Sleep Pattern Interference in the Cognitive Performance of Lusitano Horses.

Like most mammalian, polyphasic sleep, equine sleep can be divided into two phases: the REM (rapid eye movement) phase and the NREM (non-rapid eye movement) phase. For this study, a randomized crossover experiment was conducted using ten purebred Lusitano horses, all dressage athletes aged from three to seven years old. The horses were filmed before the intervention to characterize their sleep patterns. REM sleep deprivation was achieved by not letting the horses attain sternal or lateral recumbency for three consecutive days, totaling 72 h. A spatial memory task and a visual attention test were performed. A recording time of 48 h appeared to be long enough to characterize the sleep patterns of the stalled horses. The total recumbency time of the studied population was lower than that previously reported in horses. Although the recumbency times before and after the intervention were similar, there was a tendency shown by the delta (p = 0.0839) towards an increased time needed to resolve spatial memory tasks in the sleep-deprived group. Future studies may deepen the understanding of horse sleep requirements and patterns, and the effects of environmental changes on horse sleep.

Translation, adaptation and validation of the Chrononutrition Profile - Questionnaire (CP-Q) in Brazilian Portuguese.

Chrononutrition is a science that studies the relationship between mealtimes and sleep/wake habits. However, these behaviors are not evaluated by a single questionnaire. Therefore, this study aimed to translate and culturally adapt the Chrononutrition Profile - Questionnaire (CP-Q) into Portuguese and validate the Brazilian version. The translation and cultural adaptation process consisted of: translation; synthesis of translations; backtranslation; expert committee and pre-test. The validation was performed with 635 participants (32.4 ± 11.2 years) who answered the CPQ-Brazil and Pittsburgh Sleep Quality Index (PSQI); Munich Chronotype Questionnaire (MCTQ); Night Eating questionnaire; Quality of life and health index (SF-36) and 24 h-recall. The participants were mostly female, single, from the northeastern region, a eutrophic profile, and average quality of life score of 55.8 ± 17.9. Moderate to strong correlations were observed in the sleep/wake schedules between CPQ-Brazil, PSQI and MCTQ, both for work/study days and free days. The correlations between largest meal, skipping breakfast, eating window, nocturnal latency, and last eating event with the same variables in the 24 h-recall showed moderate to strong positive correlations. The translation, adaptation, validation and reproducibility of the CP-Q generates a valid and reliable questionnaire to assess the sleep/wake and eating habits in the Brazilian population.

How much does sleep deprivation impair endurance performance? A systematic review and meta-analysis.

We conducted a systematic review and meta-analysis to investigate the effect of sleep deprivation on endurance performance, as well as possible effect-modifying factors. Searches were done in Pubmed, Web of Science, Embase, and Scopus on 12 July 2022. We additionally searched the bibliographic references and citations on Google Scholar of the papers whose full text was analyzed. Eligible studies were randomized and non-randomized controlled trials that compared sleep deprivation and habitual-sleep night effects on endurance performance in healthy humans. The studies' quality was examined by the Cochrane Collaboration's risk of bias tool. We calculated the pooled standardized mean differences (pooled SMD) and 95% confidence interval (95%CI) by a random-effects model. A mixed-effects model analyzed subgroups. Thirty-one studies were analyzed (n = 478), generating 38 effect sizes in full. The overall risk of bias was low in 8% of the studies, unclear in 74%, and high in 18%. Sleep deprivation in general had a moderate negative effect on endurance performance (polled SMD [95%CI] = -0.52 [-0.67; -0.38]). Training status, sleep deprivation magnitude, assessment time, exercise mode, and endpoint type did not influence the sleep deprivation effect, whereas longer exercises (>30 min) were more affected by sleep deprivation than shorter ones (P = 0.035). Therefore, the available evidence supports that sleep deprivation's deleterious effect on endurance performance is of moderate size and depends on exercise duration. This information can be useful to estimate the performance decrement of endurance exercise practitioners under sleep deprivation in training routines and competitions.PROSPERO registration number CRD42021229717.

Sleep deprivation causes a moderate deleterious effect on endurance performance.Sleep deprivation similarly impairs endurance performance in untrained, recreationally-trained, and trained people, but its effect on well-trained and professional endurance athletes is unknown.One or more nights of partial sleep deprivation or one night of total sleep deprivation similarly compromise endurance performance. Uncertainties about the effect of more than one night of total sleep deprivation warrant more studies.Sleep deprivation impairs walking, running, and cycling endurance performance regardless of the exercise endpoint being unknown (i.e. incremental or constant load tests) or known (i.e. time trial tests) and assessment time. However, sleep deprivation causes a more deleterious effect on endurance performance in exercises lasting more than 30 min.

Breathing modulates gamma synchronization across species.

Nasal respiration influences brain dynamics by phase-entraining neural oscillations at the same frequency as the breathing rate and by phase-modulating the activity of faster gamma rhythms. Despite being widely reported, we still do not understand the functional roles of respiration-entrained oscillations. A common hypothesis is that these rhythms aid long-range communication and provide a privileged window for synchronization. Here we tested this hypothesis by analyzing electrocorticographic (ECoG) recordings in mice, rats, and cats during the different sleep-wake states. We found that the respiration phase modulates the amplitude of cortical gamma oscillations in the three species, although the modulated gamma frequency bands differed with faster oscillations (90-130 Hz) in mice, intermediate frequencies (60-100 Hz) in rats, and slower activity (30-60 Hz) in cats. In addition, our results also show that respiration modulates olfactory bulb-frontal cortex synchronization in the gamma range, in which each breathing cycle evokes (following a delay) a transient time window of increased gamma synchrony. Long-range gamma synchrony modulation occurs during quiet and active wake states but decreases during sleep. Thus, our results suggest that respiration-entrained brain rhythms orchestrate communication in awake mammals.

Low frequency oscillations drive EEG's complexity changes during wakefulness and sleep.

Recently, the sleep-wake states have been analysed using novel complexity measures, complementing the classical analysis of EEGs by frequency bands. This new approach consistently shows a decrease in EEG's complexity during slow-wave sleep, yet it is unclear how cortical oscillations shape these complexity variations. In this work, we analyse how the frequency content of brain signals affects the complexity estimates in freely moving rats. We find that the low-frequency spectrum - including the Delta, Theta, and Sigma frequency bands - drives the complexity changes during the sleep-wake states. This happens because low-frequency oscillations emerge from neuronal population patterns, as we show by recovering the complexity variations during the sleep-wake cycle from micro, meso, and macroscopic recordings. Moreover, we find that the lower frequencies reveal synchronisation patterns across the neocortex, such as a sensory-motor decoupling that happens during REM sleep. Overall, our works shows that EEG's low frequencies are critical in shaping the sleep-wake states' complexity across cortical scales.

Changes in sleep habits during the lockdown for the COVID-19 pandemic in the population and people attending a morning or an afternoon shift in Monterrey, Mexico.

To fight the Covid-19 pandemic, most countries implemented a lockdown that involved restricting the activity and confining the population to their homes. The objective of this paper is to analyze the impact of the lockdown on sleep in people from the population of Monterrey, Mexico, and people attending a morning or afternoon work or study shift after more than a month adaptation period. Participants were 861 residents from Monterrey, Mexico, who completed an anonymous 20-minute web-based survey. The survey asked for information about sleep habits both before and during the lockdown. In Mexico, a national lockdown was declared on March 23rd, 2020. Data collection began 38 days after the start of the lockdown, from April 30th to May 23rd, 2020, allowing enough time for the participants to adjust to the new conditions. The lockdown affected the sleep of the population, producing a phase delay of the sleep-wake cycle, a reduction of sleep duration, as well as an increase in sleep latency and in time awake during night sleep, resulting in a reduction of sleep efficiency. People attending an afternoon shift also showed a phase delay and a reduction in sleep quality during the lockdown. In conclusion, the lockdown produced a delay of sleep and a reduction of sleep quality of the population, even in people with an afternoon shift. It is necessary to design and implement better strategies in the fight against the pandemic, without compromising the wellbeing of the population.

Social, Biological and Behavioral Factors Associated with Social Jet Lag and Sleep Duration in University Students from a Low Urbanized City.

INTRODUCTION: Sleep deprivation and social jet lag are observed in college students from highly urbanized cities. However, does these consequences also present in college students from a low urbanization city? OBJECTIVE: To evaluate the prevalence and social, biological and behavioral factors associated with sleep deprivation and social jet lag in university students from a low urbanized city of Brazil. METHODS: A total of 298 university students participated in the study through application of the Health and Sleep and the Munich Chronotype Questionnaires. Multiple linear regression with stepwise-forward method was adopted to assess the associations of the factors with the outcome variables. RESULTS: Doing leisure activities (LA) (B = 23.24) and academic demand (AD) before bedtime (B = 19.51), both on the weekend, and doing household chores (HC) before bedtime (B = 17.61) in the week were associated with an increase in social jet lag, while stimulating drinks (SD) were associated with a decrease (B = -15.17). Shorter sleep duration in the week was related to chronotype (B = -0.56), male (B = -26.51), doing LA (B = -27.63), poor perception about sleeping place (PPSP) (B = -43.02) and daily commute (B = -68.97). The shorter sleep duration in the weekend was associated to male (B = -36.36), PPSP (B = -58.16), have recreational and religious activities (B = -31.11), doing LA (B = -25.10) and AD (B = -23.60). Just chronotype was associated with longer sleep duration in the weekend (B = 0.25). CONCLUSION: University students from a low urbanized city present social jet lag, shorter sleep duration on school days and longer sleep duration on free days as a result of biological and social factors, and mostly behavioral factors.

Identifying electronic-sport athletes' sleep-wake cycle characteristics.

Organized electronic-sport competitions (e-Sport) is related to several health problems, including sleep disorders. The objective of this study was to evaluate the characteristics of the sleep-wake cycle of League of Legends (LoL) athletes during their pre-training, training, pre-competition, and competition routines. Twenty male elite LoL players completed the questionnaires related to sleep pattern (Pittsburgh Sleep Quality Index), sleepiness (Epworth Sleepiness Scale), and chronotype (Morningness-Eveningness Questionnaire), and they wore an actigraph for 7 days. Pre-training and pre-competition assessments were carried out by questionnaires (n = 20) and training and competition assessments by actigraph (n = 16). The chronotype that most Eathletes presented was a moderately evening type. They presented a poor sleep quality and were borderline for excessive daytime sleepiness. Sleep onset and offset times were significantly prolonged during the competition condition (t = 2.11, p < .05; t = 2.51, p < .05). Correlations showed a relationship between PSQI and Sleepiness in the pre-training and pre-competition conditions (r = 0.50, p = .02) and chronotype with sleep onset (r = 0.61, p = .01), total sleep time (r = 0.55, p = .02), and time awake (r = 0.49, p = .04) in the competition condition. Linear regression analysis indicated associations between the PSQI and sleepiness (25%; p = .02) during pre-training and pre-competition. During the competition there were associations between chronotype and sleep onset (37%; p = .01), chronotype and time awake (24%; p = .04), and chronotype and TST (30%; p = .02). In general, the findings support the conclusion that LoL athletes presented an altered sleep pattern during their training routines.

Relação do cronotipo nos níveis de ansiedade e consumo Máximo de oxigênio em jovens / Relation between chronotype on anxiety levels and maximum oxygen consumption in young people

O presente estudo analisou a relação entre cronotipo, níveis de ansiedade, depressão e estresse, bem como níveis de condicionamento cardiorrespiratório em jovens. Métodos: Foi analisado um total de 36 participantes com idades entre 18 e 28 a nos, saudáveis e que atendessem ao cronotipo matutino e vespertino. Análises de nível de atividade física, consumo máximo de oxigênio, níveis de depressão, ansiedade e estresse foram realizadas com testes específicos. Em todos os cálculos foram utilizados um alfa de p<0.05 para análise estatística. Resultados: O nível de atividade física mostrou que a porcentagem dos matutinos suficientemente ativos foi de 58% comparado com 23.5% dos vespertinos. Mulheres com cronotipo vespertino apresentaram níveis menores de VO2máx quando comparados com as mulheres com cronotipo matutino (p=0.04). Os participantes vespertinos apresentaram níveis maiores de ansiedade (p=0.02) comparados com os matutinos e esses dados foram evidentes nos participantes do sexo feminino onde as mulheres do cronotipo vespertino apresentaram níveis maiores de ansiedade (p=0.03) comparados com mulheres de cronotipo matutino. Conclusão: Portanto, o estudo conclui que indivíduos do cronotipo vespertino apresentaram menores níveis de atividade física e maiores níveis de ansiedade evidenciados principalmente nas mulheres.(AU)

The present study analyzed a relationship between schedule, anxiety, depression and stress levels, as well as cardiorespiratory fitness levels in young people. Methods: A total of 36 healthy participants aged 18 to 28 years who met the criteria for chronotypes morning type and evening type were analyzed. Analyzes of physical activity level, maximal oxygen uptake, depression, anxiety and stress levels were performed. In all calculations, an alpha of p <0.05 was used for statistical analysis. Results: The level of physical activity was higher in morning types 58% compared to 23.5% of evening types. Women with evening chronotype had lower VO2max levels compared with women with a morning chronotype (p= 0.04). Evening types had higher anxiety levels (p= 0.02) compared to morning types and these data were evidenced in female participants with higher anxiety levels (p=0.03) compared to women with a morning chronotype. Conclusion: Therefore, the study concludes that young people with a evening chronotype exhibited lower levels of physical activity and higher anxiety levels, especially in women.(AU)

Elderly as a High-risk Group during COVID-19 Pandemic: Effect of Circadian Misalignment, Sleep Dysregulation and Melatonin Administration.

The association of age with a higher vulnerability to COVID-19 infection is a subject of major importance. Several factors, including higher stress due to social isolation, diminished melatonin levels with age, and higher exposure of individuals to light at the evening, which reduces melatonin levels and disrupts circadian rhythmicity are relevant for maintaining the circadian health in aged individuals. Properly administered, chronotherapy restores the optimal circadian pattern of the sleep-wake cycle in the elderly. It involves adequate sleep hygiene, timed light exposure, and the use of a chronobiotic medication like melatonin, which affects the output phase of circadian rhythms thus controlling the biological clock. Besides, the therapeutic potential of melatonin as an agent to counteract the consequences of COVID-19 infections has been advocated due to its wide-ranging effects as an antioxidant, anti-inflammatory, and as an immunomodulatory agent, as well as to a possible antiviral action. This article discusses how chronotherapy may reverse the detrimental circadian condition of the elderly in the COVID-19 pandemic.

Home-based outsourced informal work by children and adolescents impacts sleep and leisure-a preliminary study.

Child labor is a serious and controversial issue. Despite governments establishing health policies prohibiting or restricting the age of entry to the job market, there is still a large number of working children and adolescents worldwide, particularly informal workers. This study aimed to evaluate the living and working conditions of adolescents. Work activities were home-based involving the production of jewelry and fashion jewelry, in a Brazilian city, Limeira, São Paulo. Participants were 11-17-year-old workers and non-workers, who answered a comprehensive questionnaire on their living and working conditions and filled out a time-budget protocol for 10 consecutive days. Both instruments were applied twice during both school and vacation terms. Chi-square/Fisher and Student's t tests were used, and Bonferroni corrections were performed in the significance levels of the statistical methods. During school time, working children/adolescents had lower mean sleep duration (p < 0.01) than non-working ones. During vacation, non-working youths enjoyed longer leisure time (p < 0.04). Comparing school and vacation times, working youths showed no significant difference in daily routine (p > 0.05), while non-workers spent more time on leisure activities during the vacation period (p = 0.005). In summary, this study found that working at home had a deleterious effect on the sleep and leisure of the youths studied. These data should be considered as an exposome component (specific external exposure) in evaluations of long-term health endpoints and their possible causes.

Unveiling sleep mysteries: Sleep-wake cycle as a biological parameter of the circadian typology (Chronotype) / Revelando mistérios do sono: Ciclo sono-vigília como parâmetro biológico da tipologia circadiana (cronotipo)

The sleep-wake cycle that is circadian rhythm may have different patterns according to sex, environment and genetics determinants. This chronological cycle type, chronotype, may be populational expressed by the extremes, early or later going to bed and waking up, in a continuum. The first, the Morning-type individuals (the lark) and the later, the Evening types (the owl). Between the two extremes, there is the majority of these chronotypes ­ the intermediate ones. These patterns may be classified according to the questionnaires such as Horne and Ostberg Morningness/ Eveningness Questionnaire (MEQ) and the Munich Chrono Type Questionnaire (MCTQ). The rural population tends to be Morning-type, as well as children and younger women, more than men. The Morning person tends to be more healthy than the Evening ones who are more prone to diseases, as depression and metabolic syndrome. This basic knowledge may be helpful to patient's counseling and management: to avoid mismatch of circadian physiology and social duties / sleep. This circadian desynchrony can increase the risk of diseases, consequently there is a need to chrono-medicine into current treatment strategies.

O ciclo sono-vigília, que é um ritmo circadiano, pode ter padrões diferentes de acordo com os determinantes sexuais, ambientais e genéticos. Esse tipo de ciclo cronológico, cronótipo, pode ser expresso em termos populacionais pelos extremos, indo cedo ou mais tarde para a cama ou saindo dela, em um continuum. O primeiro, os indivíduos do tipo Manhã (a cotovia) e o posterior, os tipos da Tarde (a coruja). Entre os dois extremos, há a maioria desses cronotipos - os intermediários. Esses padrões podem ser classificados de acordo com questionários como o Horne e Ostberg Morningness/Eveningness Questionnaire (MEQ) e o Munich Chrono Type Questionnaire (MCTQ). A população rural tende a ser do tipo matutino, assim como crianças e mulheres mais jovens, mais que os homens.A pessoa da manhã tende a ser mais saudável do que as da noite, mais propensa a doenças, como depressão e síndrome metabólica. Esse conhecimento básico pode ser útil para o aconselhamento e tratamento dos pacientes: para evitar incompatibilidade entre a fisiologia circadiana e os deveres sociais / sono. Essa dessincronia circadiana pode aumentar o risco de doenças, consequentemente, é necessário a cronomedicina nas atuais estratégias de tratamento.

Dysregulation of Circadian Rhythms in Autism Spectrum Disorders.

BACKGROUND: The alterations in neurological and neuroendocrine functions observed in the autism spectrum disorder (ASD) involves environmentally dependent dysregulation of neurodevelopment, in interaction with multiple coding gene defects. Disturbed sleep-wake patterns, as well as abnormal melatonin and glucocorticoid secretion, show the relevance of an underlying impairment of the circadian timing system to the behavioral phenotype of ASD. Thus, understanding the mechanisms involved in the circadian dysregulation in ASD could help to identify early biomarkers to improve the diagnosis and therapeutics as well as providing a significant impact on the lifelong prognosis. OBJECTIVE: In this review, we discuss the organization of the circadian timing system and explore the connection between neuroanatomic, molecular, and neuroendocrine responses of ASD and its clinical manifestations. Here we propose interconnections between circadian dysregulation, inflammatory baseline and behavioral changes in ASD. Taking into account, the high relevancy of melatonin in orchestrating both circadian timing and the maintenance of physiological immune quiescence, we raise the hypothesis that melatonin or analogs should be considered as a pharmacological approach to suppress inflammation and circadian misalignment in ASD patients. STRATEGY: This review provides a comprehensive update on the state-of-art of studies related to inflammatory states and ASD with a special focus on the relationship with melatonin and clock genes. The hypothesis raised above was analyzed according to the published data. CONCLUSION: Current evidence supports the existence of associations between ASD to circadian dysregulation, behavior problems, increased inflammatory levels of cytokines, sleep disorders, as well as reduced circadian neuroendocrine responses. Indeed, major effects may be related to a low melatonin rhythm. We propose that maintaining the proper rhythm of the circadian timing system may be helpful to improve the health and to cope with several behavioral changes observed in ASD subjects.

Circadian activity rhythm and fragmentation are associated with sleep-wake patterns and sleep quality in patients with stroke.

BACKGROUND: Activity levels and disturbances of the sleep-wake pattern affect health and quality of life and need to be further explored in patients with stroke. OBJECTIVE: To evaluate activity levels and their association with sleep-wake patterns in patients with stroke. METHODS: Ten adults with (51±6 years) and 10 without stroke (52±7 years) participated in the study; they were matched on age, sex and educational level. Neurological status, motor function, sleep quality, and activity levels were measured. The groups were compared using Student t-tests and the association between the measures was assessed using Pearson's correlation. RESULTS: Compared to people without stroke, those with stroke had worse sleep quality (p = 0.044), twice lower 24h-activity levels (p < 0.0001), higher interdaily stability and intradaily variability, lower activity during the most active 10 h and during the least active 5 h. Sleep quality was associated with activity level (r= -0.72) and with within-day activity variability (r= 0.53). CONCLUSIONS: Activity level and fragmentation are associated with sleep-wake patterns and sleep quality in patients with stroke.

Cardiovascular and respiratory profiles during the sleep-wake cycle of rats previously submitted to chronic intermittent hypoxia.

NEW FINDINGS: What is the central question of this study? Chronic intermittent hypoxia (CIH) causes increased arterial pressure (AP), sympathetic overactivity and changes in expiratory modulation of sympathetic activity. However, changes in the short-term sleep-wake cycle pattern after CIH and their potential impact on cardiorespiratory parameters have not been reported previously. What is the main finding and its importance? Exposure to CIH for 10 days elevates AP in wakefulness and sleep but does not cause major changes in short-term sleep-wake cycle pattern. A higher incidence of muscular expiratory activity was observed in rats exposed to CIH only during wakefulness, indicating that active expiration is not required for the increase in AP in rats submitted to CIH. ABSTRACT: Chronic intermittent hypoxia (CIH) increases arterial pressure (AP) and changes sympathetic-respiratory coupling. However, the alterations in the sleep-wake cycle after CIH and their potential impact on cardiorespiratory parameters remain unknown. Here, we evaluated whether CIH-exposed rats present changes in their short-term sleep-wake cycle pattern and in cardiorespiratory parameters. Male Wistar rats (∼250 g) were divided into CIH and control groups. The CIH rats were exposed to 8 h day-1 of cycles of normoxia (fraction of inspired O2  = 0.208, 5 min) followed by hypoxia (fraction of inspired O2  = 0.06, 30-40 s) for 10 days. One day after CIH, electrocorticographic activity, cervical EMG, AP and heart rate were recorded for 3 h. Plethysmographic recordings were collected for 2 h. A subgroup of control and CIH rats also had the diaphragm and oblique abdominal muscle activities recorded. Chronic intermittent hypoxia did not alter the time for sleep onset, total time awake, durations of rapid eye movement (REM) and non-REM (NREM) sleep and number of REM episodes in the 3 h recordings. However, a significant increase in the duration of REM episodes was observed. The AP and heart rate were increased in all phases of the cycle in rats exposed to CIH. Respiratory frequency and ventilation were similar between groups in all phases, but tidal volume was increased during NREM and REM sleep in rats exposed to CIH. An increase in the incidence of active expiration during wakefulness was observed in rats exposed to CIH. The data show that CIH-related hypertension is not caused by changes in the sleep-wake cycle and suggest that active expiration is not required for the increase in AP in freely moving rats exposed to CIH.

Identification of earlier predictors of pregnancy complications through wearable technologies in a Brazilian multicentre cohort: Maternal Actigraphy Exploratory Study I (MAES-I) study protocol.

INTRODUCTION: Non-invasive tools capable of identifying predictors of maternal complications would be a step forward for improving maternal and perinatal health. There is an association between modification in physical activity (PA) and sleep-wake patterns and the occurrence of inflammatory, metabolic, pathological conditions related to chronic diseases. The actigraphy device is validated to estimate PA and sleep-wake patterns among pregnant women. In order to extend the window of opportunity to prevent, diagnose and treat specific maternal conditions, would it be possible to use actigraphy data to identify risk factors for the development of adverse maternal outcomes during pregnancy? METHODS AND ANALYSIS: A cohort will be held in five centres from the Brazilian Network for Studies on Reproductive and Perinatal Health. Maternal Actigraphy Exploratory Study I (MAES-I) will enrol 400 low-risk nulliparous women who will wear the actigraphy device on their wrists day and night (24 hours/day) uninterruptedly from 19 to 21 weeks until childbirth. Changes in PA and sleep-wake patterns will be analysed throughout pregnancy, considering ranges in gestational age in women with and without maternal complications such as pre-eclampsia, preterm birth (spontaneous or provider-initiated), gestational diabetes, maternal haemorrhage during pregnancy, in addition to perinatal outcomes. The plan is to design a predictive model using actigraphy data for screening pregnant women at risk of developing specific adverse maternal and perinatal outcomes. ETHICS AND DISSEMINATION: MAES-I has been reviewed and approved by each institutional review board and also by the National Council for Ethics in Research. Detailed information about the study is provided in the Brazilian Cohort website (www.medscinet.com/samba) and findings will be published in the scientific literature and institutional webpages.

Chronic Consumption of Fructose Induces Behavioral Alterations by Increasing Orexin and Dopamine Levels in the Rat Brain.

It has been widely described that chronic intake of fructose causes metabolic alterations which can be associated with brain function impairment. In this study, we evaluated the effects of fructose intake on the sleep⁻wake cycle, locomotion, and neurochemical parameters in Wistar rats. The experimental group was fed with 10% fructose in drinking water for five weeks. After treatment, metabolic indicators were quantified in blood. Electroencephalographic recordings were used to evaluate the sleep architecture and the spectral power of frequency bands. Likewise, the locomotor activity and the concentrations of orexin A and monoamines were estimated. Our results show that fructose diet significantly increased the blood levels of glucose, cholesterol, and triglycerides. Fructose modified the sleep⁻wake cycle of rats, increasing the waking duration and conversely decreasing the non-rapid eye movement sleep. Furthermore, these effects were accompanied by increases of the spectral power at different frequency bands. Chronic consumption of fructose caused a slight increase in the locomotor activity as well as an increase of orexin A and dopamine levels in the hypothalamus and brainstem. Specifically, immunoreactivity for orexin A was increased in the ventral tegmental area after the intake of fructose. Our study suggests that fructose induces metabolic changes and stimulates the activity of orexinergic and dopaminergic neurons, which may be responsible for alterations of the sleep⁻wake cycle.

No Acute Effects of Cannabidiol on the Sleep-Wake Cycle of Healthy Subjects: A Randomized, Double-Blind, Placebo-Controlled, Crossover Study.

Cannabidiol (CBD) is a component of Cannabis sativa that has a broad spectrum of potential therapeutic effects in neuropsychiatric and other disorders. However, few studies have investigated the possible interference of CBD on the sleep-wake cycle. The aim of the present study was to evaluate the effect of a clinically anxiolytic dose of CBD on the sleep-wake cycle of healthy subjects in a crossover, double-blind design. Twenty-seven healthy volunteers that fulfilled the eligibility criteria were selected and allocated to receive either CBD (300 mg) or placebo in the first night in a double-blind randomized design (one volunteer withdrew from the study). In the second night, the same procedure was performed using the substance that had not been administered in the previous occasion. CBD or placebo were administered 30 min before the start of polysomnography recordings that lasted 8 h. Cognitive and subjective measures were performed immediately after polysomnography to assess possible residual effects of CBD. The drug did not induce any significant effect (p > 0.05). Different from anxiolytic and antidepressant drugs such as benzodiazepines and selective serotonin reuptake inhibitors, acute administration of an anxiolytic dose of CBD does not seem to interfere with the sleep cycle of healthy volunteers. The present findings support the proposal that CBD do not alter normal sleep architecture. Future studies should address the effects of CBD on the sleep-wake cycle of patient populations as well as in clinical trials with larger samples and chronic use of different doses of CBD. Such studies are desirable and opportune.

Gender differences in sleep habits and quality and daytime sleepiness in elementary and high school teachers.

The extensive workload of teachers inside and outside the classroom may contribute to sleep problems. Such problems may occur more frequently in women due to the combination of professional demands, domestic tasks, and their relatively greater sleep needs compared to men. The objective of this cross-sectional study was to evaluate the influence of gender on sleep habits and quality, and daytime sleepiness in a sample of 243 teachers (77 men and 166 women) using questionnaires. Linear regression models were used to examine the effect of gender on sleep measures; the unadjusted model considered only gender and the adjusted model considered chronotype and work characteristics as potential confounders. Bedtimes of women were significantly earlier than men during the week, but not on weekends, in the unadjusted and adjusted models. Time in bed was longer for women throughout the week and weekend in the unadjusted model. However, in the adjusted model, this statistical significance disappeared, and longer time in bed during the week was associated with teaching in one shift and for both levels of education. In addition, the female gender was associated with higher sleepiness scores compared to males in both models, and worse sleep quality in the adjusted model. Also, sleep quality was worse in subjects working in three shifts and in both types of schools (public and private). The tendency to eveningness was associated with later bedtimes and wake up times during both week days and weekends, higher irregularity of bedtimes and wake up times, and higher sleepiness scores in the adjusted model. Therefore, we suggest that female teachers do not fulfill their sleep needs and show higher levels of diurnal sleepiness and poor sleep quality that can be modulated by chronotype and some work characteristics. More studies are needed to evaluate the role of double workload on this pattern.

High and low use of electronic media during nighttime before going to sleep: A comparative study between adolescents attending a morning or afternoon school shift.

This study compared the effects of time spent on electronic media devices during nighttime before going to sleep on the sleep-wake cycle, daytime sleepiness, and chronotype in 568 Mexican students (288 girls, mean age = 14.08) attending a double school shift system (287 from morning shift and 281 from afternoon shift). Students completed anonymous self-report questionnaires. Results suggest that high exposure to an electronic media device may have an impact on their sleep-wake cycle, regardless of their school shift. Adolescents from the afternoon shift reported more time spent on devices. Those from the morning shift reported daytime sleepiness with the use of MP3 player, and from the afternoon shift with the use of computer, MP3 player, and television. Both school shifts reported an intermediate chronotype with all electronic media devices, but the afternoon shift with a tendency towards eveningness with the use of the computer, smartphone, and MP3 player.