Bimodal diurnal preference in undergraduate students is associated with negative health and sleep outcomes.

The bimodal preference is a fourth diurnal preference proposed by re-scoring the Morningness-Eveningness Questionnaire. The present work aimed to describe the prevalence of the bimodal preference in a sample of undergraduate students and to characterize the bimodal type in terms of their health and sleep-related outcomes. A web-based cross-sectional study conducted between September 2018 and March 2021 (convenience sampling method). The sample was composed of undergraduate students who completed an electronic form that included the Morningness and Eveningness Questionnaire, the Pittsburgh Sleep Quality Index, the Self-Compassion Scale, the Epworth Sleepiness Scale, the Hospital Anxiety and Depression Scale, and the World Health Organization Subjective Well-Being Index. The final sample consisted of 615 students (82% female, mean age: 23.4 ± 6.5 years), of whom 108 (18%) had positive bimodality indexes. Bimodal subjects comprised 48 students, 8% of the total sample. Bimodal subjects had poorer subjective sleep quality, more daytime sleepiness, lower subjective well-being, greater anxiety and depression symptoms, and lower self-compassion than morning and/or intermediate types; they did not differ from evening types. The description of bimodal diurnal preference in this population may be of interest for the design of academic policies more in line with the circadian reality of students.

Evening chronotype predicts dropout of physical exercise: a prospective analysis.

Purpose: Eveningness preference to sleep/wake and perform physical/cognitive activities has been associated with worse health outcomes, when compared to morningness preference. Physical activity is one potential mediator that could explain this relationship; however, most of these evidences come from cross-sectional design studies. Our goal was to assess whether chronotype could predict the risk of dropout of physical exercise programs. Methods: We followed 153 newly enrolled volunteers at three different gyms, from both sexes, aged between 18 and 65 years, during 12 weeks. The daily frequency of exercises in the programs was objectively measured (gym's electronic turnstiles). Using questionnaires, we collected data of variables related to demographic characteristics, health, physical activity, sleep, anthropometric and chronobiological parameters (Morningness-Eveningness Questionnaire-MEQ). Two multivariate models were created using Cox regression analysis to test the risk of dropout of physical exercise practice. Both models accounted for age, educational level, civil status, membership plan duration, physical exercise practice frequency during week 1 and chronotype (MEQ score and chronotypes). Results: Model 1 results showed that higher MEQ score was associated with a lower chance of quitting the program (HR = 0.98; CI95% 0.95-1.00; p = 0.046). Considering the chronotypes, E-types showed the highest dropout risk compared to that of M-types (HR = 2.22; CI95% 1.09-4.52; p = 0.027). Conclusion: Our results suggest that chronotype is another variable to be considered in future studies on promoting PAs in formal environments. Likewise, the practice frequency during week 1 and duration of membership plan also deserve more attention in additional studies.

Worse sleep quality predicts early drop out from physical exercise programs.

Introduction and Objective: Sleep quality (SQ) benefits from regular physical exercise (PE) practice, but the effect of SQ over behavioral aspects of PE is not well known. In this study, we tested whether sleep variables can predict the drop out risk for PE programs during a six-week critical period for habit formation at gyms. Material and Methods: We assessed 153 volunteers, freshly enrolled at three different gyms and from both sexes, with average age of 33.6 (±11.9) years. Questionnaires provided sociodemographic, health, sleep, physical activity and circadian rhythmicity information. Daily PE practice frequency was monitored using the gym's turnstiles electronic records. We created a multivariate model using Cox regression in order to test the risk of PE program drop out during the first six weeks. Results: Worse SQ predicted a higher drop out risk (HR=1.11; 95%CI = 1.02-1.21; p<0.05), even when adjusted for other potential confounding variables. Conclusion: We found that worse SQ predicted a higher early drop out from PE programs in the formal context of gyms during the first six weeks, along with other variables related to PE practice.

Child sleep habits and maternal perception during the child's first year of life / Hábitos do sono infantil e percepção materna ao longo do primeiro ano de vida da criança

Introdução: na Introdução: Na saúde infantil, o sono desempenha um papel significativo, especialmente na maturação física e cognitiva e nas capacidades de lidar com estresse, regular emoções e socializar.Objetivo: analisar hábitos do sono infantil ao longo do primeiro ano de vida e fatores associados aos despertares noturnos segundo percepções maternas.Método: estudo longitudinal, prospectivo, com acompanhamento de 144 mães e crianças no primeiro mês, terceiro/quarto mês e 12º/13º mês de idade, de um município de médio porte do interior paulista, Brasil. Hábitos de sono foram analisados com medidas de tendência central e dispersão e testes de associação válido Qui-quadrado e Exato de Fisher, nível de significância α=0,05.Resultados: o local predominante onde as crianças dormem é o mesmo quarto e mesma cama dos cuidadores parentais. A maior parte das crianças dorme em decúbito lateral e dorsal. Tempo médio de sono foi 12,5h no primeiro mês, 11,5h no terceiro/quarto mês e 11,5h no 12º/13º mês. Tempo médio do sono noturno aumentou e sono diurno diminuiu. Do primeiro mês para o 12° mês de vida, não houve mudanças nos despertares noturnos. Percepção do sono como problema aumentou de 4% para 9% entre as participantes.Conclusão: três momentos no primeiro ano de vida trazem características dos hábitos do sono infantil, sobre local onde as crianças dormem, posição de dormir, tempo médio de sono e despertares noturnos, sugerindo a importância de informações obtidas longitudinalmente. Despertares noturnos mostraram-se associados à ocorrência do desmame e à percepção materna de considerar o sono da criança um problema.

Introduction: in children's health, sleep plays a significant role, especially in physical and cognitive maturation and in the abilities to deal with stress, regulate emotions and socialize.Objective: to analyze children's sleep habits during the first year of life and factors associated with nighttime awakenings according to maternal perceptions.Methods: a longitudinal, prospective study, with follow-up of 144 mothers and their children in the first month, third/fourth month and 12th/13th month of age, in a medium-sized city in the interior of São Paulo, Brazil. Sleep habits were analyzed using measures of central tendency and dispersion and valid association tests Chi-square and Fisher's exact, significance level α=0.05.Results: the predominant place where children sleep is the same room and bed as the parental caregivers. Most children sleep in the lateral and dorsal decubitus position. Mean sleep time was 12:30h in the first month, 11:30h in the third/fourth month and 11:24h in the 12th month. Mean nighttime sleep time increased and daytime sleep decreased. From the first month to the 12th month of life, there were no changes in nocturnal awakenings. Perception of sleep as a problem increased from 4% to 9% among participants.Conclusion: three moments in the first year of life show characteristics of children's sleep habits, about where children sleep, sleeping position, average sleep time and nocturnal awakenings, suggesting the importance of information obtained longitudinally. Nocturnal awakenings were associated with the occurrence of weaning and the maternal perception about child sleep as a problem.

Association of food intake with sleep disorders in children and adolescents with obesity.

Introduction: the great increase in childhood obesity rates is well documented in the scientific literature. However, the influence of diet on sleep quality in children and adolescents still needs further research in order to be better understood. The objective of this study was to evaluate the association between diet and sleep characteristics and in children and adolescents with obesity. Methods: observational analytical cross-sectional study with prospective data collection. Forty-three children and adolescents aged between 6 and 13 years diagnosed with obesity and treated at a public tertiary care institution participated in the study. The 6-day Food Intake Registry was used to evaluate the intake of energy and macronutrients. To investigate the risk of sleep disturbances and to know the routine and characteristics of sleeping habits, the Sleep Disturbance Scale for Children (SDSC) questionnaire was used. Results: and discussion: Food intake showed association with Sleep Breathing Disorders (SBD) and Sleep Wake Transition Disorders (SWTD). The sum of all SDSC factors demonstrated the presence of pathological sleep in most patients (n = 25).

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.

Daytime sleepiness in elementary school students: the role of sleep quality and chronotype.

OBJECTIVE: To investigate the occurrence of daytime sleepiness and associated sleep factors in a sample of elementary school students who attended school in the afternoon schedule. METHODS: Sleep data from 363 Brazilian public school students (12.78 ± 1.36 years, 206 girls) were obtained by applying questionnaires in classrooms. All subjects attended school in the afternoon schedule, with classes starting between 1:00 and 1:20 p.m. Daytime sleepiness was assessed by the pediatric daytime sleepiness scale; sleep quality, by the mini-sleep questionnaire; and sleep patterns and chronotypes, by the Munich chronotype questionnaire. Scores equal to or greater than 15 pediatric daytime sleepiness scale points were considered as excessive daytime sleepiness. The predictive power of sleep variables on daytime sleepiness was evaluated by a multiple linear regression. RESULTS: The subjects in the sample had an average time in bed greater than nine hours both on school days and on weekends. Nevertheless, 52.1% had an average pediatric daytime sleepiness scale score equal to or greater than 15 points, indicative of excessive daytime sleepiness. As for their quality of sleep, 41.1% had a very altered sleep. We observed, by a multiple linear regression, that quality of sleep (ß = 0.417), chronotype (ß = 0.174), mid-sleep on school days (ß = 0.138), and time in bed (ß = - 0.091) were all significant in predicting daytime sleepiness. CONCLUSION: This study showed the occurrence of excessive daytime sleepiness in non-sleep deprived students who attended school in the afternoon. The worst quality of sleep and eveningness had a greater predictive power on daytime sleepiness than time in bed. Therefore, we must consider other factors in addition to sleep duration when planning interventions for daytime sleepiness.

Changes in adolescents' sleep during COVID-19 outbreak reveal the inadequacy of early morning school schedules.

Objectives: The forced closure of schools during the COVID-19 outbreak imposed on adolescents a new reality of home-schooling. This new situation has affected adolescent sleep patterns due to the absence of the pressure to wake up earlier induced by school times during pandemic. This study aimed to investigate the changes in sleep and napping habits in Brazilian adolescents during the COVID-19 outbreak. Methods: A sample of 259 high school adolescents (mean age = 15.5 years) reported sleep and napping habits by means validated questionnaires in both baseline year (March-June 2019) and during COVID-19 lockdown (July 2020). Results: The tendency to eveningness was higher and daytime sleepiness was reduced during the social isolation. Time in bed (TIB) increased by more than 2 hours and sleep onset time was delayed during the pandemic. More adolescents reported getting enough TIB during the pandemic. Moreover, sleepiness during remote classes was reduced compared to that reported during traditional classes one year before. The nap habit decreased during the pandemic compared to the baseline year. Discussion: The lack of early wake-up pressure to attend school in the morning could explain the sleep improvements perceived during the COVID-19 outbreak. Therefore, parents, educators, and policy makers need to discuss more feasible school times for adolescents in order to implement these changes as soon as returning to presential/hybrid learning.

Daytime sleepiness in elementary school students: the role of sleep quality and chronotype

ABSTRACT OBJECTIVE To investigate the occurrence of daytime sleepiness and associated sleep factors in a sample of elementary school students who attended school in the afternoon schedule. METHODS Sleep data from 363 Brazilian public school students (12.78 ± 1.36 years, 206 girls) were obtained by applying questionnaires in classrooms. All subjects attended school in the afternoon schedule, with classes starting between 1:00 and 1:20 p.m. Daytime sleepiness was assessed by the pediatric daytime sleepiness scale; sleep quality, by the mini-sleep questionnaire; and sleep patterns and chronotypes, by the Munich chronotype questionnaire. Scores equal to or greater than 15 pediatric daytime sleepiness scale points were considered as excessive daytime sleepiness. The predictive power of sleep variables on daytime sleepiness was evaluated by a multiple linear regression. RESULTS The subjects in the sample had an average time in bed greater than nine hours both on school days and on weekends. Nevertheless, 52.1% had an average pediatric daytime sleepiness scale score equal to or greater than 15 points, indicative of excessive daytime sleepiness. As for their quality of sleep, 41.1% had a very altered sleep. We observed, by a multiple linear regression, that quality of sleep (β = 0.417), chronotype (β = 0.174), mid-sleep on school days (β = 0.138), and time in bed (β = - 0.091) were all significant in predicting daytime sleepiness. CONCLUSION This study showed the occurrence of excessive daytime sleepiness in non-sleep deprived students who attended school in the afternoon. The worst quality of sleep and eveningness had a greater predictive power on daytime sleepiness than time in bed. Therefore, we must consider other factors in addition to sleep duration when planning interventions for daytime sleepiness.

Chronic sleep restriction triggers inadequate napping habits in adolescents: a population-based study.

BACKGROUND: The prevalence of chronic sleep restriction during adolescence is a major public health issue. Napping has been adopted to alleviate sleep pressure complaints. However, it also has the potential to amplify sleep restriction due to a vicious cycle triggered by delayed sleep times. The aim of this study was to investigate sleep and napping habits in a sample of Brazilian adolescents. METHODS: This study enrolled 1554 high school students and included the evaluation of sleep times, daytime sleepiness, sleep quality, and circadian preference. The students were asked about their napping routine, ie its frequency and duration per week. RESULTS: The adolescent sleep recommendation was achieved by only 27.6% of the sample. Napping habit was reported by 58.1%, with 36.2% of nappers informing naps in 1-2 times per week. Prolonged naps were reported by 44.9% of nappers. Nappers had later median bedtime (23:30) and reduced time in bed (TIB) (median = 07:00 h) compared to non-nappers. The frequency of nappers who did not achieve satisfactory TIB was higher than non-nappers. In addition, nappers reported increased daytime sleepiness and poor sleep quality. Later bedtimes and reduced TIB were associated with longer nap duration. Increased sleepiness and poor sleep quality were linked to a higher nap frequency. CONCLUSIONS: This exploratory survey demonstrated a severe sleep restriction faced by Brazilian adolescents. Napping can be an efficient strategy to counteract sleep restriction, but it needs to be adopted with caution due to the detrimental effects of frequent and prolonged naps on nocturnal sleep.