bluuebunny/crossref_metadata_2025_split huggingface dataset:
0005 A circadian-informed lighting intervention markedly improves vigilance in a simulated night shift setting
Authors: Scott Hannah , Stuart Nicole , Manners Jack , Guyett Alisha , Kemps Eva , Lechat Bastien , Lack Leon , Lovato Nicole , Vakulin Andrew , Banks Siobhan , Dorrian Jill , Adams Robert , Eckert Danny , Catcheside Peter 
Published: May 2023

Abstract

Introduction
Due to misalignment between circadian timing and the work/rest schedule, cognitive performance during night shift-work is often poor. This study tested a circadian-informed lighting strategy designed to improve on-shift cognitive performance through alerting effects, faster circadian adjustment to the shift-work schedule and promoting more sleep off-shift, compared to standard lighting.

Methods
A randomised controlled, within-subjects, counter-balanced cross-over study was performed to examine circadian-informed versus standard lighting on cognitive performance during a simulated 8-day night shift-work schedule. Nineteen healthy sleepers (12 males/7 females, mean±SD aged 28.7±10.4 years) underwent two separate 8-day experimental conditions in the sleep laboratory. The standard lighting condition mimicked current lighting on submarines (largely dim, blue-depleted light), while the circadian-informed lighting administered bright, blue-enriched and dim, blue-depleted lighting at times estimated to facilitate rapid circadian delay. After an adaptation sleep opportunity from 22:00 – 07:00 (day 1), participants remained awake for 27 hours to transition to sleeping during the day (10:00 - 19:00) and undertaking simulated night shift-work (00:00 - 08:00) at night on days 3-7. The primary performance outcome was the number of lapses (&gt;500ms responses) on the psychomotor vigilance task (PVT), administered six times across each simulated work shift. Median reaction time and other PVT outcomes were also compared between lighting conditions.

Results
There were significant day-by-condition interactions on PVT lapses, p&lt; 0.05. The circadian-informed lighting intervention resulted in ~50% fewer lapses by the final day compared to standard lighting (mean±SD 7.4±5.0 vs. 15.6±6.1 lapses). Similar effects were observed across other PVT outcomes.

Conclusion
Circadian-informed lighting resulted in markedly better vigilance than standard lighting under simulated night shift-work conditions. These findings indicate the considerable potential for automated lighting interventions to improve performance and safety in shift-workers.

Support (if any)
This research is supported by the Commonwealth of Australia as represented by the Defence Science and Technology Group of the Department of Defence through the Research Network for Undersea Decision Superiority (research agreement number: 9334), with additional financial support from Flinders University and lighting provision support from REDARC.
0009 Circadian Athletic Performance Variations When Travelling in the Canadian Football League
Authors: Bourgon Vincent , Duval Félix Gabriel , Beauchamp Karolane , Forest Geneviève 
Published: May 2023

Abstract

Introduction
Previous studies have shown a circadian disadvantage in professional sports with teams traveling westward. This effect has been attributed to the circadian clock, core body temperature and associated decline in sports performance in the evening. Compared to the National Football League (NFL) teams, Canadian Football League (CFL) teams often travel longer distances and play at later times. As such, the objective of the present study was to investigate the circadian disadvantage in the CFL.

Methods
Data from 5 years of CFL regular season games were extracted from online databases (2016-2021). Wins, score differentials, first downs, average total, passing, penalty, and kickoff yards, pass completion percentages, interceptions, fumbles, sacks, and time of possession were extracted for both the offense (made) and defense (allowed) for every away evening game (after 6pm; n=387) as well as the direction of the travel (eastward, same time-zone, westward). Two-way ANOVAs of Direction of Travel (eastwards, same time-zone, westwards) on each performance variable were computed to study the circadian effect. Linear regression analyses were done to investigate the effect of the distance travelled by the away team (longitude travelled) on each performance variable.

Results
Significant effects of travel were found for team variables: score differentials (F[2,386]=3.86, p=.02) and time of possession (F[2,386]=5.42, p=.005). Significant results were also found for offensive variables: first downs (F(2,386)=2.91, p=.06), average kickoff return yards (F[2,386]=3.54, p=.03), fumbles (F[2,386]=2.38, p=.09), and for defensive variables: first downs allowed (F[2,386]=2.79, p=.06), average yards per play (F[2,386]=4.83, p=.008), average passing yards allowed (F[2,386]=3.14, p=.04), average kickoff yards allowed (F[2,386]=3.37, p=.04). Each significant post-hoc t-test revealed a circadian disadvantage to teams travelling westwards and a circadian advantage for teams travelling eastwards. Linear regression analyses showed that traveling westward predicts worst performances on some variables, with an increasing effect with distance travelled.

Conclusion
These results are consistent with previous findings showing that professional sports teams travelling westward show important challenges in evening games. In addition, our results highlight the fact that this disadvantage may affect not only the result of the games, but also the performance of players at a more individual level.

Support (if any)
0011 Daily verses circadian amplitude of the distal-proximal skin temperature gradient
Authors: Ballell Lidia , Ritchie Hannah K , Knauer Oliver A , Guerin Molly K , Stothard Ellen , Wright Kenneth 
Published: May 2023

Abstract

Introduction
Sleep, circadian rhythms, and thermoregulatory physiology are highly integrated and impact each other. The daily rhythm in the distal-proximal skin temperature gradient (DPG) is wider/more negative during wakefulness, and narrower/closer to zero during sleep. The circadian rhythm in the DPG is wider during the biological day and narrower during the biological night. Here we aimed to quantify and compare the amplitude of the daily rhythm in the DPG under wakefulness-sleep conditions versus the amplitude of the circadian rhythm in the DPG under sleep deprivation conditions to examine associations and magnitude differences.

Methods
Eleven [5 females] healthy adults [aged 27.6±10.2y, BMI 23.1±2.2 (mean±SD)] participated. After one week of at-home ambulatory monitoring with 8h per night sleep opportunities at habitual bedtimes, participants were studied in the laboratory for three days under controlled dim light (&lt; 8 lux maximum) and ambient temperature conditions (22-24°C). Participants arrived in the afternoon, were kept awake 4h later than typical and scheduled to a 4h sleep opportunity. The next day, participants were sleep deprived for 28h followed by recovery sleep. Skin temperature was assessed every min with iButtons placed subclavicular (proximal skin temperature) and foot palmar (distal skin temperature). The DPG was calculated as difference between proximal and distal skin temperatures. A three-harmonic regression model was used to fit DPG data and derive daily and circadian rhythm amplitudes, and percent difference in amplitude was calculated. Pearson correlations were calculated between daily and circadian rhythm DPG amplitudes.

Results
DPG amplitude was significantly greater for daily versus circadian rhythm (p &lt; 0.05). Percent difference analyses showed daily DPG rhythm was 57% larger than circadian DPG rhythm (SD 30%, range 22-134%). A significant correlation was found between daily and circadian rhythm DPG amplitudes (r = 0.71, p&lt; 0.05).

Conclusion
The amplitudes of daily and circadian rhythms of the DPG are associated, but the daily rhythm amplitude is larger. Additional research is needed to compare the relative importance of daily versus circadian skin temperature amplitudes for sleep and circadian relevant outcomes.

Support (if any)
CurAegis Technologies Inc., Fundacio Joan Riera I Gubau, Undergraduate Research Opportunities Program University of Colorado Boulder
0012 Night Owls and Morning Birds Fly Over the Gym: Circadian Misalignment Does Not Predict Physical Activity in Adolescents
Authors: Wright Isabella , Lee Lindsey , Kamhout Sarah , York Nicholas , Rugh Kathleen , Duraccio Kara 
Published: May 2023

Abstract

Introduction
Given that obesity rates have reached epidemic-level proportions in the U.S., it is more important than ever to identify preventative interventions to reduce obesity risk. Many aspects of sleep have been associated with obesity through their relationship to physical activity. Circadian misalignment is an area of sleep that is yet understudied but that may be especially relevant given the rapid biological and social changes in sleep timing seen in adolescence. This study examined the relationship between circadian misalignment and physical activity among adolescents.

Methods
Fifty adolescents completed an 11-day protocol that began with a baseline appointment where study staff measured participants’ height and weight. Over the next 10 days, participants wore waist accelerometers that measured physical activity and completed manual sleep diaries. After 10 days, participants completed a six-hour appointment in a dimly lit room (lux level &lt; 5) where study staff collected saliva samples every 30 minutes to measure the onset of participants’ melatonin levels. In this preliminary analysis, circadian misalignment was calculated by subtracting the timing of melatonin onset from the average bedtime noted in participants’ sleep diaries; lower scores are reflective of greater circadian misalignment.

Results
Adolescents engaged in 12,038.77 minutes (SD=1737.62) of sedentary activity, 767.29 minutes (SD=260.93) of light physical activity, and 1,263 (SD= 411.89) of moderate-to-vigorous physical activity across this ten-day monitoring period. We conducted multiple regression analyses with circadian misalignment as a predictor of sedentary, light, and moderate-to-vigorous physical activity levels. Circadian misalignment was not a statistically significant predictor of sedentary physical activity (p=.85), light physical activity (p=.70), or moderate-to-vigorous physical activity (p=.30).

Conclusion
In our study, circadian misalignment did not predict sedentary, light, or moderate-to-vigorous physical activity levels. Current literature on other facets of sleep suggests that sleep duration and quality is related to physical activity. However, our results suggest that improving circadian alignment may not be a viable intervention to increase physical activity. Further studies are needed to validate these results as well as to explore the effects of circadian alignment on other aspects of obesity risk.

Support (if any)
0016 Influence of Circadian Preference on Sleep, Depression, and Anxiety in Canadian Student-Athletes
Authors: Cook Jesse , Charest Jonathan , Plante David , Werthner Penny , Horsnell Matthew , Samuels Charles 
Published: May 2023

Abstract

Introduction
Student-athletes face unique demands that heighten vulnerability to both sleep and mental health problems. Circadian preference (CP) describes an individuals’ preferred timing for sleep and wake activity, with this conceived as a continuum between the extremes of morningness and eveningness. CP has been shown to influence both sleep and mental health, with greater eveningness preference generally associating with worse outcomes. However, these relationships are understudied in student-athletes. Thus, this investigation was designed to assess the influence of CP on sleep, depression, and anxiety in Canadian student-athletes.

Methods
Data were obtained throughout the academic semester from Canadian institutions, with student-athletes completing the Athlete Sleep Screening Questionnaire (ASSQ), General Anxiety Disorder-7 (GAD-7), and Patient Health Questionnaire (PHQ-9). ASSQ captured sleep health characteristics and CP, while GAD-7 and PHQ-9 assessed anxiety and depressive symptoms, respectively. ASSQ CP response options were Definitely-Morning, Morning, Evening, or Definitely-Evening as response options, and was coded on a 0-3 scale, with higher values representing increasing eveningness preference. Linear regression estimated associations of CP with sleep, depression, and anxiety. Adjusted regressions controlled for age, gender, race/ethnicity, and sport type.

Results
Sample included 559 Canadian student-athletes (Average Age = 18.9 ± 3.21 years; Percentage Women = 53%; Percentage White = 79.1%) from eight different sports. Regarding CP, 11.4% reported Definitely-Morning, 27.0% reported Morning, 41.8% reported Evening, and 19.8% reported Definitely-Evening. Greater eveningness preference significantly associated with worse overall sleep difficulties (padjusted &lt; 0.0001), longer sleep latency (padjusted &lt; 0.0001), reduced sleep satisfaction (padjusted &lt; 0.0001), more prolonged sleep inertia (padjusted &lt; 0.0001), more daytime naps (padjusted = 0.01), and more severe depressive symptomatology (padjusted = 0.0006).

Conclusion
Greater eveningness in a sample of Canadian student-athletes associated with worse sleep and psychological characteristics, including overall sleep difficulty, sleep latency, sleep satisfaction, sleep inertia, daytime napping, and depressive symptom severity. The results of this study provide compelling evidence that eveningness CP may predict poor mental and sleep health outcomes in student-athletes. Thus, further attention to circadian characteristics of student-athletes is warranted. Additionally, modifications to training schedules and team routines could be considered as preventative strategies for mental and sleep health problems.

Support (if any)
Mitacs #IT23469
0018 Perils of the nighttime: impact of behavioral timing and preference on mental and physical health
Authors: Zeitzer Jamie , Lok Renske , Weed Lara , Winer Joseph 
Published: May 2023

Abstract

Introduction
Both chronotype and the actual timing of sleep have been associated with mental and physical health outcomes. While these often align, life often intervenes and causes a misalignment between desired and actual timing of sleep. The impact of such a misalignment has not been well investigated.

Methods
Community-dwelling (n=73,888) adults participating in the UK Biobank were monitored with wrist actigraphy for one week. Timing of behavioral patterns was derived from calculation of L5 (onset of lowest five hours of activity) and parsed into quartiles (Q1: early, Q2-3: intermediate, Q4: late). Chronotype was determined by a single question and parsed into quartiles (Q1: morning-type, Q2-3: intermediate, Q4: evening-type). Mental (mental, behavioral, and neurodevelopmental disorders, generalized anxiety disorder, depression) and physical (including metabolic disorder, diabetes, obesity, hypertension, circulatory disorder, digestive disorder, respiratory disorder, all-cause cancer) health status was determined with ICD-10 codes. Prevalence and likelihood (odds ratios) of disorders were calculated and adjusted for common demographic variables (sex, age, body mass index, material deprivation) and sleep duration.

Results
As compared to morning-type individuals who went to sleep early (aligned), morning-type individuals who went to sleep late (misaligned) had increased likelihood of both mental (OR=1.52±0.06, p&lt; 0.001) and physical (OR=1.45±0.03, p&lt; 0.001) health disorders. As compared to evening-type individuals who went to sleep late (aligned), evening-type individuals who went to sleep early (aligned) had decreased likelihood of both mental (OR=0.85±0.06, p=0.002) and physical (OR=0.66±0.03, p&lt; 0.001) health disorders.

Conclusion
Going to sleep early, irrespective of natural proclivity and potential circadian misalignment, is associated with better mental and physical health.

Support (if any)
Mental Illness Research Education and Clinical Center, Department of Veterans Affairs
0020 Associations between bedtime and waketime variability and sleep outcomes in autistic children
Authors: McGovney Kevin , Hayse Braden , Stearns Melanie , Mazurek Micah , Curtis Ashley , Nair Neetu , Beversdorf David , Sohl Kristen , Davis Beth , McCrae Christina 
Published: May 2023

Abstract

Introduction
Up to 80% of autistic children experience sleep disturbances. Sleep hygiene guidelines advise patients to maintain consistent bedtimes and waketimes for the purpose of regulating one’s circadian rhythm. However, the relationship between bedtime and waketime variability and sleep outcomes in autistic children is unclear, and so the current study examines these associations.

Methods
One hundred thirty autistic children (Mage = 8.81 yrs, SD = 1.92 yrs, range = 6-12 yrs, 71% male) completed two weeks of daily sleep diaries with parental assistance and concurrently wore actigraphic wrist watches (Actiwatch-2, Respironics). Rest intervals in Actiware software were set using visual inspection while referencing self-reported bed/waketime. Boundaries of rest intervals were defined as the time when the child first attempted sleep to the time when the child vacated bed. Subjective and objective estimates of bedtime, waketime, total wake time during attempted sleep periods, and total sleep time were obtained. Bayesian multi-level models obtained individual estimates of average variability in bedtime and waketime. Multiple linear regressions were then used to examine associations between subjective and objective bedtime and waketime variability and total wake time and total sleep time, controlling for age and average levels of bed/waketime variability. Models were separated out by subjective/objective sleep outcomes (i.e., subjective waketime variability predicting subjective total sleep time).

Results
Greater objective waketime variability was associated with less objective total sleep time (B=-38.80, p&lt;.001, partial eta-squared = .071). Greater subjective waketime variability was associated with longer subjective total wake time (B = 18.58, p=.02, partial eta-squared = .058) and shorter subjective total sleep time (B=-70.60, p&lt;.001, partial eta-squared = 0.227).

Conclusion
While results do not possess causal implications, greater subjective and objective waketime variability are associated with poorer sleep outcomes in autistic children. Effect sizes ranged from approximately medium to large. Results suggest that bedtime variability may not be related to sleep outcomes in autistic children. Future studies should examine whether reductions in waketime variability mediate the effect of behavioral insomnia interventions on improved sleep in autistic children.

Support (if any)
MU Research Board Grant (McCrae, PI); Department of Defense Autism Research Program (McCrae, PI; W81XWH2010399); Thompson Center for Autism and Neurodevelopmental Disorders.
0025 Effects of NLS-4 (Lauflumide) and modafinil in a rat model of circadian rhythm and chronic severe fatigue
Authors: Bizot Jean-Charles , Massé Fabienne , Combeau Julie , Lacerda-Queiroz Norinne , David Sabrina , Benel Laurent , Apostol George , Konofal Eric 
Published: May 2023

Abstract

Introduction
The chronic fatigue syndrome (CFS) is a heterogeneous disorder characterized by easy fatigability, feverishness, diffuse pains, and depression. Many COVID-19 patients expressed a long-term effect of coronavirus (long-COVID), with some characteristics typically found in CFS. To examine the efficacy of NLS-4 (Lauflumide), in comparison with a positive control, modafinil, which has been shown to improve recovery from CFS in human, to improve recovery from severe fatigue in rats.

Methods
Male 7-8 weeks old Sprague-Dawley rats were subjected to a fatigue procedure for seven consecutive days. Their locomotor activity in home cage was then recorded for 3 days following the end of the fatigue procedure. A Sham group was subjected to the same measurement of circadian activity but without the fatigue procedure. Rats were divided into different groups which received, before the start of the dark period, three daily administrations of NLS-4, modafinil or vehicle (Control and Sham groups).

Results
The fatigue procedure induced an impairment in the circadian activity, that is a decrease in motor activity during the dark period and an increase in motor activity during the period of light. Accordingly, the difference of distance travelled between the dark period and the light period was lower in the Control group than in the Sham group. This impairment was still present 3 days after the end of the fatigue procedure. modafinil and NLS-4 dose-dependently increased locomotor activity during the dark phase and, to a lesser extent, during the light phase. The increase in activity during the dark phase was significant at doses of 16, 32 and 64 mg/kg with NLS-4 and at doses 64 and 128 mg/kg with modafinil but the effect of NLS-4 was more sustainable than that of modafinil.

Conclusion
This study suggests that the impairment of circadian rhythm induced by a fatigue procedure was reduced to a similar magnitude by modafinil (64 mg/kg) and NLS-4 (16 mg/kg). Since modafinil has been shown to improve recovery from chronic fatigue in human, these results show that NLS-4 could improve recovery from CFS in human at doses four times lower than that used for modafinil.

Support (if any)
NLS Pharmaceutics
0027 Ravaged Rat Rhythms: Circadian Rhythm Influence on Mecamylamine-Induced Nicotine Withdrawal
Authors: Garcia Cristian Douglas Sales , Prince Attaira , Schwartz Eric E J 
Published: May 2023

Abstract

Introduction
Mecamylamine (Mec) is a nicotinic acetylcholine receptor (nAChR) antagonist, serving as an important piece of nicotine addiction cessation therapies. When co-administered with nicotine, Mec blocks the positive reinforcing effects of the substance of abuse and may promote a lessened desire to perpetuate an addictive cycle. On the other hand, the magnitude of the withdrawal symptoms caused by this co-administration may reinforce addiction as users can choose to terminate the process of quitting.

Methods
The present study uses Sprague-Dawley rats to examine if the time of withdrawal onset in relation to circadian rhythms impacts the magnitude of the relevant aversive symptoms. We hypothesized that Mec injected during the rat’s dark period show significantly less aversive symptoms when compared to when it’s done during their light period. For this, we injected rats (n=3 per group) twice a day for thirteen days subcutaneously, with either saline or nicotine, a validated protocol to induce addiction. To measure aversive symptoms of nicotine precipitated withdrawal in light vs dark periods, we used a conditioned place aversion (CPA) behavioral assay in which the rats were either tested mid-light or mid-dark periods. In CPA, the rats were first introduced to the two distinct chambers and allowed to freely move in between them (day 10, for 15 minutes), while time spent in each one was analyzed. Then, they were conditioned to associate one chamber with saline and the other with Mec (days 11-12, for 30 minutes each). Finally, they were placed again in freedom, and the time spent in the mecamylamine-paired chamber was detracted from pre-conditioning to give us the results of aversion (day 13, for 15 minutes).

Results
We predicted that in the aftermath, the light-period rats on nicotine addiction schedule would show the shortest change in time in Mec-paired chamber, while saline-scheduled rats across both periods would show a change of zero—or no impact of Mec. Results indicated no significant differences between group averages for time spent in the Mec-paired chamber, but they showed saline-scheduled rats to be similarly aversive to it.

Conclusion
This result indicates the potential need for a study with a more selective nicotine blocker.

Support (if any)