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No description available.

Rapid technological change and increasing traffic volumes worldwide are adding to the safety challenges for air traffic control. The night shift has traditionally been a period of low workload and work practices have evolved to reflect this. Thus, despite the exemplary safety record, there is a need to consider further systemic defences for maintaining performance and safety on the night shift. One possible strategy is the provision of a scheduled nap at work. In order to investigate the consequences of a scheduled nap on the night shift, 28 operational air traffic controllers were monitored across four roster cycles. Each roster cycle included one of two night shifts. Air traffic controllers were given a nap opportunity on one night shift of each type, and did not nap on the other. Information on the timing, quantity, and quality of sleep during the work week and days off was collected using actigraphy, and supported with logbook data. Sleep during the nap was measured using polysomnography, and the EEG and EOG were further utilised to determine neurophysiological alertness over the latter part of the night shift. Reaction time performance was measured three times across the night shift (beginning, middle, and end) with the psychomotor vigilance test.Actigraphy data indicated that the backward, rapidly-rotating work schedule of air traffic controllers resulted in a progressive loss of sleep across the work week. The reduction in sleep lead to an increasing cumulative sleep debt that was at a maximum prior to the night shift. This sleep debt was not related to reaction time performance at the end of the night shift, but was found to influence neurophysiological alertness.It was determined that the large majority of air traffic controllers were able to sleep during the scheduled 40 minute nap opportunity. However, the latency to sleep onset was long, the sleep short, and of relatively poor quality. Circadian and homeostatic factors increased the likelihood of entry into, and waking from, slow wave sleep (SWS). They were also found to influence reaction time performance and neurophysiological alertness. More variable performance and lowered alertness were seen at the end of the later starting (and finishing) night shift, possibly due to the combined influence of circadian and time-on-task factors. Homeostatic variables had less influence on performance at the end of the night shift, but greater acute sleep loss and higher cumulative sleep debts were related to increased neurophysiological sleepiness.performance and greater neurophysiological alertness in a dose-dependent manner, with even small amounts of stage 1 sleep effecting a performance improvement. Performance improvement was consistent across a range of reaction time measures and consistent improvements were also evident in the neurophysiological data, with the occurrence of SEMs declining, and lower spectral power evident in all frequency bands and single frequencies.These findings clearly demonstrate that a minimal quantity of sleep benefits the performance and alertness of air traffic controllers despite the "noise" of a field setting, thus providing a link between laboratory studies of napping and the actual work environment. The findings also fully support management endorsing a 40 minute napping opportunity for air traffic controllers working the night shift.The short nap sleep had no measurable effect on sleep subsequent to the night shift. However, the amount of sleep obtained in the nap was related to improved reaction time.

No description available.

O objetivo geral desta tese foi avaliar o impacto do sistema de trabalho em turnos nos trabalhadores de dois setores de uma indústria de filmes e embalagens flexíveis para alimentos que opera em três turnos de trabalho fixos, considerando o cronotipo do trabalhador. Foi feita a caracterização do sexo, experiência profissional, faixa etária e cronotipo (por meio de dois questionários) de 42 trabalhadores do setor de Impressão e 43 do setor de Corte/Solda nos três diferentes turnos e avaliadas as cargas física e mental (com ferramentas subjetivas e indicadores fisiológicos) das atividades realizadas e as demandas ergonômicas dos Construtos: Ambiente, Posto de trabalho, Organização de Trabalho, Conteúdo do Trabalho, Empresa e Risco/Dor. Foram coletados parâmetros ambientais (ruído, temperatura e umidade) para identificar o seu grau de impacto sobre o desempenho do trabalhador. Embora dentro dos limites legais, principalmente o ruído e a temperatura apresentaram baixa satisfação nos dois setores. Os resultados estatísticos apontaram diferenças entre os resultados em função dos setores (o setor de Impressão com maiores demandas do que o Corte/Solda), turnos (o turno noturno com mais demandas) e influência do cronotipo discrepante ao horário de turno. Os trabalhadores com cronotipo desajustado ao horário do turno tendem a perceber mais negativamente a carga de trabalho, tendem à menor satisfação com vários itens de demanda ergonômica e a sentir maior intensidade de dor. Houve variação dos indicadores fisiológicos (nível de cortisol salivar, catecolaminas urinárias, pressão arterial, frequência cardíaca e consequentemente, do percentual da máxima capacidade aeróbica) dependendo do indivíduo e eles foram consistentes com a avaliação subjetiva de carga de trabalho. Os resultados deixam claro que os trabalhadores sabem a que horas querem iniciar e finalizar o trabalho (que são compatíveis com o cronotipo) e não gostam de trabalhar em turno, mas se o turno for necessário, a preferência é por turno fixo. A proposta é que no caso de trabalho em turno, seja considerado o cronotipo do trabalhador e que este tenha autonomia para escolher o turno, pois necessidades familiares e sociais também são fatores de decisão nesta escolha. / This thesis aimed to evaluate the impact of shiftwork on the workers of two sectors of a flexible packaging manufacturer which operates in three shifts, considering the cronotype of the worker. 42 workers from the three shifts of the Imprint sector and 43 from the Cutting/Welding sector were characterized according to sex, professional experience, age and cronotype (based on two questionnaires). Both mental and physical workload were evaluated using subjective tools and physiological parameters. The satisfaction with their work (i.e., the Environment, the Workstation, the Work Organization, the Work Content, the Enterprise and the Risk of pain) was evaluated by questionnaire. Environmental data (noise, temperature and humidity) were gathered for evaluation of their impact on the workers. Although within the law limits, noise and temperature were not satisfactory in both sectors..The statistical results showed differences between the sectors (the Imprint one with more esrgonomic demands), among the shifts (the night one with more ergonomic demandas) and influence of the worker cronotype. The workers whose cronotype were not compatible with their shiftwork tend to be less satisfied with their work, tend to feel more pain and overloaded. The physiological parameters (hormonal levels of cortisol, urinary cathecholamines, arterial pressure, heart rate and consequently the percent of maximum aerobic work capacity) varied with the individual and were consistent with the subjective workload evaluation. The results showed that the workers know their best work time (which is compatible with their cronotype), they do not like shiftwork but if it is necessary, they prefer the fixed shift. The proposal is that if shiftwork is necessary, the worker cronotype has to be considered and he/she should choose the shift because familiar and social issues are also part of this choice.

Idag möter många människor svårigheter med att balansera arbetslivet och privatlivet. Att tiden och energin inte riktigt räcker till för alla delar i livet. En grupp som särskilt möter dessa svårigheter är skiftarbetare. Syftet med studien är att undersöka hur skiftarbetare som arbetar utifrån två olika arbetstidsmodeller upplever och hanterar balansen mellan arbete och fritid. För att besvara syftet har åtta semistrukturerade intervjuer genomförts med undersköterskor från Norrlands universitetssjukhus. Resultatet från studien visar att samtliga undersökningspersoner generellt sätt upplever en god balans mellan arbete och fritid. Trots det upplever de stundtals konflikter däremellan. De främsta skillnaderna mellan hur undersköterskor som arbetar utifrån de två arbetstidsmodellerna upplever balansen är kopplade till ansvar, återhämtning samt kontroll över arbetsschemat. För att hantera konflikter mellan arbete och fritid använder sig undersökningspersonerna av olika strategier. Några av dessa är att planera och prioritera, söka stöd från omgivningen samt att acceptera läget.

O objetivo geral desta tese foi avaliar o impacto do sistema de trabalho em turnos nos trabalhadores de dois setores de uma indústria de filmes e embalagens flexíveis para alimentos que opera em três turnos de trabalho fixos, considerando o cronotipo do trabalhador. Foi feita a caracterização do sexo, experiência profissional, faixa etária e cronotipo (por meio de dois questionários) de 42 trabalhadores do setor de Impressão e 43 do setor de Corte/Solda nos três diferentes turnos e avaliadas as cargas física e mental (com ferramentas subjetivas e indicadores fisiológicos) das atividades realizadas e as demandas ergonômicas dos Construtos: Ambiente, Posto de trabalho, Organização de Trabalho, Conteúdo do Trabalho, Empresa e Risco/Dor. Foram coletados parâmetros ambientais (ruído, temperatura e umidade) para identificar o seu grau de impacto sobre o desempenho do trabalhador. Embora dentro dos limites legais, principalmente o ruído e a temperatura apresentaram baixa satisfação nos dois setores. Os resultados estatísticos apontaram diferenças entre os resultados em função dos setores (o setor de Impressão com maiores demandas do que o Corte/Solda), turnos (o turno noturno com mais demandas) e influência do cronotipo discrepante ao horário de turno. Os trabalhadores com cronotipo desajustado ao horário do turno tendem a perceber mais negativamente a carga de trabalho, tendem à menor satisfação com vários itens de demanda ergonômica e a sentir maior intensidade de dor. Houve variação dos indicadores fisiológicos (nível de cortisol salivar, catecolaminas urinárias, pressão arterial, frequência cardíaca e consequentemente, do percentual da máxima capacidade aeróbica) dependendo do indivíduo e eles foram consistentes com a avaliação subjetiva de carga de trabalho. Os resultados deixam claro que os trabalhadores sabem a que horas querem iniciar e finalizar o trabalho (que são compatíveis com o cronotipo) e não gostam de trabalhar em turno, mas se o turno for necessário, a preferência é por turno fixo. A proposta é que no caso de trabalho em turno, seja considerado o cronotipo do trabalhador e que este tenha autonomia para escolher o turno, pois necessidades familiares e sociais também são fatores de decisão nesta escolha. / This thesis aimed to evaluate the impact of shiftwork on the workers of two sectors of a flexible packaging manufacturer which operates in three shifts, considering the cronotype of the worker. 42 workers from the three shifts of the Imprint sector and 43 from the Cutting/Welding sector were characterized according to sex, professional experience, age and cronotype (based on two questionnaires). Both mental and physical workload were evaluated using subjective tools and physiological parameters. The satisfaction with their work (i.e., the Environment, the Workstation, the Work Organization, the Work Content, the Enterprise and the Risk of pain) was evaluated by questionnaire. Environmental data (noise, temperature and humidity) were gathered for evaluation of their impact on the workers. Although within the law limits, noise and temperature were not satisfactory in both sectors..The statistical results showed differences between the sectors (the Imprint one with more esrgonomic demands), among the shifts (the night one with more ergonomic demandas) and influence of the worker cronotype. The workers whose cronotype were not compatible with their shiftwork tend to be less satisfied with their work, tend to feel more pain and overloaded. The physiological parameters (hormonal levels of cortisol, urinary cathecholamines, arterial pressure, heart rate and consequently the percent of maximum aerobic work capacity) varied with the individual and were consistent with the subjective workload evaluation. The results showed that the workers know their best work time (which is compatible with their cronotype), they do not like shiftwork but if it is necessary, they prefer the fixed shift. The proposal is that if shiftwork is necessary, the worker cronotype has to be considered and he/she should choose the shift because familiar and social issues are also part of this choice.

O objetivo geral desta tese foi avaliar o impacto do sistema de trabalho em turnos nos trabalhadores de dois setores de uma indústria de filmes e embalagens flexíveis para alimentos que opera em três turnos de trabalho fixos, considerando o cronotipo do trabalhador. Foi feita a caracterização do sexo, experiência profissional, faixa etária e cronotipo (por meio de dois questionários) de 42 trabalhadores do setor de Impressão e 43 do setor de Corte/Solda nos três diferentes turnos e avaliadas as cargas física e mental (com ferramentas subjetivas e indicadores fisiológicos) das atividades realizadas e as demandas ergonômicas dos Construtos: Ambiente, Posto de trabalho, Organização de Trabalho, Conteúdo do Trabalho, Empresa e Risco/Dor. Foram coletados parâmetros ambientais (ruído, temperatura e umidade) para identificar o seu grau de impacto sobre o desempenho do trabalhador. Embora dentro dos limites legais, principalmente o ruído e a temperatura apresentaram baixa satisfação nos dois setores. Os resultados estatísticos apontaram diferenças entre os resultados em função dos setores (o setor de Impressão com maiores demandas do que o Corte/Solda), turnos (o turno noturno com mais demandas) e influência do cronotipo discrepante ao horário de turno. Os trabalhadores com cronotipo desajustado ao horário do turno tendem a perceber mais negativamente a carga de trabalho, tendem à menor satisfação com vários itens de demanda ergonômica e a sentir maior intensidade de dor. Houve variação dos indicadores fisiológicos (nível de cortisol salivar, catecolaminas urinárias, pressão arterial, frequência cardíaca e consequentemente, do percentual da máxima capacidade aeróbica) dependendo do indivíduo e eles foram consistentes com a avaliação subjetiva de carga de trabalho. Os resultados deixam claro que os trabalhadores sabem a que horas querem iniciar e finalizar o trabalho (que são compatíveis com o cronotipo) e não gostam de trabalhar em turno, mas se o turno for necessário, a preferência é por turno fixo. A proposta é que no caso de trabalho em turno, seja considerado o cronotipo do trabalhador e que este tenha autonomia para escolher o turno, pois necessidades familiares e sociais também são fatores de decisão nesta escolha. / This thesis aimed to evaluate the impact of shiftwork on the workers of two sectors of a flexible packaging manufacturer which operates in three shifts, considering the cronotype of the worker. 42 workers from the three shifts of the Imprint sector and 43 from the Cutting/Welding sector were characterized according to sex, professional experience, age and cronotype (based on two questionnaires). Both mental and physical workload were evaluated using subjective tools and physiological parameters. The satisfaction with their work (i.e., the Environment, the Workstation, the Work Organization, the Work Content, the Enterprise and the Risk of pain) was evaluated by questionnaire. Environmental data (noise, temperature and humidity) were gathered for evaluation of their impact on the workers. Although within the law limits, noise and temperature were not satisfactory in both sectors..The statistical results showed differences between the sectors (the Imprint one with more esrgonomic demands), among the shifts (the night one with more ergonomic demandas) and influence of the worker cronotype. The workers whose cronotype were not compatible with their shiftwork tend to be less satisfied with their work, tend to feel more pain and overloaded. The physiological parameters (hormonal levels of cortisol, urinary cathecholamines, arterial pressure, heart rate and consequently the percent of maximum aerobic work capacity) varied with the individual and were consistent with the subjective workload evaluation. The results showed that the workers know their best work time (which is compatible with their cronotype), they do not like shiftwork but if it is necessary, they prefer the fixed shift. The proposal is that if shiftwork is necessary, the worker cronotype has to be considered and he/she should choose the shift because familiar and social issues are also part of this choice.

Although prior research has documented the harmful effects of shiftwork on health and well-being, the relationship between shiftwork and other workplace stressors remains unclear. The current study addresses this gap by using longitudinal data from three cycles of the National Population Health Survey to explore 1) the direct effects of shiftwork and JDCSM variables (job demands, job control, social support, and mastery) on health and well-being, 2) whether shiftwork moderates the effects of JDCSM variables, and 3) whether the effects of shiftwork are mediated by these variables. In addition, “reverse” causal relationships between four measures of strain and workplace stressors are investigated. The results suggest that shiftwork is associated with a reduction in job satisfaction over two cycles. However, there was no evidence of a relationship between shiftwork and changes in chronic health conditions, psychological distress, or health-related quality of life. Consistent with the JDCSM model, increased job demands predicted more distress and less job satisfaction, while greater mastery predicted less distress and more job satisfaction. In addition, job control and social support predicted improved health-related quality of life. The associations were more consistent with the thesis’s predictions across two cycles than across three. There was only weak support for the hypotheses that shiftwork moderates the effects of JDCSM variables. However, there was evidence that changes in job control and social support mediate the effects of shiftwork on job satisfaction. There was also support for reverse causal effects between various outcomes and workplace stressors. However, the prediction that shiftwork moderates these reverse effects received only weak and inconsistent support. Exploratory analyses found specific JDCSM and strain variables to predict an individual’s continuation in shiftwork over time. The theoretical and practical implications of these findings are discussed. / Thesis / Doctor of Philosophy (PhD)