This study aims to explore the association between dysfunctional sleep beliefs and vulnerability to stress-related transient sleep disturbance in people without sleep disturbance. One hundred thirty-two good sleepers and 307 poor sleepers were included in this study. As expected, poor sleepers showed more dysfunctional beliefs than good sleepers on the Dysfunctional Beliefs and Attitudes about Sleep scale-10 item version (DBAS-10). More important, even in good sleepers, DBAS-10 scores positively correlated with the vulnerability to stress-related sleep disturbance as measured by the Ford Insomnia Response to Stress Test. The results suggest that dysfunctional sleep belief is not only a perpetuating factor for chronic insomnia, it may also serve as a risk factor for stress-related transient insomnia.

Objective: Depression is highly prevalent among 1st-year college students, and evening chronotype is an important risk factor associated with depression. This study investigates the mediating role of sleep quality and the moderating role of resilience between chronotype and depressive symptoms. Methods: A total of 4531 students were included in this cross-sectional study. Mediation and moderated mediation models were applied. Results: The association between chronotype and depressive symptoms was partially mediated by sleep quality, and the direct and indirect effects were moderated by resilience. The negative correlation between chronotype and depressive symptoms was significant in students with low levels of resilience compared with moderate/high levels. The positive correlation between sleep quality and depressive symptoms was strongest in low-level resilience students. Conclusion: This study reveals that greater eveningness is associated with poorer sleep quality among 1st-year college students, which may lead to severer depression, and highlights the importance of resilience training in reducing depressive symptoms.

Exposure to bright light is typically intermittent in our daily life. However, the acute effects of intermittent light on alertness and sleep have seldom been explored. To investigate this issue, we employed within-subject design and compared the effects of three light conditions: intermittent bright light (30-min pulse of blue-enriched bright light (~1000 lux, ~6000 K) alternating with 30-min dim normal light (~5 lux, ~3600 K) three times); continuous bright light; and continuous dim light on subjective and objective alertness and subsequent sleep structure. Each light exposure was conducted during the three hours before bedtime. Fifteen healthy volunteers (20 ± 3.4 years; seven males) were scheduled to stay in the sleep laboratory for four separated nights (one for adaptation and the others for the light exposures) with a period of at least one week between nights. The results showed that when compared with dim light, both intermittent light and continuous bright light significantly increased subjective alertness and decreased sleep efficiency (SE) and total sleep time (TST). Intermittent light significantly increased objective alertness than dim light did during the second half of the light-exposure period. Our results suggested that intermittent light was as effective as continuous bright light in their acute effects in enhancing subjective and objective alertness and in negatively impacting subsequent sleep.

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Light can induce an alertness response in humans. The effects of exposure to bright light vs. dim light on the levels of alertness during the day, especially in the afternoon, as reported in the literature, are inconsistent. This study employed a multiple measurement strategy to explore the temporal variations in the effects of exposure to bright light vs. regular office light (1,200 lx vs. 200 lx at eye level, 6,500 K) on the alertness of participants for 5 h in the afternoon. In this study, 20 healthy adults (11 female; mean age 23.25 ± 2.3 years) underwent the Karolinska sleepiness scale (KSS), the auditory psychomotor vigilance test (PVT), and the waking electroencephalogram (EEG) test for two levels of light intervention. The results yielded a relatively lower relative delta power and a relatively higher beta power for the 1,200 lx condition in comparison with the 200 lx condition. However, the light conditions elicited no statistically significant differences in the KSS scores and performance with respect to the PVT. The results suggested that exposure to bright light for 5 h in the afternoon could enhance physiological arousal while exerting insignificant effects on subjective feelings and performance abilities relating to the alertness of the participants.