Night shift: the dangers of working around the clock
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 4 p.m., 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 7 p.m. 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 10 a.m. “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% 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% higher mortality risk than someone getting seven to nine hours, according to the research organization 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 Organization 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 center. “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 socioeconomic 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 program] 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 work force seems to be growing, as consumer businesses meet 24-hour demand for their services and manufacturers seek to maximize 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 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 program 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, organize your feelings or heal the body.