Time Asleep Research Articles

8352 Association Between Sleep and Physical Activity Among Women with Obesity and Infertility

Abstract Disclosure: K. Brûlé: None. F. Jean-Denis: None. M. Belan: None. M. Langlois: None. S. Ruchat: None. J. Baillargeon: Grant Recipient; Self; Ferring Pharmaceuticals. BACKGROUND: Infertility affects up to 15% of couples and a major modifiable risk factor is obesity. Thus, it has been recommended that women with obesity should be assisted to adopt healthy lifestyle behaviors prior to conception. Also, individuals with obesity often present reduced sleep quantity and quality, which could affect their physical activity (PA) practice. On the other hand, PA seems to improve sleep quality. Regular practice of PA could also improve an individual’s functional capacity, and thus could be an objective measure of a person's level of PA. Hence, our study aimed to: 1) compare the sleep quantity of women with obesity and infertility to the Canadian population; and 2) determine the relationship between their PA practice, functional capacity and sleep quantity and quality. Methods: This cross-sectional study is nested within a multicenter randomized controlled trial recruiting women of 18-40 years old with obesity and infertility in Canadian fertility clinics. At their initial research visit, they were assessed for body mass index (BMI), functional capacity (distance at 6-min walk test); total energy expenditure (EE, kcal/day), total PA (steps/day) and time spent in light (min/day) or moderate-to-vigorous physical activity (MVPA, min/day) or sedentarity (min/day) (Fitbit monitor); as well as sleep quality and duration (Pittsburgh Sleep Quality Index questionnaire and Fitbit monitor), and total time asleep per night (Fitbit monitor). For the Canadian population, we used the mean sleep duration of women aged 18-60 years reported in the Canadian Community Health Survey of 2020. Associations were tested using Pearson’s correlations (some measures were made normally distributed by square root transformation). Results: A total of 98 women (mean age = 31.5 years and mean BMI = 39.2 kg/m2) from 5 centers were included, 48% of whom were recruited in Sherbrooke (Qc). Their sleep duration was significantly lower than that of Canadian women (7.2±1.1 vs 8.1 h; p<0.001). Poor perceived sleep quality was negatively associated with EE (r=-0.271; p=0.020) and steps (r=-0.280; p=0.026), but directly with sedentary time (r=0.277; p=0.033). Light PA was negatively associated with measured sleep duration (r=-0.241; p=0.016), but positively associated with measured sleep efficiency (r=0.237; p=0.036). Functional capacity is positively associated with measures of EE, steps and MVPA (r=0.239 to 0.347; p=0.005 to 0.031), and there is a tendency with total time asleep (r=0.238, p=0.061). Conclusion: Canadian women with obesity and infertility have, on average, less sleep time than women in the general Canadian population. Their PA practice is associated with better perceived sleep quality but does not improve their sleep quantity per se. Furthermore, the association between their functional capacity and PA practice suggests that it is a valid objective indirect measure of PA practice. Presentation: 6/1/2024

Self-supervised learning of accelerometer data provides new insights for sleep and its association with mortality

Sleep is essential to life. Accurate measurement and classification of sleep/wake and sleep stages is important in clinical studies for sleep disorder diagnoses and in the interpretation of data from consumer devices for monitoring physical and mental well-being. Existing non-polysomnography sleep classification techniques mainly rely on heuristic methods developed in relatively small cohorts. Thus, we aimed to establish the accuracy of wrist-worn accelerometers for sleep stage classification and subsequently describe the association between sleep duration and efficiency (proportion of total time asleep when in bed) with mortality outcomes. We developed a self-supervised deep neural network for sleep stage classification using concurrent laboratory-based polysomnography and accelerometry. After exclusion, 1113 participant nights of data were used for training. The difference between polysomnography and the model classifications on the external validation was 48.2 min (95% limits of agreement (LoA): −50.3 to 146.8 min) for total sleep duration, −17.1 min for REM duration (95% LoA: −56.7 to 91.0 min) and 31.1 min (95% LoA: −67.3 to 129.5 min) for NREM duration. The sleep classifier was deployed in the UK Biobank with ~100,000 participants to study the association of sleep duration and sleep efficiency with all-cause mortality. Among 66,262 UK Biobank participants, 1644 mortality events were observed. Short sleepers (<6 h) had a higher risk of mortality compared to participants with normal sleep duration 6–7.9 h, regardless of whether they had low sleep efficiency (Hazard ratios (HRs): 1.36; 95% confidence intervals (CIs): 1.18 to 1.58) or high sleep efficiency (HRs: 1.29; 95% CIs: 1.04–1.61). Deep-learning-based sleep classification using accelerometers has a fair to moderate agreement with polysomnography. Our findings suggest that having short overnight sleep confers mortality risk irrespective of sleep continuity.

Immediate effects of Ramadan on objective time asleep in male youth football players from the Middle East: an interrupted time-series study

ABSTRACT Objective To examine the abrupt effects of Ramadan onset on actigraphy-based time asleep in male youth Muslim football players. Methods We adopted a quasi-experimental, interrupted time-series research design and tracked objective time asleep over a minimum of 12 consecutive nights in the two weeks prior to and immediately after Ramadan onset, respectively. Twenty-two, male academy student-athletes (chronological age range: 12.6 to 16.2 years) participated in the study (464 individual observations). Segmented generalized mixed-effects modelling estimated the effects of Ramadan onset on time asleep during the first period of night sleep only. Results Ramadan onset led to an immediate mean reduction of 89 min (95% confidence interval [CI], 54 to 123 min) in time asleep during the first period of night sleep compared to pre-Ramadan sleep patterns. Model-adjusted estimated marginal means for time asleep were ~ 5.7 h (95%CI, 5.1 to 6.2 h) before and ~ 4.2 h (95%CI, 3.6 to 4.7 h) after Ramadan onset. Night sleep interruptions resulting in two or more fragmented periods accounted for 8% (95%CI, 2 to 21%) to 19% (95%, 11 to 29%) of sleep observations before and after Ramadan onset, respectively. Conclusions The onset of Ramadan determined an abrupt reduction in time asleep of ~ 1 h 30 min in the first period of a night cycle and contributed to additional problems of heterogeneous sleep fragmentation that can impact optimal school learning and youth athlete performance development processes.

Analysis of Sleep, Nocturnal Physiology, and Physical Demands of NCAA Women's Ice Hockey Across a Championship Season.

Merrigan, JJ, Stone, JD, Kraemer, WJ, Friend, C, Lennon, K, Vatne, EA, and Hagen, JA. Analysis of sleep, nocturnal physiology, and physical demands of NCAA women's ice hockey across a championship season. J Strength Cond Res 38(4): 694-703, 2024-The aims of this study were to evaluate the (a) relationships between daily physical demands and nighttime sleep, heart rate (HR), and heart rate variability (HRV); (b) weekly changes in physical demands and sleep; and (c) differences among positions and between training and competition during a competitive season in National Collegiate Athletic Association (NCAA) women's ice hockey. Twenty-five NCAA Division I women's ice hockey athletes wore a sensor at night to monitor sleep quantity or quality (e.g., time asleep and sleep efficiency) and physiology (e.g., HR and HRV). During training and competitions (31 regular season and 7 postseason), athletes wore performance monitoring systems to assess workload demands (e.g., training impulse and TRIMP). As internal workload (TRIMP, Time >80% of HRmax, Average HR) during training or competition increased, nocturnal HRV decreased, HR increased, and Sleep Duration, Sleep Score, and Readiness Score decreased that night. Across the season, athletes experienced lower HRV, but exhibited longer sleep durations. Training Distance, Duration, Time >80% HRmax, Average HR, and TRIMP decreased, whereas competition Total Distance, Duration, and TRIMP increased across weeks throughout the season. There were differences across positions and season blocks when evaluating these data at the mesocycle level. Athletes slept longer before competition compared with training, but physiological data did not differ. Competitions had greater physiological demands than training. We speculate that the increased focus on sleep hygiene, as evidenced by the increase in sleep over the season, may have served as a recovery aid to combat physiological stress of accumulated demands of competitions that increased over time into postseason tournaments.

Night-to-night variability of objective sleep outcomes in youth Middle Eastern football players

ObjectiveTo describe components of night-to-night variation in objective measures of sleep. MethodsWe conducted a secondary data analysis of consecutive and chronologically ordered actigraphy-based measurements for time in bed (min), time asleep (min), and wake-after-sleep onset (min). This investigation examined 575 individual night-based measures available for a sub-sample of fifty-two, male youth Middle Eastern football players tracked over a 14-day surveillance period (chronological age range: 12.1 to 16 years). Distinct multivariable-adjusted generalized additive models included each objective sleep outcome measure as dependent variable and disaggregated components of variation for night measurement-by-sleep period interaction, week part (weekday or weekend), and study participant random effects from within-subject night-to-night sleep variation. ResultsThe within-subject standard deviation (SD) of ±98 min (95% confidence interval [CI], 92 to 104 min) for time in bed, ±87 min (95%CI, 82 to 93 min) for time asleep, and ±23 min (95%CI, 22 to 25 min) for wake-after-sleep-onset overwhelmed other sources of variability and accounted for ∼44% to 53% of the overall night-to-night variation. The night measurement-by-fragmented sleep period interaction SD was ±83 min (95%CI, 44 to 156 min) for time in bed, ±67 min (95%CI, 34 to 131 min) for time asleep, and ±15 min (95%CI, 7 to 32 min) for wake-after-sleep-onset that accounted for ∼22% to 32% of each sleep outcome measure overall variability. ConclusionsSubstantial random night-to-night within-subject variability poses additional challenges for strategies aiming to mitigate problems of insufficient and inconsistent sleep that are detrimental to school learning and youth athlete development processes.

Abstract 15635: Sex Differences in the Effect of Nocturnal Hypoxia on Right Ventricular Myocardial Blood Flow

Introduction: Nocturnal hypoxia is common in patients with obstructive sleep apnea (OSA). However, it is unclear how nocturnal hypoxia affects the structure and function of the right ventricle (RV), and if there are sex differences in the impact of nocturnal hypoxia on RV dysfunction. We examined the sex-specific relationship between nocturnal hypoxia, as measured as T90% (time asleep with &lt;90% oxygen saturation), and RV myocardial blood flow (MBF) and myocardial flow reserve (MFR). Methods: RV MBF and MFR were examined for 78 patients who had a cardiac PET stress test and a sleep test between 2015 to 2019. MBF was analyzed using FlowQuant software (Ottawa, Canada). MFR was defined as the ratio of stress to rest MBF. We categorized reduced RV MFR as &lt; 2.3 (corresponding to the median value) and nocturnal hypoxia as T90 ≥ 8%. Results: The mean (± SD) age was 63 ± 10 years. Most patients (83%) were obese (BMI ≥ 30kg/m3). Fifty-one patients (63%) were female. Although not statistically significant, the median RV MFR was higher among females (2.4 vs. 2.2, p = 0.158). RV MFR was higher among those without nocturnal hypoxia compared to those with nocturnal hypoxia (2.4 vs. 2.0, p = 0.023). Among females, the median RV MFR was higher among those without significant nocturnal hypoxia (2.5 vs. 1.8, p = 0.004), while males showed no relationship (2.2 vs. 2.2, p = 0.696; see table for details). In age and BMI adjusted logistic regression analysis, patients with nocturnal hypoxia were 3X as likely to have reduced RV MFR (OR = 3.2, 95% CI: 1.1 - 9.3) and there was a significant statistical interaction by sex (p = 0.046). Conclusions: These findings suggest that nocturnal hypoxia is associated with a reduction in RV MFR, more prominently among females. Future studies should focus on elucidating the pathophysiologic implications of our findings and understanding the biologic processes that account for the sex differences observed.

A Pilot Randomized Control Trial Demonstrating the Efficacy of the SIESTA Sleep Hygiene Intervention.

Shorter sleep duration can negatively impact children's daytime functioning and health. Latino children living near urban areas in the Mainland U.S. and Island Puerto Rico (PR) can be exposed to urban poverty and sociocultural stressors that challenge optimal sleep outcomes. Interventions to improve urban Latino children's sleep health should consider families' cultural background and environmental context to enhance acceptability and feasibility. This work describes our stepwise, multimethod approach to adapting a culturally and contextually tailored "School Intervention to Enhance Latino Students' Time Asleep (SIESTA)" for sixth- to eighth-grade Latino children residing in Greater Providence and San Juan and findings from a pilot randomized control trial (RCT) demonstrating SIESTA's efficacy. Results indicated high acceptability and greater improvement of sleep duration and behaviors in SIESTA versus control participants. The SIESTA shows potential to improve sleep outcomes in urban Latino middle schoolers. Results will inform a large-scale RCT to evaluate SIESTA's effectiveness and barriers to implementation.

O.4.5-1 Device-measured physical activity and sedentary time in a national sample of Luxembourg residents: moving beyond the traditional metrics in the ORISCAV-LUX 2 study

Abstract Purpose This is the first study aiming at describing the volume and pattern of device-measured movement behaviours performed by adults living in Luxembourg, spanning the full intensity spectrum, and including markers of sedentary time accumulation. We also demonstrated the added value of a multidimensional approach for the comparison of sub-populations. Methods This observational study included Luxembourg residents aged 18-79y who each provided ≥4 valid days of triaxial accelerometry in 2016-18 (n = 1122). Compliance with the current international physical activity (PA) guideline was quantified. Linear regression models were used to quantify variability in average 24h acceleration (indicative of PA volume), awake-time PA levels, sedentary time and accumulation pattern with sociodemographic characteristics and other covariates. Data were weighted to be nationally representative. Results Overall, participants spent 51% of daily sedentary time (12.1 h/day), 11% in light PA (2.7 h/day), 6% in moderate to vigorous PA (MVPA; 1.5 h/day), and remaining time asleep (7.7 h/day). Adherence to the current PA guideline was high (98.1%), but drop to 22% when including only bouts &amp;gt;10min. Although time spent in MVPA did not differ between women and men, average 24h acceleration and light PA were higher in women than men, while men achieved higher average accelerations across the most active periods of the day. Women performed less sedentary time and shorter sedentary bouts. Older participants (≥55y) registered a lower average 24h acceleration and engaged in less MVPA, more sedentary time and longer sedentary bouts. Average 24h acceleration was higher in participants of lower educational attainment, who also performed less sedentary time, shorter bouts, and fewer bouts of prolonged sedentariness. Average 24h acceleration and levels of PA were higher in participants with standing and manual occupations than a sedentary work type, but manual workers registered lower average accelerations across the most active periods of the day. Standing and manual workers accumulated less sedentary time and fewer bouts of prolonged sedentariness than sedentary workers. Conclusions Traditional metrics may incompletely reflect differences in the physical behaviour between sub-populations. Breaking up continuous sedentary periods and replacing sedentary time with active alternatives should be the focus of public health initiatives in Luxembourg. Funding Luxembourg Institute of Health.

Start-of-day oculomotor screening demonstrates the effects of fatigue and rest during a total immersion training program

BackgroundInvestigating changes in sleep and fatigue metrics during intensive surgical and trauma skills training, this study explored the dynamic association between oculomotor metrics and fatigue. Specifically, alterations in these relations over extended stress exposure, the influence of time of day, and the impact of fatigue exposure on sleep metrics were examined. MethodsThirty-nine military medical students participated in 6 days of immersion, hyper-realistic, and high-stress experiential casualty training. Participants completed surveys assessing the state of sleepiness with oculomotor tests performed each morning and evening, analyzing eye movement and pupillary change to characterize fatigue. Participants wore Fitbit TM devices to measure overall time asleep and time in each sleep stage during the training. ResultsFitbit data showed increased average minutes in rapid eye movement, deep sleep, and less time in light sleep from day 1 to day 4. The microsaccade peak velocity-to-displacement ratio exhibited a morning decrease but not in afternoon sessions, indicating repeated but temporary effects of accumulated fatigue. There were no findings regarding pupil reactivity to illumination changes. ConclusionThis study describes characteristics of fatigue measured by rapid and individually calibrated oculomotor tests. It demonstrates oculomotor relationships to fatigue in start-of-day testing, providing a direction for timing for optimal fatigue testing. These data suggest that improved sleep could signal resilience to fatigue during afternoon testing. Further investigation with more participants and longer duration is warranted. A deeper understanding of the interrelationships between training, sleep, and fatigue could improve surgical and military fitness.

Assessing the Feasibility of Replacing Subjective Questionnaire-Based Sleep Measurement with an Objective Approach Using a Smartwatch

In order to ensure sufficient recovery of the human body and brain, healthy sleep is indispensable. For this purpose, appropriate therapy should be initiated at an early stage in the case of sleep disorders. For some sleep disorders (e.g., insomnia), a sleep diary is essential for diagnosis and therapy monitoring. However, subjective measurement with a sleep diary has several disadvantages, requiring regular action from the user and leading to decreased comfort and potential data loss. To automate sleep monitoring and increase user comfort, one could consider replacing a sleep diary with an automatic measurement, such as a smartwatch, which would not disturb sleep. To obtain accurate results on the evaluation of the possibility of such a replacement, a field study was conducted with a total of 166 overnight recordings, followed by an analysis of the results. In this evaluation, objective sleep measurement with a Samsung Galaxy Watch 4 was compared to a subjective approach with a sleep diary, which is a standard method in sleep medicine. The focus was on comparing four relevant sleep characteristics: falling asleep time, waking up time, total sleep time (TST), and sleep efficiency (SE). After evaluating the results, it was concluded that a smartwatch could replace subjective measurement to determine falling asleep and waking up time, considering some level of inaccuracy. In the case of SE, substitution was also proved to be possible. However, some individual recordings showed a higher discrepancy in results between the two approaches. For its part, the evaluation of the TST measurement currently does not allow us to recommend substituting the measurement method for this sleep parameter. The appropriateness of replacing sleep diary measurement with a smartwatch depends on the acceptable levels of discrepancy. We propose four levels of similarity of results, defining ranges of absolute differences between objective and subjective measurements. By considering the values in the provided table and knowing the required accuracy, it is possible to determine the suitability of substitution in each individual case. The introduction of a “similarity level” parameter increases the adaptability and reusability of study findings in individual practical cases.

0501 Manganese and sleep health outcomes in U.S. adults: analysis of the NHANES 2017-2020

Abstract Introduction Manganese (Mn) is an essential trace mineral required for normal growth and physiological processes. However, inadequate or excess Mn can have a detrimental impact on human health. Despite the essentiality, little is known about the relationship between Mn and sleep. The objective of this study is to examine the relationships between blood Mn levels and sleep patterns (duration, midpoint of sleep, obstructive sleep apnea [OSA] symptoms, and trouble sleeping) in U.S. adults. Methods Data from the 2017 to 2020 National Health and Nutrition Examination Survey (NHANES) was used for the analysis. Adults aged 18 or older with both blood Mn levels and sleep parameters were included (n=8356). Self-reported fall asleep time and wake up time in the past week were used to calculate sleep duration and midpoint. Trouble sleeping and symptoms of OSA were also collected. Blood Mn levels were divided into quintiles for analysis. Multivariable logistic regressions that accounted for complex study design were used. Results The mean (SE) blood Mn concentration was 9.7 (0.1) µg/L, and was higher among participants who were younger, female, identified as non-Hispanic Asian, had lower income, were non-smokers, and had lower iron levels (P&amp;lt; 0.05, for all). About 25% of adults had short sleep duration (&amp;lt; 7 hours) on weekdays. OSA symptoms were noted in 49% of adults. In men, the odds of short sleep duration on weekdays were higher among those with the lowest Mn level (Q1: &amp;lt; 7.0 µg/L) than the reference group (Q3: 8.5-10.0 µg/L) after adjusting for age, race, income, smoking, and iron (OR: 1.5, 95% CI: 1.1-2.1, P=0.03). Among women, Q2 (7.0-8.4 µg/L) was the related to the lowest odds of OSA symptoms compared to all other groups after adjusting for covariates (P=0.049). Conclusion Lower or higher Mn levels in blood were related to poor sleep health in U.S. adults, which suggests that inadequate or excessive Mn intake might be harmful to sleep. Future studies on the mechanisms of these relationships are needed. Support (if any) This work was supported by National Institutes of Health R01DK123022, R21NS112974 to YAS, and K01HL151673 to ECJ.

The Impact of Using Technological Devices on Mental and Physical Health in Adolescents

Objectives: In recent years, adolescents spend increasingly more time on technologic devices such as smartphones, televisions, computers, and tablets. The aim of the present study was to investigate the relationship between the usage of digital technology and health-related problems among adolescents. Methods: A cross-sectional exploratory study was conducted by using a face-to-face survey administered to a sample of students studying at 4 randomly chosen public middle school and 4 randomly chosen public high school in the city of Istanbul. In this study recruited 1147 volunteer adolescents. All participants were answered a questionnaire regarding the demographic characteristics, technological devices useage patterns and health-related problems. Results: Most of the adolescents had smartphones (99.4%) and the fewest had game consoles (18.2%). The rate of using television and smartphone for more than two hours a day among adolescents was 13.1% and 28.4%, respectively. A decrease in sleep duration, increase in falling asleep time, distraction, fatigue, eating disorders and psychological symptoms were significantly more present for individuals using smartphone more than two hours. A positive and very weak relationship was detected between the duration of smartphone use and neck (r=0.096; p=0.002), wrist (r=0.079; p=0.008) and shoulder (r=0.069; p=0.021) pain. Also, positive and very weak relationship was detected between the duration of computer use and upper back (r=0.102; p=0.001), lower back (r=0.078; p=0.011) and shoulder (r=0.069; p=0.041) pain. Conclusion: This study showed the most widely used technological device among adolescents is smartphones and it was observed that the excessive use of this device among adolescents is more associated with many different health-related problems than other technological devices.

Sleep Disparities Across Pregnancy: A Michigan Cohort Study.

Poor sleep health during pregnancy is related to adverse pregnancy outcomes. This study aims to identify sociodemographic characteristics associated with sleep health during pregnancy and to examine how they relate to changes in sleep during pregnancy. Participants (n = 458) were from the Michigan Archive for Research on Child Health, which is a prospective pregnancy cohort. Sociodemographic characteristics and self-reported sleep timing and quality were collected in phone interviews. This longitudinal study collected sleep parameters once during the early trimesters and once during the third trimester. Fall asleep and wake-up times were used to calculate sleep duration and sleep midpoint. Compared to the third trimester, sleep duration was 12 minutes longer (p = 0.02), fall asleep time was 21 minutes earlier (p < 0.001), and the midpoint of sleep was 12 minutes earlier (p = 0.01) in early trimesters. Shorter sleep duration was noted in younger women. Sleep midpoint was later in those who were younger, overweight, or obese, racial minorities, unmarried, and with lower educational levels or socioeconomic status, and who smoked before pregnancy after adjusting for covariates. After controlling for confounders, women who were not working for pay had higher likelihood of reduced sleep duration, and women who were unmarried were more likely to have a delayed sleep midpoint in the third trimester compared to the early trimesters. This study suggests that sleep parameters changed during pregnancy and sleep health differed by sociodemographic characteristics. Understanding sleep disparities could help with early detection of at-risk populations during prenatal care.

PRELIMINARY EVIDENCE FOR A RELATIONSHIP BETWEEN HEART RATE VARIABILITY AND FATIGUE IN PATIENTS WITH INFLAMMATORY BOWEL DISEASE (IBD)

Abstract INTRODUCTION Heart Rate Variability (HRV), the variation in time between each heartbeat, is a proxy for vagus nerve function and validated indicator of cardiovascular health. Lower HRV is associated with increased risk of cardiac events and greater vulnerability to psychological stress. Fatigue is a common, frustrating and persistent symptom for IBD patients, with multifaceted mechanisms including nutrient deficiencies, inflammation, and poor sleep. Lower HRV is associated with higher fatigue in patients with cancer and myalgic encephalomyelitis. We postulate lower HRV could be associated with fatigue in IBD patients. METHODS Adults recruited from an outpatient IBD clinic wore a FitBit Inspire 2.0 for 14 days to monitor nighttime total time asleep, restlessness (# of ~30 second awakenings), and HRV (RMSSD in milliseconds (ms)). At baseline, weeks 1 and 2, participants completed the IBD Fatigue Scale and Harvey Bradshaw Index (HBI) or Simple Colitis Clinical Activity Index (SCCAI). Baseline laboratory testing for c-reactive protein (CRP), vitamins B12 and D, and ferritin was done. Averages for HRV and sleep metrics were computed for the 14-day period. Pearson’s correlations assessed relationships between all study variables (any p &amp;lt; .10). Then, partial correlations calculated the relationship between HRV and fatigue scores while controlling for identified confounding variables. We report an interim analysis. RESULTS 41 participants (63% female, 72.5% White, 92.7% non-Hispanic, 61% Crohn’s, 40.02 (SD=14.18) yrs old). Most (&amp;gt;75%) were in remission (HBI/SCCAI&amp;lt; 4). 34% had B12&amp;lt; 400 pg/mL, 20% vitamin D&amp;lt; 30 ng/mL, 54% ferritin&amp;lt; 50 ng/mL. Participants slept an average of 6.6 hours with 24.1(5.48) awakenings per night. All reported fatigue, with 43.9% having severe levels. Fatigue severity and impact remained consistent over the study (p=.106). Average HRV was 31.79(19.0) ms (Range: 11 - 92). Older patients had lower HRV (r= -0.34, p=.025) with no gender differences. Patients who reported more fatigue had higher CRP (r= 0.29), more active IBD symptoms (r= 0.62), and spent more time asleep (r= 0.20). When controlling for these variables and age, IBD patients with lower HRV reported significantly more global fatigue (r= -0.38, p=.041). The relationship between HRV and fatigue was larger for lower HRV and fatigue impact (r= -0.37, p=.047) than fatigue severity (r= -0.30, p=.11). No relationships existed for restlessness, vitamins B12 or D, or ferritin and fatigue. CONCLUSIONS When controlling for other contributors, patients with IBD and lower HRV reported more significant global fatigue and impact of fatigue on daily functioning. Findings may suggest lower HRV increases physical feelings of fatigue and reduces ability to manage fatigue impacts. Increasing HRV, e.g., with biofeedback training, may be a way to improve fatigue symptoms and management in IBD.

Device-measured physical activity and sedentary time in a national sample of Luxembourg residents: the ORISCAV-LUX 2 study

BackgroundExisting information about population physical activity (PA) levels and sedentary time in Luxembourg are based on self-reported data.MethodsThis observational study included Luxembourg residents aged 18-79y who each provided ≥4 valid days of triaxial accelerometry in 2016-18 (n=1122). Compliance with the current international PA guideline (≥150 min moderate-to-vigorous PA (MVPA) per week, irrespective of bout length) was quantified and variability in average 24h acceleration (indicative of PA volume), awake-time PA levels, sedentary time and accumulation pattern were analysed by linear regression. Data were weighted to be nationally representative.ResultsParticipants spent 51% of daily time sedentary (mean (95% confidence interval (CI)): 12.1 (12.0 to 12.2) h/day), 11% in light PA (2.7 (2.6 to 2.8) h/day), 6% in MVPA (1.5 (1.4 to 1.5) h/day), and remaining time asleep (7.7 (7.6 to 7.7) h/day). Adherence to the PA guideline was high (98.1%). Average 24h acceleration and light PA were higher in women than men, but men achieved higher average accelerations across the most active periods of the day. Women performed less sedentary time and shorter sedentary bouts. Older participants (aged ≥55y) registered a lower average 24h acceleration and engaged in less MVPA, more sedentary time and longer sedentary bouts. Average 24h acceleration was higher in participants of lower educational attainment, who also performed less sedentary time, shorter bouts, and fewer bouts of prolonged sedentariness. Average 24h acceleration and levels of PA were higher in participants with standing and manual occupations than a sedentary work type, but manual workers registered lower average accelerations across the most active periods of the day. Standing and manual workers accumulated less sedentary time and fewer bouts of prolonged sedentariness than sedentary workers. Active commuting to work was associated with higher average 24h acceleration and MVPA, both of which were lower in participants of poorer self-rated health and higher weight status. Obesity was associated with less light PA, more sedentary time and longer sedentary bouts.ConclusionsAdherence to recommended PA is high in Luxembourg, but half of daily time is spent sedentary. Specific population subgroups will benefit from targeted efforts to replace sedentary time with PA.

Measurement of bradykinesia and chorea in Huntington's Disease using ambulatory monitoring

ObjectivesThe feasibility of measuring bradykinesia and chorea in Huntington's Disease using a wearable sensor system (Parkinson’s Kinetigraph: PKG) developed for measuring bradykinesia and dyskinesia in Parkinson’s Disease was assessed. MethodsUnified Huntington’s Disease Rating Scales (UHDRS) and a PKG were obtained for 25 people with Huntington's Disease. Bradykinesia and Chorea Score were derived from relevant sub-scores of the UHDRS and compared with the PKG’s bradykinesia and dyskinesia scores. The PKG’s daytime sleepiness score was also used. ResultsThere was good correlation between Chorea Scores and the PKG’s dyskinesia score (Pearson’s ρ = 0.66). Correlation between the Bradykinesia Scores and the PKG’s bradykinesia score was also good (Pearson’s ρ = 0.51) in cases whose PKG scores were in the normal or bradykinetic range. The PKG’s bradykinesia score of 23, which is in the higher range of control subjects, separated participants into those with Independence Score ≥ 80 or < 80 and a Functional Assessment (FAS) score ≥ 18 or < 18. The PKG’s daytime sleep score was high in 44 % of participants, whose average time asleep was 21 % compared to 1.6 % in participants with a normal sleep index. Participants with high sleep scores were significantly more likely to have low Independence and TFC scores. ConclusionsMeasures of bradykinesia and dyskinesia from clinical scales have acceptable correlations with those from the PKG. Continuous monitoring provides information about daytime sleep, which was associated with lower functional status. Further studies and larger sample sizes are required to confirm these findings and the utility of this measure in Huntington's Disease.

P105 Women with greater post-traumatic stress symptom severity and less disrupted sleep have improved fear extinction recall compared to men

Abstract Sleep has been found to play a key role in fear conditioning, extinction learning and extinction recall, the paradigm modelling the development, maintenance and treatment of anxiety disorders including post-traumatic stress disorder (PTSD), which are disorders commonly associated with sleep disturbances. Previous studies examining associations between sleep and fear or extinction processes predominately focused on objectively measured sleep architecture using polysomnography, and the majority of the research has been done in healthy populations. To date, little research has focused on subjective sleep measures and particularly in clinical populations including PTSD, which often experience subjectively poor sleep. Here we investigated whether subjective sleep disturbance, sleep onset latency, wake after sleep onset or sleep efficiency were related to fear conditioning, extinction learning or extinction recall in a large sample of individuals with a range of PTSD symptom severity and healthy controls. Overall, we did not find that sleep was associated with fear conditioning extinction learning or extinction recall. However, emerging evidence highlighting the critical role of sex in PTSD risk, fear conditioning processes, as well as in the sleep-fear conditioning relationship. Exploratory analyses examining sex-specific effects found that shorter sleep onset latency and greater sleep efficiency during the previous night were associated with improved extinction recall in women with higher PTSD symptom severity. This suggests that less time falling asleep and longer time asleep while in bed may be protective against the commonly observed impaired extinction recall in PTSD in highly symptomatic women, but is not relevant in men.

Sex differences in the effect of subjective sleep on fear conditioning, extinction learning, and extinction recall in individuals with a range of PTSD symptom severity

Sleep has been found to play a key role in fear conditioning, extinction learning and extinction recall, and sleep disturbances are linked to many mental disorders including post-traumatic stress disorder (PTSD). Previous studies examining associations between sleep and fear or extinction processes primarily focused on objectively measured sleep architecture. Little research has so far focused on subjective sleep measures and particularly in clinical populations, which often experience subjectively poor sleep, including PTSD. Here we investigated whether subjective sleep disturbance, sleep onset latency, wake after sleep onset or sleep efficiency were related to fear conditioning, extinction learning or extinction recall in a large sample of individuals with a range of PTSD symptom severity (n = 248). Overall, we did not find that subjective sleep was associated with fear conditioning or extinction processes. However, exploratory analyses examining the moderating effect of sex found that shorter sleep onset latency and greater sleep efficiency were associated with improved extinction recall in women with higher PTSD symptom severity. This suggests that less time falling asleep and longer time asleep while in bed may be protective in highly symptomatic women against the commonly observed impaired extinction recall in PTSD. More studies are needed to explore sex-specific effects further.

Movement Behaviors In Short Versus Adequate Nocturnal Sleepers: A Compositional Analysis Of Preschoolers

PURPOSE: This study investigated: 1) if there are differences in a movement behaviours composition among adequate and short nocturnal sleepers; and 2) the association between preschoolers' time spent in PA, SB, and sleep among adequate and short nocturnal sleepers. METHODS: A total of 270 preschoolers (132 boys; 3.97 ± 0.81 years old; 15.48 ± 1.62 kg/m2) participated in this study. PA and SB were assessed using accelerometry (model wGT3X). Sleep duration was assessed through a parental-proxy interview, and preschoolers were stratified as short and adequate sleepers, according to attendance to international sleep duration guidelines. Compositional data analysis was used to explore the time-use patterns of behaviors among adequate and short sleepers. RESULTS: Short sleepers spent 64 minutes less time asleep, accumulated 32 minutes in more sedentary time (p = 0.005, Cohen’s d = 0.36, Bayes Factor: 6.17), and 24 minutes more in light PA (p = 0.0005, Cohen’s d = 0.44, Bayes Factor: 46.37) compared to adequate sleepers. CONCLUSIONS: Being a short sleeper was associated with greater time spent in SB and light PA during their waking hours. The health implications of movement behaviors composition among short sleep preschoolers should be further investigated.

Sleep, Sedentary Time and Physical Activity Levels in Children with Cystic Fibrosis.

The aim of this study was to compare the use of generic and cystic fibrosis (CF)-specific cut-points to assess movement behaviours in children and adolescents with CF. Physical activity (PA) was assessed for seven consecutive days using a non-dominant wrist-worn ActiGraph GT9X in 71 children and adolescents (36 girls; 13.5 ± 2.9 years) with mild CF. CF-specific and generic Euclidean norm minus one (ENMO) cut-points were used to determine sedentary time (SED), sleep, light physical activity (LPA), moderate physical activity and vigorous physical activity. The effect of using a CF-specific or generic cut-point on the relationship between PA intensities and lung function was determined. Movement behaviours differed significantly according to the cut-point used, with the CF-specific cut-points resulting in less time asleep (−31.4 min; p < 0.01) and in LPA (−195.1 min; p < 0.001), and more SED and moderate-to-vigorous PA (159.3 and 67.1 min, respectively; both p < 0.0001) than the generic thresholds. Lung function was significantly associated with LPA according to the CF-specific cut-points (r = 0.52; p = 0.04). Thresholds developed for healthy populations misclassified PA levels, sleep and SED in children and adolescents with CF. This discrepancy affected the relationship between lung function and PA, which was only apparent when using the CF-specific cut-points. Promoting LPA seems a promising strategy to enhance lung function in children and adolescents with CF.