If you work nights, you already know how tough it can be. The tiredness hits differently, your routines fall apart and even your days off feel upside down.
But you are not stuck, and you’re definitely not alone.
Researchers have learned a lot about how to help night workers stay healthy and clear headed. This guide breaks it down in simple, practical steps so you can get through your shifts feeling steadier and more in control.
Shift work means businesses and organisations can be productive for 24-hours a day. It was initially adopted to protect camps or cities against predators, enemies or disasters.
Since the industrial revolution and the development of artificial lighting, manufacturing, service and retail sectors have used shift work to increase productivity and profitability, and provide continuous health care and emergency services.
Around 20% of the workforce are now shift workers, with 25-30% of those working nights.
But working when you’re supposed to sleep and rest disrupts your normal physiology.
Before the 1990s, little was known about the impact of shift work on health.
Then a landmark study using clinical data from the mid-1990s found nurses working at night had an increased risk of breast cancer. This risk increased with the number of years spent performing shift work.
This and other studies led the International Agency for Research on Cancer to conclude in 2007 that night shift work should be classified as “probably carcinogenic to humans” (Group 2A), meaning experts suspect it increases the chance of cancer. This statement was confirmed in 2019.
Since then, studies have shown shift work, particularly rotating shift work, also increases the risk of heart disease, obesity and type 2 diabetes, dementia, and overall premature death.
It is also associated with decreased alertness and a higher risk of accidents.
Growing evidence points to the disruption of the circadian clock caused by being active or awake at night when we are supposed to sleep.
During evolution, living species – from bacteria and plants to humans – have acquired a circadian clock to optimise bodily processes in an environment that changes throughout the day.
Consequently, almost all aspects of behaviour, physiology and metabolism are rhythmically organised to anticipate these daily changes.
Muscle strength, the immune system, and cognitive performances, for example, are higher during the day when the body is also storing nutrients from food. These functions decrease in the night when the body starts to use the stored nutrients during this period of fasting.
These circadian clocks are present in almost every cell of our organism. The central clock in the brain acts as a kind of conductor of an orchestra that synchronises all these clocks and is synchronised every day by the environmental light.
If these clocks now get input from other sources like food at night, or if the conductor gets distracted with something like light during the night, this synchrony gets lost.
This leads to increased weight gain, type 2 diabetes, increased blood pressure, and compromised immune response. This is seen even in cases of low-intensity light in the bedroom such as a TV screen.
In studies using animal models, this lost synchronicity leads to an increased incidence of breast cancer and faster tumour growth. It also exacerbates the symptoms of Alzheimer’s disease in studies of mice.
There is no simple explanation, and it likely involves multiple components.
Like in animal models, the disruption of the well-organised physiology caused by light at night or feeding at the wrong time disturbs the organs’ natural function, particularly the capacity to store and use nutrients during the proper period.
Circadian disruption is also associated with a disturbance of the autonomous nervous system that orchestrates our basic functions like breathing or keeping our heart beating. This impacts the connection between the brain and surrounding tissues, and their proper function.
Finally, shift-work simulation in humans showed an impact on the immune system. This contributes to a higher risk of infection among shift workers, notably COVID, and could also play a role in cancer progression.
Altogether, this contributes to a globally increased predisposition to several illnesses, including cancer diabetes and heart disease.
The circadian clock also plays a critical role in the efficacy and toxicity of most drugs, including cancer chemotherapy. And a sustained circadian rhythm impacts the response to treatments.
The first step should be to limit rotating shift work as much as possible. While people can adapt to work at the “wrong” time to some extent, it’s impossible to adapt to schedules that constantly change.
Several trials studying the impact of lighting showed bright light increases alertness during the night and help the organisms to adapt to night work by shifting the phase of the circadian clock. However the long-term impact on health is still to be determined.
Controlling and limiting the time during which people are eating (for example ten hours during the day and not eating overnight) appears to be a promising approach that could be beneficial for heart and metabolic health, and seems compatible with shift work. It also reduces tumour growth in animal studies of breast cancer.
This article is republished from The Conversation under a Creative Commons license. Read the original article.
A British study of more than 100,000 women over ten years finds “no overall link” between cancer and night work.
A link between night shift work and breast cancer risk was first proposed 30 years ago. Studies since then have been inconclusive.
The Institute of Cancer Research in Britain conducted the latest study. It was published in the peer-reviewed British Journal of Cancer.
“In our new study we found no overall link between women having done night shift work in the last 10 years and their risk of breast cancer, regardless of the different types of work they did involving night shifts, and the age at which they started such work,” the researchers said.
They also found no significant difference in risk relating to the type of night shift work, the age at which the work was started, or whether it began before or after a first pregnancy.
Delyth Morgan, chief executive at Breast Cancer Care and Breast Cancer Now, which funded the study, said: “We hope these findings will help reassure the hundreds of thousands of women working night shifts that it’s unlikely their job patterns are increasing their risk of breast cancer.”
This article was originally published in the NSW Nurses and Midwives’ Association publication, Lamp.
Adjusting health care work as a newly qualified registered nurse can be challenging for many reasons.
While adjusting to the professional role is difficult in its own right, add in the extra element of shift work and it’s not surprising that the words ‘culture shock’ are often used to describe the new grad experience. There really aren’t many professions like nursing that have such a difficult pattern of shift work hours. Even compared to other shift workers, nursing shift hours in acute and aged care stand out as being some of the most difficult to manage. It is common place to see weekly rosters with mixes of morning and evening shifts. Night shifts provide another layer of complexity. Other professions with a requirement to provide services 24/7 have moved over to a slightly more palatable shift pattern where weeks of early shifts, late shifts, and night shifts are sequentially rotated. Not nursing. For the most part our shifts remain jumbled together and provide little opportunity for establishing routine.
Quite understandably, many newly qualified registered nurses find that the adjustment to shift work, especially night shift, is the most difficult element of their first year. They may find that it’s rarely talked about or the difficulties acknowledged. It’s not that no one cares or is not experiencing the same level of work / life chaos. It’s just that experienced registered nurses who have done shift work for years have probably become somewhat desensitised to the overwhelming exhaustion that comes with being in a constant state of sleep deprivation and severely disrupted circadian rhythms. After a while, even the abnormal starts to feel normal.
The key to surviving shift work is sleep, good quality sleep is vital for those required to do shift work. The focus must always be on getting enough good quality sleep to avoid severe fatigue. Many nurses who work night shifts have developed a range of techniques over that time that can help to achieve good quality sleep during the day. As we all sleep better at night, most nurses who do shift work would agree on some basic strategies to aid day-time sleeping.
Most nurses who do shift work find that it helps if the room you are sleeping in during the day is dark. Black-out curtains are best, but some find eye masks can create the same effect. It can also help if the room you are sleeping in during the day is cool. As body temperature naturally drops at night, making the room as cool as possible can re-create a more ‘night-time’ sleeping environment.
Some nurses also swear by actively tricking the subconscious brain into believing its night-time. I’ve known nurses who eat the equivalent of an evening meal and drink a glass of wine after a night shift. Many other nurses watch typical night-time TV programmes before drifting off to sleep. It may take some time to develop coping strategies for adjusting to shift work, however like everything related to the new grad experience, things do tend to improve with time.
Kath Sharples is the owner of Health Education Consultants Australia
Researchers from the Sleep and Chronobiology Laboratory at the University of South Australia examined whether meal timing could improve how shiftworkers performed and felt during the evening.
Lead researcher Charlotte Gupta said they observed 44 healthy, non-shift working adults at the University of South Australia Sleep Lab across seven days.
“We put them on a shiftwork schedule and we had them stay awake overnight and sleep during the day,” Gupta said.
“We had them do a lot of performance tests and give us ratings on how they were feeling.
“We had three groups: one that was given a big meal during the night, one that had a smaller snack and one that didn’t eat.”
While Gupta said all three groups received the adequate number of calories during a 24-hour period, the time participants ate their main meal varied.
The Australian Bureau of Statistics shows 1.4 million Australians list shiftwork as their main job, with 15 per cent regularly working a night or evening shift.
“In today’s 24/7 economy, working the nightshift is increasingly common, with many industries – healthcare, aviation, transport and mining – requiring employees to work around the clock,” Gupta said.
“We know that many nightshift workers eat on-shift to help them stay awake, but until now, no research has shown whether this is good or bad for their health and performance.
“This is the first study to investigate how workers feel and perform after eating different amounts of food.
“The findings will inform the most strategic eating patterns on-shift and can hopefully contribute to more alert and better performing workers.”
Gupta said the researchers were particularly interested in the participants’ level of hunger, gut reaction and sleepiness after eating at 12.30am.
She said participants who had a snack just after midnight felt more awake than the other two groups, were the most satisfied with the amount of food and had the best mental performance.
“They were reacting faster. We had them do a driving simulator and they were driving safer. So, there were less crashes and they were staying in the speed limit with that small snack, opposed to the big meal,” she said.
“Those that didn’t have any food performed better and more alert than those that had the big meal but the snack group still felt and performed the best.”
Participants given the main meal received 30 per cent of their required energy intake in one sitting, while those who got the snack received 10 per cent of their energy intake. One group were given no food at 12.30am.
Despite performing better after eating a snack, Gupta said people should not try applying the same eating routine to meals during the day.
“We find there is always that post lunch lull in alertness, which is just part of our circadian rhythm. We just feel sleepier at that time of day,” she said.
“Having a really big heavy meal can make us feel sleepier, but the body is also primed to be digesting food and it wants to be digesting food and digesting it during the day.
“But at night when our body isn’t fine to be digesting food that’s when a snack is better.”
The circadian rhythm is a 24-hour cycle that regulates when people sleep, eating habits and digestion, body temperature and other bodily functions.
Gupta said the next step would be to examine what type of snacks are best for shiftworkers.
“We gave people a muesli bar and an apple, which is a fairly healthy snack, but we know that many shiftworkers are limited in what they can buy, or are getting food from vending machines,” she said.
“There’s also a craving during the middle of the night, when you’re working a hard night shift, for chocolate or something a bit more exciting to eat. So, we want to know what the different types of snack do in how people perform during the night.”
Gupta said the study followed research which showed not eating anything at all of an evening was better than having a large meal.
“Telling people not to eat during the night can be a hard recommendation and is quite restricting, so we wanted to look at whether a small amount of food would be better,” she said.
People who are genetically programmed to be early risers have a lower risk of schizophrenia or depression, according to a large new genetics study.
“Being a morning person is causally associated with better mental health,” an international team of researchers has reported in the journal Nature Communications.
The study of nearly 700,000 people found 324 new genes associated with the body clock on top of the 24 genes already known to influence whether someone is an early riser or a night owl.
The study found that being biologically programmed to wake up early is linked to greater happiness and a lower risk of schizophrenia and depression.
The researchers said night owls may be at greater risk from the mental toll of having to fight their natural body clock due to most schools and workplaces having early start times.
Ian Hickie of the Brain and Mind Centre at the University of Sydney told the ABC that the genetic study backed up what psychiatrists had long thought: that mood disorders were linked to circadian rhythms, not sleep disorders.
“They’ve finally cracked the nut by saying ‘you know what, we were looking at the wrong thing’. It’s not sleep, it’s the body clock,” he said.
Being an evening person does not mean you are poorly motivated, Professor Hickie said.
“There is an idea that morning people are all good, hardworking people, but they are just genetically set that way.”
