[Effects of Schisandrae Chinensis Fructus Lignans on Alertness of Rats With Sleep Deprived by Treadmill Exercise].

Objective To investigate the effects of Schisandrae Chinensis Fructus lignans on the alertness of the rats with sleep deprived by treadmill exercise and the underlying neurobiological mechanism. Methods According to the random number table method,SD male rats were assigned into control,sleep deprivation,low-,medium-,and high-dose Schisandrae Chinensis Fructus lignans,and atomoxetine hydrochloride groups,with 8 rats in each group.The rats in other groups except the control group were subjected to sleep deprivation by treadmill exercise for 3 d.During the deprivation period,each administration group was administrated with the corresponding drug by gavage,and a 5-9 hole tester was used to test the alertness performance of rats in each group. Furthermore,other SD male rats were selected and randomized into control,sleep deprivation,Schisandrae Chinensis Fructus lignans (67.2 mg/kg) and atomoxetine hydrochloride groups,with 10 rats in each group.The rats were modeled with the sleep deprivation method the same as that above and administrated with corresponding agents.ELISA was employed to measure the serum level of orexin A in each group of rats.The protein levels of c-Fos,orexin receptor 1,and orexin receptor 2 in the prefrontal cortex of rats in each group were observed by immunofluorescence and Western blotting. Results Compared with the control group,sleep deprivation reduced the choice accuracy (P<0.001) and increased the omission responses,omission percent,and mean correct response latency (P=0.002,P=0.003,P=0.020).Compared with the sleep deprivation group,medium- and high-dose Schisandrae Chinensis Fructus lignans and atomoxetine hydrochloride improved the alertness of rats,as demonstrated by the increased choice accuracy (P=0.001,P=0.006,P<0.001) and reduced omission responses (P=0.001,P=0.001,P<0.001),omission percent (P=0.001,P=0.002,P<0.001),and mean correct response latency (P=0.018,P=0.003,P=0.014).Compared with the control group,the sleep deprivation group showed elevated level of orexin A in the serum (P<0.001),up-regulated expression of c-Fos (P<0.001),and down-regulated expression of orexin receptor 1 (P=0.037) in the prefrontal cortex.Compared with the sleep deprivation group,Schisandrae Chinensis Fructus lignans (67.2 mg/kg) and atomoxetine hydrochloride lowered the orexin A level in the serum (P=0.005,P=0.029),down-regulated the expression of c-Fos (P=0.028,P=0.036),and up-regulated the expression of orexin receptor 1 (P=0.043,P=0.013) in the prefrontal cortex. Conclusion Schisandrae Chinensis Fructus lignans may antagonize the alertness decrease caused by sleep deprivation by regulating the secretion of orexin and the expression of orexin receptor 1 in the prefrontal cortex.

The influence of time of day on memory recognition for faces.

Time of day can alter memory performance in general. Its influence on memory recognition performance for faces, which is important for daily encounters with new persons or testimonies, has not been investigated yet. Importantly, high levels of the stress hormone cortisol impair memory recognition, in particular for emotional material. However, some studies also reported high cortisol levels to enhance memory recognition. Since cortisol levels in the morning are usually higher than in the evening, time of day might also influence recognition performance. In this pre-registered study with a two-day design, 51 healthy men encoded pictures of male and female faces with distinct emotional expressions on day one around noon. Memory for the faces was retrieved two days later at two consecutive testing times either in the morning (high and moderately increased endogenous cortisol levels) or in the evening (low endogenous cortisol levels). Additionally, alertness as well as salivary cortisol levels at the different timepoints was assessed. Cortisol levels were significantly higher in the morning compared to the evening group as expected, while both groups did not differ in alertness. Familiarity ratings for female stimuli were significantly better when participants were tested during moderately increased endogenous cortisol levels in the morning than during low endogenous cortisol levels in the evening, a pattern which was previously also observed for stressed versus non-stressed participants. In addition, cortisol levels during that time in the morning were positively correlated with the recollection of face stimuli in general. Thus, recognition memory performance may depend on the time of day and as well as on stimulus type, such as the difference of male and female faces. Most importantly, the results suggest that cortisol may be meaningful and worth investigating when studying the effects of time of day on memory performance. This research offers both, insights into daily encounters as well as legally relevant domains as for instance testimonies.

Effects of job demands, job resources, personal resources on night-shift alertness of ICU shift nurses: a cross­sectional survey study based on the job demands-resources model.

BACKGROUND: A positive work environment can enhance nursing safety and patient satisfaction while alleviating nurse stress. Conversely, a poor work environment can harm nurses' physical and mental health and compromise the quality of care, particularly in the high-intensity and shift-based setting of the ICU. OBJECTIVES: Based on the Job demands-resources (JD-R) model, this study examined the effects of job demands and job resources in the work environment, as well as personal resources, on the night-shift alertness of ICU shift nurses. METHODS: This cross-sectional correlational exploratory study, conducted from July to September 2022, recruited 291 ICU shift nurses from a hospital in Beijing, China. The Copenhagen Psychosocial Questionnaire (COPSOQ), the Self-resilience scale, the General Self-Efficacy Scale (GSES), and the Psychomotor Vigilance Task (PVT) were used to subjectively and objectively measure the job demands, job resources, personal resources, and night-shift alertness. SPSS 26.0 and Mplus 8.3 were used to analyze the data and construct the structural equation model. RESULTS: The night-shift reaction time was 251.0 ms (Median), indicating a relatively high level of alertness. Job demands were negatively correlated with both job resources (r=-0.570, P < 0.001) and personal resources (r=-0.462, P < 0.001), while a positive correlation existed between job resources and personal resources (r = 0.554, P < 0.001). The results show that increased job demands can lead to higher levels of nurse strain (ß = 0.955, P < 0.001), whereas job resources were found that it can decrease strain (ß=-0.477, P = 0.047). Adequate job resources can enhance motivation directly (ß = 0.874, P < 0.001), subsequently reducing reaction time (ß=-0.148, P = 0.044) and improving night-shift alertness among ICU shift nurses. CONCLUSION: Enhancing ICU shift nurses' work motivation through bolstering job resources can boost night-shift alertness. However, it is noteworthy that, in this study, neither strain nor individual resources significantly influenced nurses' night-shift alertness. This may be attributed to the complexity of the ICU environment and individual differences. Future research should explore the relationship between these factors and nurses' work alertness.

Magnesium-L-threonate improves sleep quality and daytime functioning in adults with self-reported sleep problems: A randomized controlled trial.

Objective/Background: Sleep problems challenge overall wellbeing. Magnesium has been implicated to benefit sleep, although the clinical evidences varied based on the magnesium source used. Magnesium L-threonate (MgT) is a promising intervention due to its brain bioavailability and effects on cognition, memory and mood. We investigated MgT supplementation on sleep quality and daily function. Patients/methods: Eighty 35-55-year-olds with self-assessed sleep problems participated in a randomized, double-blind, placebo-controlled, parallel-arm study, taking 1 g/day of MgT or placebo for 21 days. Sleep and daily behaviors were measured subjectively using standardized questionnaires including the Insomnia Severity Index, Leeds Sleep Evaluation Questionnaire, and Restorative Sleep Questionnaire, and objectively using an Oura ring. The Profile of Mood States questionnaire and a daily diary were used to evaluate mood, energy and productivity, and record any safety concerns. Results: The MgT group maintained good sleep quality and daytime functioning, while placebo declined. From objective Oura ring measurements, MgT significantly (p < 0.05) improved vs placebo deep sleep score, REM sleep score, light sleep time, and activity and readiness parameters activity score, activity daily movement score, readiness score, readiness activity balance, and readiness sleep balance. From subjective questionnaires, MgT significantly (p < 0.05) improved vs placebo behavior upon awakening, energy and daytime productivity, grouchiness, mood and mental alertness. MgT was safe and well tolerated. Conclusions: This showed MgT improved sleep quality, especially deep/REM sleep stages, improved mood, energy, alertness, and daily activity and productivity. These are consistent with how MgT works in neuron cells and animal models, suggesting broader positive impacts on overall brain health.

How to quantify sleepiness during an attempt to sleep?

Background. Sleepiness assessment tools were mostly developed for detection of an elevated sleepiness level in the condition of sleep deprivation and several medical conditions. However, sleepiness occurs in various other conditions including the transition from wakefulness to sleep during an everyday attempt to get sleep.Objective. We examined whether objective sleepiness indexes can be implicated in detection of fluctuations in sleepiness level during the polysomnographically-monitored attempt to sleep, i.e. in the absence of self-reports on perceived sleepiness level throughout such an attempt.Approach. The polysomnographic signals were recorded in the afternoon throughout 106 90 min napping attempts of 53 university students (28 females). To calculate two objective sleepiness indexes, the electroencephalographic (EEG) spectra were averaged on 30 s epochs of each record, assigned to one of 5 sleep-wake stages, and scored using either the frequency weighting curve for sleepiness substate of wake state or loadings of each frequency on the 2nd principal component of variation in the EEG spectrum (either sleepiness score or PC2 score, respectively).Main results. We showed that statistically significant fluctuations in these two objective sleepiness indexes during epochs assigned to wake stage can be described in terms of the changes in verbally anchored levels of subjective sleepiness assessed by scoring on the 9-step Karolinska Sleepiness Scale.Significance. The results afford new opportunities to elaborate importance of intermediate substates between wake and sleep states for sleep-wake dynamics in healthy individuals and patients with disturbed sleep.

Association between Enhanced Effective Connectivity from the Cuneus to the Middle Frontal Gyrus and Impaired Alertness after Total Sleep Deprivation.

BACKGROUND: Sleep deprivation (SD) can impair an individual's alertness, which is the basis of attention and the mechanism behind continuous information processing. However, research concerning the effects of total sleep deprivation (TSD) on alertness networks is inadequate. In this study, we investigate the cognitive neural mechanism of alertness processing after TSD. METHODS: Twenty-four college students volunteered to participate in the study. The resting-state electroencephalogram (EEG) data were collected under two conditions (rested wakefulness [RW], and TSD). We employed isolated effective coherence (iCoh) analysis and functional independent component analysis (fICA) to explore the effects of TSD on participants' alertness network. RESULTS: This study found the existence of two types of effective connectivity after TSD, as demonstrated by iCoh: from the left cuneus to the right middle frontal gyrus in the ß3 and γ bands, and from the left angular gyrus to the left insula in the δ, θ, α, ß1, ß3, and γ bands. Furthermore, Pearson correlation analysis showed that increased effective connectivity between all the bands had a positive correlation with increases in the response time in the psychomotor vigilance task (PVT). Finally, fICA revealed that the neural oscillations of the cuneus in the α2 bands increased, and of the angular gyrus in the α and ß1 bands decreased in TSD. CONCLUSIONS: TSD impairs the alertness function among individuals. Increased effective connectivity from the cuneus to the middle frontal gyrus may represent overloads on the alertness network, resulting in participants strengthening top-down control of the attention system. Moreover, enhanced effective connectivity from the angular gyrus to the insula may indicate a special perception strategy in which individuals focus on salient and crucial environmental information while ignoring inessential stimuli to reduce the heavy burden on the alertness network. CLINICAL TRIAL REGISTRATION: No: ChiCTR2400088448. Registered 19 August 2024, https://www.chictr.org.cn.

Beyond the Buzz: Do Energy Drinks Offer More Than Caffeine for Mental and Physical Tasks?

Energy drinks are marketed for enhancing mental and physical performance, often containing ingredients beyond caffeine. This study investigated whether an energy drink (ED), Gorilla Mind, exerted greater effects on sustained attention, mood, handgrip strength, and push-up performance than a caffeine-matched control drink (CAF) in exercise-trained individuals (n = 21, age: 22 ± 5.9 years). In a randomized, counterbalanced, crossover design, participants first completed tests assessing mood (Profile of Mood States; POMS), sustained attention (Psychomotor Vigilance Test; PVT), handgrip strength (HG), and 1-minute maximum push-up performance (PU). They then consumed either an ED or CAF drink (200mg caffeine) in a randomized order. After 45 minutes, the tests were repeated. Following a 1-week washout period, participants returned to consume the other drink and completed the same protocol. While the ED group improved reaction time (PVT), the Delta score between ED and CAF was not statistically significant (p = 0.3391). No significant differences were found between ED and CAF groups for other measures (POMS: p = 0.152, HG: p = 0.499, PU: p = 0.209). These findings suggest that the additional ingredients in the ED may not offer substantial benefits beyond caffeine for these measures in active individuals. It is important to note that the caffeine dose was, on average, less than 3.0 mg/kg body mass, which may have influenced the outcomes.

Assessment of Efficacy and Safety of Mangifera indica Extract (Stadice®) for Cognitive Function: A Randomized, Double-Blind, Placebo-Controlled Study.

Background and objectives Stadice® is a proprietary herbal ingredient preparation standardized to mangiferin, developed to support cognitive wellness in healthy adults. Mangifera indica extract and its active constituent, mangiferin were known for its positive cognitive health benefits at experimental levels. This was an attempt to evaluate the clinical efficacy and safety of Stadice® on healthy subjects. Materials and methods A randomized, double-blind, placebo-controlled clinical study was designed to study the efficacy and safety of Stadice®. Sixty healthy subjects who were regularly playing virtual/mobile/computer/laptop games online or offline were asked to consume a capsule containing 300 mg of Stadice® or placebo per day for seven days. Cognitive ability tests, that were part of the NIMHANS Neuropsychological Battery and Auditory verbal learning tests were used to assess the cognitive health effects. Psychological stress response, anxiety, mood, subjective working memory, and cortisol levels were also assessed. All assessments were carried out at the baseline and at the end of the study. Results Stadice® was found to significantly improve mental speed, attention, working memory, response inhibition, and verbal learning and memory as evidenced by the results of the multiple cognitive ability tests. Additionally, Stadice ® showed beneficial responses in managing psychological stress in terms of handling nervousness, irritability, or mood swings. No safety concerns were found in the laboratory safety test parameters as they were within the normal physiological range and no adverse events were reported in this study. Conclusion The proprietary Mangifera indica extract (Stadice®) holds promise for enhancing cognitive abilities in healthy adults, particularly those engaged in esports. Improvements in learning, memory, mental speed, attention, response inhibition, and working memory among participants supplemented with Stadice® were observed with a good safety profile. Further exploration is warranted to ascertain its broader applicability as well as to elucidate the possible mechanisms.

Phenotyping patients treated for obstructive sleep apnea with persistent objective impaired alertness or subjective sleepiness.

BACKGROUND AND OBJECTIVES: Sleepiness in patients with obstructive sleep apnea (OSA) is associated with accidental and economic burden, as well as cardiovascular risk. Despite OSA treatment, 10-28 % of patients report residual sleepiness. Its determinants, as well as those of objective impaired alertness remain poorly known. In this study, we investigated factors associated with residual subjective sleepiness and objective impaired alertness in patients treated for OSA. METHODS: Consecutive OSA treated patients referred for maintenance of wakefulness tests (MWT) at a tertiary university center were recruited between 2017 and 2020. Clinical data and polysomnography parameters were compared between patients with vs without subjective sleepiness (Epworth Sleepiness Scale, ESS≥11) and those with vs without impaired alertness (at least one trial with sleep onset on MWT). A multivariate logistic model was used to assess explanatory variables of MWT and ESS results. RESULTS: We included 141 patients, of whom 12.8 % had both subjective sleepiness and objective impaired alertness, 17.7 % objective impaired alertness only and 9.2 % subjective sleepiness only. Self-reported history of car accident/near miss, smoking history and ESS≥11 were significantly associated with objective impaired alertness whereas residual Apnea-hypopnea Index and CPAP use were not. The only significant variable associated with ESS at the time of MWT evaluation was initial ESS. Patients with objective impaired alertness only were more often smokers (52 % vs 19 %, p = 0.01), had a higher body mass index (BMI) (32 vs 29 kg/m2, p = 0.05), and showed lower initial ESS (11 vs 13, p < 0.01). CONCLUSIONS: More than one third of OSA treated patients referred for MWT have objective impaired alertness and/or subjective sleepiness. Our findings highlight the need for a comprehensive medical assessment including accident history, subjective sleepiness and comorbidities. Particular attention should be paid to smoking patients with high BMI, who are at risk of impaired alertness with no report of subjective sleepiness.

Participatory Design in Suicide Prevention: A Qualitative Study of International Students' Experiences of Adapting the LivingWorks safeTALK Programme.

BACKGROUND: Current suicide prevention approaches are not adapted to international student needs, and participatory design is a method that may facilitate the development or adaptation of appropriate programmes for this group. METHODS: This qualitative study investigated the experiences of international university students studying in Australia who participated in a co-consultation process to adapt the LivingWorks safeTALK suicide prevention programme. Eight international students from the co-consultation workshop completed semi-structured interviews about their workshop experience. The data were analysed using reflexive thematic analysis. RESULTS: The findings showed that participants found the co-consultation process empowering and engaging. They also reported that the experience promoted mutual learning and challenged simplistic views of suicide. No students reported experiencing distress. Suggestions for improving participatory design for international students focussed on enhancing participant interaction, supporting quiet voices to be heard and ensuring understanding of mental health and suicide through shared language. CONCLUSIONS: This study underscores the value of participatory design in suicide prevention, emphasising its potential to empower international students and facilitate culturally sensitive programme adaptations. PATIENT OR PUBLIC CONTRIBUTION: International students were involved in the co-consultation process to redevelop the training content and provided a series of recommendations for improving such processes for international students in the future. The two researchers who conducted the interviews and data analysis were former international students.

Time-Dependent Effects of Altered Prebedtime Light Exposure in Enclosed Spaces on Sleep Performance Associated with Human States.

Purpose: Exposure to artificial light influences human performance, which is essential for maintaining healthy work and sleep. However, existing research has not explored the intrinsic links between sleep performance and human states over time under prebedtime light exposure interventions (LEIs). Methods: To investigate the time-dependent effects of altered prebedtime light exposure, four LEI groupings (#L1 - #L4) and a Time factor (D8, D9, and D10) were chosen for sleep experiments in enclosed spaces. Forty-eight young adults recruited were available for data analysis. Subjective alertness (SA), negative affect (NA), subjective sleep, and objective sleep were measured via the Karolinska Sleepiness Scale, Positive and Negative Affect Schedule, Next-day Self-assessment Sleep Quality, and joint assessment of wrist actigraphy and sleep diaries, respectively. Statistical analysis was used for the effects of light exposure on the human states (corresponding to the SA and NA) and sleep performance, while the process model helped construct the associations between the two. Results: The statistical effects revealed that the Time had a significant main effect on subjective sleep and changes in prebedtime alertness; the LEI had a significant main effect only on sleep onset latency (SOL). After undergoing altered prebedtime light exposure, the mean SA increased at prebedtime of D9 (p = 0.022) and D10 (p = 0.044); No significant effect on the NA was observed; Mean subjective sleep had a significant increase from D8 to D10. Moreover, five actigraphy-estimated sleep parameters were interrelated. In light of this, a chained pathway relationship was identified. The SOL played a mediating predictor between prebedtime state and objective sleep, which was linked to the awakening state through subjective sleep. Conclusion: Our study suggests that time-dependent effects of altered prebedtime light exposure on sleep performance are associated with human states at prebedtime and awakening, with implications for its prediction of sleep health.

Pupillometry as a biomarker of postural control: Deep-learning models reveal side-specific pupillary responses to increased intensity of balance tasks.

Pupillometry has been used in the studies of postural control to assess cognitive load during dual tasks, but its response to increased balance task intensity has not been investigated. Furthermore, it is unknown whether side-specific changes in pupil diameter occur with more demanding balance tasks providing additional insights into postural control. The two aims of this study were to analyze differences in steady-state pupil diameter between balance tasks with increased intensity and to determine whether there are side-specific changes. Forty-eight healthy subjects performed parallel and left and right one-legged stances on a force plate with and without foam with right and left pupil diameters measured with a mobile infrared eye-tracker. Differences between balance tasks in parameters (average pupil diameter of each eye, average of both pupil diameters and the difference between the left and right pupil diameter) were analyzed using a two-way repeated measures analysis of variance, and deep learning neural network models were used to investigate how pupillometry predicted each balance task. The pupil diameter of the left eye, the average pupil diameter of both eyes and the difference in pupil diameters increased statistically significantly from simpler to more demanding balance tasks, with this being more pronounced for the left eye. The deep learning neural network models revealed side-specific changes in pupil diameter with more demanding balance tasks. This study confirms pupillary responses to increased intensity of balance task and indicates side-specific pupil responses that could be related to task-specific involvement of higher levels of postural control.

An Investigation into the Effects of Correlated Color Temperature and Illuminance of Urban Motor Vehicle Road Lighting on Driver Alertness.

Current international optical science research focuses on the non-visual effects of lighting on human cognition, mood, and biological rhythms to enhance overall well-being. Nocturnal roadway lighting, in particular, has a substantial impact on drivers' physiological and psychological states, influencing behavior and safety. This study investigates the non-visual effects of correlated color temperature (CCT: 3000K vs. 4000K vs. 5000K) and illuminance levels (20 lx vs. 30 lx) of urban motor vehicle road lighting on driver alertness during various driving tasks. Conducted between 19:00 and 20:30, the experiments utilized a human-vehicle-light simulation platform. EEG (ß waves), reaction time, and subjective evaluations using the Karolinska Sleepiness Scale (KSS) were measured. The results indicated that the interaction between CCT and illuminance, as well as between CCT and task type, significantly influenced driver alertness. However, no significant effect of CCT and illuminance on reaction time was observed. The findings suggest that higher illuminance (30 lx) combined with medium CCT (4000K) effectively reduces reaction time. This investigation enriches related research, provides valuable reference for future studies, and enhances understanding of the mechanisms of lighting's influence on driver alertness. Moreover, the findings have significant implications for optimizing the design of urban road lighting.

Acute effects of light during daytime on central aspects of attention and affect: A systematic review.

Light regulates both image- and various non-image forming responses in humans, including acute effects on attention and affect. To advance the understanding of light's immediate effects, this systematic review describes the acute effects of monochromatic/narrow bandwidth and polychromatic white light during daytime on distinct aspects of attention (alertness, sustained attention, working memory, attentional control and flexibility), and measures of affect (self-report measures, performance-based tests, psychophysiological measures) in healthy, adult human subjects. Original, peer-reviewed (quasi-) experimental studies published between 2000 and May 2024 were included according to predefined inclusion and exclusion criteria. Study quality was assessed, and results were synthesized across aspects of attention and affect and grouped according to light interventions; monochromatic/narrowband-width or polychromatic white light (regular white, bright white, and white with high correlated color temperature (CCT)). Results from included studies (n = 62) showed that alertness and working memory were most affected by light. Electroencephalographic markers of alertness improved the most with exposure to narrow bandwidth long-wavelength light, regular white, and white light with high CCT. Self-reported alertness and measures of working memory improved the most with bright white light. Results from studies testing the acute effects on sustained attention and attentional control and flexibility were inconclusive. Performance-based and psychophysiological measures of affect were only influenced by narrow bandwidth long-wavelength light. Polychromatic white light exerted mixed effects on self-reported affect. Studies were strongly heterogeneous in terms of light stimuli characteristics and reporting of light stimuli and control of variables influencing light's acute effects.

A scoping review of olfactory interventions for fatigue relief: addressing occupational health hazards.

Background: Fatigue poses risks to occupational health and safety, affecting individuals' work efficiency, physical health, and social security, as well as human wellbeing and quality of life. Olfactory interventions, due to their low interference, are considered promising strategies for mitigating fatigue and reducing occupational health hazards. Objective: The objective of this review is to bridge the current gaps in the literature by conducting a scoping review of olfactory interventions on human alertness. It aims to explore their application in various occupational settings and to provide comprehensive and practical guidance for the practical application of olfactory interventions in mitigating fatigue and reducing occupational risks. Methods: The literature research was conducted in English using electronic databases such as Web of Science. Keywords related to scent and fatigue and the review followed PRISMA Extension for Scoping Reviews and PICO framework. Results: 28 studies were included in this work. Participant characteristics, fatigue measurement methods, and scent intervention methods, such as types of scents, intervention strategies, and scent presentation systems, are thoroughly investigated and discussed. Additionally, the study places a specific emphasis on the applications and research within the field of scent interventions for fatigue driving. Olfactory interventions have been applied to populations in various occupational fields, demonstrating beneficial effects on both physiological and psychological fatigue. Conclusions: Olfactory intervention is effective and promising for enhancing alertness and improving the occupational environment. To provide detailed and practical guidance for the actual application of olfactory intervention in fatigue relief and reducing occupational health and safety hazards, further research into the potential mechanisms, applications, and efficacy assessment systems of fatigue-related olfactory interventions is necessary.

Factors facilitating and hindering the implementation of digital sleep coaching for bus drivers.

Improving fatigue management is critical to the occupational safety of professional drivers. We aimed to identify the factors that facilitated or hindered the implementation of digital sleep coaching in bus companies and to explore bus drivers' experiences with it. Two bus companies implemented coaching for bus drivers. Using a mixed methods design, we collected data through two workshops (n = 30 and n = 27) attended by key personnel from the organisations and through questionnaires to the drivers (n = 30). Implementation was facilitated by, for example, the flexible participation and multichannel information of coaching, and hindered by restrictions on social support due to the COVID-19 pandemic, and lack of interest and inspiring examples. On average, the drivers rated the appropriateness and the feasibility of coaching as good. However, further development could lead to wider dissemination. It would also be important to involve the key people in the organisations and stakeholders more in supporting the implementation.

Towards an evidence-based integrative lighting score: a proposed multi-level approach.

Background: Human circadian clocks are synchronized daily with the external light-dark cycle and entrained to the 24-hour day. There is increasing evidence that a lack of synchronization and circadian entrainment can lead to adverse health effects. Beyond vision, light plays a critical role in modulating many so-called non-visual functions, including sleep-wake cycles, alertness, mood and endocrine functions. To assess (and potentially optimize) the impact of light on non-visual functions, it is necessary to know the exact 'dose' (i.e. spectral irradiance and exposure duration at eye level) of 24-hour light exposures, but also to include metadata about the lighting environment, individual needs and resources.Problem statement: To address this problem, a new assessment tool is needed that uses existing metrics to provide metadata and information about light quality and quantity from all sources. In this commentary, we discuss the need to develop an evidence-based integrative lighting score that is tailored to specific audiences and lighting environments. We will summarize the most compelling evidence from the literature and outline a future plan for developing such a lighting score using internationally accepted metrics, stakeholder and user feedback.Conclusion: We propose a weighting system that combines light qualities with physiological and behavioral effects, and the use of mathematical modelling for an output score. Such a scoring system will facilitate a holistic assessment of a lighting environment, integrating all available light sources.

To assess the impact of light on non-visual functions, it is essential to know the exact 'dose' of 24-hour light exposures and metadata about the lighting environment and the individual.There is to date no measurement method available that allows a holistic assessment of a lighting environment for visual and non-visual aspects in humans.We discuss the need for an evidence-based integrative lighting score and outline a plan for its development.An evidence-based integrative lighting score, which includes a weighting system to combine light qualities with physiological and behavioral effects, will only be possible by joining forces, knowledge, and methodologies from many disciplines.Such a score entails the potential to sustainably assess, improve and maintain optimized lighting environments that promote the health and productivity of any cohort over the long term.

When to sleep and consume caffeine to boost alertness.

STUDY OBJECTIVES: Sleep loss can cause cognitive impairments that increase the risk of mistakes and accidents. However, existing guidelines to counteract the effects of sleep loss are generic and are not designed to address individual-specific conditions, leading to sub-optimal alertness levels. Here, we developed an optimization algorithm that automatically identifies sleep schedules and caffeine-dosing strategies to minimize alertness impairment due to sleep loss for desired times of the day. METHODS: We combined our previous algorithms that separately optimize sleep or caffeine to simultaneously identify the best sleep schedules and caffeine doses that minimize alertness impairment at desired times. The optimization algorithm uses the predictions of the well-validated Unified Model of Performance to estimate the effectiveness and physiological feasibility of a large number of possible solutions and identify the best one. To assess the optimization algorithm, we used it to identify the best sleep schedules and caffeine-dosing strategies for four studies that exemplify common sleep-loss conditions and compared the predicted alertness-impairment reduction achieved by using the algorithm's recommendations against that achieved by following the U.S. Army caffeine guidelines. RESULTS: Compared to the alertness-impairment levels in the original studies, the algorithm's recommendations reduced alertness impairment on average by 63%, an improvement of 24 percentage points over the U.S. Army caffeine guidelines. CONCLUSIONS: We provide an optimization algorithm that simultaneously identifies effective and safe sleep schedules and caffeine-dosing strategies to minimize alertness impairment at user-specified times.

Subanesthetic Ketamine Suppresses Locus Coeruleus-Mediated Alertness Effects: A 7T fMRI Study.

BACKGROUND: The NMDA antagonist S-ketamine is gaining increasing use as a rapid-acting antidepressant, although its exact mechanisms of action are still unknown. In this study, we investigated ketamine in respect to its properties toward central noradrenergic mechanisms and how they influence alertness behavior. METHODS: We investigated the influence of S-ketamine on the locus coeruleus (LC) brain network in a placebo-controlled, cross-over, 7T functional, pharmacological MRI study in 35 healthy male participants (25.1 ± 4.2 years) in conjunction with the attention network task to measure LC-related alertness behavioral changes. RESULTS: We could show that acute disruption of the LC alertness network to the thalamus by ketamine is related to a behavioral alertness reduction. CONCLUSION: The results shed new light on the neural correlates of ketamine beyond the glutamatergic system and underpin a new concept of how it may unfold its antidepressant effects.

Biomathematical modeling of fatigue due to sleep inertia.

Biomathematical models of fatigue capture the physiology of sleep/wake regulation and circadian rhythmicity to predict changes in neurobehavioral functioning over time. We used a biomathematical model of fatigue linked to the adenosinergic neuromodulator/receptor system in the brain as a framework to predict sleep inertia, that is, the transient neurobehavioral impairment experienced immediately after awakening. Based on evidence of an adenosinergic basis for sleep inertia, we expanded the biomathematical model with novel differential equations to predict the propensity for sleep inertia during sleep and its manifestation after awakening. Using datasets from large laboratory studies of sleep loss and circadian misalignment, we calibrated the model by fitting just two new parameters and then validated the model's predictions against independent data. The expanded model was found to predict the magnitude and time course of sleep inertia with generally high accuracy. Analysis of the model's dynamics revealed a bifurcation in the predicted manifestation of sleep inertia in sustained sleep restriction paradigms, which reflects the observed escalation of the magnitude of sleep inertia in scenarios with sleep restriction to less than âˆ¼ 4 h per day. Another emergent property of the model involves a rapid increase in the predicted propensity for sleep inertia in the early part of sleep followed by a gradual decline in the later part of the sleep period, which matches what would be expected based on the adenosinergic regulation of non-rapid eye movement (NREM) sleep and its known influence on sleep inertia. These dynamic behaviors provide confidence in the validity of our approach and underscore the predictive potential of the model. The expanded model provides a useful tool for predicting sleep inertia and managing impairment in 24/7 settings where people may need to perform critical tasks immediately after awakening, such as on-demand operations in safety and security, emergency response, and health care.