As your head sinks softly onto your pillow this evening, spare a thought for the millions of people who are heading to work. From nurses, to firefighters and HGV drivers, over three million Brits regularly clock on for the graveyard shift.
But while night work plays a vital role in keeping our health service and economy ticking over, Dr Michael Mosley tells Work in Mind that it plays havoc with our wellbeing. In fact, it’s said to cause “chaos” to the body, potentially even leading to long-term damage. So much so, that The World Health Organisation has even classified it as a probable cause of cancer, due to the way it disrupts our circadian rhythms.
“Night shift work can have a terrible effect, such as reduced life expectancy, poor sleep, weight gain, type 2 diabetes and depression,” says the TV presenter and author of new book, Fast Asleep. “It messes with your sleep and your circadian clock, which drives most of the hormones in the body.
“And the effects are not just physical, they are psychological too. Your social life is shot, you’re not seeing family and the chances are you row with your partner. There’s a massive increase in the risk of divorce – if you or your partner are shift workers, you are six times more likely to get divorced than if you work days.[i] One of the reasons is that shift workers find it harder to take part in ‘normal’ family life and plan family events.”
Yet despite an increasing amount of research, Dr Mosley believes remarkably little support is put in place to help those working nights.
“I’m astonished by how much we know about the impact of shift work, and how poorly it’s supported,” he says. “What I found startling, when I’ve talked to firefighters, police officers, nurses and paramedics, is that none of them get any specific advice on how to cope with being a shift worker. They are just left to get on with it.”
But while the potential implications of shift work may paint a “gloomy picture,” Dr Mosley is quick to add that there are plenty of things that can be done to help.
“Companies should try to sort the larks from the owls,” he explains. “If you have employees who like to stay up late and get up early, make their shifts work for them.
“Light is important too – most workplaces are very dim, but we need decent exposure to light to reset the body clock This could involve doing something simple like installing light boxes – bright light is better than drinking coffee to wake you up. I use a lightbox myself for SAD [seasonal affective disorder].
“People should also be aware that employees over the age of 45 are less able to adapt to shift work, and the impact on their bodies and brains is greater.”
Of course, diet is all too often affected by shift work, which in turn has health ramifications.
“Light and food are the two great drivers of your circadian rhythm,” says Dr Mosley. “There is a lot of evidence that eating when your body thinks it should be asleep is bad for the heart.
“Few employers provide healthy food at 3am, it’s often stodgy things like sausages and chips. Or, people go to a vending machine and grab a bar of chocolate. They tend to reach for poor quality snacks, but the body is less efficient at processing food at night, which means the bad stuff will hang around your system for longer. Just when the body thinks its digestive system is having a breather, it gets whacked full of sugar and fat. Heart disease is a major killer of people who do shift work.”
Dr Mosley is famously a huge advocate of time restricted eating (TRE) and his BBC series Trust Me, I’m a Doctor was involved in one of the first human studies to explore the benefits, with Dr Jonathan Johnston of the University of Surrey.
For the research, 16 volunteers were assigned to either a time restricted eating or control group. The TRE group were then asked to stick to their normal diet but move their dinner 90 minutes earlier and their breakfast 90 minutes later. The upshot was that for an extra three hours a day, they were fasting. Incredibly, when their body fat, blood sugar and cholesterol levels were measured ten weeks later, it was discovered that the TRE group had on average lost around 1.6kg of body fat, and seen bigger drops in blood sugar and cholesterol.
“There are a couple of major studies at the moment in the US and Australia, looking at the benefits of limiting the hours within which you eat [TRE] while doing an overnight shift,” says Dr Mosley. To support our circadian rhythm, he advises avoiding heavy meals during the night. Instead he recommends that workers eat before an overnight shift, take a healthy snack with them if necessary and save a proper meal until 8 or 9am. He also says that when businesses do give employees access to food, it would be helpful to supply healthy options instead of junk.
“Try to eat your main meal before midnight, and take in nuts, apples and pears to snack on if you can’t endure a long night without anything,” he says. “Take on plenty of fluids and don’t drink caffeinated fizzy drinks.”
Of course, it’s not just the timing of our meals that counts. When we sleep is important too, and Dr Mosley urges businesses to provide a space where employees can take a brief nap.
Shockingly, one online survey of 1,135 doctors by doctors.net.uk revealed that 41% of UK doctors had nodded off at the wheel while driving home from a night shift.[ii] The survey results – which also revealed that 29% of respondents knew a colleague who had died driving after a night shift – were so staggering that they led to a parliamentary petition, calling on NHS trusts and deaneries to make adequate provision, so staff could rest once they’d finished their shift.
“We know from a study in New Zealand that even providing engineers with 20-minute snooze during their shift had good impact,”[iii] says Dr Mosley. “And a study of American nurses found that a 20-minute nap meant they were less drowsy on their way home.”
Importantly though, he adds that once you do return home from a night shift, it’s advisable to resist the temptation to sink straight into bed.
“If you work nights, try to get in the majority of your sleep in the hours leading up to work,” he says. “There is evidence that it’s better to have an evening sleep (from 2pm to 9am) than a morning sleep. In one study, shift workers who slept in the afternoon made fewer mistakes at work than the morning sleepers.[iv]
“Shift work can be deadly, but there are plenty of things that both employers and employees can do. Businesses should really be investing in this – it could make a huge difference. Poor sleep also has a huge impact on productivity after all.”
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Dr Michael Mosley is a trained doctor, TV presenter and science journalist. He has won numerous television awards and his latest book, Fast Asleep, is out now, published by Short Books. He has also helped develop The Fast 800 digital programme, which brings together the latest science around what we eat, how to exercise and mindfulness to help people take back control of their health.
[i] Shift work, role overload, and the transition to parenthood. Wiley Online, 2007. https://onlinelibrary.wiley.com/doi/full/10.1111/j.1741-3737.2006.00349.x
[ii] The dangers of doctors driving home. Guardian, 2016. https://www.theguardian.com/healthcare-network/2016/jul/26/two-in-five-doctors-fallen-asleep-wheel-night-shift
[iii] Workplace interventions to promote sleep health and an alert, healthy workforce. J of Clinical Sleep Medicine, 2019. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6457507
[iv] The impact of sleep timing and bright light exposure on attentional impairment during night work. J of Biological Rhythms, 2008. https://pubmed.ncbi.nlm.nih.gov/18663241-the-impact-of-sleep-timing-and-bright-light-exposure-on-attentional-impairment-during-night-work
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