scholarly journals 0777 Variations in Vigilance and Sleep Among Underground Mine Workers During 14 Consecutive Night Shifts

SLEEP ◽  
2020 ◽  
Vol 43 (Supplement_1) ◽  
pp. A295-A296
Author(s):  
L Laberge ◽  
A A Lavigne ◽  
J Auclair ◽  
M Hébert
Keyword(s):  
Older Workers ◽  
Repeated Measures ◽  
Light Exposure ◽  
Night Shift ◽  
Consecutive Night ◽  
Linear Regression Models ◽  
Engineering Research ◽  
Partial Sleep Deprivation ◽  
Night Shifts ◽  
Mine Workers

Abstract Introduction Adverse effects of night shift work are well known but there is scarce data on how vigilance and sleep vary across a large number of consecutive night shifts. Methods In summer, 38 underground miners (mean age (SD): 36.8 (13.9) years) wore an actigraph, filled out the Morningness-Eveningness questionnaire, and completed a Visual Analog Scale capturing subjective vigilance (very sleepy to very alert) 4 times per shift (19:00, 22:00, 02:00, and 05:30) for 14 consecutive night shifts. Mixed effects linear regression models were used to account for repeated measures. Results Mean vigilance level is lower at 22:00, 02:00 and 05:30 than at the beginning of the shift at 19:00 (p<0.001). Also, a more pronounced decrease in vigilance during the night was observed among older workers compared to younger workers (p<0.05). Moreover, workers with greater eveningness have higher vigilance at the beginning of the first night shift at 19:00 (p<0.001), but their decline in vigilance level during the night is faster than that observed in workers with greater morningness (p<0.01). Interestingly, the mean vigilance decline observed at 02:00 and 05:30 (compared to 19:00) is slowed down for each additional night shift (p<0.001). Furthermore, mean sleep efficiency is negatively associated with morningness and gradually decreases across consecutive night shifts (p<0.05). In addition, mean sleep duration is shorter in older workers and is positively associated with morningness (p<0.05). Conclusion Results show a progressive improvement in vigilance of mine workers assigned to a large number of consecutive 12-hour night shifts from 2 am onwards. This may probably be ascribed to an adjustment in homeostatic sleep propensity consecutive to the partial sleep deprivation associated with time spent traveling to the remote site before the first shift. However, circadian adjustment is unlikely considering the strong morning light exposure experienced daily after the night shift. Support College and Community Innovation Program of the Natural Sciences and Engineering Research Council of Canada (NSERC) (CUI2I 472201-14)

scholarly journals Chronotype-specific Sleep in Two Versus Four Consecutive Shifts

2021 ◽  
pp. 074873042110060
Author(s):  
Dorothee Fischer ◽  
Till Roenneberg ◽  
Céline Vetter
Keyword(s):  
Night Shift ◽  
Sleep Diary ◽  
Sequence Length ◽  
Consecutive Night ◽  
Shift Workers ◽  
Subject Field ◽  
Sleep Diaries ◽  
Social Jetlag ◽  
Sleep Debt ◽  
Night Shifts

The study aimed to explore chronotype-specific effects of two versus four consecutive morning or night shifts on sleep-wake behavior. Sleep debt and social jetlag (a behavioral proxy of circadian misalignment) were estimated from sleep diary data collected for 5 weeks in a within-subject field study of 30 rotating night shift workers (29.9 ± 7.3 years, 60% female). Mixed models were used to examine whether effects of shift sequence length on sleep are dependent on chronotype, testing the interaction between sequence length (two vs. four) and chronotype (determined from sleep diaries). Analyses of two versus four morning shifts showed no significant interaction effects with chronotype. In contrast, increasing the number of night shifts from two to four increased sleep debt in early chronotypes, but decreased sleep debt in late types, with no change in intermediate ones. In early types, the higher sleep debt was due to accumulated sleep loss over four night shifts. In late types, sleep duration did not increase over the course of four night shifts, so that adaptation is unlikely to explain the observed lower sleep debt. Late types instead had increased sleep debt after two night shifts, which was carried over from two preceding morning shifts in this schedule. Including naps did not change the findings. Social jetlag was unaffected by the number of consecutive night shifts. Our results suggest that consecutive night shifts should be limited in early types. For other chronotypes, working four night shifts might be a beneficial alternative to working two morning and two night shifts. Studies should record shift sequences in rotating schedules.

61. Can Melatonin Improve Adaptation To Night Shift? A Pilot Study Using an Urban EMS System

1996 ◽  
Vol 11 (S2) ◽  
pp. S34-S34
Author(s):  
Michael Tremea ◽  
Mark James ◽  
Jeffrey Jones ◽  
Jon Krohmer
Keyword(s):  
Job Performance ◽  
Night Shift ◽  
Biological Clock ◽  
Consecutive Night ◽  
Sleep Diaries ◽  
Visual Analog Scales ◽  
Significant Difference ◽  
Clinical Benefits ◽  
Double Blinded ◽  
Night Shifts

Purpose: To determine whether melatonin (N-acetyl-5-methoxytryptamine) is effective in helping prehospital personnel working consecutive night shifts reset their biological clock and minimize circadian rhythm disruption.Methods: A double-blinded, randomized, cross-over study was performed using 12 paramedic volunteers. Paramedics were working a span of consecutive night (2300-0700) shifts and received either a melatonin capsule (6 mg) or placebo to be taken prior to each of the consecutive day sleeps. Each participants completed a total of four spans of consecutive night shifts (2-melatonin, 2-placebo). Collected data included daily sleep diaries, quantification of alcohol/caffeine consumed, and possible drug side-effects. Assessment of job performance, mood and alertness were measured every day using 10-cm visual analog scales (VAS).Results: Analysis of sleep diaries demonstrated no significant difference (p >0.05) between the two treatments in respect to mean sleep latency (melatonin = 15.4 min. vs. placebo = 14.6 min), mean sleep duration (melatonin = 6.7 hrs. vs. placebo = 6.9 hrs), or subjectively rated sleep quality (melatonin = 5.8 VAS vs placebo = 5.6 VAS). Similarly, no significant benefits were noted between the mean VAS scores for daily job performance, mood and alertness. Adverse effects were rare, one patient taking melatonin reported a prolonged sedative effect.Conclusion: Despite widespread belief in the benefits of melatonin as a hypnotic agent, no clinical benefits were noted in terms of daytime sleep or job performance in paramedics working consecutive night shifts.

scholarly journals Poor Sleep Quality in Nurses Working or Having Worked Night Shifts: A Cross-Sectional Study

2021 ◽  
Vol 15 ◽  
Author(s):  
Qiao Huang ◽  
Chong Tian ◽  
Xian-Tao Zeng
Keyword(s):  
Sleep Quality ◽  
Clinical Care ◽  
Night Shift ◽  
Cross Sectional Study ◽  
Poor Sleep ◽  
Consecutive Night ◽  
Sectional Study ◽  
Poor Sleep Quality ◽  
Cross Sectional ◽  
Night Shifts

Night shifts are part of clinical care. It is unclear whether poor sleep quality of nurses working both consecutive night shifts and day shifts after quitting night shifts is common. In this cross-sectional study, Pittsburgh Sleep Quality Index (PSQI) was used to assess sleep quality as study outcome. Univariable and multivariable linear and logistic regressions were performed to compare PSQI score and prevalence of poor sleep quality between 512 nurses currently working consecutive night shifts and 174 nurses having worked night shifts in the past. The prevalence of poor sleep quality was 62.11% in nurses working consecutive night shifts and 55.75% in nurses having worked night shifts before. In multivariable regressions with adjustment for potential confounders, compared with nurses working consecutive night shifts, nurses having worked past night shifts reported decreased PSQI score [mean difference: −0.82 (95% CI: −1.27 to −0.38, p < 0.001)] and lower poor sleep quality [odds ratio (OR): 0.49 (95% CI: 0.29 to 0.80, p = 0.005)]. In nurses working consecutive night shifts, a rising curve that plateaued at the end was observed between years of consecutive night shifts and PSQI score, p = 0.004. To explore the change in PSQI score after quitting night shift, we constructed a hypothetical prospective cohort from the cross-sectional data. Here, 98 pairs of nurses with consecutive and past night shifts were matched for the number of night shift years, religion, marital status, living condition, hypertension, and hyperlipidemia. In each pair, a hypothetical change in PSQI score was calculated between the two types of nurses and hypothetical years after quitting night shifts was obtained from the matched nurse with past night shifts. A U-shaped curve between change in PSQI and years after quitting night shifts was observed, p = 0.007. The rising curve and U-shaped curve together formed an S-shaped curve, which mapped the change in sleep quality. These results based on the hypothetical cohort constructed from cross-sectional data suggested the presence of persistent poor sleep quality in night shift nurses. Also, we support early and continuous sleep hygiene education and reflection for an optimal strategy for when to cease working night shifts with regard to sleep-related problems.

scholarly journals Diurnal rhythms of cortisol and melatonin in night eating and non-night eating male police officers

2019 ◽  
Vol 29 (Supplement_4) ◽  
Author(s):  
J K Sørensen ◽  
M A Jensen ◽  
ÅM Hansen ◽  
R Rugulies ◽  
A H Garde
Keyword(s):  
Diurnal Rhythm ◽  
Police Officers ◽  
Night Shift ◽  
Eating Behaviour ◽  
Cortisol Concentration ◽  
Diurnal Rhythms ◽  
Consecutive Night ◽  
Night Eating ◽  
Main Meal ◽  
Night Shifts

Abstract Background Working during the night has in previous studies been associated with behavioural changes and diseases. Disturbance between behavioural and biological circadian rhythms have been suggested as a possible mechanism linking night work with cardiovascular diseases and pre-diabetic changes. The aim of this study was to investigate if night eating during two, four and seven consecutive night shifts is associated with differences in the diurnal rhythms of cortisol and melatonin in male police officers in Denmark. Methods We conducted an experimental study among 37 male police officers in Denmark who all collected data on the last night shift in three different work schedules with two, four and seven consecutive night shifts, respectively. Night eating was self-reported and defined as eating at least one main meal between midnight and early morning. Differences in the diurnal rhythms of concentrations of cortisol and melatonin in saliva were tested by phase changes and amplitude differences. Results Sixteen (43.2%) police officers ate a main meal during the last night shift in all three work schedules. The timing of the lowest cortisol concentration was on average delayed with 2:10 hours (95% CI 0:24-3:56 hours) and the level of the lowest cortisol concentration was on average supressed with 66% (95% CI 47-94%) for night eaters compared to non-night eaters. There was no association with number of consecutive night shifts. The phase and amplitude of melatonin were not statistically significantly different between night eaters and non-night eaters. Conclusions Night eating behaviour is associated with differences in the diurnal rhythm of cortisol in Danish male police officers working during the night. The difference in cortisol rhythm between night eaters and non-night eaters on night shifts is not affected by the number of consecutive night shifts. Key messages Night eating behaviour is associated with differences in the diurnal rhythm of cortisol. Future studies should focus on potential health outcomes of night eating behaviour among night workers.

Differential effects of light at night and shift rotation pattern on the circadian system in night workers.

2012 ◽  
Vol 30 (15_suppl) ◽  
pp. 1556-1556
Author(s):  
Pedram Razavi ◽  
Eva S Schernhammer ◽  
Keyword(s):  
Shift Work ◽  
Night Shift ◽  
Circadian System ◽  
Activity Level ◽  
Melatonin Level ◽  
Consecutive Night ◽  
Light At Night ◽  
Night Shift Work ◽  
Single Night ◽  
Night Shifts

1556 Background: Light at night as in shift work suppresses nocturnal secretion of melatonin, a pineal hormone with oncostatic properties. Several studies have associated night shift work with higher risk of cancer, leading WHO in 2007 to classify rotating night shift work as “probably carcinogenic”. We conducted one of the most comprehensive studies, to date, to evaluate the effects of light and night shift work on melatonin measurements in the field. Methods: Study participants were 130 active nurses (84 current rotating night shift workers and 46 day shift workers) participating in NHS2. Each nurse wore a head-mounted light- and accelerometer for a 3-day study period, during which each spontaneous urine was collected for repeated urinary 6-sulfatoxymelatonin (melatonin) measurements. In addition, nurses were asked to fill out paper questionnaires and diaries. We used mixed models to evaluate the influence of light, activity and night shift work on urinary melatonin level adjusting, for age, lifestyle, and occupational history. We log-transformed main variables and report geometric means (GM [standard deviation]). Results: Greater levels of light were associated with lower melatonin (P < 0.0001), independent of activity level. An increase in light intensity from 10 to 100 lux was associated with a 12% decrease in geometric mean of melatonin level; however, this inverse association was only significant at night (Ptrend = 0.01). At night, each hour increase in exposure to ≥ 20 lux light lowered melatonin level by 5.7% (Ptrend < 0.0001). A single night shift affected the circadian system by lowering melatonin peak by 22% (day shift: GM = 17.57 [2.73]; night shift: GM = 13.64 [2.54]) and induced a phase shift (PS) of 0.9 hours, -changes that reset to normal by the next day. Two consecutive night shifts had a similar effect as a single shift. However, the effect was worse after three consecutive night shifts (GM = 10.11 [2.77]; PS = 2.2 hours). Conclusions: We found significant inverse associations of intensity and duration of exposure to light at night with urinary melatonin, independent of activity level. Three consecutive night shifts affected the circadian system more strongly than two consecutive, or a single night shift.

scholarly journals The Association Between the Number of Consecutive Night Shifts and Insomnia Among Shift Workers: A Multi-Center Study

2021 ◽  
Vol 9 ◽  
Author(s):  
Juho Sim ◽  
Byung-Yoon Yun ◽  
Jiho Lee ◽  
Sung Kyung Kim ◽  
Seunghyun Lee ◽  
...  
Keyword(s):  
Data Model ◽  
Sleep Problems ◽  
Night Shift ◽  
Common Data Model ◽  
Consecutive Night ◽  
Multivariate Logistic Regression ◽  
Shift Workers ◽  
Multi Center Study ◽  
Night Shifts ◽  
Center Study

Objectives: There is a need to determine the optimal limit of consecutive night shift work to reduce insomnia caused by the accumulation of sleep problems among night shift workers. This study aimed to investigate the prevalence of insomnia caused by consecutive night shifts and evaluate the night shift duration that worsens insomnia the most, using a large amount of medical examination data.Methods: Night shift profiles and baseline demographics data of three hospitals were collected from January 2015 to December 2017. For subjects who had been examined more than once at the same institution, information corresponding to the most recent date was used. Multivariate logistic regression was performed to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Pooled ORs were calculated by using the results of the three institutions.Results: Of the 33,669 participants, 31.3% were female. The average age was 41.1 ± 11.1 years and the prevalence of insomnia was 38.7% (n = 13,025). After adjusting for potential confounders and compared to workers who reported not working in consecutive night shifts, odds of insomnia were greatest among workers reporting working three consecutive nights (OR 2.65, 95% CI 1.97–3.56) followed by those working two nights (OR 1.81, 95% CI 1.45–2.26), five nights (OR 1.78, 95% CI 1.56–2.03), and four nights (OR 1.68, 95% CI 1.55–1.82).Conclusion: Our study demonstrates a significant relationship between consecutive night shift and insomnia with multicenter examination data, using common data model. This study could be a basis for establishing policies and guidelines that improve night shift workers' health.

scholarly journals O4A.4 The relationship between shift work and sleep disturbance in hospital workers

2019 ◽  
Vol 76 (Suppl 1) ◽  
pp. A33.1-A33
Author(s):  
Dong-Hee Koh ◽  
Ju-Hyun Park ◽  
Seo-Hyun Yoon ◽  
Hyun-Joo Kim
Keyword(s):  
Sleep Disturbance ◽  
Shift Work ◽  
Night Shift ◽  
Sleep Onset ◽  
Consecutive Night ◽  
Hospital Workers ◽  
Sleep Maintenance ◽  
Sleep Questionnaires ◽  
The Relationship ◽  
Night Shifts

IntroductionMany hospital workers suffer from sleep disturbance due to shift work. The best way to mitigate the problem would be reducing night shift. However, that is commonly impossible in reality. Thus, we aimed to examine the factors associated with sleep disturbance and suggest better-rotating schedules for hospital workers.MethodsWe used sleep questionnaires asking sleep disturbance including sleep onset and maintenance problems for measuring health outcomes. Also, We obtained a duty schedule of the workers for assessing exposure. We examined the effect of the pattern of shift schedule and amount of night shifts on sleep disturbance.ResultsA total of 590 workers participated in this study. Female (95%) 3-rotating shift (92%) workers dominated. For workshift pattern, two consecutive night shifts increased the risk of sleep maintenance problem significantly. For the amount of night shift, two or more night shifts per week increased the risk of sleep onset problem significantly.ConclusionOur results suggest that avoding consecutive night shifts and restricting night shift to one time per week would be helpful to prevent sleep disturbance in hospital workers.

Nighttime Blue Light Exposure and Breast Cancer

2021 ◽  
pp. 30-33
Author(s):  
David Jaynes ◽  
Paul Switzer
Keyword(s):  
Breast Cancer ◽  
Risk Factor ◽  
Blue Light ◽  
Shift Work ◽  
Light Exposure ◽  
Night Shift ◽  
Background Information ◽  
Common Disease ◽  
Essential Information ◽  
Night Shift Work

The purpose of this article is to provide background information and the current understanding of a less familiar cause of female breast cancer; exposure to ultraviolet light at night. Breast cancer is a common disease that causes significant morbidity and mortality in women. There are several risk factors for breast cancer, most of which are genetic and environmental in nature. An often-overlooked risk factor is exposure to blue light during night shift work, which decreases melatonin production. One of the many cancer-preventing properties of melatonin is to limit estrogen production. Increased lifetime exposure to estrogen is a well-known cause of breast cancer. Awareness of nighttime blue light exposure as a breast cancer risk factor by women doing night shift work and those exposed to nighttime light via smartphones and laptops, is essential information to know so that protective measures can be taken.

Sign in / Sign up

Export Citation Format

Share Document