Clocks & Sleep最新文献

Light use is rising steeply, mainly because of the advent of light-emitting diode (LED) devices. LEDs are frequently blue-enriched light sources and may have different impacts on the non-image forming (NIF) system, which is maximally sensitive to blue-wavelength light. Most importantly, the timing of LED device use is widespread, leading to novel light exposure patterns on the NIF system. The goal of this narrative review is to discuss the multiple aspects that we think should be accounted for when attempting to predict how this situation will affect the NIF impact of light on brain functions. We first cover both the image-forming and NIF pathways of the brain. We then detail our current understanding of the impact of light on human cognition, sleep, alertness, and mood. Finally, we discuss questions concerning the adoption of LED lighting and screens, which offer new opportunities to improve well-being, but also raise concerns about increasing light exposure, which may be detrimental to health, particularly in the evening.

Background: Activity plays a very important role in keeping bodies strong and healthy, slowing senescence, and decreasing morbidity and mortality. Drosophila models of evolution under various selective pressures can be used to examine whether increased activity and decreased sleep duration are associated with the adaptation of this nonhuman species to longer or harder lives.

Methods: For several years, descendants of wild flies were reared in a laboratory without and with selection pressure. To maintain the "salt" and "starch" strains, flies from the wild population (called "control") were reared on two adverse food substrates. The "long-lived" strain was maintained through artificial selection for late reproduction. The 24 h patterns of locomotor activity and sleep in flies from the selected and unselected strains (902 flies in total) were studied in constant darkness for at least, 5 days.

Results: Compared to the control flies, flies from the selected strains demonstrated enhanced locomotor activity and reduced sleep duration. The most profound increase in locomotor activity was observed in flies from the starch (short-lived) strain. Additionally, the selection changed the 24 h patterns of locomotor activity and sleep. For instance, the morning and evening peaks of locomotor activity were advanced and delayed, respectively, in flies from the long-lived strain.

Conclusion: Flies become more active and sleep less in response to various selection pressures. These beneficial changes in trait values might be relevant to trade-offs among fitness-related traits, such as body weight, fecundity, and longevity.

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In humans, physiological outputs of the body's internal clock (i.e., saliva, serum, and temperature) can be collected to quantify the timing of the circadian system. In-lab assessment of salivary melatonin in a dimly lit environment is a common approach for adolescents and adults; however, the reliable measurement of melatonin onset in toddlers and preschoolers requires a modification of laboratory methods. For > 15 years, we have successfully collected data from ~250 in-home dim light melatonin onset (DLMO) assessments of children aged 2-5 years. Although in-home studies of circadian physiology may introduce a host of challenges and may increase the risk of incomplete data (e.g., accidental light exposure), in-home studies afford more comfort (e.g., less arousal in children) and flexibility for families. Here, we provide effective tools and strategies to assess children's DLMO, a reliable marker of circadian timing, through a rigorous in-home protocol. We first describe our basic approach, including the study protocol, collection of actigraphy data, and strategies for training child participants to complete procedures. Next, we detail how to convert the home into a "cave", or dim-light environment, and present guidelines for timing the salivary data collection. Lastly, we provide helpful tips to increase participants' compliance based upon behavioral and developmental science tenets.

Retrieving previously stored information makes memory traces labile again and can trigger restabilization in a strengthened or weakened form depending on the reactivation condition. Available evidence for long-term performance changes upon reactivation of motor memories and the effect of post-learning sleep on their consolidation remains scarce, and so does the data on the ways in which subsequent reactivation of motor memories interacts with sleep-related consolidation. Eighty young volunteers learned (Day 1) a 12-element Serial Reaction Time Task (SRTT) before a post-training Regular Sleep (RS) or Sleep Deprivation (SD) night, either followed (Day 2) by morning motor reactivation through a short SRTT testing or no motor activity. Consolidation was assessed after three recovery nights (Day 5). A 2 × 2 ANOVA carried on proportional offline gains did not evidence significant Reactivation (Morning Reactivation/No Morning Reactivation; p = 0.098), post-training Sleep (RS/SD; p = 0.301) or Sleep*Reactivation interaction (p = 0.257) effect. Our results are in line with prior studies suggesting a lack of supplementary performance gains upon reactivation, and other studies that failed to disclose post-learning sleep-related effects on performance improvement. However, lack of overt behavioural effects does not detract from the possibility of sleep- or reconsolidation-related covert neurophysiological changes underlying similar behavioural performance levels.

Cavefish are vertebrates living in extreme subterranean environments with no light, temperature changes, and limited food. Circadian rhythms in these fish are suppressed in natural habitats. However, they can be found in artificial light-dark cycles and other zeitgebers. The molecular circadian clock has its peculiarities in cavefish. In Astyanax mexicanus, the core clock mechanism is tonically repressed in the caves due to the overactivation of the light input pathway. A lack of functional light input pathway but rather the entrainment of circadian genes' expression by scheduled feeding were revealed in more ancient Phreatichthys andruzzii. Different evolutionarily determined irregularities in the functioning of molecular circadian oscillators can be expected in other cavefish. The unique property of some species is the existence of surface and cave forms. Along with the ease of maintenance and breeding, it made cavefish a promising model for chronobiological studies. At the same time, a divergence of the circadian system between cavefish populations requires the strain of origin to be indicated in further research.

Environmental, social, and behavioral variables influence sleep timing and duration. Using wrist-worn accelerometers, we recorded 31 dancers (age = 22.6 ± 3.5) for 17 days and who trained either in the morning (n = 15) or in the late evening (n = 16). We estimated the dancers' daily sleep pattern: onset, end, and duration. In addition, their minutes of moderate-to-vigorous physical activity (MVPA) and mean light illuminance were also calculated daily and for the morning-shift and late-evening-shift time windows. On training days, the shifts involved differences in sleep timing, alarm-driven waking frequency, and the pattern of light exposure and MVPA duration. Sleep was strongly advanced when dancers trained in the morning and when alarms were used, while morning light had a low influence. Sleep was delayed when dancers were more exposed to light and displayed longer MVPA during the late evening. Sleep duration was strongly reduced on weekends and when alarms were used. A small reduction in sleep duration was also observed when morning illuminance was lower or when late evening MVPA was longer. Training in shifts influenced the timing of environmental and behavioral factors, which added up to shape dancers' sleep timing and duration.

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As many as 80% of women report experiencing poor sleep throughout pregnancy. Exercise is associated with many health benefits during pregnancy and is established as a non-pharmacological method to improve sleep in both pregnant and non-pregnant populations. Given the importance of sleep and exercise during pregnancy, the aim of this cross-sectional study was to (1) examine pregnant women's attitudes and beliefs towards sleep and exercise during pregnancy, and (2) investigate the barriers women face to achieving good sleep and engaging in healthy levels of exercise. Participants were comprised of 258 pregnant Australian women (31.3 ± 5.1 years) who completed a 51-question online survey. Almost all (98%) participants believed exercise during pregnancy to be safe, whilst over half (67%) believed participating in more exercise will improve their sleep. Over 70% of participants reported experiencing barriers such as physical symptoms related to pregnancy that negatively impacted their ability to exercise. Almost all (95%) participants reported experiencing barriers to sleep in their current pregnancy. Present findings suggest that overcoming intrapersonal barriers should be a priority for any intervention aiming to improve sleep or increase exercise levels in pregnant populations. Findings from the present study highlight the need for a better understanding of women's sleep experiences during pregnancy, and demonstrate how exercise may improve sleep and health outcomes.

Sleep patterns and problems vary in relation to internal (e.g., sex, age, circadian preference) and external (e.g., social structures) factors. The main aim of the present study was to describe habitual sleep patterns and chronic sleep problems in a population-based sample of Norwegian adults. During spring 2022, a sample of 1028 adults completed an online survey on sleep habits and problems. Response rate was 33.5%. The survey included the Munich ChronoType Questionnaire and items on circadian preference and chronic sleep problems. Mean workday sleep duration was 7:19 h (±199 min), and shorter in males (p = 0.035) and evening persons (p = 0.003). Short workday sleep duration (<6 h) was reported by 3.1% and was associated with evening preference (p = 0.001). Mean social jetlag was 0:51 h (±75 min), and longer in males (p = 0.036), younger adults (p < 0.001) and evening persons (p < 0.001). Long social jetlag (≥2 h) was reported by 11.2% and associated with younger age (p < 0.001) and evening preference (p < 0.001). Chronic sleep problems (≥3 months) were reported by 44.1%, and associated with female sex (p < 0.001) and evening preference (p = 0.002). Results underscore the importance of considering evening circadian preference as a risk factor for short workday sleep duration, long social jetlag and self-reported chronic sleep problems.