Today’s modern society is exposed to artificial electric lighting in addition to the natural light-dark cycle. Studies assessing the impact of electric light exposure on sleep and its relation to work hours are rare due to the ubiquitous presence of electricity. Here we report a unique study conducted in two phases in a homogenous group of rubber tappers living and working in a remote area of the Amazon forest, comparing those living without electric light (n = 243 in first phase; n = 25 in second phase) to those with electric light at home (n = 97 in first phase; n = 17 in second phase). Questionnaire data (Phase 1) revealed that rubber tappers with availability of electric light had significantly shorter sleep on work days (30 min/day less) than those without electric light. Analysis of the data from the Phase 2 sample showed a significant delay in the timing of melatonin onset in workers with electric light compared to those without electric light (p < 0.01). Electric lighting delayed sleep onset and reduced sleep duration during the work week and appears to interfere with alignment of the circadian timing system to the natural light/dark cycle.

OBJETIVO: Analisar os fatores associados à capacidade inadequada para o trabalho e à percepção de fadiga entre os profissionais de enfermagem. MÉTODO: Estudo transversal desenvolvido com 272 trabalhadores em um hospital de urgência e emergência de Rio Branco/Acre. A coleta de dados ocorreu por meio dos seguintes instrumentos: questionário sobre dados sociodemográficos, condições de trabalho e estilo de vida; Índice de Capacidade para o Trabalho - ICT; e Questionário de Percepção de Fadiga. Para análise dos fatores associados à capacidade inadequada para o trabalho e à percepção de fadiga elevada foi utilizada a regressão de Poisson bivariada e múltipla. RESULTADOS: A prevalência de capacidade inadequada para o trabalho foi de 40,8%, tendo como fatores associados: sexo feminino (RP = 1,84; IC95% 1,06 - 3,18); referir outro vínculo empregatício (RP = 1,71; 1,25 - 2,35); número de funcionários insuficiente (RP = 1,96; 1,10 - 3,47); tarefas repetitivas e monótonas (RP = 1,84; 1,24 - 2,72); três ou mais morbidades sem diagnóstico médico (RP = 1,48; 1,06 - 2,06); fadiga elevada (RP = 2,37; 1,81 - 3,12). A prevalência de fadiga elevada foi de 25,7% e os fatores associados foram: tarefas repetitivas e monótonas (RP = 1,74; 1,00 - 3,03); referir de três a cinco morbidades com diagnóstico médico (RP = 1,98; 1,00 - 3,11) e seis ou mais morbidades (RP = 3,79; 2,04 - 7,03), segundo a auto-avaliação do profissional. CONCLUSÕES: O estudo evidencia que grande parte população estudada apresenta capacidade inadequada para o trabalho e níveis elevados de fadiga, apontando para a necessidade de intervenções no plano individual (condições de vida) e no ambiente de trabalho, principalmente no que tange aos aspectos organizacionais.

ObjectivesThis study aimed to investigate the relationship between individual natural light exposure, sleep need, and depression at two latitudes, one extreme with a few hours of light per day during winter, and the other with equal hours of light and darkness throughout the year.MethodsThis cross-sectional study included a sample of Brazilian workers (Equatorial, n = 488 workers) and a Swedish sample (Arctic, n = 1,273).ResultsThe reported mean total natural light exposure per 4-week cycle differed significantly between the Equatorial and Arctic regions. However, shiftworkers from both sites reported similar hours of natural light exposure. Short light exposure was a predictor for insufficient sleep.ConclusionReduced exposure to natural light appears to increase the perception of obtaining insufficient sleep. Arctic workers were more prone to develop depression than Equatorial workers.

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Physical activity has been recommended as a strategy for improving sleep. Nevertheless, physical effort at work might not be not the ideal type of activity to promote sleep quality. The aim of this study was to evaluate the effects of type of job (low vs. high physical effort) and life-style on sleep of workers from an Amazonian Extractivist Reserve, Brazil. A cross-sectional study of 148 low physical activity (factory workers) and 340 high physical activity (rubber tappers) was conducted between September and November 2011. The workers filled out questionnaires collecting data on demographics (sex, age, occupation, marital status and children), health (reported morbidities, sleep disturbances, musculoskeletal pain and body mass index) and life-style (smoking, alcohol use and practice of leisure-time physical activity). Logistic regression models were applied with the presence of sleep disturbances as the primary outcome variable. The prevalence of sleep disturbances among factory workers and rubber tappers was 15.5% and 27.9%, respectively. The following independent variables of the analysis were selected based on a univariate model (p<0.20): sex, age, marital status, work type, smoking, morbidities and musculoskeletal pain. The predictors for sleep disturbances were type of job (high physical effort); sex (female); age (>40 years), and having musculoskeletal pain (≥5 symptoms). Rubber tapper work, owing to greater physical effort, pain and musculoskeletal fatigue, was associated with sleep disturbances. Being female and older than 40 years were also predictors of poor sleep. In short, these findings suggest that demanding physical exertion at work may not improve sleep quality.

Several studies have shown a bidirectional relationship between insomnia and pain. The aim of this study was to evaluate whether working hours and type of occupation are associated with insomnia, pain and insomnia plus pain. Insomnia and musculoskeletal pain symptoms were measured in airline pilots, rural workers and factory workers using validated indexes. Rural and night work were predictors for the outcomes (insomnia and pain). However, musculoskeletal pain was found to be a predictor of insomnia but not vice versa. The current findings suggest that working hours and type of occupation play a role in the sleep-pain relationship.

Introduction: Work organization patterns and working conditions experienced by nursing personnel in the hospital settings may be associated to increased morbidity among these health workers. Aim: To estimate the prevalence and factors associated with self-reported diseases among nursing personnel at the emergency hospital in Rio Branco/State of Acre, Brazil. Methods: A cross-sectional study was conducted involving 272 participants who answered a questionnaire including sociodemographic characteristics, working conditions, lifestyles, work ability, and a fatigue perception scale. The selfreported diseases in the 12 months prior to data collection were considered the dependent variable. Results: A total of 85.7% of the participants reported one or more diseases in the past 12 months. Most prevalent diseases were: musculoskeletal diseases (37.1%), digestive diseases (28.7%), mental disorders (28.3%), work injuries (27.9%), and respiratory diseases (26.8%). The following significant variables remained in the final model: high work demands (OR 2.69), reported fatigue (OR 3.59), night work (OR 6.55) and being a technician or nursing assistant (OR 4.23). Conclusions: Variables related to working conditions and work organization were associated with the occurrence of reported diseases among nursing professionals. Health promotion measures at work require a comprehensive approach including the working conditions and the work organization.

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