bluuebunny/crossref_metadata_2025_split huggingface dataset:
076 Bright light during wakefulness improves objective and subjective sleep quality: a forced desynchrony study
Authors: Lok Renske , Woelders Tom , Gordijn Marijke , van Koningsveld Minke , Oberman Klaske , Fuhler Sebastiaan , Beersma Domien , Hut Roelof 
Published: May 2021

Abstract

Introduction
Under real life conditions, increased light exposure during wakefulness seems associated with improved sleep quality, quantified as reduced time awake during bed time, increased time spent in non-REM (NREM) sleep or increased power in the EEG delta band (0.5–4 Hz). The causality of these important relationships and their dependency on circadian clock phase and/or time awake has not been studied in depth. To establish causality of light effects during wake time on subsequent sleep, and to disentangle possible circadian and homeostatic interactions, we employed a forced desynchrony (FD) protocol under dim light (6.5 lux) and bright light (1307 lux) during wakefulness.

Methods
The protocol consisted of a fast cycling sleep-wake schedule (13h wakefulness – 5h sleep; 4 cycles), followed by 3h recovery sleep in a within subject cross-over design. Individuals (7 men) were equipped with 10 polysomnography electrodes. Subjective sleep quality was measured immediately after wakening.

Results
Results indicated that circadian variation in delta power was only detected under dim light. Circadian variation in time in rapid eye movement (REM) sleep and wakefulness were uninfluenced by light. Prior light exposure increased accumulation of delta power and time in NREM sleep, while decreasing wakefulness, especially during the circadian wake phase. Subjective sleep quality scores showed that participants were only able to assess light induced improvement of sleep quality correctly when the circadian system promoted wakefulness.

Conclusion
This study presents significant effects of bright light exposure on sleep architecture, leading to sleep pressure related changes in objective sleep quality. At the end of the scheduled sleep phase after increased light exposure, more delta power and NREM sleep were detected, especially when sleep occurred outside the normal sleep phase. Subjective sleep quality scores showed light-induced improvements coinciding with increased delta power and time spend in NREM sleep, suggesting that light during wakefulness may improve subsequent sleep quality. These findings may have important implications for insomnia treatment and clinical applications of light therapy.

Support (if any)
This research was funded by the University of Groningen Campus Fryslân (Grant No. 01110939; co-financed by Philips Drachten and Provincie Fryslân). Additional financial support was obtained from a NWO-STW Program Grant “OnTime” (project 12185).
078 Chronic sleep and circadian disruption differentially affects blood pressure, renal sodium retention, and aldosterone secretion
Authors: McHill Andrew , McMullan Ciaran , Hull Joseph , Wang Wei , Klerman Elizabeth 
Published: May 2021

Abstract

Introduction
Chronic sleep restriction (CSR) and recurrent circadian disruption (RCD; e.g., rotating shiftwork) can increase an individual’s risk of cardiovascular and kidney disease. However, no study has assessed whether CSR and RCD together increase blood pressure (BP) and alter renal function (RF). We tested the hypotheses that the combination of CSR and RCD would increase blood pressure, renal sodium retention, and aldosterone secretion in individuals living for 3 weeks on an imposed non-24-h sleep-wake (SW) schedule (induces RCD) and controlled diet with or without CSR.

Methods
Seventeen (9M) healthy participants (aged 26.1±4.5y [mean±SD]) were scheduled to twenty-four 20-h Forced Desynchrony days and were randomized to either Control (1:2 sleep:wake, 6.67h sleep:13.33h wake; n=8) or CSR (1:3.3 sleep:wake, 4.67h sleep: 5.33h wake; n=9) SW conditions during a 32-day inpatient protocol. BP was measured following ~80–90 min in constant seated posture after scheduled waketime. All urine voids were collected, combined and sampled in 3-6h blocks throughout the study. Samples were assayed for sodium, potassium and aldosterone and analyzed as both excretion rates and total secretion (both per 20h). Data were assigned circadian phase using fitted core body temperature and analyzed using mixed-effects models with circadian phase, aligned/misaligned sleep, or time awake (with associated scheduled activity, sleep/wake, and feeding behaviors) and their interactions as fixed effects.

Results
There was a significant interaction between aligned/misaligned sleep and condition for resting BP (p=0.02), such that systolic BP was ~6% higher following circadian-misaligned sleep in CSR compared to Control (p=0.04). Renal sodium and potassium followed a robust circadian pattern (p&lt;0.0001), with limited influence of time awake. In contrast, the timing of aldosterone excretion was affected by time awake (p&lt;0.05). Total daily renal sodium secretion decreased from beginning to end of the protocol (p=0.03), with no change in sodium consumption and aldosterone secretion (p=0.95).

Conclusion
Under conditions similar to rotating shiftwork, systolic BP increased and sodium, potassium, and aldosterone were differentially influenced by circadian phase and scheduled behaviors. Additionally, renal sodium secretion decreased despite minimal changes in aldosterone secretion, suggesting increased renal aldosterone sensitivity. These findings may provide insight into mechanisms contributing to poor cardiovascular and renal health observed in shiftwork.
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081 Implicit and Explicit Stigma Towards Evening Types
Authors: Kim Kelly , Dietch Jessica , Douglas Megan 
Published: May 2021

Abstract

Introduction
Negative explicit and implicit stigma surrounding mental and physical health conditions are endorsed by people with and without these conditions. Stigma can lead to adverse consequences such as higher levels of distress and isolation. People with insomnia report internalized stigma associated with their insomnia and often delay treatment as a result. Although anecdotal reports of a similar stigma exist for delayed chronotypes, particularly among emerging adults, this effect has not been empirically examined. The present study aims to examine explicit and implicit attitudes about chronotype in a sample of emerging adults.

Methods
Participants were undergraduates (M age=19.9 [SD=1.5], 83.7% female). Demographic, sleep, and circadian questionnaires, including the Morningness-Eveningness Questionnaire to assess chronotype, were collected. Explicit stigma was measured by rating morning and evening types from 0–100 on eight pairs of opposing characteristics (e.g., lazy/motivated) and means were compared with paired samples t-tests using correction for multiple comparisons. Implicit stigma was measured using the Implicit Association Test with attributes associated with “good” and “bad” and targets of “night owl” or “early bird” and the mean score was compared to benchmarks. Regression was conducted to determine whether chronotype predicted implicit or explicit attitudes.

Results
Analyses of explicit attitudes revealed evening types were rated as possessing significantly more of the following characteristics: Lazy (Cohen’s d=0.71), Unhealthy (1.22), Undisciplined (1.19), Immature (0.64), Creative (0.59), and Young (1.20), adjusted ps&lt;.01. Analysis of implicit attitudes revealed a d score of 0.57 (SD=0.47), which indicates a moderate implicit bias of pairing “night owl” with “bad” and “early bird” with “good.” Chronotype was not significantly associated with implicit or explicit attitudes, F(1,47)=0.04, p=.849.

Conclusion
Overall, greater negative explicit and implicit stigma were found for eveningness tendency compared to morningness tendency. Creativity and youthfulness were also rated higher for eveningness. Individual chronotype did not predict implicit or explicit attitudes, suggesting a potential broad societal bias rather than a specific internalized bias. As explicit and implicit stigma often predict discriminatory behavior and lead to negative consequences for the target group, future studies should examine how negative stigma may impact evening types and the behavioral and psychological consequences of stigma.
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085 Effort Exertion and Good Sleep Interactively Increase the Subjective Value of the Future
Authors: Butterworth James , Kelley Nicholas , Boland Elaine , Sedikides Constantine 
Published: May 2021

Abstract

Introduction
The present study examined how habitual variation in sleep quality shapes reward responsivity following effort exertion. Behavioural and neuroscientific theory and research suggest that expending effort leads to compensatory increases in reward responsivity. Converging evidence links the preference for larger-but-delayed rewards to increases in reward sensitivity in psychophysiological, psychopharmacological, and animal studies. Accordingly, we hypothesized that exerting mental effort would increase the preference for larger-but-delayed rewards (i.e., the subjective value of the future) insofar as these preferences reflect elevated reward responsivity. Furthermore, given that sleep shapes perceptions of effort and preferences for larger-but-delayed rewards, we hypothesized that this finding would be moderated by habitual variation in sleep quality, with the strongest effects apparent among participants reporting habitually good sleep.

Methods
To test these hypotheses, we recruited 79 participants to complete a 10-minute effortful (vs. control) writing task followed by a delay discounting task and the Pittsburgh Sleep Quality Index.

Results
As hypothesized, the effortful writing task (vs. control) participants demonstrated a greater preference for larger-but-delayed rewards (vs. smaller-but-immediate rewards). This effect was moderated by sleep quality with those high but not low in sleep quality showing the hypothesized effect.

Conclusion
Ultimately, we found that exerting mental effort increases the subjective value of the future, particularly among participants who habitually report good sleep. These results suggest that good sleep quality helps us contend with the effortful demands of daily life in a way that promotes long-term goal pursuit.
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097 Subjective Sleep Quality is Associated with the Regulation of Positive Emotions
Authors: Powell Suzanna , Bower Joanne , Deutchman Dagny , Palmer Cara 
Published: May 2021

Abstract

Introduction
Sleep disturbances have been associated with emotion regulation difficulties, which in turn predicts the onset and maintenance of mental health disorders. However, research has primarily focused on the regulation of negative emotions. Associations between sleep and positive emotion regulation strategies are unknown. The current research examined relationships between subjective sleep disturbances (Study 1 and Study 2), objective sleep (Study 2), and positive emotion regulation strategies, including strategies that enhance or maintain positive emotions (i.e., savoring) and strategies that reduce positive emotion (i.e., dampening).

Methods
In Study 1, participants (N = 388, ages 18–64 years, 65% female) completed the Pittsburgh Sleep Quality Index and the Responses to Positive Affect questionnaire to assess their positive emotion regulation strategy use, which consists of three subscales (emotion-focused savoring, self-focused savoring, and dampening). Participants in Study 2 (N = 59, ages 18–30 years, 84% female) completed the Pittsburgh Sleep Quality Index, the Responses to Positive Affect questionnaire, and wore an actigraph for one week.

Results
In Study 1, greater subjective sleep disturbances were associated with increased dampening (β = .45, B = .45, SE = .05, 95% C.I. = .35, .55, p &lt;.001), less emotion-focused savoring (β = -.16, B = -.10, SE = .03, 95% C.I. = -.16, -.04, p &lt;.005) and less self-focused savoring (β = -.16, B = -.08, SE = .03, 95% C.I. = -.13, -.03, p &lt; .05). In Study 2, subjective sleep disturbances were associated with greater dampening (β = .31, B = .70, SE = .32, 95% C.I. = .07, 1.34, p &lt; .05), and marginally less self-focused savoring (β = -.28, B = -.82, SE = .42, 95% C.I. = -1.67, .02, p = .05). Actigraphy-measured sleep was unrelated to positive emotion regulation. All models adjusted for adjusted for age and gender.

Conclusion
Subjective sleep disturbances are associated with positive emotion regulation strategies, particularly strategies that dampen positive emotional experiences. These findings complement prior associations among sleep and the dysregulation of negative emotions, and suggest that sleep-related positive emotion dysregulation may be one mechanism by which sleep can lead to the development of emotional disorders.
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108 Attentional Control Deficits during Total Sleep Deprivation: Independence from Reduced Vigilant Attention
Authors: Lawrence-Sidebottom Darian , Hinson John , Whitney Paul , Honn Kimberly , Van Dongen Hans 
Published: May 2021

Abstract

Introduction
Total sleep deprivation (TSD) has been shown to impair performance on a two-phase attentional control task, the AX-type continuous performance task with switch (AX-CPTs). Here we investigate whether the observed AX-CPTs impairments are a downstream consequence of TSD-induced non-specific effects (e.g., reduced vigilant attention) or reflect a distinct impact on attentional control.

Methods
N=55 healthy adults (aged 26.0±0.7y; 32 women) participated in a 4-day laboratory study with 10h baseline sleep (22:00-08:00) followed by 38h TSD and then 10h recovery sleep. At baseline (09:00 day 2) and after 25h and 30h TSD (09:00 and 14:00 day 3), subjects were tested on a 10min psychomotor vigilance test (PVT), an assay of vigilant attention, and on the AX-CPTs. The AX-CPTs required subjects to differentiate designated target from non-target cue-probe pairs. In phase 1, target trials occurred frequently, which promoted prepotent anticipatory responses; in phase 2, the target pair was switched. Accuracy of responses to various different AX-CPTs trial types was expressed relative to accuracy on phase 1 neutral (non-target cue and probe) trials, which should capture non-specific impairments on the task. For all three test sessions, these relative accuracy measures, along with accuracy on phase 1 neutral trials and lapses (RT&gt;500ms) on the PVT, were subjected to principal component analysis (PCA).

Results
The PCA revealed three statistically independent factors. Following varimax rotation, factor 1 (36.3% variance explained) and factor 3 (14.8% variance explained) each had high loadings for relative accuracy on multiple AX-CPTs trial types from phases 1 and 2; whereas factor 2 (17.9% variance explained) had high loadings for accuracy on phase 1 neutral trials, relative accuracy on phase 1 target trials, and PVT lapses.

Conclusion
These results indicate a statistical separation between AX-CPTs phase 1 neutral trials and phase 1 target trials, in conjunction with PVT lapses, versus the various other AX-CPTs trial types. This suggests a dissociation between TSD-induced, non-specific impairments on the task—potentially related to reduced vigilant attention—and TSD-induced specific impairments related to attentional control. Thus, TSD-induced deficits in attentional control are unlikely to be a downstream consequence of non-specific impairments.

Support (if any)
CDMRP grant W81XWH-16-1-0319
122 Different Duration Psychomotor Vigilance Tests Show Robust Stable Relationships Across Sleep Loss That Deteriorate in Recovery
Authors: Antler Caroline , Yamazaki Erika , Casale Courtney , Brieva Tess , Goel Namni 
Published: May 2021

Abstract

Introduction
The Psychomotor Vigilance Test (PVT), a behavioral attention measure widely used to capture sleep loss deficits, is available in 10-minute (PVT10) and 3-minute (PVT3) versions. The PVT3 is a briefer and presumably comparable assessment to the more commonly used PVT10 yet the relationship between the measures from the two versions across specific time points and in recovery after sleep loss has not been investigated. Repeated measures correlation (rmcorr) evaluated within-individual associations between measures on the PVT10 and PVT3 throughout a highly controlled sleep deprivation study.

Methods
Forty-one healthy adults (ages 21-49; mean±SD, 33.9±8.9y; 18 females) participated in a 13-night experiment consisting of 2 baseline nights (10h-12h time in bed, TIB) followed by 5 sleep restriction (SR1-5) nights (4h TIB), 4 recovery nights (R1-R4; 12h TIB), and 36h total sleep deprivation (TSD). A neurobehavioral test battery, including the PVT10 and PVT3 was completed every 2h during wakefulness. Rmcorr compared PVT10 and PVT3 lapses (reaction time [RT] &gt;355ms [PVT3] or &gt;500ms [PVT10]) and response speed (1/RT) by examining correlations by day (e.g., baseline day 2) and by time point (e.g., 1000h-2000h). Rmcorr ranges were as follows: 0.1-0.3, small; 0.3-0.5, moderate; 0.5-0.7, large; 0.7-0.9, very large.

Results
All time point correlations (1000h-2000h) were significant (moderate to large for lapses; large to very large for 1/RT). Lapses demonstrated large correlations during R1, moderate correlations during SR1-SR5 and TSD, and small correlations during R2 and R4, and showed no significant correlations during baseline or R3. 1/RT correlations were large for SR1-SR4 and TSD, moderate for SR5 and R1-R4, and small for baseline.

Conclusion
The various PVT relationships were consistently strong at specific times of day throughout the study. In addition, higher correlations observed for 1/RT relative to lapses and during SR and TSD relative to baseline and recovery suggest that the PVT10 and PVT3 are most similar and best follow performance when most individuals are experiencing behavioral attention deficits during sleep loss. Both measures track SR and TSD performance well, with 1/RT presenting as more comparable between the PVT10 and PVT3.

Support (if any)
ONR Award N00014-11-1-0361; NIH UL1TR000003; NASA NNX14AN49G and 80NSSC20K0243; NIHR01DK117488
125 Increased plasma renin activity during wake in a repetitive sleep restriction protocol
Authors: Yang Huan , Vazquez Michael , Haack Monika , Mullington Janet 
Published: May 2021

Abstract

Introduction
Insufficient sleep is associated with an increased risk of hypertension. It is well established that long-term BP regulation is modulated by the renin-angiotensin-aldosterone system (RAAS) and chronic kidney disease is a strong independent risk factor for development of cardiovascular disease. This study investigated the biomarkers of RAAS and renal function during repetitive exposures to controlled, experimental sleep restriction (SR). We hypothesized an upregulation of RAAS and increased markers of impaired renal function.

Methods
Twenty-one healthy participants (11 women, average age 31±2 years) completed the 22-day in-hospital SR protocol: permitted 4h of sleep/night from 0300-0700 for 3 nights followed by a recovery sleep, repeated 4 times. Blood samples were collected and plasma renin activity (PRA) was assessed in the morning (7:05am) and in the evening before bedtime (22:45pm) at baseline, experimental days (3rd day of each of the 4 blocks), and recovery. Urinary albumin to creatinine ratio (ACR) was measured from 24-h urinary collection at baseline, first and fourth SR blocks. Estimated glomerulus filtration rate (eGFR) was calculated based on the serum cystatin C levels at baseline and last block of SR.

Results
Percent change of evening PRA significantly increased during 4 blocks of SR and recovery (SR effect p=0.039), but not morning PRA (SR effect p=0.34). Specifically, evening PRA increased up to 98.4% in the first (p&lt;0.01), 61.3% in the second (p=0.04) SR blocks, and 57.5% (p=0.05) in recovery. Urinary ACR showed no significant changes during first or fourth SR blocks (SR effect p=0.28). In addition, eGFR did not change in the fourth SR block compared to BL (paired t-test, p=0.27).

Conclusion
We did not see increased markers of impaired renal function (ACR or eGFR). Rather, short-term repetitive exposures to SR significantly increased percent change of PRA measured before bedtime, and evening PRA did not return to BL level during recovery. Our results suggested that sleep deficiency may contribute to hypertension through upregulation of RAAS during wake time.

Support (if any)
SRSF (CDA to Huan Yang), NIH (R01HL106782 to Dr. Janet Mullington), Harvard Catalyst, Harvard Clinical and Translational Science Center (UL1TR001102).
130 Individual Differences in Skin Temperature Responses to Cold Pressor Stress During Sleep Restriction and Circadian Misalignment
Authors: Linton Sabrina , Sprecher Kate , Depner Christopher , Burke Tina , Dorrestein Pieter , Fleshner Monika , Knight Rob , Lowry Christopher , Turek Fred , Vitaterna Martha , Wright Kenneth 
Published: May 2021

Abstract

Introduction
Individual differences in cognition during sleep restriction and circadian misalignment have been shown to be trait-like. Here we explored the consistency of individual differences in cardiovascular responses to the cold pressor test (CPT) measured by changes in the distal-proximal skin temperature gradient (DPG) using the contralateral hand to that immersed in the ice water bath, which reflects a reflex cutaneous vasoconstriction.

Methods
Eighteen healthy participants (8 females) mean (±SD) age 25.28 (±4.3), underwent two identical in-laboratory combined sleep restriction and circadian misalignment protocols preceded by an 8h baseline in-laboratory sleep opportunity. The participants were given a 3h sleep opportunity on night 2 and a 3h sleep opportunity on days 3 and 4 followed by recovery sleep. The CPT occurred the morning after the baseline sleep opportunity and the morning before recovery sleep. Participants maintained a seated posture beginning 30 min prior to the CPT and skin temperature was assessed starting 15 min before until 45 min after the CPT. DPG (proximal=subclavicular; distal=hand palmar) data were averaged into 3 min bins. Changes in DPG from pre-CPT and 5 min post-CPT were assessed as the primary outcome using mixed-model ANOVAs. Intra-class correlation coefficients (ICC) were calculated to measure consistency of individual differences for DPG responses.

Results
Mixed-model ANOVA revealed significant effects of time and combined sleep restriction and circadian misalignment on DPG during the CPT (both p&lt;0.05), such that the DPG was wider (i.e., more negative) post-CPT and during sleep restriction and circadian misalignment. Participants showed moderately consistent DPG responses across visits 1 and 2 at baseline (ICC=0.59) and substantially consistent DPG responses during sleep restriction and circadian misalignment (ICC=0.67). Further, participants showed moderately consistent DPG responses when comparing changes between baseline and sleep restriction and circadian misalignment across visits (ICC=0.58).

Conclusion
Findings support that combined sleep restriction and circadian misalignment is associated with sympathetic activation and that individual differences in the DPG response to cold pressor stress are consistent.

Support (if any)
Office of Naval Research MURI grant N00014-15-1-2809, NIH/NCATS Colorado CTSA Grant UL1TR002535