scholarly journals Shift-work: is time of eating determining metabolic health? Evidence from animal models

2018 ◽  
Vol 77 (3) ◽  
pp. 199-215 ◽  
Author(s):  
Natalí N. Guerrero-Vargas ◽  
Estefania Espitia-Bautista ◽  
Ruud M. Buijs ◽  
Carolina Escobar
Keyword(s):  
Food Intake ◽  
Shift Work ◽  
Temporal Patterns ◽  
Experimental Models ◽  
Circadian Disruption ◽  
Metabolic Dysfunction ◽  
Light At Night ◽  
Shift Workers ◽  
Time Signals ◽  
Altered Metabolism

The circadian disruption in shift-workers is suggested to be a risk factor to develop overweight and metabolic dysfunction. The conflicting time signals given by shifted activity, shifted food intake and exposure to light at night occurring in the shift-worker are proposed to be the cause for the loss of internal synchrony and the consequent adverse effects on body weight and metabolism. Because food elicited signals have proven to be potent entraining signals for peripheral oscillations, here we review the findings from experimental models of shift-work and verify whether they provide evidence about the causal association between shifted feeding schedules, circadian disruption and altered metabolism. We found mainly four experimental models that mimic the conditions of shift-work: protocols of forced sleep deprivation, of forced activity during the normal rest phase, exposure to light at night and shifted food timing. A big variability in the intensity and duration of the protocols was observed, which led to a diversity of effects. A common result was the disruption of temporal patterns of activity; however, not all studies explored the temporal patterns of food intake. According to studies that evaluate time of food intake as an experimental model of shift-work and studies that evaluate shifted food consumption, time of food intake may be a determining factor for the loss of balance at the circadian and metabolic level.

scholarly journals Measuring Light at Night and Melatonin Levels in Shift Workers: A Review of the Literature

2017 ◽  
Vol 19 (4) ◽  
pp. 365-374 ◽  
Author(s):  
Claudia M. Hunter ◽  
Mariana G. Figueiro
Keyword(s):  
Shift Work ◽  
Quantitative Methods ◽  
English Language ◽  
Circadian Disruption ◽  
Light At Night ◽  
Shift Workers ◽  
Pubmed Database ◽  
Increased Risk ◽  
Disease Risks ◽  
Cancerous Cells

Shift work, especially that involving rotating and night shifts, is associated with an increased risk of diseases, including cancer. Attempts to explain the association between shift work and cancer in particular have focused on the processes of melatonin production and suppression. One hypothesis postulates that exposure to light at night (LAN) suppresses melatonin, whose production is known to slow the development of cancerous cells, while another proposes that circadian disruption associated with shift work, and not just LAN, increases health risks. This review focuses on six studies that employed quantitative measurement of LAN and melatonin levels to assess cancer risks in shift workers. These studies were identified via searching the PubMed database for peer-reviewed, English-language articles examining the links between shift work, LAN, and disease using the terms light at night, circadian disruption, health, risk, cancer, shift work, or rotating shift. While the results indicate a growing consensus on the relationship between disease risks (particularly cancer) and circadian disruption associated with shift work, the establishment of a direct link between LAN and disease has been impeded by contradictory studies and a lack of consistent, quantitative methods for measuring LAN in the research to date. Better protocols for assessing personal LAN exposure are required, particularly those employing calibrated devices that measure and sample exposure to workplace light conditions, to accurately assess LAN’s effects on the circadian system and disease. Other methodologies, such as measuring circadian disruption and melatonin levels in the field, may also help to resolve discrepancies in the findings.

scholarly journals Relationship between Sleep and Hedonic Appetite in Shift Workers

Nutrients ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2835
Author(s):  
Parisa Vidafar ◽  
Sean W. Cain ◽  
Ari Shechter
Keyword(s):  
Weight Gain ◽  
Food Intake ◽  
Circadian Rhythms ◽  
Sleep Quality ◽  
Shift Work ◽  
Poor Sleep ◽  
Shift Workers ◽  
Disturbed Sleep ◽  
Food Intake Regulation ◽  
Intake Regulation

Short and/or poor sleep are established behavioral factors which can contribute to excess food intake, and emerging evidence suggests that disturbed circadian rhythms may also impact food intake regulation. Together, disturbed sleep and circadian rhythms may help explain the excess risk for obesity seen in shift workers. To date, however, the details of how shift work may impact food intake regulation are still not fully defined. Here we examined the relationship between sleep characteristics and hedonic control of appetite in shift workers. A total of 63 shift workers (mean (M) age: 36.7 years, standard deviation (SD): 12.0; 59% women) completed an online survey comprising self-reported measures of body weight regulation, sleep (Pittsburgh Sleep Quality Index, Sleep Hygiene Index), and hedonic control of appetite (Food Craving Inventory, Power of Food Scale). Seventy-one percent reported some weight change since starting shift work, and 84% of those reported weight gain (M = +11.3 kg, SD = 9.1). Worse sleep quality and shorter sleep duration were associated with more food cravings, and worse sleep quality and hygiene were associated with higher appetitive drive to consume palatable food (greater hedonic drive). This preliminary study suggests hedonic pathways are potentially contributing to weight gain in shift workers with disturbed sleep.

scholarly journals Objective Food Intake in Night and Day Shift Workers: A Laboratory Study

2018 ◽  
Vol 1 (1) ◽  
pp. 42-49 ◽  
Author(s):  
Yichi Chen ◽  
Shaza Lauren ◽  
Bernard P. Chang ◽  
Ari Shechter
Keyword(s):  
Food Intake ◽  
Sleep Duration ◽  
Shift Work ◽  
Test Meal ◽  
Food Choice ◽  
Night Shift ◽  
Overweight And Obesity ◽  
Shift Workers ◽  
Sleep Episode ◽  
Night And Day

Night shift work is associated with risk of overweight and obesity. In night shift workers, short sleep duration combined with circadian misalignment may contribute to altered food intake regulation, favoring positive energy balance and weight gain. Prior work investigating food intake in shift workers has suffered methodologically due to reliance on subjective self-report for dietary assessment. No study has yet been done to examine the impact of night shift work on food intake in real-life shift workers using objective measures. Female day (n = 12) and night (n = 12) shift workers from a hospital setting participated in a laboratory-based objective food intake assessment. Participants entered the laboratory in the fasted state after awakening from the sleep episode following a final work shift, and underwent an ad libitum 14-item test meal buffet to objectively quantify food choice/intake. Sleep duration (measured via wrist-accelerometry) during the sleep episode before laboratory assessment was significantly longer in day vs. night workers (373.9 ± 127.5 vs. 260.6 ± 102.9 min, p = 0.03). No significant group difference was observed in calories consumed during the test meal (943.08 ± 469.55 vs. 878.58 ± 442.68 kcal, p = 0.74). When expressed as percent of energy consumed, day workers had higher protein consumption vs. night workers (16.03 ± 5.69 vs. 11.82 ± 4.05%; p = 0.05). To our knowledge, this is the first laboratory-based behavioral assessment of food choice/intake in actual night and day shift workers. Although not studied here, work by others has linked protein intake to satiety. This may be a potential pathway placing shift workers at risk for overweight and obesity.

scholarly journals Environmental Circadian Disruption Increases Stroke Severity and Dysregulates Immune Response

2020 ◽  
Vol 35 (4) ◽  
pp. 368-376
Author(s):  
Anne M. Ramsey ◽  
Adam Stowie ◽  
Oscar Castanon-Cervantes ◽  
Alec J. Davidson
Keyword(s):  
Shift Work ◽  
Inflammatory Responses ◽  
Infarct Volume ◽  
Artery Occlusion ◽  
Circadian Disruption ◽  
Stroke Severity ◽  
Shift Workers ◽  
History Of ◽  
Cerebral Artery Occlusion ◽  
The Brain

Understanding the health consequences of chronic disruption of circadian rhythms can contribute to improving prevention strategies for shift workers. Chronic circadian disruption in shift work has been linked to a higher risk of stroke. Dysregulated immune responses are also linked to circadian disruption and may be a factor in stroke outcomes in shift workers. In this study, we test the hypotheses that specific schedules of circadian disruption exacerbate inflammatory responses in the brain, causing an increase in infarct size after experimentally induced ischemic stroke. Mice were exposed to 1 of 5 different lighting schedules followed by a 30-min middle cerebral artery occlusion, then reperfusion and 3-day recovery. A history of weekly phase advances resulted in an increased infarct volume versus the control lighting schedule. These effects were shift-direction specific, nonpermanent, and required multiple shifts to occur. In a separate cohort, stereotaxic injections of lipopolysaccharide were given bilaterally after exposure to 1 of 3 different lighting schedules. Ratios of pro- to anti-inflammatory cytokine expression show dysregulated responses after a history of phase advances. We conclude that chronic circadian disruption leads to worsened stroke outcome in a direction- and schedule-specific manner likely because of priming of the inflammatory response in the brain. These pieces of evidence suggest that the health impacts of shift work may be improved by targeting shift work scheduling, inflammatory mediators, or both.

Shift work and cancer

2020 ◽  
pp. 838-838
Author(s):  
M. C. Turner
Keyword(s):  
General Population ◽  
Shift Work ◽  
Preventive Measures ◽  
Night Shift ◽  
Circadian Disruption ◽  
Light Spectrum ◽  
Light At Night ◽  
Epidemiological Evidence ◽  
Cardiometabolic Diseases ◽  
Breast And Prostate Cancer

Circadian disruption and night-shift work have been associated with a range of acute and chronic health effects including cardiometabolic diseases, obesity, as well as breast and prostate cancer. Circadian disruption may also affect the health of the general population because of widespread mistimed lifestyle practices including mistimed eating and sleep patterns and increasing exposure to light-at-night and particularly blue light spectrum through the use of e-readers, LEDs and smartphones. New epidemiological evidence on the effects of circadian disruption and light-at-night in workers and the general population will be presented, and mechanisms of disease and potential preventive measures discussed.

scholarly journals Risk of cardiovascular diseases and gastrointestinal tract disorders in relation to the impact of shift work among male workers of textile mills in Pali district of Rajasthan, India

2017 ◽  
Vol 9 (3) ◽  
pp. 1329-1337
Author(s):  
R. Ranawat ◽  
R. Srivastava
Keyword(s):  
Food Intake ◽  
Lipid Profile ◽  
Shift Work ◽  
Smoking Habit ◽  
Daily Intake ◽  
Gastric Diseases ◽  
Shift Workers ◽  
Significant Difference ◽  
The Impact ◽  
Male Workers

he present study was conducted in textile mill of Pali city with the objective to study the risk of cardiac and gastric problems in relation to shift work among male workers. The results showed significant difference between Body Mass Index (χ2=14.2, p=0.0008) and waist hip ratio (χ2=5.2, p=0.0226) of shift and non shift workers. Results on food intake showed comparatively more deficient daily intake of nutrients like fiber (7.21 g), β carotene (1842.89 μg), and folic acid (99.03 μg) in shift workers with respect to recommended dietary allowances and an overconsumption of fats (37.72 g). Alcoholism (χ2=17.3, p=0.0001) and smoking habit (χ2=14, p=0.0029) was found to be significantly higher among shift workers. Comparatively higher segment of shift workers suffered from hypertension (56.0%), disturbed appetite (87.50%), stomach upsets (90.0%), nausea (88.50%), heartburn (85.0%) and breathlessness (34.0%). Shift workers also had higher mean levels of lipid profile fractions and relatively more subjects fell into the category of high risk (20.50%) of CVD. Longer duration of involvement in shift work also influenced the occurrence of gastric and cardiac problems like disturbed appetite (χ2=9.96, p=0.0411), stomach upsets (χ2=9.73, p=0.0452), stomach ache (χ2=10.1, p=0.0389), constipation (χ2=9.88, p=0.0424), dizziness (47.37%), breathlessness (50.0%) and swollen feet (44.74%). The study concludes that shift work affects food intake, BMI, WHR, BP, alcohol intake, smoking habits and lipid profile of the subjects, thus increasing the risk of health problems like cardiovascular and gastric diseases.

scholarly journals Lack of food intake during shift work alters the heart transcriptome and leads to cardiac fibrosis and inflammation in rats

2021 ◽  
Author(s):  
Alexandra J Trott ◽  
Ben J Greenwell ◽  
Tejas J Karhadkar ◽  
Natali N Guerrero-Vargas ◽  
Carolina Escobar ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cardiovascular Diseases ◽  
Food Intake ◽  
Cardiac Hypertrophy ◽  
Food Consumption ◽  
Shift Work ◽  
Metabolic Disorders ◽  
Shift Workers ◽  
Shift Worker ◽  
Increased Risk

Many epidemiological studies revealed that shift work is associated with increased risk of cardiovascular diseases. However, the underlying mechanisms remain poorly understood. An experimental model of shift work in rats has been shown to recapitulate the metabolic disorders observed in human shift workers, and used to demonstrate that restricting food consumption outside working hours prevents shift work-associated obesity and metabolic disturbance. Here we used this model to characterize the effects of shift work in the heart. We show that experimental shift work reprograms the heart cycling transcriptome independently of food consumption. While phases of rhythmic gene expression are distributed across the 24-hour day in control rats, they are clustered towards discrete times in shift workers. Additionally, preventing food intake during shift work affects the expression level of hundreds of genes in the heart. Many of them are found in transcriptional signatures associated with pressure overload and cardiac hypertrophy, and encode for components of the extracellular matrix and inflammatory markers. Consistent with this, the heart of shift worker rats not eating during work exhibits fibrosis and is colonized by immune cells. While maintaining food access during shift work has less effects on gene expression, genes found in transcriptional signatures of cardiac hypertrophy remain affected, and the heart of shift worker rats exhibits fibrosis without inflammation. Together, our findings provide insights into how shift work affects cardiac function, and suggest that some interventions aiming at mitigating metabolic disorders in shift workers may have adverse effects on cardiovascular diseases.

scholarly journals Environmental circadian disruption suppresses rhythms in kidney function and accelerates excretion of renal injury markers in urine of male hypertensive rats

2020 ◽  
Author(s):  
Atlantis M Hill ◽  
G. Ryan Crislip ◽  
Adam Stowie ◽  
Ivory Ellis ◽  
Anne Ramsey ◽  
...  
Keyword(s):  
Shift Work ◽  
Kidney Injury ◽  
Circadian Disruption ◽  
Light Cycle ◽  
Work Schedules ◽  
Shift Workers ◽  
Spontaneously Hypertensive ◽  
Genetic Manipulations ◽  
Adverse Health Outcomes ◽  
Traditional Work

Non-traditional work schedules, such as shift work, have been associated with numerous health issues including cardiovascular and metabolic disease. These work schedules can chronically misalign environmental timing cues with internal circadian clock systems in the brain and in peripheral organs, leading to dysfunction of those systems and their associated biological processes. Environmental circadian disruption in the kidney may be an important factor in the increased incidence of hypertension and adverse health outcomes in human shift workers. The relationship between renal rhythmicity and injury resilience is not well understood, especially in the context of environmental, rather than genetic manipulations of the circadian system. We conducted a longitudinal study to determine whether chronic shifting of the light cycle that mimics shift work schedules would disrupt output rhythms of the kidney and accelerate kidney injury in salt-loaded male spontaneously hypertensive, stroke-prone rats. We observed that chronic shifting of the light-dark (LD) cycle misaligned and decreased the amplitude of urinary volume rhythms as the kidney phase-shifted to match each new lighting cycle. This schedule also accelerated glomerular and tubular injury marker excretion, as quantified by nephrin and KIM-1 compared with rats kept in a static LD cycle. These data suggest that disrupted rhythms in the kidney may decrease resilience and contribute to disease development in systems dependent on renal and cardiovascular functions.

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