (KSS)) during TSD. EEG was also analyzed during the 09:15 PVT. Carriers of the TNF-α SNP A allele appear to be more sensitive than homozygote G/G genotype to an attenuating effect of caffeine on PVT lapses during sleep deprivation only because they seem more degraded, but they do not perform better as a result. The A allele carriers of COMT were also more degraded and sensitive to caffeine than G/G genotype after 20 h of sleep deprivation, but not after 26 and 32 h. Regarding PVT reaction time, ADORA2A influences the TSD effect but not caffeine, and PER3 modulates only the caffeine effect. Higher EEG theta activity related to sleep deprivation was observed in mutated TNF-α, PER3, and COMT carriers, in the placebo condition particularly. In conclusion, there are genetic influences on neurobehavioral impairments related to TSD that appear to be attenuated by caffeine administration. (NCT03859882).
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6.
Interindividual differences in attentional vulnerability moderate cognitive performance during sleep restriction and subsequent recovery in healthy young men.
Mathew, GM, Strayer, SM, Ness, KM, Schade, MM, Nahmod, NG, Buxton, OM, Chang, AM
Scientific reports. 2021;(1):19147
Abstract
We investigated whether interindividual attentional vulnerability moderates performance on domain-specific cognitive tasks during sleep restriction (SR) and subsequent recovery sleep. Fifteen healthy men (M ± SD, 22.3 ± 2.8 years) were exposed to three nights of baseline, five nights of 5-h time in bed SR, and two nights of recovery sleep. Participants completed tasks assessing working memory, visuospatial processing, and processing speed approximately every two hours during wake. Analyses examined performance across SR and recovery (linear predictor day or quadratic predictor day2) moderated by attentional vulnerability per participant (difference between mean psychomotor vigilance task lapses after the fifth SR night versus the last baseline night). For significant interactions between day/day2 and vulnerability, we investigated the effect of day/day2 at 1 SD below (less vulnerable level) and above (more vulnerable level) the mean of attentional vulnerability (N = 15 in all analyses). Working memory accuracy and speed on the Fractal 2-Back and visuospatial processing speed and efficiency on the Line Orientation Task improved across the entire study at the less vulnerable level (mean - 1SD) but not the more vulnerable level (mean + 1SD). Therefore, vulnerability to attentional lapses after SR is a marker of susceptibility to working memory and visuospatial processing impairment during SR and subsequent recovery.
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7.
The impact of short sleep on food reward processes in adolescents.
Duraccio, KM, Krietsch, KN, Zhang, N, Whitacre, C, Howarth, T, Pfeiffer, M, Beebe, DW
Journal of sleep research. 2021;(2):e13054
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Abstract
Short sleep has been linked to adolescent risk of obesity, but questions remain regarding the dietary mechanisms by which this occurs. We tested whether mildly shortening sleep influences how rewarding and appealing healthy adolescents find several kinds of foods. Eighty-eight healthy adolescents completed a within-subjects crossover sleep experiment comparing 5 days of Short Sleep (6.5 hr sleep opportunity) with 5 days of Healthy Sleep (9.5 hr sleep opportunity). Following each condition, adolescents completed measures of food appeal and reinforcing value of food across five food types: sweets/desserts, fruits/vegetables, lean meats/eggs, fast food and processed snacks. Adolescents averaged 2.2 hr/night longer sleep periods in Healthy Sleep versus Short Sleep. We observed a significant interaction of experimental order with sleep condition on three of four primary outcomes related to the appeal and reinforcing value of foods (p's < .005). When Short Sleep preceded Healthy Sleep, adolescents endorsed significantly greater appeal (p < .04) and rewarding value of food (p's ranging from <.01 to .048) during Short Sleep (compared to Healthy Sleep). However, when Healthy Sleep preceded Short Sleep, we did not observe a main effect of sleep condition on the same outcomes (p's > .05). This study provides evidence that restricting adolescents' sleep opportunity to 6.5 hr (compared to sleeping a healthy amount) increases the appeal and reinforcing value of a variety of foods, but this may occur only under protracted short sleep. Increased food reward may be one mechanism linking chronically shortened sleep with risk of obesity in adolescence.
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Partial sleep deprivation on dietary energy intake in healthy population: a systematic review and meta-analysis.
González-Ortiz, A, López-Bautista, F, Valencia-Flores, M, Espinosa Cuevas, Á
Nutricion hospitalaria. 2020;(5):1052-1060
Abstract
Background: the restriction of nocturnal sleep has immediate effects, including the presence of excessive daytime sleepiness, general fatigue, or impaired concentration. In the long term, it increases the risk of death from cardiac, respiratory, and metabolic disorders, and the prevalence of obesity in healthy populations. However, despite the existence of a large number of studies on this topic, results have been controversial. Objective: to discuss and analyze the evidence on the effects of nocturnal sleep restriction versus habitual sleep on dietary energy intake, including specific meals, as well as the relationship between ghrelin and leptin levels in a healthy population. Methods: a systematic search of the literature was conducted in October 2016 and February 2019 using the PubMed, Scopus, Lilacs, and Embase databases. Terms used were "sleep," "feeding behavior," "dietary energy intake," "energy intake," "meal," "ghrelin," and "leptin." Results: the bibliographic search identified 384 potential articles. Of a total of eight articles accepted in the review, six contain information available for the analysis of total energy intake. The overall result shows a significant difference in energy intake between study groups (149.86 (95 % CI: 10.09-289.63); p = 0.04), and a higher intake of all macronutrients. Conclusions: the present systematic review and meta-analysis demonstrated that partial sleep deprivation increases total energy intake, as well as all macronutrients, when compared to habitual sleep.
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Effects of Sleep Deprivation on Acute Skeletal Muscle Recovery after Exercise.
Dáttilo, M, Antunes, HKM, Galbes, NMN, Mônico-Neto, M, DE Sá Souza, H, Dos Santos Quaresma, MVL, Lee, KS, Ugrinowitsch, C, Tufik, S, DE Mello, MT
Medicine and science in sports and exercise. 2020;(2):507-514
Abstract
PURPOSE Sleep is considered essential for muscle recovery, mainly due to its effect on hormone secretion. Total sleep deprivation or restriction is known to alter not only blood hormones but also cytokines that might be related to skeletal muscle recovery. This study aimed to evaluate whether total sleep deprivation after eccentric exercise-induced muscle damage (EEIMD) modifies the profiles of blood hormones and cytokines. METHODS In two separate conditions, with a crossover and randomized model, 10 men (age, 24.5 ± 2.9 yr; body mass index, 22.7 ± 2.3 kg·m) performed a unilateral EEIMD protocol that comprised 240 eccentric contractions of the knee extensor muscles using an isokinetic dynamometer. In one condition, a "muscle damage" protocol was followed by 48 h of total sleep deprivation and 12 h of normal sleep (DEPRIVATION). In the other condition, the same muscle damage protocol was conducted, followed by three nights of regular sleep (SLEEP). Isometric muscle voluntary contraction tests and blood samples were collected serially throughout the protocol and analyzed for creatine kinase, free and total testosterone, IGF-1, cortisol, tumor necrosis factor-alpha, interleukin (IL)-1beta, IL-6, receptor antagonist of IL-1 and IL-10. RESULTS Muscle voluntary contraction and serum creatine kinase increased equally over the study period in both conditions. From the cytokines evaluated, only IL-6 increased in DEPRIVATION. No differences were detected in testosterone levels between conditions, but IGF-1, cortisol, and cortisol/total testosterone ratio were higher in DEPRIVATION. CONCLUSIONS Total sleep deprivation after EEIMD does not delay muscle strength recovery but modifies inflammatory and hormonal responses.
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Chronobiological aspects of sleep restriction modulate subsequent spontaneous physical activity.
Wilms, B, Kuhr, M, Chamorro, R, Klinsmann, N, Spyra, D, Mölle, M, Kalscheuer, H, Schultes, B, Lehnert, H, Schmid, SM
Physiology & behavior. 2020;:112795
Abstract
PURPOSE First evidence suggests that chronobiological aspects of sleep restriction affect metabolic conditions. Our aim was to investigate whether spontaneous free-living physical activity likewise is affected by chronobiological timing of short sleep. METHODS In an experimental randomized, balanced cross-over design, eleven healthy, normal-weight (BMI: 23.9 ± 0.4 kg/m2) men were evaluated. Physical activity was assessed by tri-axial wrist actigraphy after (i) four-hour sleep during the first night-half of the night ('late night sleep loss'), (ii) four-hour sleep during the second night-half ('early night sleep loss'), and (iii) eight-hour regular sleep ('regular sleep'), from 7:00 to 24:00 (17 h). Feelings of tiredness and activity were measured by semi-quantitative questionnaires. RESULTS Physical activity differed between sleep conditions (P < 0.05) with the lowest physical activity after 'late night sleep loss'. Accordingly, less time was spent in high-intensity physical activity after 'late night sleep loss' as compared to the 'early night sleep loss' and 'regular sleep' conditions (both P < 0.05). Perceived feelings of tiredness were higher after both short sleep conditions as compared to 'regular sleep' (both P < 0.05). CONCLUSIONS Sleep restriction during the second half of the night elicits stronger effects on spontaneous physical activity than sleep restriction during the first half of the night despite identical sleep duration, but the impact of longer period awake needs to be evaluated in further research. In sum, these data indicate that not only short sleep per se but also chronobiological aspects modulate physical activity pattern.