Behavioral Intervention that Extends Sleep Duration Leads to Greater Self-Control in School-Aged Children.

OBJECTIVE: Short sleep and evening phase preference associate with impaired self-control, yet few studies have assessed the efficacy of sleep extension for improving this behavioral domain. Thus, this secondary analysis of a behavioral sleep intervention measured whether an intervention that enhanced children's sleep also affected self-control. Differences by chronotype were also explored. METHODS: Sixty-seven children (8-11 yr), who reportedly slept <9.5 hr/d, were randomized to either a control or sleep intervention condition (i.e., 4-session behavioral intervention to enhance sleep by 1-1.5 hr/night). Chronotype was assessed using the Child Chronotype Questionnaire at baseline, and self-control was assessed using the Self-Control Rating Scale (SCRS, a caregiver report) at baseline and 8 weeks postrandomization. Total sleep time (TST) was measured using wrist actigraphy for 1 week at both baseline and 8 weeks postrandomization. Partial correlations and mixed-model ANOVAs were used for statistical analyses, with age as a covariate. RESULTS: At baseline, children with shorter TST (r = -0.29, p = 0.02) and an evening preference (r = 0.26, p = 0.049) were perceived as having lower self-control by their caregivers. Significant condition*time interaction effects were found for TST (p < 0.001) and SCRS score (p = 0.046): From baseline to follow-up, children randomized to the sleep intervention exhibited a significant increase in TST and were perceived as having greater self-control by their caregiver; children randomized to the control condition exhibited no change in TST or in SCRS score. The condition*chronotype*time interaction effect was not significant. CONCLUSION: A brief sleep intervention that enhanced TST also resulted in enhanced caregiver reported self-control in school-age children. Results add to the growing evidence for the importance of sleep health in children.

Dose-dependent Relationships of Same-day and Typical Substance Use to Sleep Duration in College Cannabis and Alcohol Users: A Multilevel Modeling Approach Using Daily Diary Data.

This study characterized how quantities of cannabis and alcohol use affect sleep. Single-day and typical cannabis and alcohol use patterns were considered to assess acute-chronic use interactions. Linear and non-linear associations assessed dose-dependence. College students (n=337; 52% female) provided 11,417 days of data, with up to five time points per day. Daily self-reported sleep duration, cannabis use quantity, and alcohol use quantity were subjected to linear mixed modeling to capture linear and curvilinear associations between single-day and typical use on same-night and typical sleep. Sleep duration (difference between bedtime and waketime) was the outcome. Quantity of cannabis used each day andtypical quantity used across all days were predictors in the cannabis models. Parallel single-day and typical alcohol variables were predictors in the alcohol models. Follow-up analyses excluded days with alcohol-cannabis co-use. Main effects of single-day and typical cannabis quantity on sleep duration were observed when all cannabis-use days were modeled. Higher than typical doses of single-day and typical cannabis were associated with longer sleep durations, but only to a point; at the highest doses, cannabis shortened sleep. A main effect of single-day alcohol quantity and two interactions (single-day use with both linear and curvilinear typical use) on sleep duration were observed when all alcohol-use days were modeled. Greater alcohol consumption on a given day led to shorter same-night sleep, but typically heavier drinkers required higher doses than typically lighter drinkers to experience these adverse effects. Follow-up models suggested alcohol co-use may contribute to the purported sleep-promoting effects of cannabis.

The Role of Meeting Exercise and Nutrition Guidelines on Sleep during Pregnancy.

Sleep disturbances are common during pregnancy. This study determined whether meeting physical activity or dietary guidelines during pregnancy was associated with improved sleep. Third trimester pregnant women (n = 49, 31.9 ± 4.1 years) completed physical activity and sleep questionnaires and then wore a wrist actigraph 24 h/day and completed three 24 h dietary recalls across two weeks. Participants who reported meeting physical activity guidelines (>150 min moderate-to-vigorous physical activity [MVPA]/week, n = 23) or dietary guidelines (≥1.1 g protein/kg body weight/day, n = 26 or ≥25 g fiber/day, n = 16) were compared to those who were physically inactive (<90 min/week) or did not meet dietary guidelines, respectively. Multivariate ANOVAs and Mann-Whitney U tests compared groups and correlations were conducted between physical activity, diet, and sleep variables. Physical activity groups did not differ in objective sleep measures (ps > 0.05); however, the active group reported better sleep quality (p = 0.049). Those who met protein guidelines exhibited longer sleep duration and less wake-after-sleep-onset (ps < 0.05). Across all participants, higher weekly MET mins/week of MVPA associated with better sleep quality (p = 0.02), and a diet higher in fat and lower in carbohydrates associated with longer sleep duration (ps < 0.05). Meeting physical activity and nutrition guidelines positively associates with improved sleep, with protein associated with objective measures and physical activity with subjective measures.

Pediatric sleep: current knowledge, gaps, and opportunities for the future.

This White Paper addresses the current gaps in knowledge, as well as opportunities for future studies in pediatric sleep. The Sleep Research Society's Pipeline Development Committee assembled a panel of experts tasked to provide information to those interested in learning more about the field of pediatric sleep, including trainees. We cover the scope of pediatric sleep, including epidemiological studies and the development of sleep and circadian rhythms in early childhood and adolescence. Additionally, we discuss current knowledge of insufficient sleep and circadian disruption, addressing the neuropsychological impact (affective functioning) and cardiometabolic consequences. A significant portion of this White Paper explores pediatric sleep disorders (including circadian rhythm disorders, insomnia, restless leg and periodic limb movement disorder, narcolepsy, and sleep apnea), as well as sleep and neurodevelopment disorders (e.g. autism and attention deficit hyperactivity disorder). Finally, we end with a discussion on sleep and public health policy. Although we have made strides in our knowledge of pediatric sleep, it is imperative that we address the gaps to the best of our knowledge and the pitfalls of our methodologies. For example, more work needs to be done to assess pediatric sleep using objective methodologies (i.e. actigraphy and polysomnography), to explore sleep disparities, to improve accessibility to evidence-based treatments, and to identify potential risks and protective markers of disorders in children. Expanding trainee exposure to pediatric sleep and elucidating future directions for study will significantly improve the future of the field.

Insulin Sensitivity and Metabolic Flexibility Parallel Plasma TCA Levels in Early Chronotype With Metabolic Syndrome.

CONTEXT: People characterized as late chronotype have elevated type 2 diabetes and cardiovascular disease risk compared to early chronotype. It is unclear how chronotype is associated with insulin sensitivity, metabolic flexibility, or plasma TCA cycle intermediates concentration, amino acids (AA), and/or beta-oxidation. OBJECTIVE: This study examined these metabolic associations with chronotype. METHODS: The Morningness-Eveningness Questionnaire (MEQ) was used to classify adults with metabolic syndrome (ATP III criteria) as either early (n = 15 [13F], MEQ = 64.7 ±â€…1.4) or late (n = 19 [16F], MEQ = 45.5 ±â€…1.3) chronotype. Fasting bloods determined hepatic (HOMA-IR) and adipose insulin resistance (Adipose-IR) while a 120-minute euglycemic clamp (40 mU/m2/min, 5 mmoL/L) was performed to test peripheral insulin sensitivity (glucose infusion rate). Carbohydrate (CHOOX) and fat oxidation (FOX), as well as nonoxidative glucose disposal (NOGD), were also estimated (indirect calorimetry). Plasma tricarboxylic acid cycle (TCA) intermediates, AA, and acyl-carnitines were measured along with VO2max and body composition (DXA). RESULTS: There were no statistical differences in age, BMI, fat-free mass, VO2max, or ATP III criteria between groups. Early chronotype, however, had higher peripheral insulin sensitivity (P = 0.009) and lower HOMA-IR (P = 0.02) and Adipose-IR (P = 0.05) compared with late chronotype. Further, early chronotype had higher NOGD (P = 0.008) and greater insulin-stimulated CHOOX (P = 0.02). While fasting lactate (P = 0.01), TCA intermediates (isocitrate, α-ketoglutarate, succinate, fumarate, malate; all P ≤ 0.04) and some AA (proline, isoleucine; P = 0.003-0.05) were lower in early chronotype, other AA (threonine, histidine, arginine; all P ≤ 0.05) and most acyl-carnitines were higher (P ≤ 0.05) compared with late chronotype. CONCLUSION: Greater insulin sensitivity and metabolic flexibility relates to plasma TCA concentration in early chronotype.

Effect of changes in children's bedtime and sleep period on targeted eating behaviors and timing of caloric intake.

Short sleep is associated with obesity risk. Experimental studies with adults and observational studies with children demonstrate that changes in eating, including increased caloric intake from energy-dense foods and sugar-sweetened beverages as well as increased caloric intake in the evening, may partially account for this increased risk. We therefore examined whether experimental changes in children's sleep period lead to changes in reported caloric intake from energy-dense snack foods and sugar-sweetened beverages, and in the evening. Thirty-seven children, 8-11 years old, completed a three-week study that used a within-subject randomized cross-over design. Children slept their typical amount for one week and were subsequently randomized to either increase or decrease their typical amount by 1.5 h/night for one week; the alternate schedule was completed during the third week of the study, creating a 3-h time in bed difference between the increase and decrease conditions. Sleep was monitored with actigraphy, and dietary intake was assessed with 24-hour dietary recalls. Participants reported consuming 35 kcal per day more from sugar-sweetened beverages during the decrease sleep than the increase sleep condition, p = .033. There were no reported differences between conditions from energy-dense snack foods. Although no differences in reported intake were observed earlier in the day, from 2000 h (8:00 PM) and later, children reported consuming 132 kcal more during the decrease sleep condition than the increase condition, p < 0.001. Shortened sleep achieved by delaying bedtimes led to increased caloric intake in the evening and from sugar-sweetened beverages. Clinical Trials Registration: clinicaltrials.gov Identifier: NCT01030107.

Role of Blood Pressure Responses to Exercise and Vascular Insulin Sensitivity with Nocturnal Blood Pressure Dipping in Metabolic Syndrome.

INTRODUCTION: Nocturnal systolic blood pressure (SBP) dipping is independently related to cardiovascular disease risk, but it is unclear if vascular insulin sensitivity associates with SBP dipping in patients with metabolic syndrome (MetS). METHODS: Eighteen adults with MetS (ATP III criteria 3.3 ± 0.6; 53.2 ± 6.5 years; body mass index 35.8 ± 4.5 kg/m2) were categorized as "dippers" (≥10% change in SBP; n = 4 F/3 M) or "non-dippers" (<10%; n = 9 F/2 M). Twenty-four-hour ambulatory blood pressure was recorded to assess SBP dipping. A euglycemic-hyperinsulinemic clamp (40 mU/m2/min, 90 mg/dL) with ultrasound (flow mediated dilation) was performed to test vascular insulin sensitivity. A graded, incremental exercise test was conducted to estimate sympathetic activity. Heart rate (HR) recovery after exercise was then used to determine parasympathetic activity. Metabolic panels and body composition (DXA) were also tested. RESULTS: Dippers had greater drops in SBP (16.63 ± 5.2 vs. 1.83 ± 5.6%, p < 0.01) and experienced an attenuated rise in both SBPslope (4.7 ± 2.3 vs. 7.2 ± 2.5 mm Hg/min, p = 0.05) and HRslope to the incremental exercise test compared to non-dippers (6.5 ± 0.9 vs. 8.2 ± 1.7 bpm/min, p = 0.03). SBP dipping correlated with higher insulin-stimulated flow-mediated dilation (r = 0.52, p = 0.03), although the relationship was no longer significant after covarying for HRslope (r = 0.42, p = 0.09). CONCLUSION: Attenuated rises in blood pressure and HR to exercise appear to play a larger role than vascular insulin sensitivity in SBP dipping in adults with MetS.

Gender Differences in the Relationship Between Exercise, Sleep, and Mood in Young Adults.

Insufficient sleep is a serious public health problem in college students. Exercise is a widely prescribed behavioral treatment for sleep and mood issues; however, more focused and gender-specific prescriptions are needed. The present study examined relationships between exercise, sleep, and mood in undergraduate men and women. Students (N = 866, 19.6 ± 1.4 years, 38.7% women) were recruited from campus recreation facilities and completed demographic, the Pittsburgh Sleep Quality Index, mood (Patient-Reported Outcomes Measurement Information System), and exercise questionnaires. The Department of Health and Human Services Physical Activity Guidelines were used to dichotomize those who did and did not meet weekly aerobic and strength training exercise recommendations. In men, greater exercise frequency associated with less daytime dysfunction (ß = 0.147) and less depressive mood (ß = -0.64, ps < .05). In women, greater exercise frequency associated with earlier bedtime (ß = -12.6), improved sleep quality (ß = 0.17), increased positive affect (ß = 0.91), less depressive mood (ß = -0.71), and less anger (ß = -1.24, ps < .05). Compared to men, women reported earlier bedtime, poorer sleep efficiency, and more anxiety and depressive mood (ps < .05, ηp2 range: 0.01-0.04). Compared to individuals who met physical activity guidelines, those who did not meet the guidelines reported later bedtimes, less positive affect, more anxiety, and more anger (ps < .05 ηp2s = 0.01). Among men, those who met physical activity guidelines reported falling asleep more quickly than those who did not meet guidelines (ηp2 = 0.01, p = .007); however, no relationship between guideline adherence and sleep latency was observed in women. Adhering to physical activity guidelines may be important for optimal sleep and emotional health. Clinicians should consider gender when creating exercise prescriptions for sleep issues.

Randomized controlled trial to enhance children's sleep, eating, and weight.

BACKGROUND: The present study assessed the efficacy of a behavioral intervention to enhance children's sleep and reduce caloric intake and body mass index (BMI) change. METHODS: Seventy-eight children 8-11 years old who slept 9.5 h/night or less were randomized to the sleep intervention or to no treatment control. The primary outcome was 2-month change in the actigraph-estimated sleep period; changes in reported caloric intake, percent calories from fat, and BMI/BMI z-score (BMIz) were assessed. RESULTS: Children randomized to intervention enhanced their sleep period by 40 ± 7 min/night relative to control (p < 0.001), and were more likely to increase their sleep period by 30 min/night or more (52% versus 15%, p = 0.003). No differences were observed for reported dietary intake or BMI/BMIz. However, in post-hoc analyses collapsing across groups, those who increased sleep by 30 min/night or more had lower BMI (-0.31 kg/m2, p = 0.01) and BMIz (-0.07, p = 0.03) and reported fewer percent calories from fat at 2 months (-2.2%, p = 0.04). CONCLUSIONS: A brief behavioral intervention can enhance children's sleep, but did not result in changes in caloric intake or weight status. Enhancing sleep by 30 min/night or more may be beneficial for weight regulation. IMPACT: A brief behavioral intervention improved children's nocturnal sleep relative to no treatment control. Given the many benefits of a good night's sleep across domains of functioning, findings have significant implications for children's health and wellbeing. There were no differences between groups on eating behaviors or BMI. However, across groups, children who increased their sleep period by at least 30 min/night, reported reduced intake from fat and evidenced lower BMI at 2 months. Thus, a brief intervention can improve sleep and may have potential benefits for weight regulation.

Considerations for Maximizing the Exercise "Drug" to Combat Insulin Resistance: Role of Nutrition, Sleep, and Alcohol.

Insulin resistance is a key etiological factor in promoting not only type 2 diabetes mellitus but also cardiovascular disease (CVD). Exercise is a first-line therapy for combating chronic disease by improving insulin action through, in part, reducing hepatic glucose production and lipolysis as well as increasing skeletal muscle glucose uptake and vasodilation. Just like a pharmaceutical agent, exercise can be viewed as a "drug" such that identifying an optimal prescription requires a determination of mode, intensity, and timing as well as consideration of how much exercise is done relative to sitting for prolonged periods (e.g., desk job at work). Furthermore, proximal nutrition (nutrient timing, carbohydrate intake, etc.), sleep (or lack thereof), as well as alcohol consumption are likely important considerations for enhancing adaptations to exercise. Thus, identifying the maximal exercise "drug" for reducing insulin resistance will require a multi-health behavior approach to optimize type 2 diabetes and CVD care.

The Insomnia-Addiction Positive Feedback Loop: Role of the Orexin System.

Significant sleep impairments often accompany substance use disorders (SUDs). Sleep disturbances in SUD patients are associated with poor clinical outcomes and treatment adherence, emphasizing the importance of normalizing sleep when treating SUDs. Orexins (hypocretins) are neuropeptides exclusively produced by neurons in the posterior hypothalamus that regulate various behavioral and physiological processes, including sleep-wakefulness and motivated drug taking. Given its dual role in sleep and addiction, the orexin system represents a promising therapeutic target for treating SUDs and their comorbid sleep deficits. Here, we review the literature on the role of the orexin system in sleep and drug addiction and discuss the therapeutic potential of orexin receptor antagonists for SUDs. We argue that orexin receptor antagonists may be effective therapeutics for treating addiction because they target orexin's regulation of sleep (top-down) and motivation (bottom-up) pathways.

Determinants of postpartum sleep duration and sleep efficiency in minority women.

STUDY OBJECTIVES: To examine demographic, psychosocial, and behavioral determinants of postpartum sleep duration and sleep efficiency among a cohort of black and Latina women. METHODS: Data were from 148 women (67% black, 32% Latina) at 5 months postpartum, recruited from an academic medical center in Philadelphia. Relevant demographic, psychosocial and behavioral predictors were assessed via questionnaire. Nocturnal sleep was objectively measured for 1 week using wrist actigraphy. Sleep duration was examined as a continuous variable and in categories (<7 versus ≥7 h per night); sleep efficiency was examined as a continuous variable. Independent multiple linear regression models were built to evaluate significant determinants of sleep. RESULTS: Adjusted models revealed that breastfeeding, having a bedtime after midnight, and being employed were associated with shorter sleep duration (-25-33 min, all p < 0.05). Multiparity, being unmarried, being employed, breastfeeding, having a bedtime after midnight, bedsharing, and responding to infant awakenings by getting up immediately rather than waiting a few minutes to see if the infant fell back asleep, were all significant determinants of sleeping <7 h per night (OR varying: 2.29-4.59, all p < 0.05). Bedsharing was the only variable identified from the multiple regression model that associated with poorer sleep efficiency (-3.8%, p < 0.05). CONCLUSIONS: Findings may inform interventions for improving postpartum sleep in socioeconomically disadvantaged, racial/ethnic minority postpartum women.

Relationships between sleep, exercise timing, and chronotype in young adults.

To examine the relationships between exercise timing, chronotype, sleep, and mood, college students (N = 909, 19.6 ± 1.4 years, 38% female) completed questionnaires immediately after exercising. Evening exercisers had later bedtimes, poorer sleep quality, and lower sleep efficiency compared to morning exercisers. Evening chronotypes reported poorer sleep quality, greater daytime dysfunction, and less positive affect compared to morning/neither chronotypes. Chronotype moderated the relationship between exercise timing and bedtime; with each minute delay in exercise timing, bedtime was delayed by 6.1 minutes in morning-types and only 3.6 minutes in evening-types. University health initiatives should target evening exercisers to mitigate the consequences of prolonged insufficient sleep.

Prolonged, Controlled Daytime versus Delayed Eating Impacts Weight and Metabolism.

A delayed eating schedule is associated with increased risk of obesity and metabolic dysfunction in humans.1-9 However, there are no prolonged, highly controlled experimental studies testing the effects of meal timing on weight and metabolism in adults with a body mass index (BMI) of 19-27 kg/m2.10-18 Twelve healthy adults (age: 26.3 ± 3.4 years; BMI: 21.9 ± 1.7 kg/m2; 5 females) participated in a randomized crossover study in free-living conditions. Three meals and two snacks with comparable energy and macronutrient contents were provided during two, 8-week, counterbalanced conditions separated by a 2-week washout period: (1) daytime (intake limited to 0800 h-1900 h) and (2) delayed (intake limited to 1200 h-2300 h). Sleep-wake cycles and exercise levels were held constant. Weight, adiposity, energy expenditure, and circadian profiles of hormones and metabolites were assessed during four inpatient visits occurring before and after each condition. Body weight, insulin resistance (homeostatic model assessment of insulin resistance [HOMA-IR]), trunk-to-leg fat ratio, resting energy expenditure, respiratory quotient, and fasting glucose, insulin, total and high-density lipoprotein (dHDL) cholesterol, and adiponectin decreased on the daytime compared to the delayed schedule. These measures, as well as triglycerides, increased on the delayed compared to the daytime schedule (effect size range: d = 0.397-1.019). Circadian phase and amplitude of melatonin, cortisol, ghrelin, leptin, and glucose were not differentially altered by the eating schedules. Overall, an 8-week daytime eating schedule, compared to a delayed eating schedule, promotes weight loss and improvements in energy metabolism and insulin in adults with BMI 19-27 kg/m2, underscoring the efficacy and feasibility of daytime eating as a behavioral modification for real-world conditions.

Caloric and Macronutrient Intake and Meal Timing Responses to Repeated Sleep Restriction Exposures Separated by Varying Intervening Recovery Nights in Healthy Adults.

Sleep restriction (SR) reliably increases caloric intake. It remains unknown whether such intake cumulatively increases with repeated SR exposures and is impacted by the number of intervening recovery sleep opportunities. Healthy adults (33.9 ± 8.9y; 17 women, Body Mass Index: 24.8 ± 3.6) participated in a laboratory protocol. N = 35 participants experienced two baseline nights (10 h time-in-bed (TIB)/night; 22:00-08:00) followed by 10 SR nights (4 h TIB/night; 04:00-08:00), which were divided into two exposures of five nights each and separated by one (n = 13), three (n = 12), or five (n = 10) recovery nights (12 h TIB/night; 22:00-10:00). Control participants (n = 10) were permitted 10 h TIB (22:00-08:00) on all nights. Food and drink consumption were ad libitum and recorded daily. Compared to baseline, sleep-restricted participants increased daily caloric (+527 kcal) and saturated fat (+7 g) intake and decreased protein (-1.2% kcal) intake during both SR exposures; however, intake did not differ between exposures or recovery conditions. Similarly, although sleep-restricted participants exhibited substantial late-night caloric intake (671 kcal), such intake did not differ between exposures or recovery conditions. By contrast, control participants showed no changes in caloric intake across days. We found consistent caloric and macronutrient intake increases during two SR exposures despite varying intervening recovery nights. Thus, energy intake outcomes do not cumulatively increase with repeated restriction and are unaffected by recovery opportunities.

Test-retest reliability of cerebral blood flow for assessing brain function at rest and during a vigilance task.

Arterial spin labeled (ASL) perfusion magnetic resonance imaging (MRI) is increasingly used to assess regional brain activity and cerebrovascular function in both healthy and clinical populations. ASL perfusion imaging provides a quantitative measure of regional brain activity by determining absolute cerebral blood flow (CBF) values at a resting state or during task performance. However, the comparative reliability of these ASL measures is not well characterized. It is also unclear whether the test-retest reliability of absolute CBF or task-induced CBF change measures would be comparable to the reliability of task performance. In this study, fifteen healthy participants were scanned three times in a strictly controlled in-laboratory study while at rest and during performing a simple and reliable psychomotor vigilance test (PVT). The reliability of absolute CBF and task-induced CBF changes was evaluated using the intraclass correlation coefficient (ICC) and compared to that of task performance. Absolute CBF showed excellent test-retest reliability across the three scans for both resting and PVT scans. The reliability of regional absolute CBF was comparable to that of behavioral measures of PVT performance, and was slightly higher during PVT scans as compared with resting scans. Task-induced regional CBF changes demonstrated only poor to moderate reliability across three scans. These findings suggest that absolute CBF measures are more reliable than task-induced CBF changes for characterizing regional brain function, especially for longitudinal and clinical studies.

Sleep, energy balance, and meal timing in school-aged children.

OBJECTIVE: To determine associations among objectively-measured nocturnal sleep time, bedtime and obesogenic behaviors, including dietary intake, timing of intake, and physical activity, in a diverse sample of school-aged children who presented for behavioral treatment to enhance sleep duration. METHODS: Eighty-seven children (8-11 y, 66.7% female, zBMI: 0.86 ± 1.0) who self-reported sleeping <9.5 h/night were studied for one week using wrist actigraphy to estimate sleep; hip-worn accelerometers to measure physical activity; and 24 h dietary recalls to capture dietary intake and meal timing. Pearson and Spearman's rho correlations and linear regressions controlling for age, gender and race were used for statistical analyses. RESULTS AND CONCLUSION: Mean bedtime was 10:31 PM (±58.2 min) and mean nocturnal sleep time was 7.7 h (±37.5 min). Although later bedtime was associated with shorter sleep time (r = -0.61, p < 0.001), the two variables were differentially related to obesity risk factors. Later bedtime, but not sleep time, correlated with greater daily fat intake, later first meal of the day, and greater after-dinner intake (all p < 0.05). Nocturnal sleep time, but not bedtime, correlated with zBMI (p = 0.04). Both sleep time and later bedtime were associated with a later last meal of the day (all p < 0.05). Findings remained consistent after controlling for demographic factors. In short-sleeping school-aged children, bedtime may be more predictive of dietary obesity risk factors whereas sleep duration may be more predictive of zBMI. Results suggest that health providers should consider both bedtime and sleep duration for reducing obesity risk in children. CLINICAL TRIAL: Enhancing Sleep Duration: Effects on Children's Eating and Activity Behaviors, NCT03186508, https://clinicaltrials.gov/ct2/show/NCT03186508.

Influence of Sleep Duration on Postpartum Weight Change in Black and Hispanic Women.

OBJECTIVE: The primary purpose of this study was to examine associations of objectively measured sleep duration with weight changes in black and Hispanic mothers over the first postpartum year. METHODS: Data were from 159 mothers (69% black, 32% Hispanic). Nocturnal sleep duration was assessed using wrist actigraphy at 6 weeks and 5 months post partum, examined as a continuous variable and in categories (< 7 vs. ≥ 7 hours/night, consistent with American Academy of Sleep Medicine recommendations). Body weights were abstracted from medical records in pregnancy and measured at 6 weeks, 5 months, and 12 months post partum. Outcomes included early postpartum (6 weeks to 5 months) and late postpartum (5 to 12 months) weight changes. RESULTS: The majority of participants slept < 7 hours/night at 6 weeks (75%) and 5 months (63%) post partum. Early postpartum weight change did not differ by 6-week sleep duration category. By contrast, adjusted average late postpartum weight gain (SE) was 1.8 (0.7) kg higher in participants sleeping < 7 hours/night at 5 months post partum compared with those sleeping ≥ 7 hours/night (P = 0.02). Results did not show statistically significant associations of continuous measures of sleep duration, nor of measures of sleep quality, with postpartum weight changes. CONCLUSIONS: Sleeping < 7 hours/night was associated with late postpartum weight gain in minority mothers.

Objective Measurements of Energy Balance Are Associated With Sleep Architecture in Healthy Adults.

Study Objectives: We objectively measured body composition, energy expenditure, caloric intake, and sleep in a large, diverse sample of healthy men and women and determined how energy balance and diet associated with sleep physiology. Methods: Healthy adults (n = 50; 21-50 years) participated in an in-laboratory study involving two baseline sleep nights (BL1-2, 10 hours time-in-bed/night, 2200-0800 hours). Polysomnography was recorded on BL2. Demographic information, body composition, and energy expenditure measurements were collected at study admittance and on BL1. Daily food/drink intake was recorded both before (on BL1) and after (on BL2) the sleep measurement. Partial Pearson's correlations assessed the relationship between energy balance and sleep physiology variables. Results: At baseline, greater fat-free mass associated with lower total sleep time (r = -0.52, p = .030), lower sleep efficiency (r = -0.53, p = .004), and greater wake after sleep onset (r = 0.55, p = .002). Higher body fat percentage (r = 0.39, p = .038) and being overweight (Body Mass Index [BMI] 25-30; p = .026) associated with more rapid eye movement (REM) sleep. Higher protein intake (r's = 0.46-0.52; p's < .001-.002) and lower carbohydrate intake (r's = -0.31 to -0.34; p's = .027-.046) on BL1 and BL2 associated with more REM sleep. Greater fiber consumption on BL1 and BL2 associated with more slow-wave sleep (SWS; r's = 0.33-0.35; p's = .02-.03). More SWS related to increased carbohydrate intake the following day (BL2, r = 0.32, p = .037). Conclusions: Body composition and diet were related to baseline sleep characteristics, including SWS and REM sleep duration and sleep maintenance. Future studies should further evaluate the influence of energy balance measures on sleep physiology, since dietary interventions may be useful in treating insufficient sleep, poor sleep quality, excessive sleepiness or other sleep disorders.