• Journal of Korean Society of Industrial and Systems Engineering
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• v.23 no.57
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• pp.1-10
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• 2000

The purpose of this paper is to propose a method of rest to reduce work load of night shift workers for night shift work. The experiment was carried out 10minutes preparing time, 45minutes first work, 10minutes first rest, 45minutes second work, 10minutes second rest between 2 and 4 o'clock that the lowest physiological function of workers. The methods of rest set up as four patterns (1) non-action rest (2) non-action rest + listening music (3) action rest + non-action rest, (4) action rest + non-action rest + listening music. For the measurements of experiment, heart rates(R-R interval), critical flicker fusion frequency(CFF), blood pressure, oral temperature, reaction time and error rates were considered as criteria for work performance. As a result, action rest + non-action rest and action rest + non-action rest + listening music were more effective to reduce work load additional work than non-action rest and non-action rest + listening music.

• Safety and Health at Work
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• v.11 no.2
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• pp.244-247
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• 2020

The occurrence of the shift work disorder (SWD) in health-care workers (HCWs) employed in 24/7 hospital wards is a major concern through the world. In accordance with literature, SWD is the most frequent work-related disturb in HCWs working on shift schedules including night shift. In agreement with the Luxembourg Declaration on workplace health promotion (WHP) in the European Union, a WHP program has been developed in a large Hospital, involving both individual-oriented and organizational-oriented measures, with the aim to prevent the occurrence of SWD in nurses working on shifts including night shift. The objective assessment of rotating shift work risk and the excessive sleepiness were detected before and after the implementation of the WHP program, by using the Rotating Shiftwork-questionnaire and the Epworth Sleepiness Scale. The findings of this study showed the effectiveness of the implemented WHP program in minimizing the impact of shift work on workers' health and in preventing the misalignment between sleep-wake rhythm and shift working.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.25 no.3
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• pp.418-427
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• 2015

Objectives: This study evaluated the association between work related characteristics and hypertension among white collar workers in Korea. Materials and methods: This study was based on the Third Korean Working Conditions Survey(KWCS) conducted in 2011 among workers 15 years of age or older. The total number of individuals included in the analysis was 10,365 white collar workers. Results: The prevalence rate of hypertension was 3.7% among men and 1.0% among women. In multiple logistic analysis the adjusted odds ratio showed statistically effective association to hypertension. For work related characteristics, 1.73 (95% confidence interval, 1.22-2.46) resulted for large-company workers compared with the small-company group, 2.14 (95% CI, 1.22-3.75) for the long working hours group (61 or above) compared with short working hours group(52 or below), 1.78(95% CI, 1.08-2.95) for night shift workers compared with day workers, and 1.54 (95% CI, 1.18-2.01) for high job stress workers compared with low job stress workers. Conclusions: This study showed that it is important for workers to manage their work environment in order to prevent hypertension by modifying their types of work.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.26 no.4
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• pp.426-435
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• 2016

Objectives: The major objective of this study was to analyze stress response after a change to consecutive day shifts from day and night shifts in a motor assembly factory. Methods: Using a survey conducted by a labor union, we collected data on stress response index(SRI), lifestyle factors, work-family conflict and job stress before and after a shift system change. We analyzed the transition on the SRI among 222 workers. The cut-off point for the SRI was a T-score over 60. Results: The high risk stress response group was 20.3% of the population before the shift system change. After the shift system change it decreased to 11.3%. After the shift system change, social support improved, leisure time became more sufficient, work-family conflict declined, and sleep quality in the night shift week improved. In multivariable linear regression, among workers under 40 years old sleep quality on night shift, leisure time sufficiency, social support and work-family conflict contributed to the improvement of stress response. Among workers over 40, work-family conflict contributed to the improvement of stress response. Conclusions: The change to consecutive day shifts improved stress response and mediated with improved nighttime sleep, decreased work-family conflict, increased leisure time and improved work-family conflict.

• Journal of the Ergonomics Society of Korea
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• v.29 no.3
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• pp.337-345
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• 2010

The purpose of this study was to investigate the effects of sleep/wake behavior for shiftwork in air traffic controllers (ATCs) using wrist actigraph for ten workers on a continuous full-day three-team three-shift system of forward rotation including on-duty and off-duty periods. The wrist actigraph data were recorded for three days (one shift cycle) for each subject. The mean activity counts during an on-duty period progressively increased from the night, the swing, to the morning shifts. The doze length during on-duty periods showed decreases in the morning and swing shifts as compared to the night shift. Total sleep time (TST) and sleep efficiency (SE) during off-duty periods increased in the morning-1 and swing-night shift compared to the morning-2 shift. Finally, I discussed the role of doze-taking during the burden on night shift ATCs.

• Korean Journal of Clinical Pharmacy
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• v.28 no.1
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• pp.51-56
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• 2018

Objective: An automated process for medication preparation and dispensing is essential to improve the quality of work. To reduce night pharmacy workload, a new automated dispensing cabinet system was implemented in a hospital emergency medical center. The purpose of this study is to verify that implementation of an automated dispensing cabinet system will influence the efficiency of night pharmacy work. Methods: To evaluate the new system implementation, a retrospective study and survey was performed in the Ewha Womans University medical center. We compared the dispensing and near-miss error rates between the automated dispensing cabinet system and a night pharmacy. The degree of satisfaction of night shift workers with the new system was surveyed. Results: This study showed significantly reduced dispensing rates of night medications (56.1% and 37.3%; p < 0.01) and near-miss night medications (0.27% and 0.17%; p<0.01). Thirty-two persons responded to the survey, and the satisfaction score for the new system was 4.0 (${\pm}0.8$). The scores were high in order of efficiency, management, and convenience. Time requirement was also reduced because of the simple step of only reviewing in the pharmacy with the new system. Conclusion: Due to system implementation, workload was reduced and time was saved for not only night shift workers but also patients receiving emergency discharge medicine. It was suggested that this will have a positive effect on pharmacist medical service and patient safety.

• Safety and Health at Work
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• v.10 no.1
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• pp.109-113
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• 2019

Background: In both developed and developing countries, noise is regarded as the most common occupational hazard in various industries. The present study aimed to examine the effect of sound pressure level (SPL) on serum cortisol concentration in three different times during the night shift. Methods: This case-control study was conducted among 75 workers of an industrial and mining firm in 2017. The participants were assigned to one of the three groups (one control and two case groups), with an equal number of workers (25 participants) in each group. Following the ISO 9612 standard, dosimetry was adopted to evaluate equivalent SPL using a TES-1345 dosimeter. The influence of SPL on serum cortisol concentration was measured during the night shift. The serum cortisol concentration was measured using a radioimmunoassay (RIA) test in the laboratory. Repeated measure analysis of variance and linear mixed models were used with ${\alpha}=0.05$. Results: The results indicated a downward trend in the serum cortisol concentration of the three groups during the night shift. Both SPL and exposure time significantly affected cortisol concentration (p < 0.0001, p < 0.0001). Conversely, age and body mass index had no significant influence on cortisol concentration (p = 0.360, p = 0.62). Conclusion: Based on the obtained results, increasing SPL will lead to enhancement of serum cortisol concentration. Given that cortisol concentration varies while workers are exposed to different SPLs, this hormone can be used as a biomarker to study the effect of noise-induced stress.

• Korean Journal of Occupational Health Nursing
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• v.16 no.1
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• pp.37-47
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• 2007

Purpose: To find out the relationship between the shift work, and disrupted sleep and consequent fatigue symptoms. Methods: The questionnaires were given to 345 nurses of 4 hospitals with over 400 beds in Daejeon. Results: The shift workers showed worse subjective quality of sleep than the daytime workers, and had significantly higher frequency of "cannot get to sleep within 30 minutes", "wake up in the middle of the night" and "wake up in the early morning". The shift workers had significantly higher scores of subjective symptoms of fatigue than the daytime workers, and the fatigue was found to be the mental type. The subjective symptoms of fatigue scores were significantly higher in the group who had "cannot get to sleep within 30 minutes", "wake up in the middle of the night" and "wake up in the early morning". Conclusion: The study results indicated that the shift workers had the higher level of subjective symptoms of physical fatigue as well as the worse quality of sleep than the daytime workers. It is speculated that the factors attributable to the poor quality of sleep or sleep induction disorders of nurses of hospitals could be due in major part to adaptational difficulties resulting from frequent night shifts.

• Safety and Health at Work
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• v.10 no.3
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• pp.254-259
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• 2019

Background: This cross-sectional study assessed the sleep quality using the ActiGraph and investigated the relationship between the parameters of sleep assessment and the type of shift work in Korean firefighters. Methods: The participants were 359 firefighters: 65 day workers (control group) and 294 shift workers (shift work group: 77 firefighters with 3-day shift, 72 firefighters with 6-day shift, 65 firefighters with 9-day shift, and 80 firefighters with 21-day shift). Sleep assessments were performed using the ActiGraph (wGT3X-BT) for 24 hours during day shift (control and shift work group) and night shift and rest day (shift work group). The participants recorded bed time and sleep hours during the measurement period. Results: Sleep efficiency, total sleep time, and percentage of wake after sleep onset during night work were lower in the shift work group than control group (p < 0.05). Sleep efficiency decreased in night shift and increased in rest day, whereas wake after sleep onset increased in night shift and decreased in rest day (p < 0.05). Among shift work groups, sleep efficiency of 6-day shift was higher in day shift, and sleep efficiency of 21-day shift was lower in night shift than other shift groups (p < 0.05). Conclusion: We found that the sleep quality in night shift of the shift work group was poorer than the control group. As to the type of shift work, sleep quality was good in 6-day shift and poor in 21-day shift. Thus, fast rotating shift such as 6-day shift may be recommended to improve the sleep quality of the firefighters.

• The Research Journal of the Costume Culture
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• v.26 no.4
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• pp.503-518
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• 2018

The purpose of this study is to illustrate the design of safety suits based on energy-harvesting technology, particularly targeting street cleaners who must work at night with high mobility. The design focuses on applying lightweight energy-harvesting tools and illuminant into the wear. The design development reflects feedback from testers collected via survey constituting a key methodology. The development process has two main stages. Each stage uses a process of design prototyping, internal examination, test sampling, test wearing, and wearers' feedback via survey that consists of questions on visibility, wearing convenience, and washability. The first stage results show the design of safety suits with energy-harvested LED illuminant inserted and the survey results collected from street cleaners dressed in 4 sample and 80 actual suits in total. Improved based on the first-stage survey results, the second stage designs the suits with detachable energy-harvested EL tape. From these 5 sample and 30 actual second-stage suits, the additional survey indicates that this second-stage design facilitates more visibility and convenience in washing and wearing than the first-stage design. Accordingly, one can expect that this new design can apply not only to safety suits for night workers but also to handicapped or outdoor sportswear applications in the future.