Relations among hypnagogic and hypnopompic experiences associated with sleep paralysis

The Waterloo Sleep Experiences Scale was developed to assess the prevalence of sleep paralysis and a variety of associated hypnagogic and hypnopompic hallucinoid experiences: sensed presence, felt pressure, floating sensations, auditory and visual hallucinations, and fear. Consistent with results of recent surveys, almost 30% of 870 university students reported at least one experience of sleep paralysis. Approximately three-quarters of those also reported at least one hallucinoid experience, and slightly more than 10% experienced three or more. Fear was positively associated with hallucinoid experiences, most clearly with sensed presence. Regression analyses lend support to the hypothesis that sensed presence and fear are primitive associates of sleep paralysis and contribute to the elaboration of further hallucinoid experiences, especially those involving visual experiences.     

Sleep paralysis episode frequency and number, types, and structure of associated hallucinations

Sleep paralysis (SP) episodes are often accompanied by vivid hallucinoid experiences that have been found to fall into three major categories thought to be organized according to intrinsic rapid eye movement (REM) processes. Prior research has, however, combined data for individuals with varying degrees of experience with SP episodes, rendering interpretations of the source of this structure ambiguous. The present study of 5799 current SP experients compares the nature and structure of the hallucinations of novice SP experients with those reporting varying numbers of episodes. Both qualitative and quantitative differences were found in reported hallucinations as a function of episode frequency, although the underlying three-factor structure of the hallucinoid experiences was highly similar for all groups. Novice experients' reports were, however, characterized by clearer differentiation of factors, likely because of a tendency of experienced SP experients to conflate experiences across episodes. Age and age of onset of SP episodes were associated with differences in the variety and types of hallucinations but not their underlying structure. Earlier onset of SP episodes was also associated with more frequent episodes. The results are consistent with the hypothesis that the basic form and patterning of hallucinatory experiences is a result of intrinsic processes, independent of prior experience, likely associated with underlying REM neurophysiology.     

'The devil lay upon her and held her down'. Hypnagogic hallucinations and sleep paralysis described by the Dutch physician Isbrand van Diemerbroeck (1609-1674) in 1664

Hypnagogic and hypnopompic hallucinations are visual, tactile, auditory or other sensory events, usually brief but sometimes prolonged, that occur at the transition from wakefulness to sleep (hypnagogic) or from sleep to wakefulness (hypnopompic). Hypnagogic and hypnopompic hallucinations are often associated with sleep paralysis. Sleep paralysis occurs immediately prior to falling asleep (hypnagogic paralysis) or upon waking (hypnopompic paralysis). In 1664, the Dutch physician Isbrand Van Diemerbroeck (1609-1674) published a collection of case histories. One history with the title 'Of the Night-Mare' describes the nightly experiences of the 50-year-old woman. This case report is subject of this article. The experiences in this case could without doubt be diagnosed as sleep paralysis accompanied by hypnagogic hallucinations. This case from 1664 should be cited as the earliest detailed account of sleep paralysis associated with hypnagogic illusions and as the first observation that sleep paralysis and hypnagogic experiences occur more often in supine position of the body.     

Isolated sleep paralysis and fearful isolated sleep paralysis in outpatients with panic attacksb

Isolated sleep paralysis (ISP) has received scant attention in clinical populations, and there has been little empirical consideration of the role of fear in ISP episodes. To facilitate research and clinical work in this area, the authors developed a reliable semistructured interview (the Fearful Isolated Sleep Paralysis Interview) to assess ISP and their proposed fearful ISP (FISP) episode criteria in 133 patients presenting for panic disorder treatment. Of these, 29.3% met lifetime ISP episode criteria, 20.3% met the authors' lifetime FISP episode criteria, and 12.8% met their recurrent FISP criteria. Both ISP and FISP were associated with minority status and comorbidity. However, only FISP was significantly associated with posttraumatic stress disorder, body mass, anxiety sensitivity, and mood and anxiety disorder symptomatology. © 2010 Wiley Periodicals, Inc. J Clin Psychol 66:1–15, 2010.     

Experience-dependent induction of hypnagogic images during daytime naps: a combined behavioural and EEG study

This study characterizes hypnagogic hallucinations reported during a polygraphically recorded 90‐min daytime nap following or preceding practice of the computer game Tetris. In the experimental group (N = 16), participants played Tetris in the morning for 2 h during three consecutive days, while in a first control group (N = 13, controlling the effect of experience) participants did not play any game, and in a second control group (N = 14, controlling the effect of anticipation) participants played Tetris after the nap. During afternoon naps, participants were repetitively awakened 15, 45, 75, 120 or 180 s after the onset of S1, and were asked to report their mental content. Reports content was scored by three judges (inter‐rater reliability 85%). In the experimental group, 48 out of 485 (10%) sleep‐onset reports were Tetris‐related. They mostly consisted of images and sounds with very little emotional content. They exactly reproduced Tetris elements or mixed them with other mnemonic components. By contrast, in the first control group, only one report out of 107 was scored as Tetris‐related (1%), and in the second control group only three reports out of 112 were scored as Tetris‐related (3%; between‐groups comparison; P = 0.006). Hypnagogic hallucinations were more consistently induced by experience than by anticipation (P = 0.039), and they were predominantly observed during the transition of wakefulness to sleep. The observed attributes of experience‐related hypnagogic hallucinations are consistent with the particular organization of regional brain activity at sleep onset, characterized by high activity in sensory cortices and in the default‐mode network.     

A twin and molecular genetics study of sleep paralysis and associated factors

Sleep paralysis is a relatively common but under‐researched phenomenon. In this paper we examine prevalence in a UK sample and associations with candidate risk factors. This is the first study to investigate the heritability of sleep paralysis in a twin sample and to explore genetic associations between sleep paralysis and a number of circadian expressed single nucleotide polymorphisms. Analyses are based on data from the Genesis1219 twin/sibling study, a community sample of twins/siblings from England and Wales. In total, data from 862 participants aged 22–32 years (34% male) were used in the study. This sample consisted of monozygotic and dizygotic twins and siblings. It was found that self‐reports of general sleep quality, anxiety symptoms and exposure to threatening events were all associated independently with sleep paralysis. There was moderate genetic influence on sleep paralysis (53%). Polymorphisms in the PER2 gene were associated with sleep paralysis in additive and dominant models of inheritance—although significance was not reached once a Bonferroni correction was applied. It is concluded that factors associated with disrupted sleep cycles appear to be associated with sleep paralysis. In this sample of young adults, sleep paralysis was moderately heritable. Future work should examine specific polymorphisms associated with differences in circadian rhythms and sleep homeostasis further in association with sleep paralysis.     

Cognitive effects of split and continuous sleep schedules in adolescents differ according to total sleep opportunity

Study ObjectivesWe compared the basic cognitive functions of adolescents undergoing split (nocturnal sleep + daytime nap) and continuous nocturnal sleep schedules when total sleep opportunity was either below or within the recommended range (i.e. 6.5 or 8 h).MethodsAdolescent participants (age: 15–19 year) in the 8-h split (n = 24) and continuous (n = 29) sleep groups were compared with 6.5-h split and continuous sleep groups from a previous study (n = 58). These protocols involved two baseline nights (9-h time-in-bed [TIB]), 5 nights of sleep manipulation, 2 recovery nights (9-h TIB), followed by a second cycle of sleep manipulation (3 nights) and recovery (2 nights). Cognitive performance, subjective sleepiness, and mood were evaluated daily; sleep was assessed using polysomnography.ResultsSplitting 6.5 h of sleep with a mid-afternoon nap offered a boost to cognitive function compared to continuous nocturnal sleep. However, when total TIB across 24 h increased to 8 h, the split and continuous sleep groups performed comparably in tests evaluating vigilance, working memory, executive function, processing speed, subjective sleepiness, and mood.ConclusionsIn adolescents, the effects of split sleep on basic cognitive functions vary by the amount of total sleep obtained. As long as the total sleep opportunity across 24 h is within the recommended range, students may fulfill sleep requirements by adopting a split sleep schedule consisting of a shorter period of nocturnal sleep combined with a mid-afternoon nap, without significant impact on basic cognitive functions.Clinical trial registration{"type":"clinical-trial","attrs":{"text":"NCT04044885","term_id":"NCT04044885"}}NCT04044885.     

Sleep loss affects vigilance: effects of chronic insomnia and sleep therapy

Although complaints of impaired daytime functioning are essential to the diagnosis of primary insomnia, objective evidence for cognitive dysfunction has been hard to establish. A prerequisite for understanding the neurocognitive consequences of primary insomnia is to establish task paradigms that robustly differentiate insomniacs from well-sleeping subjects. We hypothesized that the decline in performance that typically occurs with an increasing cognitive demand would provide a more sensitive measure than performance on a single task version. The hypothesis was tested, first, by assessing the performance on two vigilance tasks with different cognitive demands in 25 elderly patients with primary insomnia and 13 healthy well-sleeping age-matched subjects. Secondly, we investigated the performance response to sleep therapy using a waiting-list controlled design. Sleep therapy consisted of a multi-component intervention including sleep restriction, cognitive behavioral therapy, bright-light therapy, structured physical activity and body temperature manipulations. The results show that insomniacs differed markedly from controls in their reaction times across tasks with different cognitive demands: patients responded faster on the 'simple' vigilance task, yet slower on the 'complex' vigilance task. Sleep therapy effectively restored normal performance: patients became significantly slower on the 'simple' task and faster on the 'complex' task, returning to the performance levels of control subjects. These findings indicate that the performance decline associated with increasing cognitive demands is possibly the first sensitive and robust measure of the neurocognitive sequelae of insomnia. We suggest that future studies on cognition in primary insomnia should apply a design that varies task demands.     

Staying vigilant during recurrent sleep restriction: dose-response effects of time-in-bed and benefits of daytime napping

Study ObjectivesWe characterized vigilance deterioration with increasing time-on-task (ToT) during recurrent sleep restriction of different extents on simulated weekdays and recovery sleep on weekends, and tested the effectiveness of afternoon napping in ameliorating ToT-related deficits.MethodsIn the Need for Sleep studies, 194 adolescents (age = 15–19 years) underwent two baseline nights of 9-h time-in-bed (TIB), followed by two cycles of weekday manipulation nights and weekend recovery nights (9-h TIB). They were allocated 9 h, 8 h, 6.5 h, or 5 h of TIB for nocturnal sleep on weekdays. Three additional groups with 5 h or 6.5 h TIB were given an afternoon nap opportunity (5 h + 1 h, 5 h + 1.5 h, and 6.5 h + 1.5 h). ToT effects were quantified by performance change from the first 2 min to the last 2 min in a 10-min Psychomotor Vigilance Task administered daily.ResultsThe 9 h and the 8 h groups showed comparable ToT effects that remained at baseline levels throughout the protocol. ToT-related deficits were greater among the 5 h and the 6.5 h groups, increased prominently in the second week of sleep restriction despite partial recuperation during the intervening recovery period and diverged between these two groups from the fifth sleep-restricted night. Daytime napping attenuated ToT effects when nocturnal sleep restriction was severe (i.e. 5-h TIB/night), and held steady at baseline levels for a milder dose of nocturnal sleep restriction when total TIB across 24 h was within the age-specific recommended sleep duration (i.e. 6.5 h + 1.5 h).ConclusionsReducing TIB beyond the recommended duration significantly increases ToT-associated vigilance impairment, particularly during recurrent periods of sleep restriction. Daytime napping is effective in ameliorating such decrement.Clinical Trial Registration{"type":"clinical-trial","attrs":{"text":"NCT02838095","term_id":"NCT02838095"}}NCT02838095, {"type":"clinical-trial","attrs":{"text":"NCT03333512","term_id":"NCT03333512"}}NCT03333512, and {"type":"clinical-trial","attrs":{"text":"NCT04044885","term_id":"NCT04044885"}}NCT04044885.     

Performance and alertness effects of caffeine, dextroamphetamine, and modafinil during sleep deprivation

Stimulants may provide short-term performance and alertness enhancement during sleep loss. Caffeine 600 mg, d-amphetamine 20 mg, and modafinil 400 mg were compared during 85 h of total sleep deprivation to determine the extent to which the three agents restored performance on simple psychomotor tasks, objective alertness and tasks of executive functions. Forty-eight healthy young adults remained awake for 85 h. Performance and alertness tests were administered bi-hourly from 8:00 hours day 2 to 19:00 hours day 5. At 23:50 hours on day 4 (after 64 h awake), subjects ingested placebo, caffeine 600 mg, dextroamphetamine 20 mg, or modafinil 400 mg (n=12 per group). Performance and alertness testing continued, and probe tasks of executive function were administered intermittently until the recovery sleep period (20:00 hours day 5 to 8:00 hours day 5). Bi-hourly postrecovery sleep testing occurred from 10:00 hours to 16:00 hours day 6. All three agents improved psychomotor vigilance speed and objectively measured alertness relative to placebo. Drugs did not affect recovery sleep, and postrecovery sleep performance for all drug groups was at presleep deprivation levels. Effects on executive function tasks were mixed, with improvement on some tasks with caffeine and modafinil, and apparent decrements with dextroamphetamine on others. At the doses tested, caffeine, dextroamphetamine, and modafinil are equally effective for approximately 2-4 h in restoring simple psychomotor performance and objective alertness. The duration of these benefits vary in accordance with the different elimination rates of the drugs. Whether caffeine, dextroamphetamine, and modafinil differentially restore executive functions during sleep deprivation remains unclear.     

A Sleep Position Trainer for positional sleep apnea: a randomized,controlled trial

We tested the effect of the Sleep Position Trainer, a vibrational device, for positional sleep apnea in an open, randomized controlled trial with 101 patients, where 52 patients were allocated to Sleep Position Trainer and 49 patients to a non‐treatment control group for 2 months (Part 1). All patients were then followed as a cohort for a period of 6 months with use of the Sleep Position Trainer (Part 2). The participants were assessed with polygraphy at entry, and after 2 and 6 months. The mean apnea–hypopnea index supine was 35 per h (SD, 18) in the Sleep Position Trainer group and 38 per h (SD, 15) in the control group at entry. In a per protocol analysis, the mean total apnea–hypopnea index at entry and after 2 months in the Sleep Position Trainer group was 18 per h (SD, 10) and 10 per h (SD, 9; P < 0.001) versus 20 per h (SD, 9) and 18 per h (SD, 10; NS) in the control group. The mean supine sleep time decreased from 47% (SD, 22) to 17% (SD, 18; P < 0.001) in the Sleep Position Trainer group after 2 months. In the control group, the mean supine sleep time was 48% (SD, 20) at entry and 39% (SD, 21; NS) after 2 months. The positive effect of Sleep Position Trainer was maintained in all patients treated with Sleep Position Trainer after 6 months. Daytime sleepiness improved after 6 months. Compliance with the Sleep Position Trainer device during the first 2 months, defined as use of Sleep Position Trainer >4 h per night for all weekdays, was 75.5% (SD 21.2). The discontinuation rate was 28.8 and 49.4% after 2 and 6 months, respectively.     

24 hours of sleep deprivation in the rat increases sleepiness and decreases vigilance: introduction of the rat‐psychomotor vigilance task

A novel animal‐analog of the human psychomotor vigilance task (PVT) was validated by subjecting rats to 24 h of sleep deprivation (SD) and examining the effect on performance in the rat‐PVT (rPVT), and a rat multiple sleep latency test (rMSLT). During a three‐phase (separate cohorts) crossover design, vigilance performance in the rPVT was compared with 24 h SD‐induced changes in sleepiness assessed by polysomnographic evaluation and the rMSLT. Twenty‐four hours of SD was produced by brief rotation of activity wheels at regular intervals in which the animals resided throughout the experiment. In the rPVT experiment, exercise controls (EC) experienced the same overall amount of locomotor activity as during SD, but allowed long periods of undisturbed sleep. After 24 h SD response latencies slowed, and lapses increased significantly during rPVT performance when compared with baseline and EC conditions. During the first 3 h of the recovery period following 24 h SD, polysomnographic measures indicated sleepiness. Latency to fall asleep after 24 h SD was assessed six times during the first 3 h after SD. Rats fell asleep significantly faster immediately after SD, than after non‐SD baseline sessions. In conclusion, 24 h of SD in rats increased sleepiness, as indicated by polysomnography and the rMSLT, and impaired vigilance as measured by the rPVT. The rPVT closely resembles the human PVT test widely used in human sleep research and will assist investigation of the neurobiologic mechanisms that produce vigilance impairments after sleep disruption.     

Unusual sleep experiences and dissociation as mediators between sleep quality and proneness to hallucinations in a nonclinical population sample: a preliminary study

Introduction: The purpose of this study was to examine the relationship of sleep quality to proneness to hallucinations and the mediating role of dissociation and unusual sleep experiences in a nonclinical sample.

Methods: One hundred and seventy-seven participants completed a questionnaire on sleep quality, a dissociative experiences scale, an unusual sleep experiences scale and a hallucination proneness scale.

Results: The results showed a significant positive association between quality of sleep and hallucination proneness, dissociation and unusual sleep experiences, and that dissociation and unusual sleep experiences fully mediated between sleep quality and hallucination proneness.

Conclusions: Our study highlights the importance of variables related to sleep quality and unusual sleep experiences and dissociation in understanding hallucinations, and the importance of taking these variables into consideration in designing intervention directed at reducing distress caused by hallucinations.     

Chronotype is associated with the timing of the circadian clock and sleep in toddlers

Chronotype is a construct reflecting individual differences in diurnal preference. Although chronotype has been studied extensively in school‐age children, adolescents and adults, data on young children are scarce. This study describes chronotype and its relationship to the timing of the circadian clock and sleep in 48 healthy children aged 30–36 months (33.4 ± 2.1 months; 24 males). Parents completed the Children's Chronotype Questionnaire (CCTQ) ~2 weeks before the start of the study. The CCTQ provides three measures of chronotype: midsleep time on free days, a multi‐item morningness/eveningness score and a single item chronotype score. After 5 days of sleeping on their habitual schedule (assessed with actigraphy and sleep diaries), children participated in an in‐home salivary dim light melatonin onset assessment. Average midsleep time on free days was 1:47 ± 0:35, and the average morningness/eveningness score was 26.8 ± 4.3. Most toddlers (58.4%) were rated as ‘definitely a morning type’ or ‘rather morning than evening type’, while none (0%) were rated as ‘definitely evening type’. More morning types (midsleep time on free days and morningness/eveningness score, respectively) had earlier melatonin onset times (r = 0.45, r = 0.26), earlier habitual bedtimes (r = 0.78, r = 0.54), sleep onset times (r = 0.80, r = 0.52), sleep midpoint times (r = 0.90, r = 0.53) and wake times (r = 0.74, r = 0.34). Parent ratings using the single‐item chronotype score were associated with melatonin onset (r = 0.32) and habitual bedtimes (r = 0.27), sleep onset times (r = 0.33) and sleep midpoint times (r = 0.27). Morningness may best characterize circadian preference in early childhood. Associations between chronotype and circadian physiology and sleep timing suggest adequate validity for the CCTQ in this age group. These findings have important implications for understanding the marked variability in sleep timing during the early years of life.     

Self-reported seasonality is associated with complaints of sleep problems and deficient sleep duration: the Hordaland Health Study

Change in sleep duration dependent on time of year is a central characteristic of seasonal affective disorder (SAD). In a community health survey, we analysed associations between seasonality, subjective sleep problems and sleep duration. Totally, 8860 subjects (3531 men and 5329 women) aged between 40 and 44 years were included in the study. Seasonal changes in mood and behaviour were measured by the Global Seasonality Score (GSS) questionnaire, and subjects were grouped in high (GSS > or = 11), moderate (GSS 8-10) or low (GSS < 8) seasonality groups. Sleep symptomatology was assessed using a modified version of the Karolinska Sleep Questionnaire. Significant sleep duration deficiency was defined as the difference between subjective sleep need and sleep duration of at least 1 h. Sleep problems suggesting insomnia as well as increased daytime sleepiness were more prevalent in the high/moderate seasonality groups compared with the low seasonality group. Seasonality was furthermore associated with shorter sleep duration and increased subjective sleep need. Significant sleep duration deficiency was more prevalent in subjects reporting high (men 20% and women 21%) and moderate (men 13% and women 19%) seasonality than subjects reporting low (men 10% and women 14%) seasonality. In conclusion, we found seasonal changes in mood and behaviour to be associated with several sleep-related complaints. Sleep duration deficiency increased with increasing seasonality, mainly due to increasing subjective sleep need.     

Slow release caffeine and prolonged (64-h) continuous wakefulness: effects on vigilance and cognitive performance

Some long work or shift work schedules necessitate an elevated and prolonged level of vigilance and performance but often result in sleep deprivation (SD), fatigue and sleepiness, which may impair efficiency. This study investigated the effects of a slow-release caffeine [(SRC) at the daily dose of 600 mg] on vigilance and cognitive performance during a 64 h continuous wakefulness period. Sixteen healthy males volunteered for this double-blind, randomised, placebo controlled, two-way crossover study. A total of 300-mg SRC or placebo (PBO) was given twice a day at 21:00 and 9:00 h during the SD period. Vigilance was objectively assessed with continuous electroencephalogram (EEG), the multiple sleep latency tests (MSLT) and wrist actigraphy. Cognitive functions (information processing and working memory), selective and divided attention were determined with computerised tests from the AGARD-NATO STRES Battery (Standardised Tests for Research with Environmental Stressors). Attention was also assessed with a symbol cancellation task and a Stroop's test; alertness was appreciated from visual analogue scales (VAS). Tests were performed at the hypo (02:00-04:00 h, 14:00-16:00 h) and hypervigilance (10:00-12:00 h, 22:00-00:00 h) periods during SD. Central temperature was continuously measured and safety of treatment was assessed from repeated clinical examinations. Compared with PBO, MSLT showed that SRC subjects were more vigilant from the onset (P=0.001) to the end of SD (P < 0.0001) whereas some cognitive functions were improved till the thirty third of SD but others were ameliorated through all the SD period and alertness was better from the thirteenth hour of SD, as shown by Stroop's test (P=0.048). We showed that 300-mg SRC given twice daily during a 64-h SD is able to antagonize the impairment produced on vigilance and cognitive functions.     

The effects of sleep deprivation in humans: topographical electroencephalogram changes in non‐rapid eye movement (NREM) sleep versus REM sleep

Studies on homeostatic aspects of sleep regulation have been focussed upon non‐rapid eye movement (NREM) sleep, and direct comparisons with regional changes in rapid eye movement (REM) sleep are sparse. To this end, evaluation of electroencephalogram (EEG) changes in recovery sleep after extended waking is the classical approach for increasing homeostatic need. Here, we studied a large sample of 40 healthy subjects, considering a full‐scalp EEG topography during baseline (BSL) and recovery sleep following 40 h of wakefulness (REC). In NREM sleep, the statistical maps of REC versus BSL differences revealed significant fronto‐central increases of power from 0.5 to 11 Hz and decreases from 13 to 15 Hz. In REM sleep, REC versus BSL differences pointed to significant fronto‐central increases in the 0.5–7 Hz and decreases in the 8–11 Hz bands. Moreover, the 12–15 Hz band showed a fronto‐parietal increase and that at 22–24 Hz exhibited a fronto‐central decrease. Hence, the 1–7 Hz range showed significant increases in both NREM sleep and REM sleep, with similar topography. The parallel change of NREM sleep and REM sleep EEG power is related, as confirmed by a correlational analysis, indicating that the increase in frequency of 2–7 Hz possibly subtends a state‐aspecific homeostatic response. On the contrary, sleep deprivation has opposite effects on alpha and sigma activity in both states. In particular, this analysis points to the presence of state‐specific homeostatic mechanisms for NREM sleep, limited to <2 Hz frequencies. In conclusion, REM sleep and NREM sleep seem to share some homeostatic mechanisms in response to sleep deprivation, as indicated mainly by the similar direction and topography of changes in low‐frequency activity.     

The effects of sleep extension on cardiometabolic risk factors: A systematic review

Studies have shown bidirectional relationships between short‐ or long‐sleep duration and risk for obesity, non‐communicable diseases, all‐cause mortality and cardiovascular disease mortality. Increasing sleep duration may be an appropriate strategy to reduce cardiometabolic risk in short‐sleeping individuals. The aim is to review the effects of sleep extension interventions on cardiometabolic risk in adults. The PubMed and Scopus databases were searched for relevant, English, peer‐reviewed scientific publications (until August 2018). Seven studies that aimed to increase sleep duration in adults by any sleep extension intervention and described at least one cardiometabolic risk factor were included. These studies had a combined sample size of 138 participants who were either healthy (n = 14), healthy short‐sleeping (n = 92), overweight short‐sleeping (n = 10), or pre‐ or hypertensive short‐sleeping (n = 22) individuals. The durations of the sleep extension interventions ranged from 3 days to 6 weeks, and all successfully increased total sleep time by between 21 and 177 min. Sleep extension was associated with improved direct and indirect measures of insulin sensitivity, decreased leptin and peptide tyrosine‐tyrosine, and reductions in overall appetite, desire for sweet and salty foods, intake of daily free sugar, and percentage of daily caloric intake from protein. This review provides preliminary evidence for a role for sleep extension to improve cardiometabolic outcomes and directive towards future studies in the field of cardiometabolic health and sleep.