Measured Sleep Time Research Articles

Impact of 6 months’ Use of Intermittently Scanned Continuous Glucose Monitoring on Habitual Sleep Patterns and Sleep Quality in Adolescents and Young Adults with Type 1 Diabetes and High-Risk HbA1c

Background. The bidirectional relationship between sleep and blood glucose levels may particularly affect adolescents and young adults (AYA), who are more likely to experience less healthy glycemic outcomes and more disrupted sleep patterns. To date, few data exist describing the impact of intermittently scanned continuous glucose monitoring (isCGM) on habitual sleep patterns and sleep quality in AYA with type 1 diabetes (T1D). Objective. To evaluate the impact of 6-month use of isCGM on habitual sleep and wake timing, sleep duration, frequency, and duration of night-time awakenings, sleep efficiency, and perceived sleep quality in young people with T1D and HbA1c ≥ 75 mmol/mol. Participants. The study recruited 64 participants aged 13–20 years (mean 16.6 ± 2.1), 48% female, diabetes duration 7.5 ± 3.8 years, 41% Māori or Pasifika, and a mean HbA1c 96.0 ± 18.0 mmol/mol [10.9 ± 3.8%]; 33 were allocated to an isCGM plus self-monitoring blood glucose [SMBG] intervention, and 31 were allocated to the SMBG control group. Methods. Participants completed 7-day actigraphy measures and the Pittsburgh Sleep Quality Index questionnaire at the baseline and at 6 months. Regression analyses were used to model between-group comparisons, adjusted for baseline sleep measures. Results. At 6 months, subjective measures for overall sleep quality, latency, duration, efficiency, night-time disturbances, use of sleep medications, and daytime dysfunction were similar between the groups. Regression analyses of actigraphy found no significant differences in objectively measured sleep timing and duration across the week after adjusting for age, the period of the school year, and baseline sleep values. Conclusions. The use of first-generation isCGM in addition to finger-prick testing did not impact objective or subjective sleep measures in AYA with T1D, elevated HbA1c, and highly variable sleep patterns. Research using alternative interventions for improving glycemic outcomes and habitual sleep-wake timing, duration, and perceived sleep quality is warranted in this population group.

Daytime light exposure is a strong predictor of seasonal variation in sleep and circadian timing of university students.

In the absence of electric light, sleep for humans typically starts soon after dusk and at higher latitudes daily sleep timing changes seasonally as photoperiod changes. However, access to electric light shields humans from natural photoperiod changes, and whether seasonal changes in sleep occur despite this isolation from the natural light-dark cycle remains a matter of controversy. We measured sleep timing in over 500 university students living in the city of Seattle, WA (47.6°N) throughout the four seasons; we show that even when students are following a school schedule, sleep timing is delayed during the fall and winter. For instance, during the winter school days, students fell asleep 35 min later and woke up 27 min later (under daylight-savings time) than students during the summer school days, a change that is an hour larger relative to solar midnight. Furthermore, chronotype defined by mid-sleep on free days corrected for oversleep (MSFc), an indirect estimate of circadian phase, was more than 30 min later in the winter compared with the summer. Analysis of the effect of light exposure showed that the number of hours of light exposure to at least 50 lux during the daytime was a stronger predictor of MSFc than the exposure time to this illuminance after dusk. Specifically, MSFc was advanced by 30 min for each additional hour of light exposure during daytime and delayed by only 15 min for each additional hour of postdusk exposure to light. Additionally, the time of the day of exposure to high light intensities was more predictive of MSFc when daytime exposure was considered than when exposure for the full 24-h day was considered. Our results show that although sleep time is highly synchronized to social time, a delayed timing of sleep is evident during the winter months. They also suggest that daily exposure to daylight is key to prevent this delayed phase of the circadian clock and thus circadian disruption that is typically exacerbated in high-latitude winters.

Self-reported chronotype and objective sleep timing in university student athletes and non-athletes

ObjectiveThe aim of this paper was to test how sport participation and chronotype affect objectively measured sleep timing parameters on workdays.Material and MethodsThe sample included 82 student athletes and 40 non-athletes who completed three-day wrist actigraphy monitoring and the Polish version of the Morningness-Eveningness Questionnaire.ResultsEveningness predicted later timing of falling asleep and mid-sleep, but not the wake-up time. Student athletes had earlier wake-up time and shorter sleep duration than non-athletes.DiscussionThe results support the view that university students suffer insufficient sleep, especially those participating in extensive sport activity.

Profile of subjective-objective sleep discrepancy in patients with insomnia and sleep apnea.

Although subjective-objective sleep discrepancy has long been observed in patients with insomnia, the profiles of this discrepancy are poorly understood. Further, sleep discrepancy in insomnia with sleep comorbidities remains underexplored. We sought to better characterize sleep discrepancy among patient groups with and without insomnia and comorbid conditions such as obstructive sleep apnea (OSA). Using data from the Sleep Heart Health Study, we conducted a secondary analysis describing (1) the profile of self-reported and objective sleep measures in patients with insomnia (IS group; n = 73) and comorbid OSA (IS + OSA group; n = 143), compared with individuals with OSA only (OSA group; n = 296) and normal sleep control patients (NSC group; n = 126); (2) the comparative magnitude of sleep misperception between these 4 groups; and (3) the self-reported quality of life (QOL) in the 4 groups. Subjective-objective sleep discrepancy existed in all 4 groups, including the NSC group. Controlling for age, sex, mental health conditions, sleep apnea severity, and objectively measured sleep time, the presence of self-reported insomnia had the strongest association with sleep discrepancy. In patients with insomnia, sleep onset latency was overestimated (7.8 ± 36.8 min in the IS group; P < .001 when compared to the NSC and OSA groups), with the largest differences seen in the comorbid IS + OSA group (15.0 ± 56.8 min). Insomnia conferred the most negative impact on QOL, with the combined IS + OSA group reporting the lowest QOL. Self-reported insomnia is associated with sleep discrepancy and negative QOL. Those with comorbid OSA reported the greatest sleep discrepancy and the lowest QOL. Future research is warranted to further understand individual profiles of misperception and insomnia phenotypes. Ma Y, Goldstein MR, Davis RB, Yeh GY. Profile of subjective-objective sleep discrepancy in patients with insomnia and sleep apnea. J Clin Sleep Med. 2021;17(11):2155-2163.

385 Subjective-objective sleep discrepancy and quality of life in self-reported insomnia and sleep apnea

Abstract Introduction Current diagnostic classifications define insomnia based on self-reported sleep difficulties. However, differences between self-reported and objectively measured sleep parameters (subjective-objective sleep discrepancy or sleep misperception) are very common. Insomnia and sleep apnea cause common impairments that overlap and have negative impacts on overall health. Previous studies have encouraged an in-depth understanding of subjective-objective sleep discrepancy to inform a role for behavioral, mind-body approaches to insomnia. In this study, utilizing patients with insomnia and comorbid sleep apnea, we aimed to understand associations between self-reported insomnia, sleep difficulties, sleep misperception and quality-of-life. Methods We conducted a secondary analysis using data from the Sleep Heart Health Study (a multi-site nationally representative sample) to examine the profile of subjective and objective sleep measures in people with insomnia (IS, n=73) and comorbid sleep apnea (IS+SA, n=143), compared to individuals with sleep apnea only (SA, n=296) and normal sleep controls (NSC, n=126). We also compared the magnitude of sleep misperception between these four groups and examined the corresponding impact of subjective insomnia complaints on quality-of-life. Results Sleep discrepancy was found in all four groups. After controlling for age, sex, mental health conditions, sleep apnea severity, and objectively measured sleep time, the presence of self-reported insomnia had the strongest association with sleep discrepancy on total sleep time (TST, β=-34.4, p&amp;lt;0.001) and sleep onset latency (SOL, β=14.7, p&amp;lt;0.001). Subjects who reported no difficulty falling asleep slightly underestimated their sleep onset latency, while those who reported difficulty substantially overestimated sleep latency. Self-reported insomnia had a significantly negative impact on the quality of life in both physical and mental components (p&amp;lt;0.001). Conclusion Sleep discrepancy exists in normal controls, insomnia, and sleep apnea. Subjects with self-reported insomnia have a higher degree of sleep misperception. Both sleep apnea and self-reported insomnia are associated with negative QOL. Those with comorbid sleep apnea report the greatest sleep discrepancy and lowest QOL. Further research is needed to better understand individual profiles of misperception and insomnia phenotypes, apnea comorbidity and quality-of-life. Behavioral, mind-body interventions may offer strategies to address mental stress, sleep misperception, and insomnia. Support (if any) NCCIH T32AT000051 and NHLBI 5T32HL007901-22

Objectively measured chronotype and social jetlag are associated with habitual dietary intake in undergraduate students

This study aimed to investigate the associations between objectively measured sleep timing and habitual dietary intake among university students. We hypothesized that a later chronotype and larger social jetlag (SJL) are associated with an undesirable dietary intake. The 82 healthy university students included in this study were asked to undertake a seven-day wrist activity recording. All the participants also completed a self-administered questionnaire during the recording period, including questions on demographic characteristics and habitual dietary intakes. Dietary intake and the score for adherence to the Japanese Food Guide Spinning Top (food guide score) over the previous month were evaluated using a self-reported diet history questionnaire. Nocturnal sleep timing and total sleep time for each night were estimated using the recorded wrist activity. Chronotype was calculated as weekend (WE) mid-sleep time corrected for catch-up sleep on weekdays (WDs). SJL was calculated by subtracting WD mid-sleep time from WE mid-sleep time. Multivariable linear regression showed that a later chronotype was significantly (P < .05) associated with a lower consumption of eggs, greater consumption of grains, and lower food guide score. Multivariable linear regression also showed significant (P < .05) associations of a larger value in SJL with a lower total energy intake, lower consumption of grains, and greater consumption of sugar and confectioneries. The results suggest that chronotype and SJL may be differently associated with undesirable dietary intake in young adults. These findings have important implications for developing novel strategies, focusing on sleep timing, for improving dietary intakes and preventing lifestyle-related diseases.

Emulation of burst-based adaptive link rates in NetFPGA towards green networking

In recent times, energy consumption in communication media has been increasing drastically. In the literature, energy-saving techniques that enable network devices to enter sleep state or limit the data rate have been proposed to reduce energy costs. In our earlier work, we proposed an energy-saving technique called burst-based adaptive link rate BBALR , the simulation of which assures increased energy savings. In this paper, we have emulated the hardware implementation of BBALR and compared its performance with the outputs of other prominent energy-saving policies based on dynamic link rate adaption. The energy savings are mapped from the measured sleep time and reference power values. We have used NetFPGA as the testbed, which is a research platform for building real-time network hardware prototypes.

Circadian preference and sleep timing from childhood to adolescence in relation to genetic variants from a genome-wide association study

ObjectiveRecent genome-wide association studies (GWASs) have revealed new genetic variants behind self-reported individual circadian preference, a distinct biological trait that is fairly stable during adulthood. In this study we analyze whether these genetic variants associate with objectively measured sleep timing from childhood to adolescence, over a nine-year period, with self-reported circadian preference during late adolescence. MethodsThe participants (N = 100, 61% girls) came from a community cohort from Finland born in 1998. Sleep midpoint was measured with actigraphy at 8, 12 and 17 years. Circadian preference was self-reported at the age of 17 years. Single nucleotide polymorphisms (SNPs) were extracted at 12 years of age from the Illumina OmniExpress Exome 1.2 bead array data. Weighted polygenic risk scores (PRSs) were calculated based on top SNPs from a recent GWAS for morningness–eveningness in an adult population. ResultsThe PRS for circadian preference towards morningness was associated with earlier sleep midpoint from childhood to adolescence. When the time points were analyzed separately, the association between genetic tendency towards morning preference and earlier sleep midpoint was strongest among the 17-year-olds. Furthermore, the shift towards later sleep rhythm from early to late adolescence was milder for those with a higher PRS for morning preference. PRS for morning preference was also associated with self-reported circadian preference towards morningness in late adolescence. ConclusionOur results suggest that genetic variants found for circadian preference in adults are already associated with objective sleep timing during childhood and adolescence, and predict individual developmental sleep trajectories from childhood onwards.

Habitual Sleep and human plasma metabolomics.

Sleep plays an important role in cardiometabolic health. The sleep-wake cycle is partially driven by the endogenous circadian clock, which governs a range of metabolic pathways. The association between sleep and cardiometabolic health may be mediated by alterations of the human metabolome. To better understand the biological mechanism underlying the association between sleep and health, we examined human plasma metabolites in relation to sleep duration and sleep timing. Using an untargeted approach, 329 fasting plasma metabolites were measured in 277 Chinese participants. We measured sleep timing (midpoint between bedtime and wake up time) using repeated time-use surveys (4 weeks during one year) and previous night sleep duration from questionnaires completed before sample donation. We found 64 metabolites that were associated with sleep timing with a false discovery rate of 0.2 or lower, after adjusting for potential confounders. Notably, we found that later sleep timing was associated with higher levels of multiple metabolites in amino acid metabolism, including branched chain amino acids and their gamma-glutamyl dipeptides. We also found widespread associations between sleep timing and numerous metabolites in lipid metabolism, including bile acids, carnitines and fatty acids. In contrast, previous night sleep duration was not associated with plasma metabolites in our study. Sleep timing was associated with a large number of metabolites across a variety of biochemical pathways. Some metabolite associations are consistent with a relationship between late chronotype and adverse effects on cardiometabolic health.

Self-reported sleep disturbance is associated with elevated levels of PAI-1 in individuals with a recorded history of depressive symptoms

The majority of depressed individuals report insomnia. Self-reported symptoms of insomnia, in particular, more strongly predict adverse health effects than the actual measured sleep time. The physiological alterations in individuals with insomnia are complex, as both autonomic and endocrine dysfunctions are present. Plasminogen activator inhibitor (PAI)-1 is a stress-related acute-phase reactant that has also been suggested to regulate the circadian rhythm and sleep patterns. It has been suggested to contribute to both depressive symptoms and sleep disorders, although data on the relationships between these parameters are scarce. This study examined the role of self-reported sleep disturbance and its association with PAI-1 among individuals with a history of depressive symptoms. Differences in the serum levels of PAI-1 between two groups (group 1: moderate to very severe sleep disturbance, n=37; group 2: mild or no sleep disturbance, n = 90) were examined in a population-based sample of individuals with a recorded history of depressive symptoms. Multivariate analysis controlling for potential confounding factors (age, sex, body mass index, depression severity) showed that each 1-unit increase in PAI-1 (μg/mL) increased the likelihood for belonging to the group with moderate to very severe sleep disturbance by 23% (OR = 1.23, C.I. 95% = 1.04-1.45, p = 0.016). This statistical significance remained after additional adjustments for regular smoking and the use of sleep or lipid-lowering medication. Our observations may further clarify the physiological alterations related to sleep disturbance in depressive individuals. In the present study, self-reported sleep disturbance in individuals with a recorded history of depressive symptoms was associated with an elevation of PAI-1. This finding may illustrate the association of subjective sleep disturbance with sympathetic activation. Our study highlights the importance of effects of perceived sleep disturbance on individual homeostasis, and may provide potential directions for research on treatment options.

Do pregnant women accurately report sleep time? A comparison between self-reported and objective measures of sleep duration in pregnancy among a sample of urban mothers

Survey questions are commonly used to assess sleep duration because of their low cost and convenience. Responses to these questions correlate moderately with objectively measured sleep duration in nonpregnant individuals, but little is known about the validity of self-reported sleep measures in pregnancy. The aim of the present study was to determine the extent to which self-reported gestational sleep duration assessed by questionnaire predicted objectively measured gestational sleep duration via actigraphy. We analyzed data from 80 mothers enrolled in an ancillary study of Project BABIES, a prospective cohort study of urban, pregnant women. Sleep measurements were collected in midpregnancy and included 7days of wrist actigraphy, a sleep log, and survey questions about sleep time adapted from the Pittsburgh Sleep Quality Index. Mean measured gestational sleep duration derived from actigraphy was 6.87h [standard deviation (SD) 0.87], and questionnaire-assessed nocturnal sleep time averaged 7.29h (SD 1.84). While the difference between measures did not reach statistical significance (p = 0.07 for paired samples t test), over half (62%) of participants reported a habitual average nightly sleep time that differed more than 1h from their average actigraphically measured sleep duration (39% overestimated by more than an hour; 23% underestimated by more than an hour). There was no correlation between measures (r = 0.007; 95% confidence interval -0.21, 0.23). Questionnaire-derived reports of usual sleep hours do not reflect objectively measured sleep time in urban, pregnant women. Actigraphy is preferable to accurately assess gestational sleep duration.

임베디드 응용프로그램의 동작 특성을 이용한 에너지 인식 스케쥴링 기법

효율적인 전력관리는 모바일 휴대용 제품 시장에서 중요한 경쟁력 중의 하나이다. 본 논문은 전력을 미리 예측하는 방법으로 실행중인 응용프로그램의 sleep 상태를 이용하는 Energy-Aware Scheduling policy(EASY)를 제안한다. 기존 대기 모드에서 전력소모를 줄이는 방법과의 차이점은 응용프로그램들이 얼마나 오랫동안 스케쥴러에서 sleep 상태에 있었는지를 검사하여 각 응용프로그램들의 동작 상태를 결정한다. EASY 기법은 측정된 sleep 시간을 기준으로 현재의 작업량에 맞는 적정한 CPU 클럭 주파수를 정하고, 다음 작업량의 적정한 CPU 클럭 주파수를 예측함으로서 동작 상태에서 전력 소모를 줄일 수 있다. 실험 결과 기존의 대기모드를 이용한 전력관리 기법과 비교하여 평균적으로 10-30%의 전력소모를 줄임으로써 제안된 기법의 우수성을 입증한다. Efficient power management plays a crucial role to strengthen competitiveness in the market of portable mobile commodities. This paper presents a proactive power management technique, called by Energy-Aware Scheduling policY (EASY), to exploit the sleep time information of running applications. Different from previous power management approaches focusing on power conservation in standby mode, the proposed scheme characterizes each application program's operational characteristic in active mode by observing how long the task stays in sleep state of CPU scheduler. Based on the measured sleep time, the proposed EASY speculates an adequate CPU clock frequency according to the current CPU workload and scales the frequency directly to the predicted one. Experimental results show that the proposed scheme reduces the power consumption by 10-30% on average compared to traditional DPM approach, with a minimal impact on the performance overhead.

Maternal postpartum sleepiness and fatigue: Associations with objectively measured sleep variables

Objective To explore whether standardized survey instruments and objective performance measures differentiate traditional constructs of sleepiness and fatigue among a sample of postpartum mothers. Additionally, we wanted to explore the independent associations among these measures with actigraphically measured nocturnal sleep variables. Method Seventy-nine postpartum mothers' subjective sleepiness, fatigue, and performance measures [Stanford Sleepiness Scale (SSS), Epworth Sleepiness Scale (ESS), Visual Analogue of Fatigue Scale (VAS), Profile of Mood States (POMS) subscale items, and the Psychomotor Vigilance Test (PVT)] and objective actigraphically measured sleep were collected during postpartum week 11. A principal components analysis was calculated, then regressions were calculated among resulting factors and among individual measures with total sleep time and sleep efficiency. Results Three factors accounted for 83.84% of model variance. Factor 1 (41.41%) included the SSS, ESS, and the VAS. Factor 2 (28.13%) included only PVT variables. Factor 3 (14.30%) included the two POMS subscale items. Factor 1 was associated with nocturnal sleep time and Factor 2 was associated with sleep efficiency. The ESS was independently associated with nocturnal sleep time, whereas, POMS-Vigor subscale and median reaction time, together, were associated with sleep efficiency. Conclusion Among postpartum mothers, standard instruments used to measure sleepiness, fatigue, and performance were distributed among three distinct factors that did not clearly identify traditional sleepiness and fatigue constructs. Objectively measured sleep time and sleep efficiency were associated with specific factors, as well as specific measures, that correspond to sleepiness and fatigue states.

Subjective and Objective Sleep Quality and Aging in the Sleep Heart Health Study

To examine the extent to which subjective and objective sleep quality are related to age independent of chronic health conditions. Cross-sectional study. The Sleep Heart Health Study (SHHS) is a multicenter study designed to determine the cardiovascular consequences and the natural history of sleep disordered breathing. Five thousand four hundred seven community-dwelling adults who participated in the SHHS (mean age 63, range 45-99; 52% women). Unattended home polysomnography (PSG) and sleep questionnaires. Older age was associated with shorter sleep time, diminished sleep efficiency, and more arousals in men and women. In men, age was independently associated with more Stage 1 and Stage 2 sleep and less slow-wave (Stage 3 to 4) and rapid eye movement sleep. In women, older age was less strongly associated according to linear trend with sleep stage. Conversely, poor subjective sleep quality was not associated with older age in men, but older women had more trouble falling asleep, and there was a trend toward older women having more problems with waking up during the night and waking up too early. Associations between self-report and directly measured sleep time and sleep latency were low to moderate across age groups (correlation coefficient=0.06-0.32). Older age was more strongly associated with poorer sleep according to PSG in men than women, yet the subjective report of poor sleep with older age was stronger in women. The higher prevalence of chronic health conditions, including sleep apnea, in older adults did not explain changes of sleep parameters with aging and age-sex differences in these relationships.

GABA-benzodiazepine receptor function in alcohol dependence: a combined 11C-flumazenil PET and pharmacodynamic study

Gamma-aminobutyric acid (GABA)-benzodiazepine receptor function is hypothesised to be reduced in alcohol dependence. We used positron emission tomography (PET) with [11C]flumazenil, a non-selective tracer for brain GABA-benzodiazepine (GABA-BDZ) receptor binding, to determine in vivo the relationship between BDZ receptor occupancy by an agonist, midazolam, and its functional effects. Abstinent male alcohol dependent subjects underwent [11C]flumazenil PET to measure occupancy of BDZ receptors by midazolam whilst recording its pharmacodynamic effects on behavioural and physiological measures. Rate constants describing the exchange of [11C]flumazenil between the plasma and brain compartments were derived from time activity curves. A 50% reduction in electroencephalography (EEG)-measured sleep time was seen in the alcohol dependent group despite the same degree of occupancy by midazolam as seen in the control group. The effects of midazolam on other measures of benzodiazepine receptor function, increasing EEG beta1 power and slowing of saccadic eye movements, were similar in the two groups. No differences in midazolam or flumazenil metabolism were found between the groups. In summary, our study suggests that alcohol dependence in man is associated with a reduced EEG sleep response to the benzodiazepine agonist, midazolam, which is not explained by reduced BDZ receptor occupancy, and is consistent with reduced sensitivity in this measure of GABA-BDZ receptor function in alcohol dependence. The lack of change in other functional measures may reflect a differential involvement of particular subtypes of the GABA-BDZ receptor.