The following is a chapter in our forthcoming book – The Real Truth about Sleep.
Night Shift work comes with serious health consequences and this article presents what some of us may not be aware of.
Addressing the Health Impacts of Night Shift Work
1 in 5 people in developed countries now work night shifts.
Reasons why people work night shifts include:
- Increased pay rates
- Lack of choice
- Family responsibilities
Shift work is associated with other health risks including:
- Socioeconomic status
Night shift work increases the risk of Mental Health issues, including:
- Mood disorder
- Sleep disorder
There is an increased risk of metabolic diseases including:
New information now identifies that night shift work carries a clear and significant risk to mental and physical health, even after other factors, such as Smoking have been taken into account.
Researchers now understand WHY shift work carries the risk.
It is the mis-alignment of the biological clock in the worker with the external light-dark environment. This is a major advance, as it offers a rational target for intervention to protect the health of night shift workers. (1)
We have confirmation telling us that night shift work carries a clear and significant risk to mental and physical health and our researchers understand why – it is the mis-alignment of the biological clock in the worker.
This is called a “major advance” because now they can intervene to protect the health of nightshift workers.
Do we need to wake up literally and simply apply a dose of common sense or operate how we did in the past, using that biological clock for work and Sleep?
Can we really call this a major advance if common sense gave us the answer a long time ago and it can still apply today?
Is it a major advance because we can offer intervention?
Is interference (another name for intervention) the answer?
Can we really protect the health of nightshift workers in this way?
Keep reading this article as there is much by way of presenting a commentary, from the author, on this much needed topic about Night Shift.
Save your opinions and critique until the very end, as there is so much more being shared to bring awareness about Night Shift work.
Working night shift causes disruption to the circadian rhythm and there is greater risk of various disorders, accidents and misfortunes, including:
- Increased risk of Cardiovascular Disease
- Higher risk of mood changes
- Increased risk of gastrointestinal problems
- Higher risk of motor vehicle accidents
- Higher risk of work-related accidents
- Increased likelihood of Family problems, including divorce
Sleep deprivation caused by shift work can increase the risk of epilepsy in pre-disposed people.
Shift workers with Diabetes can experience difficulties in controlling their blood sugar levels. (2)
The Negative Health Impacts of Night Shift Work
Night shift work typically attracts higher rates of pay in compensation for being unpleasant.
Some night shift workers are unable to continue in role due to immediate difficulties in coping.
Adverse mental and physical health outcomes have been associated with night shift workers for many years.
As a group, night shift workers have been marginalised and there is a lack of evidence based advice to help night shift workers with immediate problems associated with fatigue, Sleep disorder and nutrition; and a complete lack of health surveillance and harm mitigation to protect workers from developing serious, long-term health issues such as Cancer.
There is a pressing need to ensure immediate safety for the worker and the safety implications of their work.
Major industrial accidents that have occurred during night shift include:
- Texas City
- Exxon Valdes
Recognition and Management of these immediate risks have important implications for safe night shift work and the potential to avoid massive liabilities and reputational damage resulting from accidents occurring on the night shift.
The journey home after a night shift is a dangerous time interval with many near-miss incidents reported, including sleeping while driving.
Advances in population health science, coupled to larger cohorts of night shift workers has allowed the contribution of night shift work to be measured.
Following this association, further studies have sought to identify how night shifts could cause Cancer.
These studies help to link the observations made in night shift workers to a mechanism of action, which might offer ways to intervene and reduce the risks of night shift work.
It is thought that the core body clock exists to maintain alignment with cycles in body function with the external light-dark cycle as we move through day and night.
Night shift work involves living against the clock with activity and light at the time our body clock would be expecting dark and Sleep.
This mis-alignment also occurs in those with extreme chronotypes; reference to morning or evening activity.
For shift workers there is an unmet need helping them manage their shift work schedule in terms of coping with Sleep and eating against their internal body clock.
The emergence of strong evidence that night shift exposures increase the risk of physical illnesses including Cancer, metabolic diseases and inflammatory conditions is new.
The development of these diseases is irreversible and so prevention is very important.
For example – in the Netherlands, Breast Cancer is a recognised industrial disease for female nightshift workers, with implications for compensation.
Directing effort to mitigating the risks of night shift work will be cost-effective and offer immediate improvements in well-being and reduce longer term health risks.
David Ray – Professor of Endocrinology | University of Oxford (1)
As we come to the end of this section about the Negative Health Impacts of Night Shift Work, a very important point to note is that – night shift work generally offers higher rates of pay.
How many of us are attracted by more money as a compensation, even though we all know it affects our mental and physical health, but we ignore that bit as it suits us?
Do we pay attention to the fact that some people are actually unable to continue a job because they experience “immediate difficulties in coping” when it comes to night shift?
Is this not a sign, a big red flag telling us SOMETHING IS NOT RIGHT?
Adverse mental and physical health outcomes have been associated with night shift workers for many years.
Do we understand what the word “adverse” means in the text above?
The origin of the word means against or opposite
What is this telling us and the fact we have known for many years leads to the question WHY ARE WE IGNORING this?
Why do we simply accept anything when it is not supporting the human body?
We are told that “there is a lack of evidence based advice to help night shift workers…”
This means we must wait until our researchers gather evidence as this evidence based advice is what we have to rely on to help our night shift workers with immediate problems linked to fatigue, Sleep disorder and nutrition.
Those of us who are up to date and have worked it out – we know that researchers never ever say it as it is and end the study. There is always more to research and whilst this is ok and much needed, as we all like evidence, we are not sensing the urgency as things are not improving at the pace and rate we could be at, if we used some serious common sense in our approach.
Fatigue comes because we are not resting and sleeping according to that natural clock inside us – that is what good old fashion talk from granny would have to say on that matter.
Nutrition – Granny would most certainly say, how on earth can you put food in your mouth when you are supposed to be sleeping? Working opposite to the times you should be asleep and missing out on natural light is why you need the wrong foods to keep you going and get Real – the whole thing is out of sync and that means off track.
If there is a pressing need to ensure immediate safety for the worker and their work – how come night shift work is on the rise? Have we considered this?
Those that employ night shift workers do not want the risks involved with “massive liabilities and reputational damage resulting from accidents occurring on the night shift”.
When are we going to get out of the lab, stop using the rats and mice and allow these species their own evolution and start with observational studies and take on board the anecdotal evidence, which is Real life and the proof we all need to know?
Our human body is a living science. Surely this is the best way to get to the research evidence we rely on before we make our changes.
We do not need rodents to confirm human behaviour or dis-ease, as they are gnawing, mammal and humans are not. End.
Let is repeat again –
NIGHT SHIFT WORK INVOLVES LIVING AGAINST THE CLOCK
We now have STRONG EVIDENCE that night shift increases the risk of Cancer, Metabolic Diseases and Inflammatory conditions.
The development of these diseases is ir-reversible.
How serious is this now that we know it is IRREVERSIBLE?
So what are we going to do with this ‘strong evidence’ Dear World.
Operate like before and simply wait for more research as this ‘strong evidence’ is not enough or are we going to wake up and pay attention and take a look at where we have a personal Responsibility?
Where do we make demands to want more of our 24/7 world which then means the suppliers have to employ workers 24/7 and that includes night shift work?
How are we going to direct our efforts and is effort in any form the actual true answer?
How are we going to mitigate – make this less serious, harmful and less severe really?
How are we going to offer ‘immediate improvements in well-being’ that a Professor of Endocrinology is saying to us?
3 million work night shift – 11.7% of the workforce (3)
Night Working Hours – Government Guidance
Night Period = 11pm to 6am
Unless employer or worker agree in writing a different night period.
This must be 7 hours long and include midnight to 5am.
Staff working at least 3 hours during the ‘night period’ are night workers.
Staff may also be night workers if there is a collective agreement that states their work is night work. (e.g., trade union agreement).
Night workers must not work more than an average of 8 hours in a 24 hour period. (4)
Night work that involved special hazards or heavy physical or mental strain – there cannot be more than 8 hours work in any 24 hour period. (5)
What if many night shift workers and their employers turn a blind eye to the government guidance of not working more than 8 hours in a 24 hour period?
What if night shift work as bad as it is for our true health and wellbeing offers us rewards that we simply cannot refuse? More money means we are financially sorted and the dream Holiday or an apartment with the extra room to show off to others how well off we are is a reality.
What if we like the extra income and put up with the dis-harmony we feel inside that leaves us with a constant un-rest, un-settlement because it means our kids can have More and we become the great Mum or Dad as we always do more than the average Family can?
What if we do night shifts as we see others doing it and they make it look easy and Simple, so we jump on the bandwagon (mainly to get noticed so others recognise and say ‘wow’ but we are making Mistakes, are totally off sync with our Sleep and cannot seem to get settled even on our Days Off?
What if night shift gives us the lifestyle we like – no one to talk to, just going solo and that suits us, as we don’t like the stuff that relationships come with? Who wants another reflecting something back to us to learn and evolve when we can just carry on with the single life perks and keep a distant with all of humanity at arms length? That means we don’t form true and meaningful relationships because it suits us.
Have we considered all the above “What If’s” as these are real life examples and that makes them very relatable?
Night Shift Work Linked to Increased Risk of Heart Problems
16 August 2021
People who work night shifts are at increased risk of developing an irregular and often abnormally fast heart rhythm called Atrial Fibrillation (AF), according to research published in the European Heart Journal.
This study is the first to investigate the links between night shift work and AF.
Using information from 283,657 people in the UK Biobank database, researchers found that the longer and more frequently that people worked night shifts over their lifetimes, the greater their risk of AF. Night shift work was also linked to an increased risk of Heart Disease but not to stroke or heart failure.
Our results suggest that current and lifetime night shift work may increase the risk of Atrial Fibrillation and Heart Disease.
Professor Yingli Lu – Shanghai Ninth People’s Hospital and Shanghai JiaoTong University School of Medicine, Shanghai, China. (6)
Among those who worked an average of 3 to 8 night shifts a month for 10 years or more, the risk of AF increased to 22% compared to daytime workers.
Researchers also found that among participants currently working night shifts or working night shifts for 10 or more years, or working a lifetime of 3 to 8 shifts a month, the risk of Coronary Heart Disease increased by 22%, 37% and 35%.
Women were more susceptible to Atrial Fibrillation than men when working night shifts for more than 10 years. Their risk increased significantly by 64% compared to day workers.
People reporting physical activity of 150 minutes a week or more of moderate intensity had a lower risk of Atrial Fibrillation than those with non-ideal physical activity when exposed to a lifetime of night shift work.
Thus Women and less physically active people may benefit particularly from a reduction in night shift work.
Professor Lu Qi – Tulane University School of Public Health and Tropical Medicine, New Orleans, USA (6)
This is a new research study and one we cannot just ignore.
It is the first study of its kind about the link between night shift work and Atrial Fibrillation (AF).
For those that are ready to learn more about Atrial Fibrillation – click the link for our insightful presentation on this topic.
Night shift workers are at an increased risk of developing Atrial Fibrillation.
There is also evidence of those that worked an average 3 to 8 nights shifts a month for a decade, having a greater risk of increase to AF, mainly Women.
Permanent Night Shift Workers at Heightened Risk of Moderate to Severe Asthma
An observational research study, published online in the Journal Thorax suggests shift workers, especially those working permanent night shift rotas, may be at heightened risk of moderate to severe Asthma.
Researchers warn that given the prevalence of both shift work and Asthma in industrialised nations, the public health implications of these findings are potentially “far reaching”.
1 in 5 employees in the developed world works permanent or rotating night shifts.
Shift work causes a person’s internal body clock (circadian rhythm) to be out of step with the external light and dark cycle.
It is this mis-alignment that is associated with a heightened risk of various metabolic disorders, Cardiovascular Disease and Cancer.
Compared with those working office hours, shift workers were more likely to be men, smokers and live in urban areas and in more deprived neighbourhoods. They also drank less Alcohol, slept fewer hours and worked longer hours.
Night shift workers were more likely to be owls (evening activity) and have poorer health. They were more likely to work in service jobs or as process, plant and machine operatives.
36% increase in the odds of having moderate to severe Asthma in permanent night shift workers compared to those working normal office hours.
11 – 18% higher the odds of wheeze or airway whistling among those working any of the 3 shift patterns. Shift patterns comprised:
- Never or occasional night shifts
- Rotating night shifts
- Permanent night shifts
55% higher odds of moderate to severe Asthma, among larks (a person who habitually gets up early) working irregular shifts, including nights.
Researchers point out – it is plausible that circadian mis-alignment leads to Asthma development.
The public health implications of our findings are potentially far-reaching, since both shift work and Asthma are common in the industrialised world.
339 million people worldwide affected by Asthma
£1 Billion costs in Health and Care Services UK (7)
Hello again Dear World
Yet another relatively new research study repeating what we ALL know – Night Shift work causes our internal body to be out of step with the external light and dark cycle.
Again we are told this is a MIS-ALIGNMENT and linked to “heightened risk of various Metabolic Disorders, Cardiovascular Disease and Cancer.
As a reminder, as this has been mentioned at the beginning of this article, metabolic related disorders would include the following:
This study highlights that night shift workers have poorer health and work is in the sector of industry related to process, plant and machine operatives.
36% increase of getting moderate to severe Asthma for permanent night shift workers.
Is that a small number or just a number that we do not want to consider or care about?
The word plausible has been used by the researchers and this is standard. There are no researchers on this planet that are going to be absolute because they just don’t do that. So we have to know this means ‘probable’.
Before we go any further, it would be a wise move to read our article on Asthma written by a Doctor, Pulmonologist, who gives us a great presentation about this age old human disease, which affects our ability to breathe our own breath.
151,000 Increase in Number of People Working Night Shifts in 5 Years
3,138,000 night workers in Britain, which is 1 in 9 employees.
66.8% of the increase are in Women.
101,000 more women now working at night than 5 years ago.
Growing employment in health and social care is a key reason behind more women working night shifts.
561,000 women employees working at night.
Most common professions for female night workers are care work and nursing.
259,000 men working at night as road transport drivers.
17,000 men working at night as social care assistants.
114.5% rise in number of night workers over age 50.
Increased employment in social care and the trend towards working past age 65 have spread the age profile of night working.
674,000 age 50 – 59 working at night.
94.8% increase in last 5 years.
197,000 night workers age 60 plus.
392.7% increase since 2013.
136,000 extra night workers in past 5 years comes from:
- Wholesale and Retail
- Transport and Distribution
- Health and Social Care
Negative Health impacts of night work are already well documented
Less attention has been given to the impacts on home life and Relationships.
Night work is hard and can disrupt Family life…
Frances O’Grady – Trades Union Congress (TUC) General Secretary (8)
This section is about one country – UK
The statistics are worth a stop and pause moment.
This is one country – a microcosm of our world confirming that there was a BIG increase in night shift work in 5 years.
WHY have we got more Women working night shifts?
WHY is there a 114% rise in night workers over age 50?
WHY is there a 94% rise in age 50-59 working at night?
WHY do we have a 392% increase in over 60s working nights?
The need or shall we say the demand has come from the Wholesale and Retail Industry, which of course means Transport and Distribution are included.
We want more.
We want it now.
We don’t want to wait.
We demand 24/7.
We have created a society of 24/7 when it comes to shopping, eating and entertainment and that comes with a cost to those that provide the goods and services.
Are we ready to admit that we like our lifestyle choices and pressing or clicking or tapping a screen and getting what we want, when we want with zero regard as to how it will be delivered to us? In other words, we are not interested whatsoever in knowing that night shift workers are involved to keep this demand we insist on going.
This study also confirms the rise in extra night workers in the Health and Social Care sector.
Of course we dread this because we know there will be more and more of us ending up needing an emergency hospital visit during the night and we also know that care homes and other social care needs are on the rise, as we are not really taking care of our bodies.
Time to cut to the chase and spell it out – if we were sensible in how we choose to live our life, there is much we could change in our world.
We live lifestyles that create diseases. We know this as the experts tell us these diseases are lifestyle related.
We seem to have this internal narrative that tells us we can do what we want, when we want and how we want and that is a part of our rights on this earth and our entitlement as we have done nothing wrong so we deserve to have whatever it is we demand.
Could it be possible that our lack of regard and dis-respect for our body leads to our Lifestyle Choices that are not serving us but also puts others at greater risk of illness and disease, like night shift workers that are doing a job to meet the demands we place?
What if we started making sensible choices in life like going to bed early and adhering to this consistently, which would in the long term support our Health and Social Care industry, as we would not require their services? What if this was possible and not just a way off and whacky point to consider?
We are told clearly here that the negative impacts of night work are already well documented and this means we know.
The UK’s General Secretary for the TUC states night work is hard and can disrupt Family life. If we don’t buy that, have a word with those that do night work and find out how true this actually is.
Before we move on to the next section – read carefully the following articles presented on this website (see links)
Night Work Throws Body into Chaos
Researchers warn that doing night shifts throws the body “into chaos” and could cause long-term damage.
Scientists at the Sleep Research Centre in Surrey have uncovered the disruption shift work causes at the deepest molecular level.
Experts say the scale, speed and severity of damage caused by being awake at night was a surprise.
The human body has its own natural rhythm or body clock tuned to Sleep at night and being active during the day.
It has profound effects on the body, altering everything from hormones and body temperature to athletic ability, mood and brain function.
The study, published in Proceedings of the National Academy of Sciences followed 22 participants as their body was shifted from a normal pattern to that of a night shift worker.
Blood tests showed that normally 6% of genes – the instructions contained in DNA – were precisely timed to be more or less active at specific times of the day.
Once the volunteers were working through the night, that genetic fine-tuning was lost.
97% of rhythmic genes become out of sync with mis-timed Sleep and this really explains why we feel so bad during Jet Lag or if we have to work irregular shifts.
Dr. Simon Archer – researcher at the University of Surrey (9)
It is chrono-chaos. It is like living in house where there is a clock in every room in the house and in all of those rooms, those clocks are now disrupted, which of course leads to chaos in the household.
Of course we know that shift work and Jet Lag is associated with negative side effects and health consequences.
They show up after several years of shift work. we believe these changes in rhythmic patterns of gene expression are likely to be related to some of those long-term health consequences.
Professor Derk-Jan Dijk – Fellow Researcher (9)
The study indicated that the acute effects are quite severe.
Professor Hugh Piggins – Body Clock Researcher from the University of Manchester (9)
We have old evidence. This section relates to a study back in 2014 where researchers warn us that doing night shifts throws the body “into chaos”.
Do we get it and know that means complete disorder and confusion for those that need another meaning from the dictionary?
Before we go any further, what on earth are we doing in cases where night shift is not necessary or can be avoided simply by not supplying to the demand. More on this in our final summary of this chapter on night shift in our forthcoming book – The Real Truth about Sleep.
Why are our experts surprised after uncovering the disruption that night shift work creates at a deep molecular level?
Common sense tells us going against our natural body clock is going to have serious consequences. We all do know that.
THE SCALE, SPEED AND SEVERITY OF DAMAGE CAUSED BY BEING AWAKE AT NIGHT HAS PROFOUND EFFECTS ON THE BODY.
We are being told our hormones are affected, our body temperature is affected, our mood is affected and our brain function is affected.
Is this enough or do we want more evidence or some time to consider if we want to support our body or continue with the lifestyle that night shift gives us?
Did we know that every tissue in our body has its own daily rhythm but this is lost when we work shifts because the Heart runs at a different time to the Kidneys and the brain runs to a different time too and so on…?
How serious is this now that we know?
Note – we cannot un-read what we have just read AND we cannot un-feel, what we just felt. Furthermore, we can no longer ignore, deny or negate what makes sense and is the Truth. Why wait for more and more research to tell us the harm when we use our body to work in un-natural rhythms?
Great analogy from Professor Dijk when he tells us about living in a house where the clocks in every room are disrupted and this leads to chaos in the household, meaning everything and everyone is affected.
What if our house is our body and we see each room as different parts of the body – for example our dining room is our digestion system and our bedroom symbolises our vascular system? And if this was the case, would we not be paying even more attention by making sure we take deep care of all our Heart matters as it is affecting our Sleep?
What if we actually need the rhythms to support us in life and that means adhering to the Sleep wake cycle as it is not just about our health and wellbeing but the profound effect it would have on others too?
Physical Effects of Night Shift Work on the Body
You constantly have to override this sort of biological drive from the clock saying you should be asleep.
Russell Foster – Sleep Expert and Oxford University Professor (11)
Foster explains that overriding this biological clock makes you activate your “Stress axis”, which is how your body reacts in a fight or flight situation.
We are squirting out glucose into the circulation, we are increasing blood pressure, we are driving up alertness to deal with potential threat and of course we are not – we are just working.
Russell Foster – Sleep Expert and Oxford University Professor (11)
Foster warns that sustained levels of Stress can lead to Cardiovascular Disease, or metabolic abnormalities such as Type 2 Diabetes. Stress can also suppress the immune system, which may be the basis of higher rates of Colo-Rectal Cancer and Breast Cancer.
Those are the long term effects but being Sleep deprived has affects in the short term too. The most obvious being tiredness. Failure to take in information correctly, failure to pick up on social signals and a loss of empathy are all symptoms.
Foster also warns that companies whose employees do night shift work could be setting themselves up for lawsuits in the future if they do not demonstrate they are taking all reasonable measures to try and mitigate some of the problems associated with working at night.
Knowing that there is a risk of Cardiovascular Disease and metabolic problems, such as Diabetes, Foster states that ‘appropriate nutrition should be made available to night shift workers.’
There is research to suggest that carbohydrate consumption can go up.
35-40% rise in carbohydrate consumption after 4 or 5 days of restricted Sleep due to the increased level of a hormone being released called ghrelin, which creates hunger and encourages sugar and carbohydrate consumption. This can lead to Obesity and conditions like Diabetes.
All that Sleep deprivation carries not just a health cost but an economic cost too.
In the UK, lack of sleep costs the economy up to £40 billion a year – 1.8% of the UK GDP.
This is a combination of lost productivity and mortality effects.
Marco Hafner – Senior Economist at The Research Institution Rand Europe (11)
Hafner says “we know that the Centers for Disease Control and Prevention in the United States has looked at this and has actually proclaimed insufficient Sleep a public health epidemic, so there is increasing awareness of lack of sleep being a public health problem. (11)
This section above is super important so pay attention Dear Reader.
We have an Oxford University Professor telling us that with this constantly over-riding our natural biological clock, we activate our body into the ‘fight or flight’ mode and that means we are prepared for Stress. Blood pressure increases, we have more glucose released to make us more alert to deal with a potential threat, but in truth this is not needed as we are just working a night shift.
It can come as no surprise, if we continue to live in this ‘Stress mode’ our body cannot sustain it and of course it could lead to Cardiovascular disease, Cancer or metabolic disorders like Diabetes, in the long term.
In the short term, Sleep deprivation will naturally make us tired and not process information correctly or even function socially with others.
Professor Russell Foster is warning us that companies in the future could end up with lawsuits because their employees doing night shift work were not taken care of. In his words “they do not demonstrate they are taking all reasonable measures to try and mitigate some of the problems associated with working at night”. He suggests appropriate nutrition should be made available to night shift workers.
Insufficient Sleep is a Public Health epidemic.
In the United States, the CDC (Centers for Disease Control and Prevention) have said that.
What does that mean to us and how seriously are we taking this statement from the US Government Authority on Health?
Our lack of Sleep is widespread and it is on the increase.
We have as a world created a multi-billion dollar sleeping aids industry and yet we have not nailed the Sleep thing.
WHY not is the billion dollar Question here?
If we keep it super Simple – our body is not designed to operate off sync, off track, out of rhythm and out of its natural cycles. Yet we make choices to go against our natural state and then try and fix it with our Solutions, strategies, management and all other ways to function, but never make Real and lasting changes by getting to the root of how and why it got off kilter in the first place. Is this making sense?
15 million work night shifts (4)
What Working through the Dead of the Night Does to the Body.
Millions around the world work nights.
According to a study by Princeton University, 7 – 15% of the workforce in industrialised countries were engaged in some form of night work, despite the World Health Organization having classified night work as a probable cause of Cancer due to disruption of circadian rhythms. (11)
How our Bodies Respond to Night Shifts
Gene Expression Changes in a True Night-Shift like Environment
The findings show a physiological disconnect – many of the genes associated with circadian cycles kept their rhythms but seemed to fire at lower strength.
Many genes could not adapt their expression to a flip-flopped Sleep schedule.
Gene expression related to metabolism and the function of certain immune cells and potential Cancer-causing signalling pathways were also altered.
Beyond the dampened rhythm of circadian genes, there was also some perturbed expression in immune and Cancer pathways, including the altered expression of genes related to natural killer cells, a first-line attack against tumour cells and infected cells.
Shift Work Sleep Disorder is the name given for the Sleep side of the problem and sleep centres offer help to people who work odd shifts.
Very few genes adapt to this new night shift schedule.
It is becoming more and more common because we expect services to be available 24/7.
Professions with overnight shifts – health care, security and warehouse work.
In the long term, it is becoming clearer that there are negative health effects with it.
We cannot stop night shift work as we want all these services as a society but maybe we can devise strategies to help with night shift work.
Laura Kervezee – Postdoctoral Fellow at McGill University and Study Lead
Study published in Proceedings of the National Academy of Sciences of the United States of America (PNAS). (12)
Sleep is only part of the equation and it is a harder part to treat.
Frank Scheer – Director of the Medical Chronobiology Program at Brigham and Women’s Hospital, Boston, USA (12)
His laboratory work found changes in glucose tolerance, diet-related hormones and increases in blood pressure and markers of inflammation. (12)
One country with millions working at night and then we have this statement –
WORLD HEALTH ORGANIZATION HAVE CLASSIFIED NIGHT WORK AS A PROBABLE CAUSE OF CANCER DUE TO DISRUPTION OF CIRCADIAN RHYTHMS
We know this and yet we seem to ignore it at the same time.
This study by a research university is saying that we have a workforce engaging in night work despite the organisation on World Health classifying night work as a probable cause of Cancer due to the disruption in our natural Sleep cycle.
Can we pay attention to the detail here – the findings in this study are telling us that many of the genes linked to circadian cycles “seem to fire at lower strength”.
We could say less fire = not strong quality.
Night shift work is becoming “more common because we expect services to be available 24/7.
We cannot stop night shift work as we want all these services as a society”.
The lead on this study makes a point worth noting. We the consumers, the public, the masses demand 24/7 and expect the suppliers to provide.
As a society, what if we stopped making demands that affect our fellow brothers out there that have to work against their natural clock just to provide for us, something that in most cases could wait until the next day.
And, so what if we got our online delivery a few days or even a few months later?
We want a new car and it means 6 months waiting but that would be ok as it means no human has to ever do a night shift again and this will support their health and well-being.
How about we take that kind of responsibility and knock out our un-necessary demands?
This is one example but we could easily apply it to all our goods and services that we demand 24/7 so that we would need very few workers at night, this being in the health and social care sector of course.
But even on that note, what if we ALL started taking more responsibility for our health and well-being by making SENSIBLE CHOICES instead of dis-regarding and neglecting what our body needs in any given moment? Surely that would be less burden on the health systems and our emergency hospital departments.
What if the knock on effect of making sensible choices led to less people going into social care as we are ensuring we take full Responsibility to not ignore our body when it comes to our True Health?
On a side note but relevant – this website is dedicated to doing just that.
A library of bringing simple awareness on topics of health and well-being and saying “Hey, have you considered this as there is Another Way…”.
Shift Workers “Risking” Type 2 Diabetes and Obesity
The results published in Science Translational Medicine showed changes to normal Sleep meant the body struggled to control sugar levels. (10)
Some participants even developed early symptoms of Diabetes within weeks.
We think these results support the findings from studies showing that in people with a pre-diabetic condition, shift workers who stay awake at night are much more likely to progress to full-on Diabetes than day workers.
Since night workers often have a hard time sleeping during the day, they can face both circadian (body clock) disruption working at night and insufficient Sleep during the day. The evidence is clear that getting enough sleep is important for health and that sleep should be at night for best effect.
Dr. Orfeu Buxton – Lead Researcher (13)
The researchers called for more efforts to reduce the health impact of shift working. (13)
We have known for 10 years that the results of this study above “showed changes to normal Sleep meant the body struggled to control sugar levels”.
But yet we know night shift work is on the increase in our ever fast, want it now society called 24/7.
Of course if someone already has a pre-diabetic condition and then they do night shift work, there is a high chance they will progress to full-on Diabetes BECAUSE of what we know. Yes we do know.
Add to that the lead researcher on this study states that often night shift workers struggle with sleeping during the day, so they face BOTH circadian body clock disruption. The night staying awake affects them and so does the insufficient Sleep during the day.
And finally, will our efforts work to reduce the health impact of night shift work or do we need a paradigm shift? This means another approach and another way because there is a bigger picture here to read. This is not just about a few people. Our Lifestyle Choices have major consequences on the health of others. This cannot continue if we are to ever evolve or call ourselves an Intelligent1 species.
There is absolutely nothing Intelligent2 in demanding goods and services when we know it is harmful to the health of another human being.
Systematic Review of Shift Work and Nurses’ Health
24 articles analysed and a literature review has shown that –
SHIFT WORK INVOLVES AN ALTERATION IN PSYCHOPHYSICAL HOMEOSTASIS, WITH A DECREASE IN PERFORMANCE.
Shift work is connected with high levels of work-related Stress, especially within the nursing context.
- 1 in 4 workers affected by work-related Stress
- 60% of lost working days
- €20 Billion Euros – annual cost (15)
Nurses are one of the most studied populations in terms of shift work (14)
Association Between Night Shift and Sleep Quality and Health among Nurses: A Cross-Sectional Study
3,206 Chinese Nurse participants
55.1% – Night Shift nurses demonstrated relatively worse Sleep quality
20.7% – Night Shift nurses had more health problems
Night Shift nurses have more Sleep disorders and physical health problems (16)
The above 2 sections confirm that the health of nurses worldwide is affected by shift work and this includes night shift work.
This will be addressed in further detail in our forthcoming Book on Sleep.
2007 – The International Agency for Research on Cancer, a body that is part of the World Health Organization, classified shift work with circadian disruption or chronodisruption as a probable human carcinogen. (17)
2019 – The agency carried out a further evaluation and concluded the same – night shift work is probably carcinogenic to humans. (18)
The National Toxicology Program (NTP) released a report about how persistent night shift work is related to Cancer risk.
It was concluded in the report that there is “high confidence” that persistent night shift work that results in circadian disruption can cause human Cancer.
Biological Clocks and Circadian Disruptions
Many of our biological systems – including our Sleep and wake cycle, appetites, digestive patterns, body temperatures and our moods, follow daily patterns or “circadian rhythms.”
These cycles are set by circadian clock genes that are found in nearly every cell in our bodies. The timing of our daily rhythms is strongly influenced each day when light is first detected by our eyes.
Light stimulates areas of the brain to tell our bodies to be awake, active and hungry.
When darkness falls, the hormone melatonin is secreted by the pineal gland in the brain and is produced all night long, promoting Sleep.
Our master clock in the brain controls the timing of our circadian rhythms so they work together: this harmony is important for a healthy functioning body. When our Sleep patterns or lightness and darkness cues are severely disrupted – as with night shift work or travel across multiple time zones or exposure to light during our normal sleeping hours, we can develop what is referred to as “circadian disruption.”
Circadian disruption means our circadian rhythms are not working together, which can make us feel ill, increase our risk for poor health and increase our chances for making Mistakes that risk our safety and the safety of others.
Connection Between Circadian Disruption, Melatonin and Cancer
Circadian disruption can harm biologic systems that help prevent Cancer.
For example, in addition to promoting Sleep, melatonin can also stop tumor growth and protect against the spread of Cancer cells. Laboratory animals whose days and nights were disrupted in scientific experiments had reduced levels of melatonin and increased rates of Cancer or tumor growth.
Animal studies have shown that exposure to light at night led to the growth of breast or mammary-gland Cancer.
Studies among nurses and other night shift workers showed increased risk of breast Cancer that was unexplained by reproductive history, lifestyle factors, body mass index or socioeconomic status.
In most studies, an excess risk of Breast Cancer was found mainly among Women who had worked night shifts for many years or at a high frequency or who had worked a large number of night shifts over their lifetimes.
Night Shift Workers
The NTP and IARC reports both suggest that people who work night shifts regularly, appear to be at highest risk. Specifically:
- Night shift of at least 3 hours between midnight and 5 am
- Frequent night work – 3 or more nights per week
- Long term night shift work – 10 years or more
- Beginning night shift work in early adulthood – before age 30
Other factors that are more common among night shift workers which contribute to the risk of Cancer:
Workplace and social stressors
Lifestyle behaviours, such as:
- Higher than recommended Alcohol consumption
- Poor Diet
- Not enough physical activity
- Being overweight or Obese
- Decreased exposure to sunlight and lower levels of vitamin D (19)
Other Health Effects Associated with Night Shift Work
Night shift work has also been associated with:
Night shift workers can also have an increased risk of reproductive issues, such as:
- Irregular menstrual cycles
- Pre-term Birth
More common among night shift workers:
The fatigue associated with night shift work can lead to injuries, vehicle crashes and industrial disasters. (19)
What we have learned from a recent Toxicology report in the United States is that night shift is linked to the following:
- HEART DISEASES
- DIGESTIVE PROBLEMS
- BODY TEMPERATURE
- IRREGULAR MENSTRUAL CYCLES
- PRE-TERM BIRTH
Common factors among night shift workers include:
And just to highlight the point – the fatigue associated with night shift work, can lead to injuries and accidents which include vehicle crashes and industrial disasters.
Before we continue to read on, take a stop moment and reflect on what has thus far been presented.
Insights on How Night Shift Work Increases Cancer Risk
8 March 2021
New clues as to why night shift workers are at increased risk of developing certain types of Cancer are presented in a new study conducted at Washington State University Health Sciences Spokane and published online in the Journal of Pineal Research.
Findings suggest that night shifts disrupt natural 24-hour rhythms in the activity of certain Cancer-related genes, making night shift workers more vulnerable to damage to their DNA while at the same time causing the body’s DNA repair mechanisms to be mistimed to deal with that damage.
There has been mounting evidence that Cancer is more prevalent in night shift workers, which led the World Health Organization’s International Agency for Research on Cancer to classify night shift work as a probable carcinogenic.
However, it has been unclear why night shift work elevates Cancer risk, which our study sought to address.
Shobhan Gaddameedhi – Associate Professor at North Carolina State University’s Biological Sciences Department and Center for Human Health and the Environment. (20)
Studying the Rhythms in Cancer-Related Genes
There is a central biological clock in the brain. Nearly every cell in the body also has its own built-in clock. This cellular clock involves genes known as clock genes that are rhythmic in their expression, meaning their activity levels vary with the time of day or night.
Analyses of white blood cells taken from the blood samples showed that the rhythms of many of the Cancer-related genes were different in the night shift condition compared to the day shift condition. Notably, genes related to DNA repair that showed distinct rhythms in the day shift condition lost their rhythmicity in the night shift condition.
The researchers then looked at what the consequences of the changes in the expression of Cancer-related genes might be. They found that white blood cells isolated from the blood of night shift participants showed more evidence of DNA damage than those of day shift participants.
After the researchers exposed isolated white blood cells to ionizing radiation at 2 different times of day, cells that were radiated in the evening showed increased DNA damage in the night shift condition as compared to the day shift condition. This meant that white blood cells from night shift participants were more vulnerable to external damage from radiation, a known risk factor for DNA damage and Cancer.
Taken together, these findings suggest that night shift schedules throw off the timing of expression of Cancer–related genes in a way that reduces the effectiveness of the body’s DNA repair processes when they are most needed.
Jason McDermott – Computational Scientist, Pacific Northwest National Laboratory’s Biological Sciences Division and co-corresponding author. (20)
Potential for Improved Prevention, Treatment
The next step for the researchers is to conduct the same experiment with real-world shift workers who have been consistently on day or night shifts for many years to determine whether in night workers the unrepaired DNA damage builds up over time, which could ultimately increase the risk of Cancer.
If what happens in real-world shift workers is consistent with the current findings, this work could eventually be used to develop prevention strategies and drugs that could address the mistiming of DNA repair processes. It could also be the basis for strategies to optimize the timing of Cancer therapy so that treatment is administered when effectiveness is greatest and side effects are minimal, a procedure called chronotherapy that would need to be fine-tuned to the internal rhythms of night workers.
Night Shift workers face considerable health disparities, ranging from increased risks of metabolic and Cardiovascular Disease to Mental Health disorders and Cancer.
It is high time that we find diagnosis and treatment Solutions for this underserved group of essential workers, so that the medical community can address their unique health challenges.
Hans Van Dongen – co-senior author and Professor WSU Elson S. Floyd College of Medicine and Director of the WSU Sleep and Performance Research Center. (20)
Shift Work Disrupts Circadian Regulation of the Transcriptome in Hospital Nurses
Female nurses from the University of Alabama at Birmingham (UAB) Hospital working night shift participated in a 9 day study to measure locomotor activity and core body temperature continuously.
Cortisol and Melatonin were determined and peripheral blood mononuclear cells (PBMCs) were harvested for RNA extraction, every 3 hours on a day off from work.
Data confirmed the disruptive effects that shift work has on molecular rhythmicity. The variability in molecular rhythms between individuals is an indication of the severity of *desynchrony. (21)
A condition in which the environmental cues and patterns, such as sleeping and eating conflict with an individual’s existing pattern; one type is Jet Lag (22)
Rotating Night Shift Work Can be Hazardous to Health
5 January 2015
Possible increase in Cardiovascular Disease and Lung Cancer mortality observed in nurses working rotating night shifts, according to a report in the American Journal of Preventive Medicine.
Night Shift work has been consistently associated with higher risk of Cardiovascular Disease (CVD) and Cancer.
2007 – the World Health Organization classified night shift work as a probable carcinogen due to circadian disruption.
In a study, published in the American Journal of Preventive Medicine, researchers found Women working rotating night shifts for 5 or more years appeared to have a modest increase in all-cause and CVD mortality and those working 15 or more years of rotating night shift work appeared to have a modest increase in Lung Cancer mortality. These results add to prior evidence of a potentially detrimental effect of rotating night shift work on health and longevity.
Sleep and the circadian system play an important role in Cardiovascular health and antitumor activity. There is substantial biological evidence that night shift work enhances the development of Cancer and CVD and contributes to higher mortality.
The international team of researchers investigated possible links between rotating night shift work and all-cause, CVD and Cancer mortality in a study of 75,000 registered nurses in the United States.
Using data from the Nurses’ Health Study (NHS), the authors analysed 22 years of follow-up and found that working rotating night shifts for more than 5 years was associated with an increase in all-cause and CVD mortality.
Mortality from all causes appeared to be 11% higher for Women with 6-14 and ≥15 years of rotating night shift work. CVD mortality appeared to be 19% and 23% higher for those groups, respectively.
There was a 25% higher risk for Lung Cancer in those who worked shift work for 15 or more years.
The Nurses’ Health Study, which is based at Brigham and Women’s Hospital, began in 1976 with 121,700 U.S. female nurses aged 30 – 55 years, who have been followed up with biennial (occurring every 2 years) questionnaires.
1988 – Night shift information was collected and 85,197 nurses responded.
After excluding Women with pre-existing CVD or other than non-melanoma skin Cancer, 74,862 women were included in this analysis.
Defining rotating shift work as working at least 3 nights per month, in addition to days or evenings in that month, respondents were asked how many years they had worked in this way. (23)
38% higher risk of dying from Heart Disease – nurses working more than 15 years on rotating night shifts than those who only worked during the day.
The population of nurses with the longest rotating night shifts also shared risk factors that endangered their health: they were heavier on average than their day-working counterparts, more likely to smoke, have High Blood Pressure, Diabetes and elevated cholesterol.
Connection between more rotating night shift hours and higher death rates remained strong after the scientists adjusted for them.
This data supports the idea that changing the body’s natural rhythms by being active at night and asleep during the day may have harmful consequences, especially if you shift this rhythm inconsistently.
It is like flying between London and New York every 3 days – constant Jet Lag.
However, if you fly from London to New York and stay in New York, then the Jet Lag would subside after a few days and that is what we assume happens in permanent night workers.
Dr. Eva Schernhammer – Epidemiologist at Brigham and Women’s Hospital (24)
Previous studies have shown that too little Sleep or the kind that is disrupted can alter melatonin levels so that the body never powers down and slips into restorative mode – a time when much-needed repairs are made to cells and tissues and supplies of nutrients are replenished to the body.
Without this period of rest, important processes such as inflammation, fat and sugar metabolism and immune functions get out of balance, creating fertile ground for Heart Disease or Cancer.
Researchers are studying how these people might counteract some of the effects of their unusual work hours but none of these strategies, including light lamps and Sleep aids has so far been proven to help. (24)
Our nurses are in the care profession and their job is to care for patients.
How is this going to be possible if how they are living is in any way a compromise or a dis-service to the deep care needed for their own body?
Something is clearly not working if the most studied population for shift work are nurses and we have all this evidence telling us the health impact when our body is made to work against its natural Sleep wake cycle.
Eating Daytime Meals May Reduce Health Risks Linked to Night Shift Work
A clinical trial supported by the National Institutes of Health has found that eating during the night time – like many shift workers do, can increase glucose levels, while eating only during the daytime might prevent the higher glucose levels now linked with a nocturnal work life.
The study authors said, these findings could lead to novel behavioural interventions aimed at improving the health of shift workers – grocery stockers, hotel workers, truck drivers, first responders and others, where past studies have shown, they may be at an increased risk for Diabetes, Heart Disease and Obesity.
This new study, which the researchers noted is the first to demonstrate the beneficial effect of this type of meal timing intervention in humans, appears online in the journal Science Advances. Funded primarily by the National Heart, Lung and Blood Institute, part of the National Institutes of Health.
This is the first study in humans to demonstrate the use of meal timing as a countermeasure against the combined negative effects of impaired glucose tolerance and disrupted alignment of circadian rhythms resulting from simulated night work.
Frank A.J.L. Scheer – Study Leader, Ph.D., Professor of Medicine at Harvard Medical School and Director of the Medical Chronobiology Program at Brigham & Women’s Hospital in Boston. (25)
The researchers said that the mechanisms behind the observed effects are complex. They believe that the night time eating effects on glucose levels during simulated night work are caused by circadian misalignment.
That corresponds to the mistiming between the central circadian “clock” which is located in the brain’s hypothalamus and behavioral Sleep/wake, light/dark and fasting/eating cycles and this can influence peripheral “clocks” throughout the body.
This current study shows that, in particular, mistiming of the central circadian clock with the fasting/eating cycles plays a key role in boosting glucose levels. The work further suggests the beneficial effects of daytime eating on glucose levels during simulated night work may be driven by better alignment between these central and peripheral “clocks.”
This study reinforces the notion that when you eat matters for determining health outcomes such as blood sugar levels, which are relevant for night workers as they typically eat at night while on shift.
Sarah L. Chellappa – Study Co-Leader, M.D., Ph.D., Researcher in the Nuclear Medicine Department at the University of Cologne, Germany.
Chellappa formerly worked with Scheer in Brigham & Women’s Medical Chronobiology Program (25)
Here we have another study telling us about night work and the circadian mis-alignment. But this is the first study in humans. We can assume prior to this it was on animals.
We know from the researchers that what goes on behind their observations is Complicated.
We know that the central head office clock inside us is located in a region of the fore brain known as the hypothalamus.
We have established that there is a link with night shift workers eating out of their natural rhythm and increasing their glucose levels. We know those night shift workers are there to make sure they meet the demand and that is us wanting what we want or in need of a service like first responders.
To conclude, what this study confirms is that when you eat does matter for health outcomes.
Night Shifts Disrupt Rhythm Between Brain and Gut
Scientists say working night shifts can mess up the body’s natural rhythms so much that the brain and digestive system end up completely out of kilter with one another.
Researchers found 3 night shifts in a row had little impact on the body’s master clock in the brain but it played havoc with gut function, throwing the natural cycle out by a full 12 hours.
The finding highlights the dramatic impact that night shifts can have on the different clocks that govern the natural rhythms of organs and systems throughout the human body.
Internal disagreements over night and day may explain why people on night shifts and those with Jet Lag, can suffer stomach pains and other gut problems, which clear up once their body has had time to adjust.
Researchers measured levels of hormones called melatonin and cortisol, which rise and fall according to the body’s master clock, along with levels of metabolites linked to digestion.
The results showed that 3 night shifts in a row moved the brain’s master clock by about 2 hours on average. The impact on the digestive system’s clock was profound, knocking it out by 12 hours.
Our bodies have a central master clock in the brain that draws on changes in ambient light to control when we wake up and when we fall asleep. But many other organs in the body have their own biological clocks, including the digestive system.
The night shifts also disrupted the rhythms of 2 metabolites linked to Chronic Kidney Disease.
What this suggests is that we might be able to use this to tailor meal times to minimise the impact of shift work on health. We have followed the light-dark cycle throughout the course of our evolution. But nowadays, we can do anything we like at any time of the day, so we are giving our body clock very confusing time cues.
Aarti Jagannath – Professor of Circadian Biology at the University of Oxford (26)
This relatively new study confirms yet again that night shifts mess up our body’s natural rhythms and that the brain and digestive system end up of balance.
Even just 3 night shifts consecutively had an impact on gut function, knocking it out by 12 hours AND it also altered the brains master clock.
It would be a wise move for researchers to collect evidence from the millions out there to check is there is a link with late nights – not just night shift workers and report back to humanity their findings.
We may not work but so many today stay up late and which affects their natural Sleep wake cycle.
What if a research study was done collating evidence worldwide on those that have Chronic Kidney Disease and find out how their Sleep quality is and if they tend to stay up late every night, even if they are not night shift workers?
And finally, on this section, we cannot afford to negate what this Professor of Circadian Biology is saying…”we have followed the light-dark cycle throughout the course of our evolution. But nowadays, we can do anything we like at any time of the day, so we are giving our body clock very confusing time cues”.
Enough said, what on earth are we doing messing with our natural body clock?
Shift Work Link to Increased Risk of Heart Problems
A team of researchers from Canada and Norway analysed 34 studies involving 2 million workers in the British Medical Journal said shift work can disrupt the body clock and have an adverse effect on lifestyle. It has previously been linked to an increased risk of High Blood Pressure and Diabetes. Limiting night shifts would help workers cope, experts have said.
- 17,359 coronary events including cardiac arrests
- 6,598 Heart attacks
- 1,854 strokes caused by lack of blood to the brain (27)
Shift work was linked to a –
- 23% increased risk of Heart attack
- 24% increased risk of coronary event
- 5% increased risk of stroke (28)
Shift workers were more prone to sleeping and eating badly.
Night shift workers are up all the time and they do not have a defined rest period.
They are in a state of perpetual nervous system activation, which is bad for things like Obesity and cholesterol.
Dan Hackam – Associate Professor at Western University, Ontario in Canada (27)
There were complex issue surrounding shift work.
It can result in disturbed appetite and digestion, reliance on sedatives and/or stimulants, as well as social and domestic problems.
These can affect performance, increase the likelihood of errors and accidents at work, and even have a negative effect on health.
Avoiding permanent night shifts, limiting shifts to a maximum of 12 hours and ensuring workers have a minimum of 2 full nights’ Sleep between day and night shifts are simple, practical Solutions that can help people to cope with shift work.
Jane White – Research and Information Services Manager at the Institution of Occupational Safety and Health. (28)
2 million people were involved and this study from 10 years ago confirms back then that we did know the adverse effects of shift work on the human body.
Did it work or did we the people that make demands for our 24/7 lifestyle choices ensure that it did not happen, as today we have even more night shift workers than ever before? With our need for more and more services to be provided around the clock, we have created all of this.
ADD to the above, the increased risk in Heart problems.
Do we really need another 2 million people to confirm what we ALL know and that is SOMETHING IS NOT RIGHT. We can churn out more and more data, analyse, hypothesise and come up with the next and the next research for our ‘evidence based’ confirmation but if we keep it Simple – do we know already but are not willing to admit because it would mean taking responsibility and adjusting our Lifestyle Choices?
Do we care enough that we will start to only shop in sensible hours and not in the middle of the night where people are “in a state of perpetual nervous system activation…” on our behalf because we are the ones that put them in that job?
Let us not worry at all about night shift workers losing jobs and being unable to find other work.
Let us instead consider the harm we cause when we allow another to work against their natural body clock just so we can have what we want, when we want, as it suits our lifestyle.
This study has touched on the OTHER issues that are complex which come at a price.
Working night shifts can disturb our appetite and digestion. We already know this.
To rely on sedatives or stimulants is not the way to go and we know this too.
This type of work creates un-necessary social and domestic problems – we know.
The increased likelihood of making Mistakes and having accidents at work is well known.
Will any Solution really work or are our ‘coping’ methods a bit like a band aid to a bullet wound?
Is it time to wake up and smell the damage we are causing and admit that this does affect ALL of us?
Because these guys who work during the night to ensure we get what we want are paying a price and their health costs us ALL because society cops it. Yes our health systems could be dealing with other patients if night shift workers did not have to get help for their work related illness and dis-eases as mention thus far in this article.
Pregnant Women Working Night Shifts may have Greater Risk of Miscarriage
Women who work 2 or more night shifts in one week may have a greater risk of miscarriage the following week by one third, according to a prospective study, published online in Occupational & Environmental Medicine.
Previous studies have suggested that pregnant women face a greater risk of miscarriage if they work night shifts, but they have been based on self-reported shift work and have not quantified the level of increased risk or the amount of shift work involved.
32% higher risk of miscarriage after week 8 of pregnancy in women who had worked 2 or more night shifts the previous week, compared with women who had not worked any night shifts that week.
And the risk of miscarriage increased with the number of night shifts worked per week and also by numbers of consecutive night shifts.
In terms of the underlying mechanism responsible for the association, Women working night shifts are exposed to light at night which disrupts their circadian rhythm and decreases the release of melatonin.
Melatonin has been shown to be important in maintaining a successful pregnancy, possibly by preserving the function of the placenta. (29)
We have now established beyond doubt that night shift work is NOT working for us as human beings.
It is great that we have a study showing us the harm for pregnant Women is high if they chose to work night shifts. The risk of miscarriage was evident from the past based on ‘self-reported’ but of course we tend to dismiss it as it was not “quantified” and we like the data, numbers, laboratory and all the double blind testing stuff that goes on, as Real life reporting is not enough. But what if it is the best way to learn and make Changes?
Listen up Dear World – we have people that make Mistakes and/or their body shows signs of illness or dis-ease. If they could share their lifestyle, what happened, when and how, we could ALL learn and not go down the same track.
Imagine a night shift worker admitting what they really eat and what they do to deal with working against their natural body clock.
Imagine finding out about their Relationships, how they operate behind closed doors and what health problems they had.
Imagine if we could listen to their wise words as they have walked down the ill road and continued to do so as it suited their lifestyle – it gave them the extra money which meant they had more and they forgot it came at a high price to their health and wellbeing.
Well we could imagine or we could just say this is Real and it is possible.
Imagine the public monies no longer needed on more and more research studies because we came to realise the real research is the human body – that is the living science. High time we did not dismiss this immutable fact. Yes you read correctly – the human body is the living science, so let’s start listening to what the people have to say about their own body and not over-riding it in favour of evidence based theories that are saved for the academics only.
Back to the study –
We now have the detail from this study, which tells us that the hormone melatonin is important during pregnancy and to work night shifts means a disruption in the circadian rhythm and this means a decrease in the release of melatonin.
On that note, are we aware that one of our Sleep Solutions is to take melatonin under the banner of ‘dietary supplement” to deal with our insomnia for the short term but how many of us are unable to wean ourselves off this dietary supplement, which we all know is nothing to do with supplementing our diet?
How else can we get away with legalising a drug that is being used to do the job of a hormone that naturally releases to support our Sleep wake cycle?
Shift Work Sleep Disorder (SWSD)
Shift Work Sleep Disorder (SWSD) is a type of sleep disorder that usually occurs in people who work between 10pm – 6am.
This type of schedule is outside of the normal Sleep schedule of the body’s circadian rhythm. People generally have great difficulty adjusting to this type of sleep schedule, especially if transitioning from regular working hours to night shift.
Characteristics of SWSD include:
- Sleep disruption
- Difficulty concentrating
- Lack of Energy
This disorder occurs because the body cannot synchronize the internal clock with the work schedule – staying awake when it is dark outside and sleeping when it is light.
As a result, many
- Fall asleep on the job,
- Have accidents during the shift
- Become injured themselves
- Cause injury to others
- Fall asleep during commuting to and from work
Consequences and Health Risks associated with SWSD
- Work-related Mistakes
- Increase in Sick Leave/Time Off
- Decreased Productivity
- Mood Disorders
- Heart Disease
- Gastrointestinal Disorder (30)
We even have an official wording Shift Work Sleep Disorder.
For the record – this type of Sleep disorder usually occurs in night shift workers.
Those that work between 10pm and 6am.
We do not need to bang on about the disruption we create, when we choose to be awake instead of sleeping.
Surely we cannot be alarmed or surprised that “people generally have great difficulty adjusting to this type of Sleep schedule, especially if they are transitioning from regular working hours to night shift”.
Common sense would tell us it is Simple.
To stay awake we have to ingest something as internally everything is winding down to rest and Sleep – giving us the space to not be active or in physical or mental motion.
WHY on earth would anyone choose to operate when it is dark outside and Sleep when it is light outside?
Where is our personal Responsibility when we know that falling asleep in any job is serious?
Where are our employers not taking Responsibility if they know (yes they do know) that their night shift workers are likely to have
- Make Mistakes
- Heart Disease
- Sick Leave
- Time Off
- Mood Disorders
- Gastrointestinal Disorder
AND above all DECREASE IN PRODUCTIVITY?
Are we not in business to profit and keep the shareholders tanked up with more money?
Is that not the way businesses have been operating thus far?
So how are we going to continue if night shift workers are making Mistakes and taking time off – all of which affects production?
What Solutions are we coming up with and who wins?
Are there really any winners in this game we have created?
Nothing makes sense and yet we seem to just continue on looking for Solutions to prop up what is not working, will never work because it was never designed to work.
We keep demanding and relying on more research to tell us what we know and loathe to admit as we are doing nothing other than delaying our own evolution.
Social Jet Lag
More on this in our forthcoming Book –
The Real Truth about Sleep
Social jetlag is the name given to the condition in which Sleep patterns vary widely between workdays and weekends or holidays, with sleep deprivation on weekdays being compensated for by a lie-in on weekends. This can severely confuse and disrupt the natural circadian rhythms of the body, with harmful metabolic effects. Such effects include Obesity and Diabetes, which are more common in such individuals. (31)
Shift Work, Sleep Disturbances and Social Jetlag in Healthcare Workers
One of the explanations of shift work-related Sleep problems is the discrepancy between the circadian and work-enforced sleep times – i.e. social jetlag.
Wittmann, Dinich, Merrow & Roenneberg, 2006 (32)
This discrepancy is large in shift workers, because their circadian rhythm generally remains synchronised with the light-dark cycle and hardly adjusts to the imposed sleep and activity patterns.
Akerstedt, 2003; Folkard, 2008 (32)
Previous research has shown that chronotype, the inter-individual variation in circadian preference, explains part of the variance in both social jetlag and sleep parameters in shift workers.
Juda et al., 2013 (32)
One study observed larger social jetlag and shortened sleep duration during night shifts in morning chronotypes than in evening chronotypes. Besides chronotype, age is related to shift work tolerance (e.g. sleepiness, performance, recovery after work) and sleep disturbances.
Saksvik, Bjorvatn, Hetland, Sandal & Pallesen, 2011 (32)
A few studies observed sleep duration during night shifts to decrease with increasing age.
Park, Matsumoto, Seo, Cho & Nosh, 2000; Parkes, 2002 (32)
This might be explained by the differences in sensitivity to the circadian effects on sleep and sensitivity to sleep loss by age.
Shift workers had a similar average sleep duration but their Sleep duration was more often short (7 hours) and long (9 hours) compared with non-shift workers. These differences were found in morning but not in evening chronotypes and increased with older age.
The difference in social jetlag between shift and non shift workers on work days increased with increasing age.
Irrespective of the frequency of night shifts and years of night work, shift workers were sleeping much more often shorter (7 hours per day) and longer (9 hours per day) in the week they worked in night shifts.
This increased odds of short sleep duration was mainly due to short sleep between nights shifts, which was compensated by shift workers the day before and the day after a block of night shifts.
The recovery sleep was in particular long the day after a block of night shifts, when most shift workers slept approximately 5.2 hours in the morning and had a longer main sleep duration than usual at night. These recovery sleeps explained the increased sleep duration relative to sleep need after a block of night shifts and the longer sleep duration of shift workers compared with non-shift workers. Thus, the sleep patterns in shift workers were disturbed by additional short sleep periods, decreased duration between night shifts and a longer sleep period after a block of night shifts.
Older shift workers, not younger workers, had a larger sleep debt between night shifts, compared with work-free days due to a decreased sleep duration between night shifts.
Previous research was extended by showing that social jetlag due to night work increased with older age.
In summary – these findings imply that older shift workers may have more difficulty with adjusting to night work than their younger colleagues, which leads to a larger social jetlag and shorter sleep duration between night shifts.
These findings have public health and occupational safety implications.
Sleepiness and fatigue due to sleep disturbances caused by shift work are considered major risk factors for work injuries and accidents.
Berger & Hobbs, 2006; Wagstaff & Sigstad Lie, 2011 (32)
Observed sleep disturbances in shift workers may lead to multiple hormonal and metabolic disturbances, which in turn increase the risk of chronic diseases, such as Cardiovascular Disease and metabolic syndrome.
Preventative strategies are needed to counteract sleep disturbances caused by shift work. Such measures may include maximising rest by taking strategic naps and avoiding blocks of consecutive night shifts.
Boivin & Boudreau, 2014 (32)
Social Jetlag and Sleep Debts are Altered in Different Rosters of Night Shift Work
The study confirms that partial sleep deprivation is a common consequence of shift work. Very high daily sleep debts were observed for long working hours in fast-rotating 12 hour shifts, especially after night shifts. Sleep quality was especially reduced in permanent night shift workers compared with shift workers of other rosters. (33)
The following section is well worth taking note of.
This is very serious and what have we learned, if we are continually seeing more incidents of this kind happening?
What we have are world disasters where night shift workers with sleep deprivation or sleep disorders most likely contributing to the mistakes made that led to “catastrophic events in recent history”?
How Sleep Influenced Major Disasters
Sleep deprived workers –
70% more likely to be involved in work-related accidents.
Workers reporting disturbed sleep and excessive daytime sleepiness are almost twice as likely to die in a work-related accident.
$4 billion – associated costs of work-related accidents, injuries and lost productivity, per year in the U.S. for the effects of shift work on workers’ sleep.
Shift workers are even more susceptible to the effects of Sleep deprivation than an average day-shift worker because of disruptions to their natural sleep patterns by working nights or long and irregular hours.
Workers are most susceptible to Sleep-related accidents between midnight and 8am. (34)
Drowsiness, fatigue and falling asleep are threats posed to most individuals during tasks where they may be responsible for their own lives and those of a few others, such as driving.
For people working on operations such as cargo ships, passenger jets, trains, nuclear power plants and oil refineries, losing attention for even a second can be catastrophic.
Since the 1980s, investigations into various high profile disasters have revealed contributing factors to include Sleep deprivation and Sleep disorders. Some of the most catastrophic events in recent history have been partially or totally attributable to errors caused by fatigued operators and managers.
The following are real life stories of 4 major disasters:
1. The Challenger Explosion
When: January 28th 1986, 11:39 AM local time
Where: Cape Canaveral, Florida
Event: 73 seconds into its 10th flight, the Space Shuttle Challenger broke apart due to a structural failure experienced at launch.
Losses: All 7 crew members killed | $3.2 billion in property loss/damage
How Sleep Was Involved: The official report on the Challenger accident by the Presidential Commission reviewed multiple factors in the decision-making process behind the disaster. Interviews were conducted that “revealed that because of the launch scrub on January 27 certain key managers obtained only minimal sleep the night before the teleconference or had arisen so early in the morning that they had been awake and on duty for extended periods.”
The report cites that early morning shift work and time pressure were faced by engineers and managers and subsequent sleep loss directly contributed to poor judgement.
2. Exxon Valdez Spill
When: March 24th, 1989, 12:04 AM local time
Where: Prince William Sound, Alaska
Event: On its route to Long Beach, California, the Exxon Valdez oil tanker struck Bligh Reef, releasing 10.8 million gallons of crude oil into the sound (Prince William, Alaska).
Losses: 10.8 million gallons of crude oil | 1,300 miles of coastline polluted | $2 billion spent on clean up.
How Sleep Was Involved: The tanker’s crew had been working round the clock and recorded very little sleep within the prior 16 hours. In fact, given their sleep deprivation, none of the crew could take a bridge watch legally when the accident occurred. The Third Mate, who was manning the tanker’s controls at the time of the accident, had only been able to take a “catnap” for a couple of hours.
3. American Airlines Flight 1420 Crash
When: June 1, 1999, 9:41 PM local time
Where: Little Rock National Airport, Arkansas
Event: While landing at the Little Rock airport during inclement weather, AA Flight 1420 overran the end of the runway and crashed into the airport and civilian infrastructure.
Losses: The captain and 10 passengers killed | over 100 injured | $10.7 million aircraft destroyed.
How Sleep Was Involved: The National Transportation Safety Board (NTSB) official report cited “impaired performance resulting from fatigue” along with inclement weather as a contributing factor to the crash. Both captain and first officer were deemed more error-prone at the time of the accident, as they had been awake and working for over 16 hours prior.
4. Metro-North Train Crash
When: December 1, 2013, 7:19 AM local time
Where: Bronx, New York
Event: Heading southbound on the Metro-North Hudson Line near the Spuyten Duyvil Station during the morning commute, passenger train 8808 derailed while heading around a curve at 82 mph.
Losses: 4 fatalities | 61 injuries | $9 million in property damage
How Sleep Was Involved: In the investigation, the train conductor was found to have failed to stop the train due to fatigue from undiagnosed Severe Obstructive Sleep Apnoea (OSA). The NTSB official report mentioned the conductor having multiple OSA risk factors, including:
- Male Gender
- Complaints of Fatigue
- Excessive Daytime Sleepiness
Also, the conductor had recently switched from working night shifts to early morning shifts, which can disrupt the circadian rhythm and cause drowsiness. (35)
1979 – Three Mile Island Nuclear Power Plant accident in Pennsylvania
1986 – Chernobyl Nuclear Power Plant disaster in the former USSR (36)
Three Mile Island remains the most serious United States incident in a commercial nuclear power plant. Between the hours of 4am and 6am on March 28, 1979, shift workers at the Three Mile Island Plant Unit 2 Reactor in Pennsylvania failed to recognise the loss of core coolant water resulting from a stuck valve. Although the problem was precipitated by a mechanical problem, human error was chiefly to Blame for the flawed corrective action that caused the near meltdown of the reactor later that morning.
1985 – after the Davis-Besse reactor in Ohio went into automatic shutdown at 1:35 am, an operator pushed the 2 wrong buttons in the control room, which defeated the function of the auxiliary feed-water system. Although corrective action eventually stabilised the reactor, the subsequent combination of equipment malfunctions and human errors made the situation dangerous.
The accident at the Chernobyl Nuclear Power Plant in Ukraine is considered the worse nuclear disaster on record.
30 people died | 350,000 evacuated.
$13 billion spent on recovery and environmental clean-up.
Increase rates of Cancer and birth defects as a result of the accident are still being debated (2013).
The disaster began to unfold at 1:26 am on 26 April 1986 when a power surge led workers to initiate an emergency shutdown, causing the vessel in Reactor 4 to rupture, expose the core and explode.
The International Nuclear Safety Group determined that human error related to Sleep deprivation was a factor in the accident. (37)
The effects of sleep deprivation are well understood and we know that many nuclear accidents occur early in the morning as a result of human error.
Further, reports on well-understood engineering accidents such as the Challenger disaster have explicitly pointed towards Sleep deprivation as playing a major role. These phenomena seem more than coincidental.
In public and government debates following serious nuclear incidents, the emphasis is consistently placed on the extent to which technological failures and policy decisions contributed to the catastrophes. While important, they do not abrogate the Responsibility to attend to factors such as Sleep deprivation, which have played a role in increasing the incidence of human error. (38)
India’s first major industrial disaster
When: 3 December 1984 | 12.30am
Where: Union Carbide, India’s pesticide plant in Bhopal, Madhya Pradesh
Event: Gas Leak (36)
Chemical, methyl isocyanate (MIC) spilt out from Union Carbide India Ltd’s (UCIL’s) pesticide factory and turned the city of Bhopal into a colossal gas chamber.
Losses: 30 tonnes of methyl isocyanate gas killed more than 15,000 people and affected over 600,000 workers. Bhopal gas tragedy is known as the world’s worst industrial disaster.
The stillbirth rate and the neonatal mortality rate increased by up to 300% and 200% respectively.
The gas leak impact trees and animals too. Within a few days, trees in the nearby area became barren. Bloated animal carcasses had to be disposed of.
People were running on the streets, vomiting and dying.
The city ran out of cremation grounds. (39)
How Sleep Was Involved: Caused by inattentive workers who failed to respond as a storage tank overheated. Incident occurred at 12.30am. (37)
Where: North Atlantic Ocean (40)
The ship was on its way from Southampton to New York (41)
Event: RMS Titanic Hit an iceberg and sunk
Losses: 1,503 people died out of 2,208 passengers (40)
How Sleep Was Involved: Incident happened just before midnight (42)
The ship’s radio operator dismissed a key iceberg warning (43)
Health and Safety Issues
Only 1,178 lifeboats available for 2,208 passengers
The RMS Titanic ignored 6 iceberg warnings before it crashed head first into an iceberg at full speed. (40)
NOTE – there is a commonality with these disasters mentioned above. There are many more but these have made big Media headlines at the time. ALL have a link to night shift workers operating in the early hours, at a time when we are naturally designed to be sleeping.
How many more disasters do we need to wake up and realise that human error will continue if the human being is operating in an un-natural state?
That means working against our natural Sleep wake cycle.
How are we going to address this going forward?
Is there Another Way to minimise night shift work across ALL industries?
Are we ready for a major shift in global operations and services that create un-necessary human error, because the being is working against their natural body clock?
WHY do we bother to have public and government debates following serious incidents where the EMPHASIS is consistently placed on the extent to which technological failures and policy decisions contributed?
WHY are our governments and those in the industry where these disasters occur, not addressing and bringing to light the most obvious possible fact, that human error is happening in these situations BECAUSE the human Being is operating against their natural Sleep wake cycle?
WHY are we as a world not demanding more answers and WHY are we accepting these disasters without addressing the root cause of how and WHY they are occurring?
Before we dismiss them as “yes lessons have been learned, let’s just move on” we ought to be reminded of the loss of life and the devastation that happens to the Families and all those involved when disasters of this kind occur.
Add to that the environmental damage and the costs involved, can we admit that we are not winning in any way and above all, we are not yet learning the lessons that come from world disasters such as these?
The largest supermarket with over 4,000 stores has made the move to stop night shift in 80 stores and 40 fuel stations.
Overnight stock replenishment will now be done during the daytime in 36 large stores and 49 convenience stores. In addition, 36 stores will be converted to be a “pay at the pump only” during night hours.
This great news is part of job cuts as the organisation is making effort to save £1 billion in costs over the next few years to fend off competition from discounter supermarkets.
This industry is going towards being more productive and this means less people working, more digitisation and automation. In other words, robots at the tills and less humans involved where possible. (44)
We could say this is a great sign. A supermarket bringing Change by stopping night shift work in 80 stores and it has according to a quick google search, almost 5,000 stores.
However, this move to stop night shift work is NOT because of taking care of staff’s health and well-being. No – this is simply to save money and as night shift work pays more, cutting jobs in this sector will help the organisation. They also plan to replace humans with robots in the future.
AND finally, to wrap up this chapter from Book 2
The evidence presented in this article confirms that there is nothing that supports our health and well-being when we work night shifts.
Night shift work is on the increase because we now live with a demand for 24/7 goods and services. FACT.
This means the suppliers meet the demand by working all hours, around the clock with little or no regard to what it means to adhere to our natural body cycles and rhythms.
Back in the old days, we had to Sleep as the candle would only burn for a limited time.
That means we went to bed at night time and we respected that part of our day.
When we got electricity we started to extend our natural limits by staying awake 24/7 and finding activity instead of honouring our Sleep. Today we have taken that way of living to off the scale epic proportions and messed up our sleep. Reminder – we have created a multi-billion dollar sleeping aids industry because we have sleep issues.
We want our night shift workers because we demand to have our goods when we want them. We don’t like waiting and we don’t care if another has to work at night as long as we get what we want, when we want as that suits us.
What if suppliers just told us – no choice, join the queue and wait?
Could we get used to that and know that other fellow humans get to live with a quality of sleep that would not be possible if we continued to make unreasonable demands, which meant they have to work at night time?
What if we all started to take more responsibility for Lifestyle Choices when it comes to our health and well-being?
What if we started being more sensible and this meant less need for visits to Accident & Emergency in the night, and fewer night shift staff needed?
This article is bringing awareness by confirming that there are enough scientific studies telling us that night shift work comes with health consequences.
For those of us currently engaging in night shift work or contemplating working at night because it suits us or we like the sound of more money – time to ask some serious questions –
Is it worth it and at what cost to the human frame?
(1) Ray, D. (2020, July 7). Addressing the Health Impacts of Night Shift Work. www.blog.policy.manchester.ac.uk Retrieved February 25, 2022 from
(2) (2014, June 30). Shiftwork. Better Health Channel. Retrieved February 7, 2022 from
(3) Smith, R. (2018, February 12). Working Night Shifts Could Be Killing You – Here’s Why. World Economic Forum. Retrieved February 14, 2022 from
(5) (n.d). Working at Night. www.nidirect.gov.uk Retrieved February 19, 2022 from
(6) (2021, August 16). Night Shift Work is Linked to Increased Risk of Heart Problems. Science Daily. Retrieved February 19, 2022 from
(7) (2020, November 16). Permanent Night Shift Workers at Heightened Risk of Moderate to Severe Asthma. British Medical Journal (BMJ). Retrieved February 21, 2022 from
(8) (2018, October 27). Number of People Working Night Shifts Up by More Than 150,000 in 5 Years. www.tuc.org.uk Retrieved February 19, 2022 from
(9) Gallagher, J. (2014, January 21). Night Work ‘Throws Body into Chaos’. BBC News. Retrieved February 20, 2022 from
(10) Buxton. O.M., Cain, S.W., O’Connor, S.P., Porter, J.H., Duffy, J.F., Wang, W., Czeisler, C.A., & Shea, S.A. (2012, April 11). Adverse Metabolic Consequences in Humans of Prolonged Sleep Restriction Combined with Circadian Disruption. Science Translational Medicine. Retrieved February 20, 2022 from
(11) (n.d). What Working Through the Dead of Night Does to Your Body. www.bbc.com Retrieved February 19, 2022 from
(12) Satyanarayana, M. (2018, May 7). Stubborn Genes: New Research Looks at How Our Bodies Respond (or Don’t) to Night Shift Work. www.statnews.com Retrieved February 4, 2022 from
(13) Gallagher, J. (2012, April 11). Shift Workers ‘Risking’ Type 2 Diabetes and Obesity. BBC News. Retrieved February 20, 2022 from
(14) Rosa, D., Terzoni, S., Dellafiore, F., & Destrebecq, A. (2019, May 27). Systematic Review of Shift Work and Nurses’ Health. Occupational Medicine. 69(4) 237 – 243. Retrieved February 3, 2022 from
(15) Copertaro, A. Lavoro a turni e notturno: valutazione del rischio e sorveglianza sanitaria. Buccino, Italy: BookSprint Edizioni, 2013.
(16) Feng, H., Qi, X-X., Xia, C-L., Xiao, S-Q., & Fan, L. (2021, April 28). Association Between Night Shift and Sleep Quality and Health Among Chinese Nurses: A Cross-Sectional Study. Journal of Nursing Management 29(7) pages 2123 – 2131. Retrieved February 9, 2022 from
(17) Erren, T.C., Falaturi, P., Morfeld, P., Knauth, P., Reiter, R.J., & Piekarski, C. (2010, September 24). Shift Work and Cancer. NCBI. Retrieved February 19, 2022 from
(18) (2019, July 5). IARC Monographs Meeting 124: Night Shift Work (4 – 11 June 2019). International Agency for Research on Cancer. www.iarc.who.int Retrieved February 19, 2022 from
(19) Lawson, C.C., Whelan, E.A., Carreón-Valencia, T., & Caruso, C.C. (2021, April 27). Recent News About Night Shift Work and Cancer: What Does it Mean for Workers? www.blogs.cdc.gov Retrieved February 3, 2022 from
(20) Washington State University. (2021, March 8). Insights on How Night Shift Work Increases Cancer Risk. www.sciencedaily.com Retrieved February 20, 2022 from
(21) Resuehr, D., Wu, G., Johnson, R.L., Young, M.E., Hogenesch, J.B., & Gamble, K.L. (2019, February 4). Shift Work Disrupts Circadian Regulation of the Transcriptome in Hospital Nurses. Journal of Biological Rhythms 34(2). Retrieved February 9, 2022 from
(22) (n.d). The Free Dictionary. Retrieved February 9, 2022 from
(24) Arbor, A. (2015, January 5). Rotating Night Shift Work Can Be Hazardous to Your Health. Elsevier. Retrieved February 20, 2022 from
(25) National Institutes of Health. (2021, December 11). Eating Daytime Meals May Reduce Health Risks Linked to Night Shift Work. Scitech Daily. Retrieved March 2, 2022 from
(26) Liverpool, L. (2018, July 9). Nightshifts Disrupt Rhythm Between Brain and Gut, Study Shows. The Guardian. Retrieved February 21, 2022 from
(27) (2012, July 27). Shift Work Linked to ‘Increased Risk of Heart Problems’. BBC News. Retrieved February 20, 2022 from
(28) (2012, July 26). Shift Work Linked to Increased Risk of Heart Attack and Stroke. British Medical Journal (BMJ). Retrieved February 20, 2022 from
(29) (2019, March 25). Pregnant Women Who Work Nights May Have a Greater Risk of Miscarriage. British Medical Journal (BMJ). Retrieved February 20, 2022 from
(30) (2017, April 6). Shift Work Sleep Disorder (SWSD). Michigan Head and Neck Institute. Retrieved February 9, 2022 from
(31) Thomas, L. (2019, March 21). Social Jetlag and Sleep. www.news-medical.net Retrieved February 14, 2022 from
(32) Hulsegge, G., Loef, B., van Kerkhof, L.W., Roenneberg, T., van der Beek, A.J., Proper, K.I. (2018, December 5). Shift Work, Sleep Disturbances and Social Jet Lag in Healthcare Workers. Journal of Sleep Research 28(4). Retrieved February 14, 2022 from
(33) Casjens, S., Brenscheidt, F., Tisch, A., Beermann, B., Brüning, T., Behrens, T., & Rabstein, S. (2022, January 7). Social Jet Lag and Sleep Debts are Altered in Different Rosters of Night Shift Work. www.journals.plos.org Retrieved February 14, 2022 from
(34) Schaible, R. (2015, January 14). Shift Work, Sleep Deprivation, and Industrial Accidents – Expert Article. www.robsonforensic.com Retrieved March 12, 2022 from
(35) (2019, November 21). How Sleep Influenced 5 Major Disasters. www.somnology.com Retrieved February 19, 2022 from
(36) (n.d). Coping with Shift Work. UCLA Health. Retrieved February 19, 2022 from
(37) Jamieson, V. (2013, January 30). Nightmare Images Show How Lack of Sleep Kills. www.newscientist.com Retrieved February 19, 2022 from
(38) Walker, C. (2017, May 24). Nuclear Accidents and Sleep Deprivation. www.large.stanford.edu Retrieved February 19, 2022 from
(39) (n.d). What Was Bhopal Gas Tragedy? Business Standard. Retrieved March 2, 2022 from
(40) Safety. (n.d). Five of the Worst Workplace Disaster in History. Donesafe News. Retrieved March 2, 2022 from
(41) Boyle, A. (2012, April 2). 10 Causes of the Titanic Tragedy. NBC News. Retrieved March 2, 2022 from
(42) (2021, April 13). Titanic Sinks. www.history.com Retrieved March 2, 2022 from
(43) (2021, April 20). Why Did the Titanic Sink? www.history.com Retrieved March 12, 2022 from
(44) Butler, S. (2022, February 1). Tesco Ditches Night Shifts at 120 Sites, Putting 1,500 Jobs at Risk. The Guardian. Retrieved February 15, 2022 from