Person-directed, non-pharmacological interventions for sleepiness at work and sleep disturbances caused by shift work.

BACKGROUND: Shift work is often associated with sleepiness and sleep disorders. Person-directed, non-pharmacological interventions may positively influence the impact of shift work on sleep, thereby improving workers' well-being, safety, and health. OBJECTIVES: To assess the effects of person-directed, non-pharmacological interventions for reducing sleepiness at work and improving the length and quality of sleep between shifts for shift workers. SEARCH METHODS: We searched CENTRAL, MEDLINE Ovid, Embase, Web of Knowledge, ProQuest, PsycINFO, OpenGrey, and OSH-UPDATE from inception to August 2015. We also screened reference lists and conference proceedings and searched the World Health Organization (WHO) Trial register. We contacted experts to obtain unpublished data. SELECTION CRITERIA: Randomised controlled trials (RCTs) (including cross-over designs) that investigated the effect of any person-directed, non-pharmacological intervention on sleepiness on-shift or sleep length and sleep quality off-shift in shift workers who also work nights. DATA COLLECTION AND ANALYSIS: At least two authors screened titles and abstracts for relevant studies, extracted data, and assessed risk of bias. We contacted authors to obtain missing information. We conducted meta-analyses when pooling of studies was possible. MAIN RESULTS: We included 17 relevant trials (with 556 review-relevant participants) which we categorised into three types of interventions: (1) various exposures to bright light (n = 10); (2) various opportunities for napping (n = 4); and (3) other interventions, such as physical exercise or sleep education (n = 3). In most instances, the studies were too heterogeneous to pool. Most of the comparisons yielded low to very low quality evidence. Only one comparison provided moderate quality evidence. Overall, the included studies' results were inconclusive. We present the results regarding sleepiness below. Bright light Combining two comparable studies (with 184 participants altogether) that investigated the effect of bright light during the night on sleepiness during a shift, revealed a mean reduction 0.83 score points of sleepiness (measured via the Stanford Sleepiness Scale (SSS) (95% confidence interval (CI) -1.3 to -0.36, very low quality evidence). Another trial did not find a significant difference in overall sleepiness on another sleepiness scale (16 participants, low quality evidence).Bright light during the night plus sunglasses at dawn did not significantly influence sleepiness compared to normal light (1 study, 17 participants, assessment via reaction time, very low quality evidence).Bright light during the day shift did not significantly reduce sleepiness during the day compared to normal light (1 trial, 61 participants, subjective assessment, low quality evidence) or compared to normal light plus placebo capsule (1 trial, 12 participants, assessment via reaction time, very low quality evidence). Napping during the night shiftA meta-analysis on a single nap opportunity and the effect on the mean reaction time as a surrogate for sleepiness, resulted in a 11.87 ms reduction (95% CI 31.94 to -8.2, very low quality evidence). Two other studies also reported statistically non-significant decreases in reaction time (1 study seven participants; 1 study 49 participants, very low quality evidence).A two-nap opportunity resulted in a statistically non-significant increase of sleepiness (subjective assessment) in one study (mean difference (MD) 2.32, 95% CI -24.74 to 29.38, 1 study, 15 participants, low quality evidence). Other interventionsPhysical exercise and sleep education interventions showed promise, but sufficient data to draw conclusions are lacking. AUTHORS' CONCLUSIONS: Given the methodological diversity of the included studies, in terms of interventions, settings, and assessment tools, their limited reporting and the very low to low quality of the evidence they present, it is not possible to determine whether shift workers' sleepiness can be reduced or if their sleep length or quality can be improved with these interventions.We need better and adequately powered RCTs of the effect of bright light, and naps, either on their own or together and other non-pharmacological interventions that also consider shift workers' chronobiology on the investigated sleep parameters.

The discovery of slowness: Time to deconstruct Gretzky's and Messi's predictive brains.

Jafari and Smith hypothesized that time during games may pass slower for the world's best football player, Lionel Messi, from Argentina. This hypothesis leads to two questions: How can we explain such temporal paradox and how could this explain his dominant performances? Remarkably, the Argentinian's case was preceded by the equally astonishing case of Wayne Gretzky: The Canadian considered ice hockey as a rather slow game and was the best player in the sport's history. Whether Messi's and Gretzky's motor neurons fire faster, (inter)act differently or whether other mechanisms are at (inter)play warrants targeted research. A further explanation for such dominance of football and ice hockey, respectively, could be that both athletes "buy time": To this end, automized motor skills may allow their predictive brains to make better use of time than other players to read the games and plan ahead. Deconstructing predictive minds of outperforming individuals like Gretzky and Messi could provide unique options to elucidate how differential time perception may make performances in athletes, and beyond, more swift and more efficient.

Chronomedicine: an old concept's fledging? A selective literature search.

Chronomedicine may be conceptualized as dealing with the prevention, causation, diagnosis, and treatment of diseases in humans with a particular focus on the role "time" [Greek: chrónos] plays in our physiology, endocrinology, metabolism and behavior at many organizational levels. While it has been used as a term and somewhat pursued as a discipline for decades, it appears that chronomedicine has captured a broader interest as a promising specialty only more recently. This commentary addresses roots of chronomedicine in the 1900s and perspectives for chronomedicine in the 21st century. Classical terms of chronobiology, e.g., Zeitgeber, melatonin and circadian, may be traced back to Aschoff, Lerner, and Halberg, respectively, but who actually coined the term "chronomedicine" and used it first in a publication remains unclear. Importantly, it could be(come) rather straightforward to transfer abundant insights gained from chronobiology to strategies in chronomedicine as animal models have been increasingly developed to understand human health and disease. Perspectively, chronomedicine should comprise "clinical chronomedicine" (individual-based) and "preventive chronomedicine" (population-based). Overall, due to the "maturing" of chronomedicine as a field, the near future might bring a section dedicated to chronomedicine in existing journals, or even a "Journal of Chronomedicine" as vectors of ideas and research.

Effects of noise in primary schools on health facets in German teachers.

Empirical research indicates that children and teachers are exposed to mean sound levels between 65 and 87 dB (A) and peak sound levels of 100 dB (A) in schools, which may lead to hearing loss and mental health problems. A questionnaire containing 13 targeted questions about noise and sensitivity to noise was distributed to 43 teachers aged between 25 and 64 years at five different primary schools in the Cologne municipal area. The small number of interrogated teachers leads to a wide range of deviation and little significance in the results. Thus, several results are reported following tendencies. Significant results are obtained when comparing younger and older teachers and part- and full-time occupation. Teachers experience highest sound levels in the schoolyard, corridors and classrooms, and 68% of the teachers are annoyed by the noise. Specially, teachers older than 45 years of age suffer from sleep disturbances (44%), and 90% of the full-time employees are tired and exhausted in the evening. Work is judged as physical and mental strain by 51% of the whole sample, and 81% of the older teachers report a significant increase of complaints with increasing years of professional activity. Work-related noise may contribute to physical and mental health problems in teachers. Measures to prevent disease, such as early sensitization of the children to the work-related stressor noise by adequate education with noise lights and dosimeters in the classroom and/or equipping rooms with sound-absorbing materials, have to be discussed.

Sound levels and their effects on children in a German primary school.

Considerable sound levels are produced in primary schools by voices of children and resonance effects. As a consequence, hearing loss and mental impairment may occur. In a Cologne primary school, sound levels were measured in three different classrooms, each with 24 children, 8-10 years old, and one teacher. Sound dosimeters were positioned in the room and near the teacher's ear. Additional measurements were done in one classroom fully equipped with sound-absorbing materials. A questionnaire containing 12 questions about noise at school was distributed to 100 children, 8-10 years old. Measurements were repeated after children had been taught about noise damage and while "noise lights" were used. Mean sound levels of 5-h per day measuring period were 78 dB (A) near the teacher's ear and 70 dB (A) in the room. The average of all measured maximal sound levels for 1 s was 105 dB (A) for teachers, and 100 dB (A) for rooms. In the soundproofed classroom, Leq was 66 dB (A). The questionnaire revealed certain judgment of the children concerning situations with high sound levels and their ability to develop ideas for noise reduction. However, no clear sound level reduction was identified after noise education and using "noise lights" during lessons. Children and their teachers are equally exposed to high sound levels at school. Early sensitization to noise and the possible installation of sound-absorbing materials can be important means to prevent noise-associated hearing loss and mental impairment.

The chronosense -- what light tells man about biological time.

In the past 10 years, experimental studies have provided further evidence for the suggestion that the eye serves man as a dual sense organ, viz as a sense organ for sight but also for time and the regulation of biological rhythms. A small group of scientists interested in the adjustment of biological rhythms to the key Zeitgeber light wanted to answer the question whether rods and/or cones and/or other uncharacterized retinal photoreceptors contribute to this function in mammals. Intriguingly, in the course of elegant research, a number of laboratories around the world have been zeroing in on a novel non-rod, non-cone ocular photopigment which serves a number of responses to non-image-forming (NIF) photoreception in mammals. This paper intends to draw attention to possible implications of photoreception and phototransduction research for other scientific disciplines which study health and diesase effects in man. We therefore review the pivotal role of the photoreceptors -- old and new -- for the light-related timing and coordination of the interplay of otherwise less efficient biological rhythms. To distinguish our focus on time- and timing-related effects from classic image-forming (IF) and other NIF responses to ambient light, we refer informatively to chronoreceptors which mediate the sense of time, or chronosense. We conclude that syndisciplinary research into the physiology and pathophysiological implications of the chronosense is warranted and summarize a series of research questions.