The relationship between flow, sleepiness and cognitive performance: the effects of short afternoon nap and bright light exposure

The Impact of Different Color Temperatures and Sources of Light on Mood and Vision: Acuity and Color Recognition

Background: Light is a physical factor that can influence the mood and vision of people during work and study. According to the importance of these physical factors, the present study aimed to investigate the effect of the source and color temperature on the mood and vision (acuity and color recognition) of students of TUMS and USWR medical universities. Methods: The present study is an applied study, and the research method is quasi-experimental. Twenty subjects were determined by first-type error (0.05) and test power (0.08). The mood was measured using the profile of mood states (POMS), visual acuity in different lighting conditions based on Snellen and FrACT methods, and color recognition by Ishihara’s test. Data were analyzed by SPSS 22, one-way ANOVA, and Greenhouse-Geisser. Results: The results of investigating six subscales of the POMS scale in sunlight, LED, and fluorescent with color temperatures of 4000 K and 3000 K indicated improvement in mood states (P < 0.001). Color recognition under different lighting conditions showed no significant difference (P < 0.05). However, visual acuity with the FrACT method under sunlight showed a significant difference in other lighting conditions (P < 0.001). Conclusions: Light sources can influence mood and vision states (acuity and color recognition) under different lighting conditions. Therefore, using sunlight in educational environments can improve the mood and state of students.

Effectiveness of Digital Cognitive Behavior Therapy for the Treatment of Insomnia: Spillover Effects of dCBT

The effects of digital Cognitive Behavior Therapy for insomnia (dCBT-i) on sleep quality have been previously demonstrated but the spillover effects on fatigue, flow (a state of immersion in activities of interest), and cognitive flexibility remain unclear. The current study examined the effectiveness of dCBT-i. A total of 97 college students (20.96 ± 1.87 years, 73.1% female students) were randomly selected from a shortlist and divided into sleep intervention (n = 39), conventional education (n = 37), and healthy control (n = 21) groups. Task switching paradigm, Fatigue Severity Scale (FSS), Flow Experience Scale (FES), and the Chinese version of the Pittsburgh Sleep Quality Index (CPSQI) were measured pre- and post-intervention. Results show that the sleep quality of the intervention group improved, and fatigue was relieved. Participants in the sleep intervention group had increased flow experience scores post-intervention and improved cognitive flexibility. The control group’s sleep quality deteriorated and fatigue level increased. dCBT-i can not only achieve a significant improvement in sleep quality and reduce fatigue, but also improve learning abilities, quality of life, flow, and cognitive flexibility. Future research should pay attention to indicators such as work efficiency, sedative use, and the durability and stability of such effects.

Does Bright Light Counteract the Post-lunch Dip in Subjective States and Cognitive Performance Among Undergraduate Students?

The post-lunch dip in alertness and performance was widely experienced during the early afternoon. Taking a short nap was documented as a practical strategy for habitual nappers to counteract the decline of alertness and performance. Yet, it remains unknown whether bright light exposure in the early afternoon working hours could alleviate the performance deficits caused by a post-lunch nap loss for habitual nappers. Seventeen undergraduate students who had a long-term habit of taking a post-lunch nap were assigned to three interventions: (1) a short nap + normal indoor light (100 lx, 4,000 K at eye level); (2) no nap + normal indoor light, and (3) no nap + blue-enriched bright light (1,000 lx, 6,500 K at eye level), in which subjective alertness (Karolinska Sleepiness Scale, KSS), mood (Positive and Negative Affect Schedule, PANAS), and task performance in sustained attention (psychomotor vigilance test, PVT), response inhibition (go/no-go task), and working memory (paced visual serial addition test, PVSAT) were measured. Results showed that a post-lunch nap deprivation significantly increased subjective sleepiness and negative mood and impaired performance in PVT and PVSAT, while exposure to bright blue-enriched white light vs. normal indoor light in the early afternoon significantly relieved such negative effects on mood, sleepiness, and performance in PVSAT; subjective positive mood and performance in PVT and go/no-go task remained unaffected with light intervention. These findings suggested that bright blue-enriched white light exposure could be a potential strategy for those who are suffering from drowsiness and low working memory following a habitual midday nap loss.

The Concept of Qailulah (Midday Napping) from Neuroscientific and Islamic Perspectives

Napping/siesta during the day is a phenomenon, which is widely practised in the world. However, the timing, frequency, and duration may vary. The basis of napping is also diverse, but it is mainly done for improvement in alertness and general well-being. Neuroscience reveals that midday napping improves memory, enhances alertness, boosts wakefulness and performance, and recovers certain qualities of lost night sleep. Interestingly, Islam, the religion of the Muslims, advocates midday napping primarily because it was a practice preferred by Prophet Muhammad (pbuh). The objectives of this review were to investigate and compare identical key points on focused topic from both neuroscientific and Islamic perspectives and make recommendations for future researches.

Sleep patterns and their association with depression and behavior problems among Chinese adolescents in different grades

We aimed to examine sleep patterns and their association with depression and behavior problems among Chinese adolescents in different grades. A cross-sectional study was conducted in 10 cities of mainland China. A total of 8,998 Chinese adolescents (49.3% males) aged 9-20 years completed a self-administered questionnaire that included questions on sleep patterns, depressive symptoms, behavior problems, and demographic characteristics. The percentage of adolescents who slept less than 7 hr on weekdays increased with grade, while the percentage of adolescents who slept less than 7 hr on weekends remained the same. The gap in sleep length between weekdays and weekends increased from 0.6 hr in grade 5 to 2.3 hr in Grade 12. The regression analysis showed that poor sleep habits were linked to greater emotional and behavioral problems. The associations of sleep length with those problems differed by symptom and grade. Sleeping less related to depression in all grades. More behavior problems were observed in primary school students who had less sleep and in senior high school students who had more sleep than their peers. The preference for going to bed late stably related to both adolescent depression and behavior problems in all grades, although it posed a greater risk for students in higher grades.

Using relaxation techniques to improve sleep during naps

Insufficient sleep is a common occurrence in occupational settings (e.g. doctors, drivers, soldiers). The resulting sleep debt can lead to daytime sleepiness, fatigue, mood disorder, and cognitive deficits as well as altered vascular, immune and inflammatory responses. Short daytime naps have been shown to be effective at counteracting negative outcomes related to sleep debt with positive effects on daytime sleepiness and performance after a normal or restricted night of sleep in laboratory settings. However, the environmental settings in the workplace and the emotional state of workers are generally not conducive to beneficial effects. Here, we tested whether relaxation techniques (RT) involving hypnosis might increase total sleep time (TST) and/or deepen sleep. In this study, eleven volunteers (aged 37-52) took six early-afternoon naps (30 min) in their occupational workplace, under two different conditions: control 'Naps' or 'Naps + RT' with a within-subjects design. Our results demonstrate that adding RT to naps changes sleep architecture, with a significant increase in the TST, mostly due to N2 sleep stage (and N3, to a lesser extent). Therefore, the deepening of short naps with RT involving hypnosis might be a successful non-pharmacological way to extend sleep duration and to deepen sleep in occupational settings.

Effects of Afternoon Nap Deprivation on Adult Habitual Nappers' Inhibition Functions

Multiple studies have established the effects of afternoon naps on cognition. However, relatively few studies have investigated the domain of executive functions. Moreover, the effects of napping on inhibition are far from conclusive. The present study employed adult habitual nappers to investigate the effects of afternoon nap deprivation on response-based inhibition assessed by a Go/No-go task and stimulus-based inhibition assessed by a Flanker task and on alertness assessed by a psychomotor vigilance test (PVT) and the Karolinska Sleepiness Scale (KSS). The results showed that afternoon nap deprivation significantly decreased participants' accuracy and reaction speed for the Go/No-go task but not for the Flanker task. In addition, participants' alertness was significantly impaired after nap deprivation in terms of increased subjective sleepiness and worse PVT performance. Task-specific effects of napping on inhibition were demonstrated. The implications of the results are discussed.

Impact of a single, short morning bright light exposure on tryptophan pathways and visuo- and sensorimotor performance: a crossover study

Background

Bright light (BL) has been shown to be effective in enhancing both cognitive and physical performances. Alterations in nighttime melatonin levels have also been observed. However, evaluations of light-induced changes in the preceding biochemical processes are absent. Therefore, the impact of a single morning BL exposure on sensorimotor and visuomotor performance, as well as tryptophan (trp) and trp metabolites, was evaluated in this study.

Methods

In a crossover design, 33 healthy volunteers were randomly exposed to 30 min of < 150 lx at eye level (office light, OL) and 5000 lx at eye level (bright light, BL) of 6500 K in the morning hours. Trp, sulfatoxymelatonin (aMT6s), and kynurenine (kyn) courses over the morning hours were analyzed, and changes in sensori- and visuomotor measures were examined.

Results

Motoric performance increased in both setups, independent of light intensity. aMT6s and kyn decreased equally under both lighting conditions. Trp levels decreased from a mean (95% confidence interval) of 82.0 (77.2–86.9) to 66.5 (62.5–70.1) in the OL setup only.

Conclusion

These data suggest that BL in the morning hours has a limited effect on visuo- and sensorimotor performance. Nevertheless, trp degradation pathways in the morning show diverse courses after OL and BL exposure. This suggests that trp courses can potentially be altered by BL exposure.

Interactive effects of visuomotor perturbation and an afternoon nap on performance and the flow experience

The present study was designed (1) to clarify the relationship between the flow experience and improvements in visuomotor skills, (2) to examine the effects of rotating the axis of a computer mouse on visuomotor skills, and (3) to investigate the effects of sleep for improving visuomotor skills. Participants (N = 18) responded to Perturbation and nap (PER+Nap), No-perturbation and nap (NoPER+Nap) and Perturbation and rest (PER+Rest) conditions. In the PER+Nap condition, participants conducted a visuomotor tracking task using a computer mouse, which was accompanied by perturbation caused by rotating the axis of their mouse. After the task, they took a 90 min nap. In NoPER+Nap condition, they conducted the same visuomotor task without any perturbation and took a nap. In the PER+Rest condition, participants conducted the task with the perturbation and took a 90 min break spent reading magazines instead of taking a nap. Results indicated (1) the flow experience did not occur when participants’ skills and the degree of the visuomotor challenge were matching, (2) improvements of visuomotor skills occurred regardless of the perturbation, (3) improvements of visuomotor skills occurred unrelated to the flow experience, or to mood states, and (4) improvements of visuomotor performance occurred regardless of sleep. These findings suggest that improvements of visuomotor skills occur regardless of mood status and occur independently of perturbations by axis rotation. The study also suggests that the acquisition of skills is related to merely the time elapsed since learning, rather than to sleep.

Ergonomic approach for pillow concept design

Sleep quality is an essential factor to human beings for health. The current paper conducted four studies to provide a suitable pillow for promoting sleep quality. Study 1 investigated the natural positions of 40 subjects during sleep to derive key-points for a pillow design. The results suggested that the supine and lateral positions were alternatively 24 times a night, and the current pillows were too high for the supine position and too low for lateral positions. Study 2 measured body dimensions related to pillow design of 40 subjects to determine pillow sizes. The results suggested that the pillow height were quite different in supine position and lateral position and needed to take into consideration for a pillow design. Study 3 created a pillow design based on the results of above studies. The pillow was a U-form in the front of view in which the pillow height in the middle area was lower for the supine position, and both sides were higher for the lateral positions. Study 4 assessed sleep quality of 6 subjects by using the proposed pillows and the current pillows. The results showed that the newly designed pillow led to significantly higher sleep quality, and the new design received an innovation patent.

Intense illumination in the morning hours improved mood and alertness but not mental performance

Cognitive performance and alertness are two determinants for work efficiency, varying throughout the day and depending on bright light. We conducted a prospective crossover study evaluating the impacts of exposure to an intense, early morning illumination on sustained attention, alertness, mood, and serum melatonin levels in 33 healthy individuals. Compared with a dim illumination, the intense illumination negatively impacted performance requiring sustained attention; however, it positively impacted subjective alertness and mood and had no impact on serum melatonin levels. These results suggest that brief exposure to bright light in the morning hours can improve subjective measures of mood and alertness, but can also have detrimental effects on mental performance as a result of visual distraction. Therefore, it is important that adequate lighting should correspond to both non-visual and visual demands.

Total sleep deprivation decreases flow experience and mood status

BACKGROUND

The purpose of this study was to examine the effect of sleep deprivation on flow experience.

METHODS

Sixteen healthy male volunteers of mean age 21.4±1.59 (21-24) years participated in two experimental conditions, ie, sleep-deprivation and normal sleep. In the sleep-deprived condition, participants stayed awake at home for 36 hours (from 8 am until 10 pm the next day) beginning on the day prior to an experimental day. In both conditions, participants carried out a simple reaction time (psychomotor vigilance) task and responded to a questionnaire measuring flow experience and mood status.

RESULTS

Flow experience was reduced after one night of total sleep deprivation. Sleep loss also decreased positive mood, increased negative mood, and decreased psychomotor performance.

CONCLUSION

Sleep deprivation has a strong impact on mental and behavioral states associated with the maintenance of flow, namely subjective well-being.