• Sleep Medicine and Psychophysiology
• /
• v.9 no.1
• /
• pp.41-47
• /
• 2002

Objectives: In a number of simulated night shift studies, timed exposure to bright light improves sleep quality and work performance. We evaluated the effect of bright light on adaptation to night shift work with a field study. Methods: Five female nurses working shifts at Korea University Hospital were recruited for participation in this study. We investigated two series of six consecutive shift rotations comprising three day and three night shifts, using wrist Actigraphy, the Stanford Sleepiness Scale, Visual-analogue scales, STIM and tympanic membrane temperature for daytime sleep quality, alertness, subjective feeling, attention performance, and temperature rhythm. The subjects were exposed to bright light (2,500 lux) from 24:00 to 04:00 a.m. on three consecutive night shifts during the second series, whereas they worked under normal lightening (650 lux) conditions during the first series. Results: Actigraphic assessment of daytime sleep showed no significant difference between the first and third night shift in both baseline and light exposure phase. The mean lowest temperature shifted earlier during baseline phase but not during the light exposure phase. Also, the score for subjective feelings of depression, anxiety, physical discomfort and sleepiness was significantly higher in the third night shift than the first during baseline phase but not during the light exposure phase. Attention and attention switching ability was significantly improved in the third night shift compared to the first night during the light exposure phase but there were no significant changes during the baseline phase. Conclusion: This result suggests that there were no significant differences between the two phases in measures of quality of daytime sleep, but subjective feelings, attention and alertness were enhanced during light exposure. Although some placebo effects and learning effects might influence this result, bright light exposure between midnight and 4:00 a.m. may improve adaptation to night shift. In future, further controlled studies with a larger sample size, including melatonin measurement, are needed for real shift workers.

• Journal of Korean Academy of Fundamentals of Nursing
• /
• v.21 no.2
• /
• pp.123-130
• /
• 2014

Purpose: The purpose of this study was to identify quality of sleep and health-promoting behaviors in rotating-shift nurses and to explore the influence of health promoting behaviors on quality of sleep. Method: Participants were 161 staff nurses working in an irregular three shift system in one of three general hospitals located in Kyungpook province. Data were collected using the Pittsburgh Sleep Quality Index and the Health Promoting Lifestyle Profile-IIand were analyzed using hierarchical multiple regression analysis. Results: The majority of the participants had very poor quality of sleep and performed a low level of health promoting behaviors. In terms of health promoting behaviors, nutrition and stress management significantly influenced quality of sleep of these nurses. Conclusion: Results indicate the importance of encouraging rotating-shift nurses to enhance their health promoting behaviors in order to improve quality of sleep.

• Journal of Korean Academy of Fundamentals of Nursing
• /
• v.21 no.4
• /
• pp.403-412
• /
• 2014

Purpose: Shift work disrupts the synchronization between the human biological clock and the environment. Sleep disturbances are common for shift work nurses, and may threaten patient safety. This study was done to investigate the sleep characteristics and medication errors (ME) of intensive care unit (ICU) nurses who work shifts, and ascertain if there is an association between these factors. Methods: Data were collected using a self-report questionnaire from 126 ICU nurses on three shifts. Collected data included their sleep characteristics including sleep patterns and sleep disturbances, and ME for the past 2 weeks. Results: There were significant differences in sleep duration and sleep latency according to shift. Day shift nurses had the shortest sleep duration, and their sleep latency was the longest (about 49 minutes) compared to nurses on evening and night shifts; 54% reported sleep disturbances, 16% experienced ME, and among these nurses 50% were on the night shift. Logistic regression analysis revealed significant associations between nurses' sleep duration and ME (adjusted OR 0.52 [95% CI 0.32-0.85]). Conclusions: The results confirmed that shift work nurses in the ICUs experience sleep disturbance, and that less sleep is associated with ME.

• Journal of Internet Computing and Services
• /
• v.17 no.1
• /
• pp.35-45
• /
• 2016

Melatonin hormone involved in human's circadian rhythm adjustment sensitively responds to light's specific short wavelength ratio. A shift worker's circadian rhythm disturbance and sleep disorder are caused by the existing lighting conditions, whose short wavelength ratio is fixed. The life pattern of a shift worker changes irregularly because of irregular working hours and the same lighting environment; thus, his/her concentration is reduced. For such a reason, negative effects ensue to the detriment of healthy everyday life, including a high risk of accidents or having unsound sleep after leaving work. A smartphone-based wavelength control LED lighting system that targets shift workers and that can easily measure and control lighting suitable for wake-sleep cycle, according to working hours and closing hours, is proposed in this paper. First, after the light characteristics of LED lighting that changes depending on light control ratio are measured through the color sensor installed on the smartphone and the externally-linked Mini-Spectrometer, they are stored in the database. Based on the stored optical characteristics data, the measurement module and light control module are implemented. Lighting is offered using a control ratio having the maximum rate of short wavelength in consideration of the target illuminance, classified according to work type by identifying working hours as time when waking is required for shift workers. After a shift work leaves work, the amount of lighting is varied, using a control ratio having a minimum short wavelength rate so that a shift worker can enter the sleep state naturally.

• Korean Journal of Occupational Health Nursing
• /
• v.25 no.4
• /
• pp.373-383
• /
• 2016

Purpose: The purpose of this study was to identify the factors affecting shiftwork tolerance among nurses and provide basic data, ultimately, in formulating a plan for improving their shiftwork tolerance. Methods: The participants were 317 nurses who were working at three general hospitals in Daejeon and Seoul. Data analyzed t-test, ANOVA, correlation analysis, and regression analysis using SPSS 20.0 program. Results: As for the sub-areas of shiftwork tolerance for the respondents, more than a half of nurses working at shifts suffered from insomnia, felt drowsy, complained of chronic fatigue, and were at the anxious and depressed state. Shiftwork tolerance differed by the daily intake of coffee and exercise. Shiftwork tolerance was significantly positively correlated with sleep-wake habits, hardiness, and flexibility and negatively correlated with a languidity. Regression analysis revealed that shiftwork tolerance was affected by age, sleep-wake habits, languidity, flexibility, and hardiness. Conclusion: To put the results, nurses had shiftwork tolerance affected by sleep-wake habits, languidity, and hardiness. It is therefore necessary to make a scheme for allowing nurses to improve hardiness and flexibility and decrease the languidity with the objective of improving their shiftwork tolerance.

• Journal of Korean Clinical Nursing Research
• /
• v.29 no.3
• /
• pp.223-237
• /
• 2023

Purpose: This study aimed to investigate the impact of a nurse shift improvement pilot project on nurses' shift adjustment, work-life balance, and turnover intention, as well as nurses' experiences of participating in the pilot project. Methods: An explanatory sequential mixed-methods study was performed. Survey data was collected from a total of 1,051 nurses both in participant and non-participant groups. For the qualitative study, focus group interviews were conducted with 22 nurses who participated in the shift improvement pilot, including 12 staff nurses, 7 nurse managers, and 3 substitute nurses. Results: There were significant positive effects on the key variables of nurses' shift adjustment, work-life balance, and turnover intention in the group that participated in the nurse shift improvement pilot project. Based on the qualitative study, participants in the shift improvement pilot project indicated that it enabled nurses to recover their circadian rhythm, and achieve a better work-life balance, and they wanted to continue working as a nurse, and hoped expanded application of the pilot project. Conclusion: In order for expanded implementation of the pilot project and continued improvement in the shift system, we recommend establishing compensation standard, systematizing the use of substitute nurses, developing guidelines for shift schedules, and expanding the shift improvement pilot project to other departments such as the emergency room.

• Journal of Korean Academy of Nursing
• /
• v.46 no.6
• /
• pp.769-779
• /
• 2016

Purpose: This study was an experimental study to compare the inhalation effects of aroma essential oil on the quality of sleep (QOS) for shift nurses after working nights. Methods: The participants were 60 healthy adults who didn't have any disease. As an experimental treatment, the participants in the experimental group were asked to inhale essential oil for 3 minutes at a distance of approximately 10 cm from their nose and then they were asked to sleep with the aroma stone beside their head (within a 30 cm distance). QOS were measured four times on Pretest, Day 1, Day 2, and Day 3 after they slept. To measure QOS, Perceived QOS (Numeric Rating Scale), the Verran & Synder-Halpern (VSH) Sleep Scale were used, and number of awakenings (NoA) was measured by Actigraph. Results: There were no significant differences in the homogeneity tests for general characteristics and dependent variables prior to the experiments, except for VSH of subjective sleep quality. Also, there was no significant interaction between group and time. The VSH of the experimental group was higher than the control group (F=6.39, p=.002). The NoA between the experimental group and the control group was significantly different after experimental treatment 3rd day (F=13.35, p=.001). Conclusion: The findings show that the inhalation of aroma essential oil had effects to increase the quality of sleep. Therefore, the inhalation of aroma essential oil could be applied to general nursing interventions to improve the quality of sleep.

• Korean Journal of Psychosomatic Medicine
• /
• v.11 no.2
• /
• pp.196-204
• /
• 2003

Objectives: It is known that sedative hypnotics would make cross tolerance with alcohol and deteriorate quality of sleep in alcoholics. Light therapy is effective non-pharmacological intervention for sleep disturbance in circadian phase disorders, jet-lag, shift-work and age-related sleep disorders. Authors would investigate the effects of morning light therapy on sleep of patients with alcohol dependence during recovery state without withdrawal symptoms. Methods: 13 patients with alcohol dependence who have not any alcohol withdrawal symptom were recruited. Light therapy during 1 hour in the morning had been administered by 2500 Lux light box through serial 3 days. Sleep state of subjects were assessed by sleep log and the subjective satisfaction at sleep was by 100 mm visual analogue scale. Sleepiness, depressive mood, anxiety were evaluated by 100mm visual analogue scale at 8 AM, 2 PM and 8 PM. For assessment of performance ability that would be associated with sleepiness and vigilance, trail making test A, B and digit symbol substitution test were performed by two times on base line and 4th day. Univariate repeated-measures ANOVAs were performed for each measures except performance tests which were analysed by paired t-test. Results: Sleep latency and sleep efficiency were significantly improved with light therapy and satisfaction at sleep was. There was no significant difference in sleepiness at 2 PM with light therapy but sleepiness at 8 AM significantly decreased and at 8 PM increased. The time to complete Trail making test and digit symbol substitution test were significantly shortened at 4th day compared with baseline. Fatigue at 8 AM were not significantly changed with light therapy but at 2 PM and 8 PM significantly decreased. Depressive mood and anxiety were not significantly changed with light therapy. Conclusion: Although this study had some limitations, it showed that light therapy would be effective modality on sleep disturbance of patients with alcohol dependence who have recovered from alcohol withdrawal symptoms. It is proposed that short term light therapy could be used clinically for alcoholics with insomnia. In the future, long term controlled studies using more objective tools for sleep are required to further investigate the effect of light therapy in alcoholics.

• Journal of Life Science
• /
• v.23 no.8
• /
• pp.1064-1072
• /
• 2013

Circadian rhythm is controlled by hormonal oscillations governing the physiology of all living organisms. In mammals, the main function of the pineal gland is to transform the circadian rhythm generated in the hypothalamic suprachiasmatic nucleus into rhythmic signals of circulating melatonin characterized by a largely nocturnal increase that closely reflects the duration of night time. The pineal gland has lost direct photosensitivity, but responds to light via multi-synaptic pathways that include a subset of retinal ganglion cells. Rhythmic control is achieved through a tight coupling between environmental lighting and arylalkylamine-N-acetyltransferase (AANAT) expression, which is the rhythm-controlling enzyme in melatonin synthesis. Previous studies on the nocturnal expression of AANAT protein have described transcriptional, post-transcriptional, and post-translational regulatory mechanisms. Molecular mechanisms for dependent AANAT expression provide novel aspects for melatonin's circadian rhythmicity. Extensive animal research has linked pineal melatonin for the expression of seasonal rhythmicity in many mammalian species to the modulation of circadian rhythms and to sleep regulation. It has value in treating various circadian rhythm disorders, such as jet lag or shift-work sleep disorders. Melatonin, also, in a broad range of effects with a significant regulation influences many of the body's physiological functions. In addition, this hormone is known to influence reproductive, cardiovascular, and immunological regulation as well as psychiatric disorders.