<p>At the same time as many urban economies are developing into 24-hour societies it is becoming increasingly popular amongst shift workers to compress their working hours. This is done by working longer shifts (>8h) and/or restricting free time (<16h) in between shifts – the main reasons are to gain longer bouts of free time and extra free weekends. However, there is a limited knowledge of the effects of such arrangements on sleep and wakefulness. Thus, the main purposes of the present thesis were to evaluate the effects of long working hours (in the form of 12h shifts) and short recovery periods. Another aim was to evaluate possible mechanisms that could suggest why some individuals develop problems with shift work while others do not.</p><p>We used a combination of methods - sleep diaries, wake diaries, blood samples and objective measures of sleep and cognitive performance - across whole or large parts of shift schedules to evaluate acute effects of particularly demanding working periods, as well as the total effects of a shift cycle. Study I evaluated the effect of changing from an 8h- to a 12h-shift system. Study II evaluated the effects of long shifts in a shift schedule with both 8h- and 12h-shifts. Study III evaluated the effects of several consecutive short recovery periods (8-9h of recovery) and whether satisfaction with ones’ work hours was associated to problems with sleep and sleepiness. Study IV evaluated whether endocrinological markers of catabolic (cortisol) and anabolic (testosterone) activity changed across a shift sequence and whether satisfaction were related to them. Study V was a laboratory simulation of the effects of a short recovery period (4h of sleep) and whether a short nap could counteract any detrimental effects.</p><p>There was no convincing evidence for 12h shifts inducing more problems with sleep and sleepiness than 8h shifts. With regard to recovery time between shifts, the shortest recovery times (only 8h) seriously shortened sleep duration and increased sleepiness, while 12h of recovery (between two consecutive 12h shifts) was judged as having no or limited effects on acute measures. The problems with the shortest recovery periods were worse in a schedule with several consecutive shifts and less pronounced in a schedule with few consecutive shifts. With regard to individual differences, it was found that subjects being dissatisfied with their working hours were vulnerable to short recovery periods, which was evident by less sufficient sleep and an accumulation of sleepiness across work periods with limited recovery time. Interestingly, these problems disappeared when they were allowed to recover after the work period. In addition, dissatisfied male shift workers had lower testosterone levels at the end of work periods, indicating disturbed anabolic activity. The simulated quick return supported that curtailed sleep affected sleepiness and performance and that a short nap could counteract these effects temporarily.</p><p>It is concluded that long shifts (up to 12h) may be acceptable, whereas short recovery time (8h or less) is not. Most of the problems with short recovery periods were related to short sleep and sleepiness, and there is, clearly, a subgroup of workers that suffer more from this than others. It is argued that insufficient sleep and low testosterone levels (in males) might be key factors for developing shift intolerance, mainly by reducing the capacity to recover from shift work.</p>

At the same time as many urban economies are developing into 24-hour societies it is becoming increasingly popular amongst shift workers to compress their working hours. This is done by working longer shifts (&gt;8h) and/or restricting free time (&lt;16h) in between shifts – the main reasons are to gain longer bouts of free time and extra free weekends. However, there is a limited knowledge of the effects of such arrangements on sleep and wakefulness. Thus, the main purposes of the present thesis were to evaluate the effects of long working hours (in the form of 12h shifts) and short recovery periods. Another aim was to evaluate possible mechanisms that could suggest why some individuals develop problems with shift work while others do not. We used a combination of methods - sleep diaries, wake diaries, blood samples and objective measures of sleep and cognitive performance - across whole or large parts of shift schedules to evaluate acute effects of particularly demanding working periods, as well as the total effects of a shift cycle. Study I evaluated the effect of changing from an 8h- to a 12h-shift system. Study II evaluated the effects of long shifts in a shift schedule with both 8h- and 12h-shifts. Study III evaluated the effects of several consecutive short recovery periods (8-9h of recovery) and whether satisfaction with ones’ work hours was associated to problems with sleep and sleepiness. Study IV evaluated whether endocrinological markers of catabolic (cortisol) and anabolic (testosterone) activity changed across a shift sequence and whether satisfaction were related to them. Study V was a laboratory simulation of the effects of a short recovery period (4h of sleep) and whether a short nap could counteract any detrimental effects. There was no convincing evidence for 12h shifts inducing more problems with sleep and sleepiness than 8h shifts. With regard to recovery time between shifts, the shortest recovery times (only 8h) seriously shortened sleep duration and increased sleepiness, while 12h of recovery (between two consecutive 12h shifts) was judged as having no or limited effects on acute measures. The problems with the shortest recovery periods were worse in a schedule with several consecutive shifts and less pronounced in a schedule with few consecutive shifts. With regard to individual differences, it was found that subjects being dissatisfied with their working hours were vulnerable to short recovery periods, which was evident by less sufficient sleep and an accumulation of sleepiness across work periods with limited recovery time. Interestingly, these problems disappeared when they were allowed to recover after the work period. In addition, dissatisfied male shift workers had lower testosterone levels at the end of work periods, indicating disturbed anabolic activity. The simulated quick return supported that curtailed sleep affected sleepiness and performance and that a short nap could counteract these effects temporarily. It is concluded that long shifts (up to 12h) may be acceptable, whereas short recovery time (8h or less) is not. Most of the problems with short recovery periods were related to short sleep and sleepiness, and there is, clearly, a subgroup of workers that suffer more from this than others. It is argued that insufficient sleep and low testosterone levels (in males) might be key factors for developing shift intolerance, mainly by reducing the capacity to recover from shift work.

Summaries in English and Afrikaans / Text in Afrikaans / Key terms in English and Afrikaans / Verskeie tekortkomings is in die bestaande konseptuele model en kwantitatiewe navorsingsliteratuur oor skofwerk geidentifiseer. Ontevredenheid met die oorvereenvoudigde oorsaak-gevolg-verklarings vir getroude vroue se skofwerkervaring het in die studie gelei tot die ontwikkeling van 'n ekologiese model van vroueskofwerk. Hierdie nuwe konseptuele model weerspieel 'n altematiewe benadering waar erkenning gegee word aan die bestaan van meervoudige realiteite wat mense in konsensus deur taal konstrueer. Die oogmerk met die ekologiese model is om, met inagneming van vroueskofwerkers se wyer konteks, patrone te ondersoek van hoe die verskillende beskrywings van getroude vroue se ervaring van skofwerk bymekaar pas. Daarmee kan 'n meer sistemiese begrip verkry word wat die kompleksiteit van menslike interaksie respekteer. Die ekologiese model van vroueskofwerk is ontwikkel as 'n hulpmiddel vir die waamemer om ryk, beskrywende ekologiese verhale te kan konstrueer van hoe getroude vroue se belewing van skofwerk tot sistemiese ontwrigting of behoud kan lei. / Several shortcomings have been identified in the existing conceptual model and quantitative research literature regarding shiftwork. Dissatisfaction with the oversimplified cause-effect-explanations for married women's shiftwork experience has led to the development of an ecological model of women shiftwork in this study. This new conceptual model reflects an alternative approach where recognition is given to the existence of multiple realities which are consensually created by people through language. The aim with the ecological model, by taking into account the broader context of women shiftworkers, is to search for patterns of how the different descriptions of women's experience of shiftwork fit together. This offers a more systemic view that respects the complexity of human interaction. The ecological model for women shiftwork is developed as an aid to the observer to construct rich, descriptive ecological stories about how married women's experience of shiftwork can lead to systemic disruption or conservation. / Psychology / M.A. (Clinical Psychology)

Summaries in English and Afrikaans / Text in Afrikaans / Key terms in English and Afrikaans / Verskeie tekortkomings is in die bestaande konseptuele model en kwantitatiewe navorsingsliteratuur oor skofwerk geidentifiseer. Ontevredenheid met die oorvereenvoudigde oorsaak-gevolg-verklarings vir getroude vroue se skofwerkervaring het in die studie gelei tot die ontwikkeling van 'n ekologiese model van vroueskofwerk. Hierdie nuwe konseptuele model weerspieel 'n altematiewe benadering waar erkenning gegee word aan die bestaan van meervoudige realiteite wat mense in konsensus deur taal konstrueer. Die oogmerk met die ekologiese model is om, met inagneming van vroueskofwerkers se wyer konteks, patrone te ondersoek van hoe die verskillende beskrywings van getroude vroue se ervaring van skofwerk bymekaar pas. Daarmee kan 'n meer sistemiese begrip verkry word wat die kompleksiteit van menslike interaksie respekteer. Die ekologiese model van vroueskofwerk is ontwikkel as 'n hulpmiddel vir die waamemer om ryk, beskrywende ekologiese verhale te kan konstrueer van hoe getroude vroue se belewing van skofwerk tot sistemiese ontwrigting of behoud kan lei. / Several shortcomings have been identified in the existing conceptual model and quantitative research literature regarding shiftwork. Dissatisfaction with the oversimplified cause-effect-explanations for married women's shiftwork experience has led to the development of an ecological model of women shiftwork in this study. This new conceptual model reflects an alternative approach where recognition is given to the existence of multiple realities which are consensually created by people through language. The aim with the ecological model, by taking into account the broader context of women shiftworkers, is to search for patterns of how the different descriptions of women's experience of shiftwork fit together. This offers a more systemic view that respects the complexity of human interaction. The ecological model for women shiftwork is developed as an aid to the observer to construct rich, descriptive ecological stories about how married women's experience of shiftwork can lead to systemic disruption or conservation. / Psychology / M.A. (Clinical Psychology)

Made available in DSpace on 2012-09-06T01:11:30Z (GMT). No. of bitstreams: 2 license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) 117.pdf: 1157899 bytes, checksum: 6f6021820b6176fcba6db85081d29000 (MD5) Previous issue date: 1998 / O organismo humano apresenta uma ritmicidade de eventos bioquímicos, fisiológicos e comportamentais durante as 24 horas do dia, fazendo com que o mesmo tenha peculiaridades distintas nos diferentes horários diurnos e noturnos. Esta ritmicidade circadiana encontra-se intimamente ligada a sincronizadores externos: ciclo claro/escuro; ritmos sociais; a organizaçäo temporal da atividade laborativa do indivíduo, dentre outros. A organizaçäo temporal do trabalho dos aeronautas caracteriza-se pela alternância dos seus turnos, o que em última análise, significa dizer que este trabalhador muitas vezes desempenha suas atividades profissionais em diferentes momentos do dia e da noite. Esta inversäo de horários de repouso por momentos de trabalho acarreta alteraçöes na ritmicidade biológica. Objetiva-se investigar a percepçäo de comandantes, da aviaçäo civil brasileira, que realizam jornadas transmeridionais sobre as repercussöes que estas condiçöes de trabalho podem ter sobre sua saúde. Para a coleta dos dados, foram distribuídos questionários para todos os comandantes de Boeing 767 da base Rio de Janeiro, das companhias VARIG e Transbrasil. Do total de 87 questionários enviados, obteve-se um retorno de 25. Os resultados demonstraram que as condiçöes de trabalho dos comandantes apresentam sérias e inúmeras implicaçöes sobre a sua saúde. A sensaçäo de fadiga, as alteraçöes do ciclo sono-vigília e dos hábitos alimentares e o afastamento familiar foram os fatores que mais apareceram no relato dos comandantes como sendo os mais comprometidos, causando consequências como sonolência, distúrbios gratrointestinais, comprometimentos na vida familiar como divórcios, dentre outros. Com o intuito de minimizar estes sintomas, os comandantes desenvolveram algumas estratégias como dormir assim que chegam ao local de destino, praticar algum tipo de atividade física e seguir os horários do local, que säo utilizadas com frequência e, segundo seus próprios relatos, com êxito no que se propöem. / The human body presents a rhythmicity of biochemical, physiological and behavioral events throughout the 24 hours of a day. It means that this body has different peculiarities during the day and others at night. This circadian rhythmicity is closely linked to “zeitgebers” (external synchronizers): sleep/wake cycle, social rhythms, shiftwork and so on. One of the most important characteristics within the aviation profession is the alternation of shifts, which means that the aeronauts have to develop their professional activities at different hours of the day and night. This inversion of work periods in lieu of resting ones results in rhythmicity changes. The aim of this study was to investigate the perception of Brazilian civil aviation captains and the influences of their type of work conditions upon their health. The data collection was made using questionnaires which were distributed to all Rio de Janeiro-based Boeing 767 captains employed by VARIG and Transbrasil during the research period. From all the 87 questionnaires sent, 25 returned. The results showed that flight captains` working conditions present several and serious implications on their health. The fatigue, the changes both in the sleep/wake cycle and in the eating habits and the deleterious effects on social events were the aspects cited by the captains as being the most affected ones causing consequences like sleepiness, gastro-intestinal disturbances, relationship difficulties, among others. In order to minimize these symptoms the captains developed some strategies like sleeping as soon as they arrive at their destination, practicing some physical activities and following the local time, which are used very often and successfully.

This study shows the investigation of physical activeness among the nurses whowork in night shifts in hospitals and motivates them to do physical activities in theform of gamification in their working place. A qualitative approach is applied forgathering the data in the form of interviewing nurses to inquiry the problems andtried to find out the real opinions and scenarios related with physical inactivenessbased on the nurse’s interpretation. Working-time, working-loads, leisure-time,behaviors towards physical activity, laziness, less knowledge about voluntarymovements are coming out from the findings of this study. This paper suggests someactions such as walking, doing physical exercises, playing games etc. to encouragenurses to do more physical activities in a fun way in the workplace. A fun game,called ‘Healthy steps’ is designed based on the suggested actions in the form ofgamification is presented in this paper to promote physical activity at workplace andto encourage the nurses to participate lo lead a healthy lifestyle. / Denna studie visar undersökningen av fysisk aktivitet bland sjuksköterskorna somarbetar på nattskift på sjukhus och motiverar dem att göra fysiska aktiviteter i formav gamification på sin arbetsplats. En kvalitativ metod tillämpas för att samla in datai form av intervjuande sjuksköterskor för att undersöka problemen och försökte tareda på de verkliga åsikterna och scenarierna relaterade till fysisk inaktivitet baseratpå sjuksköterskans tolkning. Arbetstid, arbetsbelastning, fritid, beteende mot fysiskaktivitet, lathet, mindre kunskap om frivilliga rörelser kommer fram från resultatenfrån denna studie. Denna uppsats föreslår några åtgärder som att gå, göra fysiskaövningar, spela spel etc. för att uppmuntra sjuksköterskor att göra mer fysiskaaktiviteter på ett roligt sätt på arbetsplatsen. Ett roligt spel, kallat ‘Healthy steps’ ärutformat baserat på de föreslagna åtgärderna i form av gamification, presenteras idenna uppsats för att främja fysisk aktivitet på arbetsplatsen och för att uppmuntrasjuksköterskorna att delta för att leva en hälsosam livsstil.

Text in Afrikaans / Summaries in English and Afrikaans / This study aims to investigate the relation between a crane operator in a slab handlingarea's experience of his/her work environment and occupational health. A study of the literature leads one to the conclusion that the nature of crane operators' work environment may cause health problems. According to the literature crane operators are high risk cases regarding musculoskeletal disorders. The empirical study affirms that there are risk factors present in the crane operator's work environment, which may influence his/her occupational health. It is statistically proven that there is a meaningful difference between crane operators with a negative experience of the work environment and crane operators with a positive experience of the work environment, and the amount of illnesses experienced by crane operators as well as their general health. Recommendations are made regarding training, adjustability and flexibility of the work station, job rotation, job expansion and enrichment, and social contact. / Die doel van die studie is om die verband tussen 'n kraanoperateur in 'n platblokhanteringsarea se ervaring van sy/haar werksomgewing en beroepsgesondheid te ondersoek. Die literatuurstudie lei tot die gevolgtrekking dat die aard van kraanoperateurs se werksomgewing aanleiding kan gee tot gesondheidsprobleme. Volgens die literatuur is kraanoperateurs hoerisikogevalle ten opsigte van spierskeletstelselbeserings. Die empiriese studie bevestig dat daar risikofaktore voorkom in die kraanoperateur se werksomgewing wat sy/haar beroepsgesondheid kan be"invloed. Statisties is bewys dat daar 'n betekenisvolle verskil is tussen kraanoperateurs met 'n negatiewe ervaring van die werksomgewing en kraanoperateurs met 'n positiewe ervaring van die werksomgewing en die hoeveelheid siektetoestande wat kraanoperateurs ervaar, en die algemene gesondheid van kraanoperateurs. Aanbevelings om risikofaktore te beheer word gemaak ten opsigte van opleiding, verstelbaarheid en buigbaarheid van die werkstasie, posrotasie, posverbreding en - verryking, en sosiale kontak. / Industrial Psychology / M. Com (Industrial Psychology)

Text in Afrikaans / Summaries in English and Afrikaans / This study aims to investigate the relation between a crane operator in a slab handlingarea's experience of his/her work environment and occupational health. A study of the literature leads one to the conclusion that the nature of crane operators' work environment may cause health problems. According to the literature crane operators are high risk cases regarding musculoskeletal disorders. The empirical study affirms that there are risk factors present in the crane operator's work environment, which may influence his/her occupational health. It is statistically proven that there is a meaningful difference between crane operators with a negative experience of the work environment and crane operators with a positive experience of the work environment, and the amount of illnesses experienced by crane operators as well as their general health. Recommendations are made regarding training, adjustability and flexibility of the work station, job rotation, job expansion and enrichment, and social contact. / Die doel van die studie is om die verband tussen 'n kraanoperateur in 'n platblokhanteringsarea se ervaring van sy/haar werksomgewing en beroepsgesondheid te ondersoek. Die literatuurstudie lei tot die gevolgtrekking dat die aard van kraanoperateurs se werksomgewing aanleiding kan gee tot gesondheidsprobleme. Volgens die literatuur is kraanoperateurs hoerisikogevalle ten opsigte van spierskeletstelselbeserings. Die empiriese studie bevestig dat daar risikofaktore voorkom in die kraanoperateur se werksomgewing wat sy/haar beroepsgesondheid kan be"invloed. Statisties is bewys dat daar 'n betekenisvolle verskil is tussen kraanoperateurs met 'n negatiewe ervaring van die werksomgewing en kraanoperateurs met 'n positiewe ervaring van die werksomgewing en die hoeveelheid siektetoestande wat kraanoperateurs ervaar, en die algemene gesondheid van kraanoperateurs. Aanbevelings om risikofaktore te beheer word gemaak ten opsigte van opleiding, verstelbaarheid en buigbaarheid van die werkstasie, posrotasie, posverbreding en - verryking, en sosiale kontak. / Industrial Psychology / M. Com (Industrial Psychology)