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Night shift: the dangers of working around the clock

A growing number of us work nights or irregular hours — but at what cost?

Robert lives with his girlfriend of 10 years and an attention-seeking black cat in their small flat. The 31-year-old from Nantes, France, likes reading science fiction and discussing world affairs on Reddit, the online chat room. In fact, the internet is where Robert gets most of his conversation these days. Because Robert’s life is back to front.

At 4pm, while I’m at my desk daydreaming about dinner or seeing friends that evening, Robert is waking up. He starts his shift as a factory security guard at 7pm and is on duty for 12 hours, alone apart from a few truckers picking up orders. He patrols the dark and deserted site, looking for intruders; twice he’s dealt with fires.

After he’s driven home, Robert snacks and then spends a few hours reading. And by the time I’m wide awake and working, Robert is struggling to get to sleep at 10am. “Now I get to see the light a little,” he says. “In the winter, not so much.” Robert (not his real name) belongs to an army of night workers, invisible to those of us who clock in by day.

Across Europe, almost one in five workers are employed on night shifts. In 2004 (the most recent data available) approximately 8 per cent of Americans worked nights or evenings, as do a slightly higher proportion of South Koreans. In the UK, night working is significantly higher among black people — one in six black workers undertake night shifts, according to research by the Trades Union Congress, compared with one in nine across the whole population.

But working through the night is a fundamental challenge to the human body. It unsettles our finely tuned biology, forcing us to be active when powerful impulses are telling us to lie down and dream. A growing body of research links a lack of sleep to increased morbidity — an average of less than six hours sleep per night in the long term puts you at a 13 per cent higher mortality risk than someone getting seven to nine hours, according to the research organisation Rand Europe.

As a cause of profound sleep disruption, shift work has been found to put people at a higher risk of chronic disease and mental illness. As early as 2007, the World Health Organisation identified the effect of night-shift work on the body’s rhythms as a ­possible carcinogen.

As a night worker, “you are in a somewhat precarious situation”, explains Derk-Jan Dijk, professor of sleep and physiology, and director of the University of Surrey’s sleep research centre. “Not only do you have to work at night when the circadian system would sleep, you have to work at night when you are already sleep-deprived.”

It is not yet clear precisely what causes shift workers to end up more at risk of disease, and it is difficult to unpick the socio-economic factors that may contribute (people with lower incomes are far more likely to be doing shift work than wealthier people). However, “disruption [of our temporal programme] could very well be related to some of these adverse health outcomes”, says Dijk. “Being aware of those risks of shift work . . . should probably have an impact on how people do their business.”

Yet, if anything, the nocturnal workforce seems to be growing, as consumer businesses meet 24-hour demand for their services and manufacturers seek to maximise their investment in factories. In Britain, the number of night-shift workers has risen by more than 250,000 in the past five years, according to the TUC.

Stagnating wages and rising living costs in many developed economies are attracting more workers to the higher pay of night shifts, or to consider additional evening jobs. These roles often come with precarious contracts — many night workers who spoke to the FT requested anonymity, fearing repercussions from their employers.

As the health risks associated with this work become better defined by scientists, companies may face pressure to do more to protect their workers. “There’s an onus on employers to design shifts that actually promote sleep,” says Michelle Miller, associate professor at Warwick Medical School, who established the school’s “Sleep, Health and Society” research programme in 2005. “From a health economic view, [it] will be problematic if we have a whole cohort of people coming through with cardiovascular disease which could be avoided.”

After seven years, night shifts are taking a toll on Robert’s body and mind. Relying on Coca-Cola, junk food and cigarettes to stay awake, he has gained 10kg-15kg and become obese. In a phone call, he explained that he has steatosis or fatty liver, an uncomfortable condition where fat deposits lodge in your liver. “I’m a walking foie gras,” he jokes, grimly.

Despite the long night’s work, he struggles to fall asleep in his time off. “Sometimes I have periods where I can barely sleep five hours and I wake up tired but can’t sleep any more,” he tells me. “It leads to heavy sleepiness, even at work: I’ll be awake and, the minute after, I’ll be deeply asleep.”

Scientists fear people working nights are paying with their health in the long term. Sleep is not just the mind turning on and off. During the day, your brain shuffles information off to one side to be processed later; during sleep, it sorts and stores it.

The brain also does emotional processing and releases growth hormones for repair work on your tissues. So without enough sleep, your brain has little chance to make memories, organise your feelings or heal the body. Shift work’s disruptive impact on our circadian rhythms — the biological clocks in our cells — has been linked to increased infection and cancer risk and higher risk of heart disease and diabetes. It can also put pressure on relationships and lead to social isolation.

Although he can only work a 35-hour week under French law, Robert’s shift pattern, which includes working every other weekend, is antisocial. “I basically lost all my friends. I can’t even see them on weekends, as I work one in two, the other one being spent with my girlfriend. Sure, there are vacations, and sometimes I could make an exception and visit [friends] but, over time, I kept seeing them less and less.”

Robert already had depression and he reckons working nights has made it much worse. He also dislikes his job — it’s tedious, lonely and doesn’t pay well. Even with weekends and a 10 per cent night premium he nets just €1,350 a month. But with no savings, endless bills and a diploma that is no longer valid, he can’t see a way out.

Shift workers feel the cognitive effect of lacking sleep immediately. Sue Prynn, 56, worked night shifts at a factory near Liverpool for a decade. “I worked on manufacturing and distribution, making doughnuts would you believe,” she says, in a light West Country lilt. After 12 hours of packing baked goods amid clouds of flour, the din of machinery and spitting deep-fat fryers, fatigue would make her feel drunk.

Prynn chose to work nights because she was a sole parent who needed to take care of her four children during the day. In a 2004 US labour force survey, 626,000 of the 3.8 million people who worked between 9pm and 8am said they did so because it fitted in better with their childcare or family needs. A further 204,000 said it allowed them to attend school or college.

The downside is that many shift workers barely get to bed. Prynn was one of many night workers with young children and no spare cash for nursery. During holidays, or when her children were below school age, she would regularly end her shift, go straight into childcare and then return to work in the evening — adding up to more than 48 hours without rest.

“There was always something kicking off,” sighs Prynn. “It can be a bit difficult to control your family . . . If you asked my kids, I’m sure they’d say, ‘Mum [just] used to cook fish fingers.’ ” There was no time for slacking on the factory floor either: “If you [and your team] were behind plan, you’d have to come in on Friday night or Saturday morning”. Prynn would pop caffeine supplements called Pro Plus to keep her eyes open. She now works normal hours for the Union of Shop, Distributive and Allied Workers (Usdaw), but one of her daughters went on to work nights baking cookies and another became a live-in care worker, a role that also entails broken sleep.

Some types of night work are relatively new products of our post-industrial economy, such as jobs fulfilling orders at Amazon warehouses or working on the checkout at a 24-hour supermarket. Other professions, however, have long entailed a degree of shift working. Medicine is one of them. “My sleep is broken,” says Angelu Amancio, a psychiatric nurse in San Diego, California, who has worked nights since 2010. “I sleep for three or four hours, wake up, do lunch, have a nap before work.”

Amancio and his wife married in 2012, and “when it was just me and her it was fine . . . when you throw kids into the picture, that’s when it gets more difficult,” he says. “When we had our first kid I was still working nights and we were trying to save up money — we had just bought a house so we didn’t do the whole day-care thing. So there were times when I would have to watch my son during the day. When he would nap, I would nap . . . I was dead tired . . . there were days where I’d be up for 20-plus hours.”

On the eve of 2017, he was diagnosed with Hodgkin lymphoma (he does not link his illness to his shift pattern). After a year of treatment, Amancio is healthy again, back playing sport and working night shifts: his three children now attend day care so he can rest. “I feel like I don’t get to see my family enough. We have three kids now, and it’s become really stressful for my wife. She’s asked me to go for days. It’s something I’ve considered, but as far as what our bills are — day care, house payments, car payments… that night-shift differential, if I were to go to days it would make stuff that much more difficult.” Moving to days would mean $800-$1,000 less a month, he explains.

While the human body may have evolved to sleep in the dark, the modern economy does not stop when the sun goes down. We want to buy fresh doughnuts in the morning; we expect train lines to be mended and ready for our commute; we want our next-day delivery to be packed in warehouses and dispatched in postal centres. If I get hungry at 3.30am somewhere in London, I can type my order into an app and someone will bring pizza. Public services are expected to keep up: the UK’s health secretary has declared that the National Health Service.

“There’s been a growth of data which means employers can better predict what their demand will be and alter their labour supply to match that,” explains Alex Wood, a sociologist specialising in employment at the University of Oxford. “If employers are trying to boost their profits as much as possible by really targeting the labour on to those times when it’s profitable for clients, you then get a situation when people are only working a few hours a day.”

For instance, someone working in a high-street shop might only be called in to help for the busiest part of the day. In addition, Wood notes, trade union power has weakened in parts of Europe and the US, leading to less collective bargaining. So low-paid workers are left in insecure situations where they are not guaranteed work. Many companies have hired workers on “zero-hour contracts”, meaning that they have no obligation to give them shifts or provide benefits such as paid holiday or sick leave. “Lots of people want flexible jobs but often the reality is that, particularly in low-wage, low-end jobs, the flexibility is not for the worker,” says Wood. “It’s all for the employer.”

Russell Foster, a neuroscience professor at the University of Oxford’s Sleep & Circadian Neuroscience Institute, has spent decades working to understand the biological clocks that determine our sleep patterns. Now he is calling on employers to protect night workers. The human body clock has been calibrated over millennia to respond to changes in the natural environment — something that is forced wildly out of sync for people who regularly work night shifts.

These biological rhythms are like an orchestra, says Foster: “Shoot the conductor, everybody plays at a slightly different time. So you’ve got this cacophony rather than a symphony.” Foster accepts that you cannot put the 24-hour genie back in its bottle but he is trying to alert the world to what he sees as a growing health crisis. He entitled a recent presentation to a public health body “Sleep: We ignore this key aspect of our biology at our peril”.

In particular, he wants employers to do more to protect their workforces from future health impacts. Different people are more energetic at different times during the day: you might be an early bird or a night owl — an inclination that can be assessed by a process called chronotyping, using a simple questionnaire. “Why the hell do we not chronotype our workforce?” Foster asks over tea in his cosy home in Oxford, frustration breaking through his avuncular demeanour.

Even small things can help. If employers gave night workers access to decent meals rather than vending machines, workers could avoid the metabolism-disrupted slide towards obesity.

“I don’t understand why M&S has not produced a whole line of night-worker food,” says Foster.

With studies suggesting night workers are more likely to develop cancer, Foster thinks employers should provide more regular health checks. Analysis by researchers at West China Medical Centre of Sichuan University, published in January 2018, found that long-term night work increases the risk of cancer in women by 19 per cent.

Foster also suggests employers increase light levels in workplaces to help employees stay alert. He worries about night workers nodding off on the way home. “There’s a duty of care,” he says, after enthusing about Attention Assist, a drowsiness-detection system developed for drivers by Mercedes-Benz. “Why don’t employers provide such devices for their impaired employees?”

Sleepiness is associated with accidents — sometimes fatally. In 2010, 158 people were killed when an Air India plane overshot a runway at Mangalore, crashing into a ravine. Shortly before the attempted landing, internal recording picked up audio of the pilot snoring.

The Royal Society for the Prevention of Accidents estimates that driver tiredness contributes to up to a quarter of fatal and serious road accidents, while a study in Canada found that rotating and night shifts were correlated with higher rates of injury for workers. If companies don’t change their ways, Foster warns, they could meet a slew of litigation in future.

Need for night work will continue but there are economic reasons for encouraging a well-rested workforce. Rand Europe estimated in 2016 that the US economy was losing $411bn annually to sleepiness — some 2.3 per cent of gross domestic product.

Some companies are promoting healthy sleep practices among their workers. For example Aetna, the US health insurance company, started a bonus scheme for staff who show they have had at least seven hours sleep per night, using a wearable fitness tracker such as a Fitbit. Nearly 17,000 Aetna employees qualified for at least one sleep incentive in 2016, and some 18,000 did in 2017, the insurer told the FT. (It declined to comment on how much the initiative had cost the company.)

Many of the night workers who spoke to the FT said they were unaware that their shifts might one day make them ill. Union representatives argue employers could do more to inform workers of the risks and help them deal with managing their sleep. “I don’t think employers do enough regarding the health risks,” says Sue Merrell, a divisional officer at Usdaw. “One of the major UK retailers has just reduced the breaks for night shifts. We’ve tried to fight it but we haven’t got a legal leg to stand on.”

Paul Evans, assistant national secretary at Bectu, the UK media and entertainment union, says that many film and TV contracts require workers to waive their rights under the European Working Time Directive. “This industry is recruiting on endurance,” he says.

Some managers recognise they have a complicated problem on their hands. Steve Corner is a manager responsible for health and safety legislation at the British Oxygen Company, an industrial gas company. The BOC has more than 30 facilities in the UK and Ireland and runs one of them — a testing facility for gas cylinders near Wolverhampton — 24 hours a day. “It’s quite expensive infrastructure,” he says. “We’ve invested in it and we want to maximise it.”

There are 20 to 25 workers on the shift at any one time, including delivery drivers. Those working nights make 10-25 per cent more money than they would working days. Unsurprisingly, “People are very keen to be deployed on to nights,” he says.

But Corner, who spent more than two years working nights himself, is worried. He recently took part in a round-table discussion with unions and a sleep specialist from Oxford University, and was alarmed to hear research had found long-term health impacts. “Most of it was brand new to us, we’d never thought about it,” he says. “We’d historically had a desire for a night shift and we’d gone into it maybe a little ignorantly.”

Now Corner has a difficult line to tread. Reducing night shifts would be “very provocative” for industrial relations because workers would lose money. Yet, he adds, “If [working nights] has a long-term effect on your health, almost no premium is worth accepting for it.”

In terms of education about the risks, his company offers “very little, if we’re honest”. It is going to start providing tinted glasses, thought to help mitigate the effect of electric light on sleep, a relatively affordable step. “It’s all in the context of quite a hard-nosed business that’s interested in making its money,” says Corner, frankly.

Proactive managers may be able to alleviate the health impacts on night-shift workers. But what about companies that cannot intervene? As people increasingly move into self-employment, with “algorithms” overseeing their hours rather than a traditional human boss, there is little to stop some of them working all hours.

Jawad, 29, is originally from Afghanistan but was granted asylum in the US and lives with his wife in Sacramento. He works for a refugee charity on weekdays and attends evening classes. But California is expensive and, like many refugees, he supports family back in Kabul. So on Friday nights he heads to San Francisco to drive for Uber and Lyft, the taxi apps, over the weekend.

Arriving in the city at 7.30pm, he works for eight or nine hours before sleeping in his car for a few hours. After 12 or 14 hours working for Uber or Lyft, respectively, the apps turn off — both companies want to encourage rest periods. “But then, if I am fine, I can switch apps,” says Jawad. This allows him to continue accepting passengers.

Working such long hours may net him $500 per weekend but leaves him exhausted during the week. He sighs: “We are not living here, we are surviving.” As for Robert, he is now trying to focus on the more romantic aspects of the night shift: “In the summer it’s cooler . . . I get to see the stars.” But then again, he shrugs, “I don’t really have much of a choice.”

How to survive night shifts

Tips from a 2006 guide for junior doctors published by the UK’s Royal College of Physicians


Build a successful normal sleep routine

Get extra sleep before working the first night shift

Take a two-hour afternoon sleep before coming on duty


Take 20- to 45-minute naps to counteract fatigue

Your alertness will be improved by exposure to bright light during the night

Do not miss proper meals when working at night

Use caffeine cautiously, if at all, as it is a stimulant


If planning a long drive home, consider the risks

On getting home, try to sleep immediately

Develop a routine for sleeping during the daytime

Keep your sleep debt to a minimum

Source: Financial Times –

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