The likelihood of crashing during a simulated post-work commute decreases across a week of consecutive night shifts

2020 ◽  
Vol 37 (9-10) ◽  
pp. 1425-1429
Author(s):  
Gregory D. Roach ◽  
Edward J. Sach ◽  
Andrew M. Reiter ◽  
Drew Dawson ◽  
Charli Sargent
2021 ◽  
pp. 074873042110060
Author(s):  
Dorothee Fischer ◽  
Till Roenneberg ◽  
Céline Vetter

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.


1996 ◽  
Vol 11 (S2) ◽  
pp. S34-S34
Author(s):  
Michael Tremea ◽  
Mark James ◽  
Jeffrey Jones ◽  
Jon Krohmer

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.


2003 ◽  
Vol 41 (3) ◽  
pp. 400-406 ◽  
Author(s):  
Denise C. Rollinson ◽  
Niels K. Rathlev ◽  
Mark Moss ◽  
Ron Killiany ◽  
Kenneth C. Sassower ◽  
...  

2016 ◽  
Vol 124 (6) ◽  
pp. 1396-1403 ◽  
Author(s):  
Julie L. Huffmyer ◽  
Matthew Moncrief ◽  
Jessica A. Tashjian ◽  
Amanda M. Kleiman ◽  
David C. Scalzo ◽  
...  

Abstract Background Residency training requires work in clinical settings for extended periods of time, resulting in altered sleep patterns, sleep deprivation, and potentially deleterious effects on safe performance of daily activities, including driving a motor vehicle. Methods Twenty-nine anesthesiology resident physicians in postgraduate year 2 to 4 drove for 55 min in the Virginia Driving Safety Laboratory using the Driver Guidance System (MBFARR, LLC, USA). Two driving simulator sessions were conducted, one experimental session immediately after the final shift of six consecutive night shifts and one control session at the beginning of a normal day shift (not after call). Both sessions were conducted at 8:00 am. Psychomotor vigilance task testing was employed to evaluate reaction time and lapses in attention. Results After six consecutive night shifts, residents experienced significantly impaired control of all the driving variables including speed, lane position, throttle, and steering. They were also more likely to be involved in collisions. After six consecutive night shifts, residents had a significant increase in reaction times (281.1 vs. 298.5 ms; P = 0.001) and had a significant increase in the number of both minor (0.85 vs. 1.88; P = 0.01) and major lapses (0.00 vs. 0.31; P = 0.008) in attention. Conclusions Resident physicians have greater difficulty controlling speed and driving performance in the driving simulator after six consecutive night shifts. Reaction times are also increased with emphasis on increases in minor and major lapses in attention after six consecutive night shifts.


2021 ◽  
Vol 15 ◽  
Author(s):  
Qiao Huang ◽  
Chong Tian ◽  
Xian-Tao Zeng

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.


2019 ◽  
Vol 29 (Supplement_4) ◽  
Author(s):  
J K Sørensen ◽  
M A Jensen ◽  
ÅM Hansen ◽  
R Rugulies ◽  
A H Garde

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.


2012 ◽  
Vol 30 (15_suppl) ◽  
pp. 1556-1556
Author(s):  
Pedram Razavi ◽  
Eva S Schernhammer ◽  

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.


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