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Study Objectives: This protocol paper outlines the methods that will be used to examine the impact of altering meal timing on metabolism, cognitive performance, and mood during the simulated night shift. Methods: Participants (male and female) will be recruited according to an a priori selected sample size to complete a 7-day within and between participant's laboratory protocol. Participants will be randomly assigned to one of the three conditions: meal at night or snack at night or no meal at night. This protocol includes an 8-hour nighttime baseline sleep, followed by 4 consecutive nights of simulated nightshift (7 hours day sleep; 10:00-17:00 hours), and an 8-hour nighttime sleep (return to dayshift). During the simulated night shift, meals will be provided at ~06:30, 09:30, 14:10, and 19:00 hours (no eating at night); ~06:30, 19:00, and 00:30 hours (meal at night); or ~06:30, 14:10, 19:00, and 00:30 hours (snack at night). Meal composition will be strictly controlled throughout the study (45%-65% carbohydrates, 15%-25% protein, and 20%-35% fat per day) with daily energy provided to meet individual needs using the Harris-Benedict equation (light/sedentary activity). The primary outcome measures are serum concentrations of blood glucose, insulin, and free fatty acids area under the curve in response to the oral glucose tolerance test. Mixed-effect ANOVAs will be conducted. Conclusions: This protocol paper describes a methodology to describe an innovative approach to reduce the metabolic disease impact associated with shift work.
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Maritime industries utilize many different watch keeping schedules to maintain vigilance and crew safety around the clock. These schedules can be fatiguing, negatively impacting vigilant attention. This has led to the consideration of schedules that might allow for more sleep time, but how these schedules impact higher order cognitive function remains unclear. These schedules require assessment with tasks that are relevant to real-world operations on maritime vessels. This study investigated the effect of four schedules on higher order cognitive function. Nâ =â 27 (16 female) participants were recruited to a 10-day laboratory study, comparing four schedules. The schedules investigated were eight-on/eight-off/four-on/four-off (8/8/4/4) with sleep from 09:30 to 16:00 (condition A); six-on/six-off (6/6) with sleep from 08:30 to 12:30 and 21:30 to 00:00 (condition B); four-on/four-off (4/4/4/4/4/4) with sleep from 18:00 to 00:30 (condition C); and four-on/four-off (4/4/4/4/4/4) with sleep from 01:30 to 08:00 (condition D). Higher order cognitive function was assessed 2-3× daily whilst "on watch" using tests of visual scanning, learning, working memory, mental flexibility, and visuomotor control. Conditions were ranked and stability of performance on watch was compared between conditions using Kruskal-Wallis tests. Cognitive function within condition B was ranked the worst for most of the tasks. However, the stability of higher order cognitive function was poorest across the waking day within condition A. These findings highlight the variability in cognitive capacities during different watch keeping schedules.
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STUDY OBJECTIVES: Shiftwork is associated with cognitive impairment and reduced sleep time and quality, largely due to circadian misalignment. This study tested if circadian-informed lighting could improve cognitive performance and sleep during simulated night shifts versus dim control lighting. METHODS: Nineteen healthy participants (Mean±SD 29±10 years, 12 males, 7 females) were recruited to a laboratory study consisting of two counterbalanced 8-day lighting conditions (order randomized) 1-month apart: 1) control lighting condition- dim, blue-depleted and 2) circadian-informed lighting condition- blue-enriched and blue-depleted where appropriate. Participants underwent an adaptation night (22:00h - 07:00h), then four nights of simulated nightwork (cognitive testing battery of nine tasks, 00:00h - 08:00h) and sleep during the day (10:00h - 19:00h). Psychomotor vigilance task (PVT) lapses, Karolinska Sleepiness Scale (KSS) scores, and polysomnography-derived sleep outcomes were compared between conditions and across days using mixed models. RESULTS: Significant condition-by-day-by-time of task interaction effects were found for PVT lapses, median reaction time, and reaction speed, with ~50% fewer lapses by the end of simulated shiftwork with circadian-informed lighting versus control (mean±SD 7.4±5.0 vs. 15.6±6.1). KSS was lower around the nightshift midpoints on days 6 and 7 with circadian versus control lighting. Participants slept 52 minutes longer [95% CIs: 27.5, 76.5 mins] by Day 7 with circadian-informed versus control lighting, p<0.001. Effects were inconsistent on other performance tasks. CONCLUSIONS: Circadian-informed lighting improved sleep, sleepiness, and vigilance compared to control lighting. These findings support the potential for lighting interventions to improve sleep and vigilance in night shift workers chronically exposed to dim lighting.
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STUDY OBJECTIVE: Night work has detrimental impacts on sleep and performance, primarily due to misalignment between sleep-wake schedules and underlying circadian rhythms. This study tested whether circadian-informed lighting accelerated circadian phase delay, and thus adjustment to night work, compared to blue-depleted standard lighting under simulated submariner work conditions. METHODS: Nineteen healthy sleepers (12 males; mean±SD aged 29 ±10 y) participated in two separate 8-day visits approximately one month apart to receive, in random order, circadian-informed lighting (blue-enriched and dim, blue-depleted lighting at specific times) and standard lighting (dim, blue-depleted lighting). After an adaptation night (day 1), salivary dim light melatonin onset (DLMO) assessment was undertaken from 18:00-02:00 on days 2-3. During days 3-7, participants completed simulated night work from 00:00-08:00 and a sleep period from 10:00-19:00. Post-condition DLMO assessment occurred from 21:00-13:00 on days 7-8. Ingestible capsules continuously sampled temperature to estimate daily core body temperature minimum (Tmin) time. Tmin and DLMO circadian delays were compared between conditions using mixed effects models. RESULTS: There were significant condition-by-day interactions in Tmin and DLMO delays (both p<0.001). After four simulated night shifts, circadian-informed lighting produced a mean [95%CI] 4.3 [3.3 to 5.4] h greater delay in Tmin timing and a 4.2 [3 to 5.6] h greater delay in DLMO timing compared to standard lighting. CONCLUSIONS: Circadian-informed lighting accelerates adjustment to shiftwork in a simulated submariner work environment. Circadian lighting interventions warrant consideration in any dimly lit and blue-depleted work environments where circadian adjustment is relevant to help enhance human performance, safety, and health.
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Biomathematical models of fatigue capture the physiology of sleep/wake regulation and circadian rhythmicity to predict changes in neurobehavioral functioning over time. We used a biomathematical model of fatigue linked to the adenosinergic neuromodulator/receptor system in the brain as a framework to predict sleep inertia, that is, the transient neurobehavioral impairment experienced immediately after awakening. Based on evidence of an adenosinergic basis for sleep inertia, we expanded the biomathematical model with novel differential equations to predict the propensity for sleep inertia during sleep and its manifestation after awakening. Using datasets from large laboratory studies of sleep loss and circadian misalignment, we calibrated the model by fitting just two new parameters and then validated the model's predictions against independent data. The expanded model was found to predict the magnitude and time course of sleep inertia with generally high accuracy. Analysis of the model's dynamics revealed a bifurcation in the predicted manifestation of sleep inertia in sustained sleep restriction paradigms, which reflects the observed escalation of the magnitude of sleep inertia in scenarios with sleep restriction to less than â¼ 4 h per day. Another emergent property of the model involves a rapid increase in the predicted propensity for sleep inertia in the early part of sleep followed by a gradual decline in the later part of the sleep period, which matches what would be expected based on the adenosinergic regulation of non-rapid eye movement (NREM) sleep and its known influence on sleep inertia. These dynamic behaviors provide confidence in the validity of our approach and underscore the predictive potential of the model. The expanded model provides a useful tool for predicting sleep inertia and managing impairment in 24/7 settings where people may need to perform critical tasks immediately after awakening, such as on-demand operations in safety and security, emergency response, and health care.
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Fatiga , Modelos Biológicos , Sueño , Humanos , Fatiga/fisiopatología , Sueño/fisiología , Vigilia/fisiología , Ritmo Circadiano/fisiología , Privación de Sueño/fisiopatologíaRESUMEN
Chronic sleep restriction, common in today's 24/7 society, causes cumulative neurobehavioural impairment, but the dynamics of the build-up and dissipation of this impairment have not been fully elucidated. We addressed this knowledge gap in a laboratory study involving two, 5-day periods of sleep restriction to 4 hr per day, separated by a 1-day dose-response intervention sleep opportunity. We measured sleep physiological and waking neurobehavioural responses in 70 healthy adults, each randomized to one of seven dose-response intervention sleep doses ranging from 0 to 12 hr, or a non-sleep-restricted control group. As anticipated, sleep physiological markers showed homeostatic dynamics throughout the study, and waking neurobehavioural impairment accumulated across the two sleep restriction periods. Unexpectedly, there was only a slight and short-lived effect of the 1-day dose-response intervention sleep opportunity. Whether the dose-response intervention sleep opportunity involved extension, further restriction or total deprivation of sleep, neurobehavioural functioning during the subsequent second sleep restriction period was dominated by prior sleep-wake history. Our findings revealed a profound and enduring influence of long-term sleep-wake history as a fundamental aspect of the dynamic regulation of the neurobehavioural response to sleep loss.
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Watchkeeping schedules are essential for maintaining submarine operations, but come with human risk factors including, disrupted sleep, circadian misalignment, and cognitive deficits. There is now an emerging literature examining the strengths and weaknesses of submarine watchkeeping schedules trialled in the field and under simulated laboratory conditions. The aim of this scoping review was to summarise this literature. A systematic search of peer-reviewed journal articles and industry reports listed in MEDLINE, PsychINFO, PubMed, Scopus, Embase and Google Scholar undertaken in May 2023 returned 7298 papers. Following screening procedures, 13 studies were identified for inclusion. The findings revealed that sleep was sufficiently preserved regardless of watchkeeping schedule (total sleep time = 5.46-7.89 h), circadian misalignment was greater for non-24 h schedules, and longer off-watch periods were associated with better cognitive performance. Taken together, when comparing between watchkeeping schedules, the present findings suggest that the 4 h-on/8 h-off and 8 h-on/16 h-off schedules may be a good compromise when balancing human risk factors and operational demands. However, submarines are complex and challenging environments to study and there is a need to expand the literature. More research comparing watchkeeping schedules is needed. Future studies should focus on cognitive performance measures, such as problem-solving, prioritisation and executive decision-making to address present shortcomings, and an examination of sleep and circadian countermeasures to assist with adaptation either initiated pre-deployment or by modifying the submarine environment itself should be considered.
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Personal Militar , Trastornos del Sueño del Ritmo Circadiano , Humanos , Ritmo Circadiano , Sueño , Trastornos del Sueño del Ritmo Circadiano/etiología , Cognición , Tolerancia al Trabajo ProgramadoRESUMEN
The present pilot study explored the research aim of understanding how independent-living older adults experience social isolation and loneliness and whether virtual tour digital technology can increase social connectedness (N = 10). Through triangulation of interviews, experiences, and feedback, this study contributes to the knowledge base on the well-being of our ageing populations and how digital technologies, specifically virtual tourism, can aid in this process. The key findings reveal that the participants in our study were moderately lonely but were open to embracing more digital technology, sharing how it is instrumental in facilitating social connection and life administration. Participating in virtual tour experiences was well accepted as participants expressed enjoyment, nostalgia, and interest in future use. However, its contribution to increasing social connections needs to be clarified and requires further investigation. Several future research and education directions are provided.
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Soledad , Aislamiento Social , Humanos , Anciano , Proyectos Piloto , EnvejecimientoRESUMEN
OBJECTIVES: Decreases in cognitive function impair occupational performance, reduce occupational safety, and increase musculoskeletal injury risk. The aim of this paper was to identify measures that may be used to monitor cognitive function in the warfighter. DESIGN: A rapid review. METHODS: A rapid search of Academic Search Complete, MEDLINE, PsycINFO, and SPORTSDiscus databases was conducted. ELIGIBILITY CRITERIA: original peer reviewed research articles, written in English, published between 2002 and 2022, and using human participants with no health issues in military training environments or active service. RESULTS: Of the 248 articles screened, 58 full-text articles were assessed for eligibility and 29 included in the review. Of these, 16 papers presented data from multi-stressor military training environments, or experimental studies where simulated military tasks were being performed. Thirteen papers focused on an aspect of military work and the implications for cognitive function (i.e., physical load, periods of extended wakefulness or fatigue, and hypoxic conditions). The domains of cognitive function that were assessed (i.e. vigilance, reaction time, working memory, situational awareness, and decision-making) were somewhat consistent among studies. CONCLUSIONS: Prolonged exposure to high-stress military environments compromises multiple aspects of cognitive function. These findings highlight the need for a suite of biomarkers to monitor cognitive function and assess the ability of military personnel to attend to and process mission-critical information and make appropriate decisions on the battlefield and other high-stress environments. Our findings suggest that a suite of common tests may provide useful information about cognitive function in the warfighter.
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Cognición , Fatiga , Humanos , Tiempo de Reacción , Examen Físico , BiomarcadoresRESUMEN
Sleep loss is common in our 24/7 society with many people routinely sleeping less than they need. Sleep debt is a term describing the difference between the amount of sleep needed, and the amount of sleep obtained. Sleep debt can accumulate over time, resulting in poor cognitive performance, increased sleepiness, poor mood, and a higher risk for accidents. Over the last 30 years, the sleep field has increasingly focused attention on recovery sleep and the ways we can recover from a sleep debt faster and more effectively. While there are still many unanswered questions and debates about the nature of recovery sleep, such as the exact components of sleep important for recovery of function, the amount of sleep needed to recover and the impacts of prior sleep history on recovery, recent research has revealed several important attributes about recovery sleep: (1) the dynamics of the recovery process is impacted by the type of sleep loss (acute versus chronic), (2) mood, sleepiness, and other aspects of cognitive performance recover at different rates, and (3) the recovery process is complex and dependent on the length of recovery sleep and the number of recovery opportunities available. This review will summarize the current state of the literature on recovery sleep, from specific studies of recovery sleep dynamics to napping, "banking" sleep and shiftwork, and will suggest the next steps for research in this field. This paper is part of the David F. Dinges Festschrift Collection. This collection is sponsored by Pulsar Informatics and the Department of Psychiatry in the Perelman School of Medicine at the University of Pennsylvania.
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OBJECTIVE: Time-restricted eating (TRE) restores circadian rhythms in mice, but the evidence to support this in humans is limited. The objective of this study was to investigate the effects of TRE on 24-hour profiles of plasma metabolites, glucoregulatory hormones, and the subcutaneous adipose tissue (SAT) transcriptome in humans. METHODS: Men (n = 15, age = 63 [4] years, BMI 30.5 [2.4] kg/m2 ) were recruited. A 35-hour metabolic ward stay was conducted at baseline and after 8 weeks of 10-hour TRE. Assessment included 24-hour profiles of plasma glucose, nonesterified fatty acid (NEFA), triglyceride, glucoregulatory hormones, and the SAT transcriptome. Dim light melatonin onset and cortisol area under the curve were calculated. RESULTS: TRE did not alter dim light melatonin onset but reduced morning cortisol area under the curve. TRE altered 24-hour profiles of insulin, NEFA, triglyceride, and glucose-dependent insulinotropic peptide and increased transcripts of circadian locomotor output cycles protein kaput (CLOCK) and nuclear receptor subfamily 1 group D member 2 (NR1D2) and decreased period circadian regulator 1 (PER1) and nuclear receptor subfamily 1 group D member 1 (NR1D1) at 12:00 am. The rhythmicity of 450 genes was altered by TRE, which enriched in transcripts for transcription corepressor activity, DNA-binding transcription factor binding, regulation of chromatin organization, and small GTPase binding pathways. Weighted gene coexpression network analysis revealed eigengenes that were correlated with BMI, insulin, and NEFA. CONCLUSIONS: TRE restored 24-hour profiles in hormones, metabolites, and genes controlling transcriptional regulation in SAT, which could underpin its metabolic health benefit.
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Tejido Adiposo , Ritmo Circadiano , Ayuno Intermitente , Obesidad , Humanos , Masculino , Persona de Mediana Edad , Ritmo Circadiano/genética , Ácidos Grasos no Esterificados , Hidrocortisona , Insulinas , Melatonina , Obesidad/genética , Transcriptoma , AncianoRESUMEN
The aim of this review was to explore the extent and nature of evidence exploring shiftwork and disruptions to cortisol. A systematic search was conducted across five databases: Medline, EMBASE, Psych INFO, Joanna Briggs Institute and PubMed between July-August 2020. Cortisol data were characterised into three main outcomes, 1) cortisol levels, 2) cortisol rhythm, and 3) cortisol awakening response (CAR) during shiftwork. Main findings demonstrate that shiftwork, especially night shift, significantly disrupts production of cortisol, the cortisol rhythm and CAR and, irregular shift schedules produce greater disruptions to cortisol than regular shift schedules. It was difficult to draw conclusions about the impact of shiftwork on movement of the cortisol rhythm and adaptation or recovery of the cortisol rhythm to and from night shift as the literature lacks consistency in definition of methods and variables. The present state of literature demonstrates cortisol levels, cortisol rhythm and the CAR are all disrupted by shiftwork, but there is a lack of consistency between studies on use of variables and most of the literature focuses on acute disruption rather than chronic effects. It will be important for future studies to investigate possible mechanisms that link shiftwork, disruptions to cortisol and chronic health conditions prevalent in shiftworkers.
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Hidrocortisona , Tolerancia al Trabajo Programado , Ritmo Circadiano/fisiología , Humanos , Tolerancia al Trabajo Programado/fisiologíaRESUMEN
Sleep deprivation and time of day have been shown to play a critical role in decreasing ability to sustain attention, such as when driving long distances. However, a gap in the literature exists regarding external factors, such as workload. One way to examine workload is via modulating time on task. This study investigated the combined effect of sleep deprivation, time of day, and time on task as a workload factor on driving performance. Twenty-one participants (18-34 years, 10 females) underwent 62 h of sleep deprivation within a controlled laboratory environment. Participants received an 8-h baseline and 9.5-h recovery sleep. Every 8 h, participants completed a Psychomotor Vigilance Task (PVT), Karolinska Sleepiness Scale (KSS), 30-min monotonous driving task and NASA-Task Load Index (TLX). Driving variables examined were lane deviation, number of crashes, speed deviation and time outside the safe zone. Workload was measured by comparing two 15-min loops of the driving track. A mixed model ANOVA revealed significant main effects of day and time of day on all driving performance measures (p < .001). There was a significant main effect of workload on lane deviation (p < .05), indicating that a longer time on task resulted in greater lane deviation. A significant main effect of day (p < .001) but not time of day for the NASA-TLX, PVT and KSS was found. Time on task has a significant further impact on driving performance and should be considered alongside sleep deprivation and time of day when implementing strategies for long-distance driving.
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Conducción de Automóvil , Privación de Sueño , Atención , Femenino , Humanos , Desempeño Psicomotor , Sueño , Vigilia , Carga de TrabajoRESUMEN
Purpose: Cancer survivors often make long-term dietary changes, and nutrition is important for survivorship outcomes. Many survivors experience persisting cognitive difficulties, which can impact health behaviors. This study aimed to identify perceived drivers of eating habit changes, and the barriers to making intentional dietary changes, among breast cancer survivors with persisting self-reported cancer-related cognitive impairment. Materials and Methods: A qualitative framework explored survivors' perceptions of dietary habit changes. Thirteen Australian breast cancer survivors (M.time since diagnosis: 23.6 months, standard deviation [SD] 15.3; M.time since completing primary treatment: 14.7 months, SD 15.3) completed semistructured interviews. Questions related to dietary changes since diagnosis and treatment. Major themes were identified from interview transcripts using thematic analysis. Results: While most individuals perceived their diet to be broadly similar to prediagnosis, several changes to diet and eating habits were identified, which were often meaningful to these survivors. Themes relating to survivors' eating habit changes included the following: (1) meal timing and frequency shifts, (2) more plant-based eating, and (3) less variety and more convenience. Changes in eating habits were attributed to the following: (1) persisting treatment-related changes, (2) help and support from others, (3) old treatment habits, (4) preventative health and self-care, and (5) changes to work schedule. Barriers to making intentional dietary changes included the following: (1) too much time and effort, (2) food cravings and enjoyment, and (3) lacking dietary ideas and resources. Conclusions: Many survivors reported long-term changes in dietary habits, some of which align with current recommendations. Causes of dietary habit changes, and barriers to engaging in healthier dietary habits, involved multiple biopsychosocial elements. Additional resources or strategies that assist navigating survivorship challenges and their effects on dietary habits are needed. Future studies should explore whether post-treatment nutritional review with a qualified dietary health professional is helpful for survivors who experience long-term cancer-related cognitive impairment.
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INTRODUCTION: Shift workers are at an increased risk of developing obesity and type 2 diabetes. Eating and sleeping out of synchronisation with endogenous circadian rhythms causes weight gain, hyperglycaemia and insulin resistance. Interventions that promote weight loss and reduce the metabolic consequences of eating at night are needed for night shift workers. The aim of this study is to examine the effects of three weight loss strategies on weight loss and insulin resistance (HOMA-IR) in night shift workers. METHODS AND ANALYSIS: A multisite 18-month, three-arm randomised controlled trial comparing three weight loss strategies; continuous energy restriction; and two intermittent fasting strategies whereby participants will fast for 2 days per week (5:2); either during the day (5:2D) or during the night shift (5:2N). Participants will be randomised to a weight loss strategy for 24 weeks (weight loss phase) and followed up 12 months later (maintenance phase). The primary outcomes are weight loss and a change in HOMA-IR. Secondary outcomes include changes in glucose, insulin, blood lipids, body composition, waist circumference, physical activity and quality of life. Assessments will be conducted at baseline, 24 weeks (primary endpoint) and 18 months (12-month follow-up). The intervention will be delivered by research dietitians via a combination of face-to-face and telehealth consultations. Mixed-effect models will be used to identify changes in dependent outcomes (weight and HOMA-IR) with predictor variables of outcomes of group, time and group-time interaction, following an intention-to-treat approach. ETHICS AND DISSEMINATION: The study protocol was approved by Monash Health Human Research Ethics Committee (RES 19-0000-462A) and registered with Monash University Human Research Ethics Committee. Ethical approval has also been obtained from the University of South Australia (HREC ID: 202379) and Ambulance Victoria Research Committee (R19-037). Results from this trial will be disseminated via conference presentations, peer-reviewed journals and student theses. TRIAL REGISTRATION NUMBER: Australian New Zealand Clinical Trials Registry (ACTRN-12619001035112).
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Diabetes Mellitus Tipo 2 , Resistencia a la Insulina , Diabetes Mellitus Tipo 2/prevención & control , Ayuno , Humanos , Obesidad/terapia , Calidad de Vida , Ensayos Clínicos Controlados Aleatorios como Asunto , Victoria , Pérdida de PesoRESUMEN
OBJECTIVE: We sought to examine the effects of 8 wk of time-restricted eating (TRE) on glucose metabolism and the adipose tissue transcriptome during a metabolic ward stay in men with obesity. METHODS: In a single-arm, pre-post trial, 15 men (ages 63 ± 4 y, body mass index = 30.5 ± 2.4 kg/m2, waist circumference = 113 ± 4 cm) with obesity but no history of diabetes were enrolled and underwent 2 wk of baseline monitoring before they were instructed to eat their regular diets within a contiguous 10-h time frame each day for 8 wk. Metabolic testing was performed at baseline and week 8 during a 35-h metabolic ward stay, during which all food intake was strictly timed and controlled. Identical meal-tolerance tests were performed at breakfast and dinner. Blood glucose, glucoregulatory hormones, and subjective appetite score were measured. Subcutaneous adipose tissue biopsies were performed and the transcriptome was assessed. RESULTS: The primary outcome, plasma glucose area under the curve, was altered by TRE, being unchanged at breakfast but increased at dinner. However, TRE reduced fasting glucose, glycated hemoglobin, body weight, and body fat, and increased glucose-dependent insulinotropic peptide area under the curve at dinner. In subcutaneous adipose tissue, 117 genes were up-regulated and 202 genes down-regulated by TRE. Pathway analysis revealed down-regulation of genes involved in proteasome function and mitochondrial regulation. CONCLUSIONS: TRE had a net effect of reducing glycemia and dampening energy-consuming pathways in adipose tissue.
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Ayuno , Control Glucémico , Tejido Adiposo/metabolismo , Anciano , Glucemia/metabolismo , Peso Corporal , Ayuno/fisiología , Humanos , Masculino , Persona de Mediana Edad , Obesidad/metabolismoRESUMEN
Shiftworkers are more likely to suffer from gastrointestinal disease and Type 2 Diabetes than the general population, likely due to their altered dietary intakes. Previous research has suggested that coping strategies and health behaviours may be linked, however, questions remain regarding these relationships in shiftworking populations. The Standard Shiftwork Index and Food Frequency Questionnaire were completed by nurses/midwives working forward rotating shifts (N=27, female=24, age=38.4 ± 13.1 y). Greater engaged coping strategy usage was associated with lower total energy, fat, carbohydrate and sugar intake (ρs>-0.1). Greater disengaged coping strategy usage was associated with greater intake of these nutrients (ρs>0.1). Results suggest that engaged coping strategies may contribute to healthier dietary choices. A greater focus on coping styles, particularly during nursing education, may improve shiftworkers' health.
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Diabetes Mellitus Tipo 2 , Partería , Adaptación Psicológica , Adulto , Carbohidratos , Ingestión de Alimentos , Femenino , Humanos , Persona de Mediana Edad , Proyectos Piloto , Embarazo , AzúcaresRESUMEN
Diet is a modifiable risk factor for chronic disease and a potential modulator of telomere length (TL). The study aim was to investigate associations between diet quality and TL in Australian adults after a 12-week dietary intervention with an almond-enriched diet (AED). Participants (overweight/obese, 50-80 years) were randomised to an AED (n 62) or isoenergetic nut-free diet (NFD, n 62) for 12 weeks. Diet quality was assessed using a Dietary Guideline Index (DGI), applied to weighed food records, that consists of ten components reflecting adequacy, variety and quality of core food components and discretionary choices within the diet. TL was measured by quantitative PCR in samples of lymphocytes, neutrophils, and whole blood. There were no significant associations between DGI scores and TL at baseline. Diet quality improved with AED and decreased with NFD after 12 weeks (change from baseline AED + 9·8 %, NFD - 14·3 %; P < 0·001). TL increased in neutrophils (+9·6 bp, P = 0·009) and decreased in whole blood, to a trivial extent (-12·1 bp, P = 0·001), and was unchanged in lymphocytes. Changes did not differ between intervention groups. There were no significant relationships between changes in diet quality scores and changes in lymphocyte, neutrophil or whole blood TL. The inclusion of almonds in the diet improved diet quality scores but had no impact on TL mid-age to older Australian adults. Future studies should investigate the impact of more substantial dietary changes over longer periods of time.
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Sobrepeso , Prunus dulcis , Adulto , Australia , Humanos , Obesidad , TelómeroRESUMEN
Human trials that compare intermittent fasting (IF) to calorie restriction (CR) with psychological, behavioral and cognition outcomes are limited. We hypothesized that there would be no difference between CR and IF on perceived eating behaviors, mood, sleep quality, quality of life (QOL) and cognition in women with overweight and obesity. In this prespecified secondary analysis of an open-label, single center, parallel assignment, randomized controlled trial, healthy women with overweight or obesity (N = 46, mean [SD] age 50 [9] years, BMI 32.9 [4.4] kg/m2), without a diagnosed eating disorder and who were randomized into 2 weight loss groups (prescribed 70% of calculated energy requirements as IF or CR) were included. Measurements were assessed in both IF and CR groups following a 12-hour overnight fast during baseline and week 8 and additionally following a 24-hour fast in the IF group only at week 8. We observed that IF produced greater weight and body fat loss than CR (P < .001). We did not detect any statistical difference between groups for the change in dietary restraint, disinhibition, hunger, mood, sleep quality, and QOL. An increase in cognitive performance was found in both IF (P = .036) and CR (P = .006) groups in one of the cognitive tasks, but there was no statistical difference between groups. Perceived eating behaviors, mood, sleep quality and cognitive performance were not changed by an acute 24-hour fast within the IF group (all P > .05). IF may be a viable alternative to CR for weight loss, in the short-term, without adversely impacting eating behaviors, mood, sleep quality, QOL or cognition in healthy women with overweight or obesity. However, larger and long term trials are required.
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Afecto , Restricción Calórica , Cognición , Ayuno , Conducta Alimentaria , Obesidad/psicología , Calidad del Sueño , Actividades Cotidianas , Adulto , Anciano , Femenino , Humanos , Persona de Mediana Edad , Sobrepeso , Calidad de VidaRESUMEN
Biomathematical models of fatigue can be used to predict neurobehavioral deficits during sleep/wake or work/rest schedules. Current models make predictions for objective performance deficits and/or subjective sleepiness, but known differences in the temporal dynamics of objective versus subjective outcomes have not been addressed. We expanded a biomathematical model of fatigue previously developed to predict objective performance deficits as measured on the Psychomotor Vigilance Test (PVT) to also predict subjective sleepiness as self-reported on the Karolinska Sleepiness Scale (KSS). Four model parameters were re-estimated to capture the distinct dynamics of the KSS and account for the scale difference between KSS and PVT. Two separate ensembles of datasets - drawn from laboratory studies of sleep deprivation, sleep restriction, simulated night work, napping, and recovery sleep - were used for calibration and subsequent validation of the model for subjective sleepiness. The expanded model was found to exhibit high prediction accuracy for subjective sleepiness, while retaining high prediction accuracy for objective performance deficits. Application of the validated model to an example scenario based on cargo aviation operations revealed divergence between predictions for objective and subjective outcomes, with subjective sleepiness substantially underestimating accumulating objective impairment, which has important real-world implications. In safety-sensitive operations such as commercial aviation, where self-ratings of sleepiness are used as part of fatigue risk management, the systematic differences in the temporal dynamics of objective versus subjective measures of functional impairment point to a potentially significant risk evaluation sensitivity gap. The expanded biomathematical model of fatigue presented here provides a useful quantitative tool to bridge this previously unrecognized gap.