Wake Time Research Articles

The Sleep, Anxiety, Mood, and Cognitive Performance of Oceanic Rocket League Esports Athletes Competing in a Multiday Regional Event

The overall aim of the present study was to examine the daily patterns and relationships between sleep behavior, anxiety, mood (i.e., depression symptoms), and cognitive performance (i.e., reaction time) in esports athletes competing in an Oceanic Rocket League Championship Series regional event. Sixteen participants completed a daily sleep diary, an evening anxiety measure, and an afternoon mood measure and cognitive performance task. Measures were taken (a) precompetition, (b) across the competition days, and (c) postcompetition. We found that participants’ lights-out time was earliest across the competition nights. Sleep-onset latency gradually lengthened precompetition and across the competition nights, eventually exceeding normal limits. Wake after sleep onset was longest across the competition nights but remained within normal limits. Wake-up time was earliest at the start of the competition period but consistently late on most other days. Total sleep time was generally adequate but mildly reduced the night before the first day of competition. There was no significant relationship between anxiety and subsequent sleep nor a relationship between total sleep time and next day mood or cognitive performance. Future research should investigate whether these findings generalize to esports athletes from other games, at higher levels of competition, and to different start times.

Correlation between Sleep Patterns, Weight, and Height Among Indonesian Female Boarding School Students

Background: Sleep is essential for growth, development, and health, with inadequate sleep linked to risks such as obesity, hypertension, and mood disorders. Sleep patterns differ by sex, with females often experiencing poorer quality and greater susceptibility to disturbances due to factors like the menstrual cycle. Adolescents, particularly boarding students, face unique sleep challenges from academic and extracurricular demands, potentially impacting growth. This study is aimed at studying the relationship between sleep patterns and height within Indonesian female boarding school students to understand the influence of sleep on their physical development. Methods: This cross-sectional study was performed in a boarding school in East Java, enrolling female students aged 13-17 years. Height and weight were assessed with standard anthropometric techniques. The BMI was computed and categorized according to age-specific percentiles. An online form collected data on bedtime, wake-up time, and sleep duration. SPSS was used for data analysis and Pearson’s correlation to explore relationships between sleep patterns and height. Result: This study included 127 female students with a mean BMI of 20.9±3.31. Mean height and weight were 154.57±5.45 and 50,08±9.38, respectively. 76% of subjects had an average of 5–5.5 hours of sleep per day. There was no significant relationship between the two (Pearson correlation=-0.009; Sig. 2-tailed=0.0923). There was a slight tendency that less sleep was associated with a slight decrease in height, but very weak and not significant (Pearson correlation = -0.090; Sig. 2-tailed = 0.313). Conclusion: Although females in boarding schools experience reduced sleep duration, they maintain normal weight and height.

A comparative study on eating habits and mental health of Korean middle school students according to their bedtime across regions: using data from the 2020-2022 Korea Youth Risk Behavior Survey.

The objective of this study was to compare dietary habits and mental health among middle school students in urban and rural areas based on bedtime, and to provide evidence supporting appropriate bedtime for Korean middle school students in relation to their healthy dietary habits and mental well-being. The study population consisted of 25,681 second-year middle school students who participated in the Korea Youth Risk Behavior Survey in 2020-2022. Participants were asked about their bedtime and wake-up time during the past 7 days and were classified into five categories. The study compared the general characteristics, academic factors, dietary habits, and mental health of urban and rural students based on their bedtime. Bedtime was found to be later in the following order: urban female students, rural female students, urban male students, and rural male students. As bedtime got later, the rates of smoking and alcohol consumption increased. Students who went to bed before 11 p.m. had lower academic performance, while rural male students who went to bed after 2 a.m. had lower academic performance. Later bedtime was associated with increased smartphone usage, skipping breakfast, consuming fast food, and drinking carbonated beverages. Later bedtime was also associated with higher perceived stress levels, particularly among students who went to bed after 2 a.m., higher rates of suicidal ideation, experiencing sadness and despair, as well as the prevalence of clinically significant anxiety disorders. These results suggest that middle school students who go to bed too late have higher rates of smoking and alcohol drinking, as well as unhealthy eating habits, stress, suicidal ideation, sadness, and anxiety. Therefore, it is necessary to provide educational and social institutional support to promote adequate sleep for the health of adolescents.

Rozdiely v kvalite spánku medzi adolescentmi v regióne Banská Bystrica

Objective: To identify the sleep quality of sixteen-year-old adolescents in the Banská Bystrica region, with a focus on gender differences. Materials and Methods: The study focused on gender differences in adolescent sleep quality. The sample consisted of 447 students from secondary vocational schools and gymnasiums in the Banská Bystrica region. The Pittsburgh Sleep Quality index (PSQI) was used to assess sleep quality. Data were collected electronically using Google Forms from april to June 2023. Gender differences were analyzed using percentage and statistical methods, specifically the ?2 test, at significance levels of p < 0.01 and p < 0.05. Results: Significant gender differences (p < 0.01, p < 0.05) were observed in sleep onset, wake-up times, subjective sleep quality, sleep latency, sleep efficiency, sleep disturbances, and medication use. No significant differences were found in sleep duration, concentration impairment, alertness, or overall sleep activity scores. More than 50% of adolescents exhibited sleep disturbances. Conclusions: Interventions by schools, families, and the media should encourage adolescents to establish healthy sleep habits. The key objectives are to optimize sleep onset times and duration, create a sleep-supportive environment, and promote daytime physical activity.

Social jetlag and diet quality among US young adults: interactions with race/ethnicity

Abstract The objective was to examine associations between social jetlag and diet quality among young adults in the US using nationally representative data from the 2017–2018 NHANES survey, and evaluate effect modification by gender and race/ethnicity. Social jetlag was considered ≥2-hour difference in sleep midpoint (median of bedtime and wake time) between weekends and weekdays. Diet quality was assessed with the Healthy Eating Index (HEI)-2015 and its 13 dietary components. Ordinal logistic models were run with diet scores binned into tertiles as the outcome. Models accounted for potential confounders and survey weights. Effect modification by gender and race/ethnicity was examined. The study sample included 1,356 adults aged 20–39 years. 31% of young adults had social jetlag. Overall, there were no associations between social jetlag and diet quality. However, interaction analysis revealed several associations were race-specific (P, interaction<0.05). Among Black adults, social jetlag was associated with lower overall diet quality (OR = 0.4, 95% CI 0.2, 0.8; i.e. less likely to be in higher diet quality tertiles) and more unfavourable scores on Total Vegetables (OR = 0.6, 95% CI 0.3, 1.0) and Added Sugar (i.e. OR = 0.6, 95% CI 0.4, 0.9). For Hispanic adults, social jetlag was associated with worse scores for Sodium (OR = 0.6, 95% CI 0.4, 0.9) However, White adults with social jetlag had better scores of Greens and Beans (OR = 1.9, 95% CI 1.1, 3.2). Within a nationally representative sample of US young adults, social jetlag was related to certain indicators of lower diet quality among Black and Hispanic Americans.

Sleep Deprivation and Fatigue among Nurses Working Consecutive Night Shifts: A Prospective Observational Study.

This study aimed to identify changes in sleep patterns and fatigue levels during consecutive night shifts among shift nurses and to determine the association between sleep parameters and increased fatigue levels during work. This prospective observational study employing ecological momentary assessments was conducted using data collected from 98 shift nurses working in Korean hospitals between June 2019 and February 2021. The sleep patterns were recorded using actigraphy. The participants reported their fatigue levels at the beginning and end of each night shift in real time via a mobile link. Linear mixed models were used for the analysis. Nurses spent significantly less time in bed and had shorter sleep durations during consecutive night shifts than on off-duty days, whereas their wake times after sleep onset were much longer on off-duty days than on on-duty days. Fatigue levels were higher on the second and third night-shift days than on the first night-shift days. A shorter time spent in bed and asleep was associated with a greater increase in fatigue levels at the end of the shift than at the beginning. Nurses experience significant sleep deprivation during consecutive night shifts compared with off-duty days, and this sleep shortage is associated with a considerable increase in fatigue levels at the end of shifts. Nurse managers and administrators must ensure sufficient intershift recovery time during consecutive night shifts to increase the time spent in bed and sleeping.

Comparison of Sleep and Physical Activity Metrics From Wrist-Worn ActiGraph wGT3X-BT and GT9X Accelerometers During Free-Living in Adults

Background: ActiGraph accelerometers can monitor sleep and physical activity (PA) during free-living, but there is a need to confirm agreement in outcomes between different models. Methods: Sleep and PA metrics from two ActiGraphs were compared after participants (N = 30) wore a GT9X and wGT3X-BT on their nondominant wrist for 7 days during free-living. PA metrics including total steps, counts, average acceleration—Euclidean Norm Minus One (ENMO) and Mean Amplitude Deviation, intensity gradient, the minimum acceleration value of the most active 10 and 30 min (M10, M30), time spent in activity intensities from vector magnitude (VM) counts, and ENMO cut points and sleep metrics (sleep period time window, sleep duration, sleep onset, and waking time) were compared. Results: Excellent agreement was evident for average acceleration-Mean Amplitude Deviation, counts, total steps, M10, and light PA (VM counts) with good agreement evident from the remaining PA metrics apart from moderate–vigorous PA (VM counts) which demonstrated moderate agreement. Mean bias for all PA metrics were low, as were the limits of agreement for the intensity gradient, average acceleration-Mean Amplitude Deviation, and inactive time (ENMO and VM counts). The limits of agreement for all other PA metrics were >10%. Excellent agreement, low mean bias, and narrow limits of agreement were evident for all sleep metrics. All sleep and PA metrics demonstrated equivalence (equivalence zone of ≤10%) apart from moderate–vigorous PA (ENMO) which needed an equivalence zone of 16%. Conclusions: Equivalent estimates of almost all PA and sleep metrics are provided from the GT9X and wGT3X-BT worn on the nondominant wrist.

Effectiveness of propofol in anesthetic management and cognitive function in schizophrenic patients undergoing convulsion-free modified electroconvulsive therapy.

To investigate the effects of propofol on anesthetic effectiveness and cognitive functioning in schizophrenic patients undergoing convulsion-free modified electroconvulsive therapy (MECT). A retrospective analysis was conducted on the clinical data of 80 schizophrenia patients treated with MECT at the Affiliated Brain Hospital of Guangzhou Medical University from January 2021 to December 2023. Patients were divided into a control group (39 patients) receiving etomidate and an observation group (41 patients) receiving a combination of etomidate and propofol for general anesthesia induction. Parameters compared between the groups included systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), arterial oxygen saturation (SaO2), time to spontaneous respiration recovery, wakefulness time, cognitive function (assessed by the Wechsler Adult Intelligence Scale-Revised in China, WAIS-RC), symptom severity (measured by the Positive and Negative Syndrome Scale, PANSS), and adverse reactions. No significant differences were observed in SBP, DBP, HR, and SaO2 between the groups over time, nor was there any interaction between group and time on these parameters (all P>0.05). However, the observation group showed significantly shorter times to spontaneous respiration recovery and wakefulness (both P<0.05). Post-treatment, the observation group also had higher WAIS-RC scores and lower PANSS scores, along with a reduced total incidence of adverse reactions (all P<0.05). Propofol for the induction of general anesthesia in MECT, enhances clinical anesthetic outcomes, diminishes the impact on cognitive functions, and reduces the incidence of adverse reactions, thereby suggesting its high safety and efficacy.

Altitude effect on Propofol Pharmacokinetics in Rats.

Propofol is an intravenous agent for clinical anesthesia. As the influence of the hypobaric-hypoxic environment (Qinghai-Tibetan region, altitude: 2800-4300 m, PaO2: 15.1-12.4 kPa) on the metabolism of Propofol is complex, the research results on the metabolic characteristics of Propofol in high-altitude areas remain unclear. This study aimed to investigate the pharmacokinetic characteristics of Propofol in a high-altitude hypoxic environment using animal experiments. Rats were randomly divided into three groups: high-altitude, medium-altitude, and plain groups. The time of disappearance and recovery of the rat righting reflex was recorded as the time of anesthesia induction and awakening, respectively. The plasma concentration of Propofol was determined by gas chromatography-mass spectrometry. A pharmacokinetic analysis software was used to analyze the blood-drug concentrations and obtain the pharmacokinetic parameters. We observed that when Propofol anesthetizes rats, the anesthesia induction time was shortened, and the recovery time was prolonged with increased altitude. Compared with the plain group, the clearance of Propofol decreased, whereas the half-life, area under the concentration-time curve, peak plasma concentration, and average residence time extension increased. The pharmacokinetic characteristics of Propofol are significantly altered in high-altitude hypoxic environments.

Extending weeknight sleep duration in late-sleeping adolescents using morning bright light on weekends: a 3-week maintenance study.

Our sleep extension intervention in adolescents showed that gradually shifting weekday bedtime earlier plus one weekend of morning bright light advanced circadian phase and increased weeknight sleep duration. Here, we examine at-home maintenance of these changes. Fourteen adolescents (15.3-17.9 years; 7 female) completed a 7-week study. After usual sleep at home (2-week baseline), intervention participants (n = 8) gradually advanced weekday bedtime (1 hour earlier than baseline during week 3; 2 hours earlier in week 4) and received bright light (~6000 lux; 2.5 hours) on both mornings of the intervening weekend. During three maintenance weeks, intervention participants were instructed to maintain their school-day wake-up time on all days, keep their early week four bedtimes, except on weekends when they could go to bed up to 1 hour later, and get a 2.5-hour light box exposure within 5 minutes of waking on one morning (Saturday orSunday) of both weekends at home. Control participants (n = 6) slept as usual at home and did not receive weekend bright light. Dim light melatonin onset (DLMO) was measured after the 2-week baseline, 2-week intervention, and 3-week maintenance in all participants. Actigraphic sleep-wake was collected throughout. After the 2-week intervention, DLMOs advanced more compared to control (37.0 ± 40.0 minutes vs. -14.7 ± 16.6 minutes), weekday sleep duration increased by 69.7 ± 27.8 minutes and sleep onset was 103.7 ± 14.2 minutes earlier compared to baseline. After three maintenance weeks, intervention participants showed negligible DLMO delays (-4.9 ± 22.9 minutes); weekday fall-asleep times and sleep durations also remained stable. Early circadian phase and extended sleep can be maintained with at-home weekend bright light.

Longitudinal changes in sleep and sleep-related symptoms among Korean adults between 2010 to 2022, including the COVID-19 pandemic period.

The coronavirus disease 2019 (COVID-19) pandemic has significantly impacted people's lifestyles, changing sleep patterns. This study investigated changes in sleep patterns and disturbances in South Koreans over the past decade, including during the pandemic. We compared data from the Korean Sleep Headache Society Phase I survey (n = 2484; conducted in 2010) and the National Sleep Survey of South Korea 2022 (n = 3729; conducted in 2022), involving participants aged 20-69 years. Changes in sleep schedule, sleep duration, social jet lag, insomnia, and daytime sleepiness were explored. Workday bedtimes were advanced and free-day bedtimes and workday and free-day waking times were delayed during the pandemic. Increased circadian preference for eveningness and social jet lag were noted. A significant decrease in sleep duration and sleep efficiency, along with an increased prevalence of insomnia and daytime sleepiness, was noted with age- and sex-specific variations. Over the past decade, including during the COVID-19 pandemic, sleep habits have changed significantly and sleep problems worsened. This study emphasize the need for more comprehensive public health strategies and research to facilitate sleep recovery in the post-pandemic period within a society known for its high prevalence of sleep deprivation.

Accelerometry-assessed physical activity and sedentary behavior patterns using single- and multi-component latent class analysis among postmenopausal women.

Patterns of physical activity and sedentary behavior among postmenopausal women are not well characterized. To describe the patterns of accelerometer-assessed physical activity and sedentary behavior among postmenopausal women. Cross-sectional study. Women 63-97 years (n = 6126) wore an ActiGraph GT3X + accelerometer on their hip for 1 week. Latent class analysis was used to classify women by patterns of percent of wake time in physical activity and sedentary behavior over the week. On average, participants spent two-thirds of their day in sedentary behavior (62.3%), 21.1% in light low, 11.0% in light high, and 5.6% in moderate-to-vigorous physical activity. Five classes emerged for each single-component model for sedentary behavior and light low, light high, and moderate-to-vigorous physical activity. Six classes emerged for the multi-component model that simultaneously considered the four behaviors together. Unique profiles were identified in both single- and multi-component models that can provide new insights into habitual patterns of physical activity and sedentary behavior among postmenopausal women. The multi-component approach can contribute to refining public health guidelines that integrate recommendations for both enhancing age-appropriate physical activity levels and reducing time spent in sedentary behavior.

Evaluation of the Application Effect of Rapid Rehabilitation Surgery Concept in Nursing

Objective: To analyze the clinical value of perioperative nursing for children with laparoscopic high ligation of hernia sac under the guidance of the concept of rapid rehabilitation surgery. Methods: A total of 74 children with laparoscopic high ligation of hernia sac were selected from March 2021 to March 2022 in our hospital. Random number table method was used to divide them into an average group of 37 children. the control group was given routine perioperative care, and the observation group was given rapid rehabilitation surgery perioperative care. the postoperative recovery, complication rate and nursing satisfaction of parents were compared between the two groups. Results: the time of wake up, exhaust time, out of bed activity time and hospital stay in the observation group were shorter than those in the control group (P &lt; 0.05). the incidence of postoperative pain was 32.42% in the observation group and 59.46% in the control group, P &lt; 0.05; Postoperative complications were 5.41% in the observation group and 18.92% in the control group, P &lt; 0.05; Parents' nursing satisfaction in the observation group and the control group was 100.00% and 89.19% respectively, P &lt; 0.05. Conclusion: Perioperative nursing of rapid rehabilitation surgery for children with laparoscopic high ligation of hernia sac can promote postoperative rehabilitation, reduce complication rate and harmonize nurse-patient relationship.

Effect of digital monitoring and counselling on self-management ability in patients with rheumatoid arthritis: a randomised controlled trial.

To assess a remote physiotherapist (PT) counselling intervention using self-monitoring tools for improving self-management ability, physical activity participation, and health outcomes in people with rheumatoid arthritis (RA). Eligible participants were randomly assigned to receive group education, a Fitbit®, a self-monitoring app, and PT counselling phone calls (Immediate Group). The Delayed Group received a monthly e-newsletter until week 26, and then the intervention. The primary outcome was Patient Activation Measure (PAM-13). Participants were assessed at baseline, 27 weeks (the primary end point) and 53 weeks. Secondary outcomes included disease activity, pain, fatigue, depression, sitting/walking habits, daily physical activity time, and daily awake sedentary time. Generalized Linear Mixed-effect Models (GLMMs) were used to assess the effect of the intervention on the change of each outcome measure from the initiation to 27 weeks after the intervention. Analysis included 131 participants (91.6% women; 80.2% completed during the COVID-19 pandemic). The mean change of PAM-13 at 27 weeks was 4.6 (SD = 14.7) in the Immediate Group vs -1.6 (SD = 12.5) in the Delayed Group. The mean change in Delayed Group at 53 weeks (after the 26-week intervention) was 3.6 (SD = 14.6). Overall, the intervention improved PAM-13 at 27 weeks post-intervention from the GLMM analysis (adjusted coefficient: 5.3; 95% CI: 2.0, 8.7; p = <0.001). Favourable intervention effects were also found in disease activity, fatigue, depression, and self-reported walking habit. Remote counselling paired with self-monitoring tools improved self-management ability in people with RA. Findings of secondary outcomes indicate that the intervention had a positive effect on symptom management.

Dissipation of Motor Sleep Inertia and Motor Wake Inertia in Early Relapsing–Remitting Multiple Sclerosis

While previous studies have described the time course of the dissipation of motor sleep inertia (around 70 min after wake-up time) and motor wake inertia (around 20 min after bedtime) in healthy controls (HCs), the corresponding knowledge for persons with early relapsing–remitting multiple sclerosis (RRMS) is lacking. To fill in this knowledge gap, we carried out a secondary analysis of previously collected data in 35 persons (24 females; mean age = 31.51 ± 7.74 years) with early relapsing–remitting multiple sclerosis (RRMS) and 35 (24 females; mean age = 31.29 ± 8.02) healthy controls (HCs). Each participant wore an actigraphic Micro Motionlogger Watch (Ambulatory Monitoring, Ardlsey, NY, USA) for seven consecutive days. The Functional Linear Modeling statistical framework was adopted to compare the dissipation of motor sleep inertia as well as motor wake inertia between RRMS and HC. As regards motor sleep inertia, no significant differences in motor activity were observed in the first 70 min after the wake-up time; however, with reference to motor wake inertia, the motor activity of RRMS persons was significantly higher than HCs in approximately the first 30 min after bedtime. Despite the small sample size, this pattern of results suggests that the dissipation of motor wake inertia is only slower in persons with RRMS as opposed to HCs.

Contributions of the light environment and co-sleeping to sleep consolidation into nighttime in early infants: A pilot study

BackgroundSleep consolidation into nighttime is considered the primary goal of sleep development in early infants. However, factors contributing to sleep consolidation into nighttime remain unclear. AimTo clarify the influences of the light environment and nighttime co-sleeping on sleep consolidation into nighttime in early infants. Study designCross-sectional study. Subjects and methodsSleep–wake time and light stimulation were measured in infants for 4 consecutive days using actigraphy. The infants’ mothers were asked to complete a sleep events diary and a questionnaire about childcare, including “co-sleeping”, defined as when the infant and mother slept on the same surface throughout the night. Outcome measuresThe data were analyzed with a focus on daytime and nighttime sleep parameters. ResultsDaytime light stimulation reduced daytime “active sleep”, tended to reduce daytime sleep, and increased daytime waking. Nighttime light stimulation reduced nighttime “quiet sleep” and nighttime sleep and increased nighttime waking. Co-sleeping reduced nighttime waking, and, as a result, nighttime sleep time and sleep efficiency increased. Co-sleeping reduced daytime sleep and tended to increase daytime waking. Consequently, co-sleeping tended to increase the ratio of nighttime sleep to daytime sleep. ConclusionsThe present findings suggest that an appropriate light environment promotes daytime waking and nighttime sleep in early infants, but it does not contribute to sleep consolidation into nighttime by itself. On the other hand, co-sleeping may promote sleep consolidation into nighttime. Therefore, further methods for safe co-sleeping need to be established while avoiding risk factors for sudden unexpected death in infancy/sudden infant death syndrome.

Cardiorespiratory fitness and circadian rhythms in adolescents: a pilot study.

Although cardiorespiratory fitness (CRF), an important marker of youth health, is associated with earlier sleep/wake schedule, its relationship with circadian rhythms is unclear. This study examined the associations between CRF and rhythm variables in adolescents. Eighteen healthy adolescents (10 females and 8 males; Mage = 14.6 ± 2.3 yr) completed two study visits on weekdays bracketing an ambulatory assessment during summer vacation. Visit 1 included in-laboratory CRF assessment (peak V̇o2) using a ramp-type progressive cycle ergometry protocol and gas exchange measurement, which was followed by 7-14 days of actigraphy to assess sleep/wake patterns and 24-h activity rhythms. During Visit 2, chronotype, social jetlag (i.e., the difference in midsleep time between weekdays and weekends), and phase preference were assessed using a questionnaire, and hourly saliva samples were collected to determine the dim light melatonin onset (DLMO) phase. All analyses were adjusted for sex, pubertal status, and physical activity. Greater peak V̇o2 was associated with earlier sleep/wake times and circadian phase measures, including acrophase, UP time, DOWN time, last activity peak (LAP) time, and chronotype (all P < 0.05). Peak V̇o2 was negatively associated with social jetlag (P = 0.02). In addition, the mixed-model analysis revealed a significant interaction effect between peak V̇o2 and actigraphy-estimated hour-by-hour activity patterns (P < 0.001), with the strongest effects observed at around the time of waking (0600-1000). In healthy adolescents, better CRF was associated with an earlier circadian phase and increased activity levels notably during the morning. Future studies are needed to investigate the longitudinal effects of the interactions between CRF and advanced rhythms on health outcomes.NEW & NOTEWORTHY In healthy adolescents, better cardiorespiratory fitness, as assessed by the gold standard measure [laboratory-based assessment of peak oxygen consumption (V̇o2)], was associated with earlier circadian timing of sleep/wake patterns, rest-activity rhythms and chronotype, and less social jetlag. These findings highlight the close interrelationships between fitness and rhythms and raise the possibility that maintaining higher cardiorespiratory fitness levels alongside earlier sleep/wake schedule and activity rhythms may be important behavioral intervention targets to promote health in adolescents.

ASSOCIATIONS OF NIGHT AND DAY SLEEP WITH COGNITIVE PERFORMANCE IN SHIFT WORKERS: PRELIMINARY RESULTS

Abstract Emerging evidence suggests that night shift workers are at higher risk of severe cognitive impairment, mainly because of the repeated disruption of the sleep–wake schedule and the resulting poor sleep (e.g., less deep sleep or shorter sleep time). However, questions remain about how daytime and nighttime sleep characteristics correlate with cognitive performance in shift workers. The purpose of this study is to examine the association of objective sleep quality, measured on workdays and days off, with cognitive performance, determined by the psychomotor vigilance task (PVT), in shift workers compared to day workers. We included eight night shift and ten day shift workers from an ongoing pilot study in this analysis. Participants undergo multiple home sleep studies with electroencephalograms on their workdays or days off. Sleep quality measures include total sleep time (TST), percentage of deep sleep stage in TST, and wake time after sleep onset (WASO). Night shift workers showed longer TST and shorter WASO during their nighttime sleep on days off compared to day shift workers. In night shift workers, longer deep sleep on days off was significantly correlated with faster mean reaction time to a visual stimulus (better cognitive performance) on the PVT (r = -.944, p = .016), after controlling for age. However, longer deep sleep during their daytime sleep was associated with slower reaction time (r = .756, p = .049). Further studies are necessary to elucidate differential impacts of daytime and nighttime sleep on the risk of future cognitive impairment in night shift workers.

SOLITUDE LINKS WITH INDIVIDUAL AND RELATIONAL WELL-BEING: EVIDENCE FROM DYADIC DAILY LIFE ASSESSMENTS

Abstract Solitude, defined as physical aloneness or the absence of social interactions, has been associated with both positive and negative outcomes. Older adults spend a significant amount of their waking time by themselves (exacerbated during the pandemic), but they may be better equipped to regulate the negative emotions that are often linked with being alone. Additionally, solitude may provide a balance between social connectedness and autonomous needs. Using pandemic, end-of-day daily diary data across 10 days from 136 older Canadian adults and a close other of their choice (59% spouses, M = 66.49 years, SD = 13.26 range: 18-87 years, 88% White, 62% women), this project aims to examine associations of actor and partner solitude with relationship quality and daily affect. Multilevel models revealed that participants who reported more voluntary solitude experienced more daily positive affect and those who reported more negative solitude experienced both more negative affect and less positive affect at both daily and overall levels. We also found daily partner effects such that more voluntary solitude of the partner was associated with less actor negative affect and negative solitude of the partner being associated with less actor positive affect and more negative affect over and above actor effects. Finally, when partners reported more voluntary solitude, participants reported higher relationship support. Findings shed light on the benefits and drawbacks of how solitude is experienced in older adulthood, highlighting the influence social partners affect quality and relationship satisfaction.

Examining Human-Smartphone Interaction as a Proxy for Circadian Rhythm in Patients With Insomnia: Cross-Sectional Study.

The sleep and circadian rhythm patterns associated with smartphone use, which are influenced by mental activities, might be closely linked to sleep quality and depressive symptoms, similar to the conventional actigraphy-based assessments of physical activity. The primary objective of this study was to develop app-defined circadian rhythm and sleep indicators and compare them with actigraphy-derived measures. Additionally, we aimed to explore the clinical correlations of these indicators in individuals with insomnia and healthy controls. The mobile app "Rhythm" was developed to record smartphone use time stamps and calculate circadian rhythms in 33 patients with insomnia and 33 age- and gender-matched healthy controls, totaling 2097 person-days. Simultaneously, we used standard actigraphy to quantify participants' sleep-wake cycles. Sleep indicators included sleep onset, wake time (WT), wake after sleep onset (WASO), and the number of awakenings (NAWK). Circadian rhythm metrics quantified the relative amplitude, interdaily stability, and intradaily variability based on either smartphone use or physical activity data. Comparisons between app-defined and actigraphy-defined sleep onsets, WTs, total sleep times, and NAWK did not reveal any significant differences (all P>.05). Both app-defined and actigraphy-defined sleep indicators successfully captured clinical features of insomnia, indicating prolonged WASO, increased NAWK, and delayed sleep onset and WT in patients with insomnia compared with healthy controls. The Pittsburgh Sleep Quality Index scores were positively correlated with WASO and NAWK, regardless of whether they were measured by the app or actigraphy. Depressive symptom scores were positively correlated with app-defined intradaily variability (β=9.786, SD 3.756; P=.01) and negatively correlated with actigraphy-based relative amplitude (β=-21.693, SD 8.214; P=.01), indicating disrupted circadian rhythmicity in individuals with depression. However, depressive symptom scores were negatively correlated with actigraphy-based intradaily variability (β=-7.877, SD 3.110; P=.01) and not significantly correlated with app-defined relative amplitude (β=-3.859, SD 12.352; P=.76). This study highlights the potential of smartphone-derived sleep and circadian rhythms as digital biomarkers, complementing standard actigraphy indicators. Although significant correlations with clinical manifestations of insomnia were observed, limitations in the evidence and the need for further research on predictive utility should be considered. Nonetheless, smartphone data hold promise for enhancing sleep monitoring and mental health assessments in digital health research.