Workers who are exposed to light during night work will have lower melatonin levels and experience disrupted sleep patterns.
Previous studies suggest this can cause health problems, as well as an increase in workplace accidents.
“There are theories that melatonin may be protective against cancer,” said Guy Leschziner, a consultant neurologist at Guy’s and St Thomas’ Hospitals.
“The key thing is to ensure you are not damaging your internal circadian rhythm by not exposing yourself to bright light; for example, when you are going home.”
Melatonin is the substance that prepares the body for sleep.
The circadian rhythm, is also known as the body’s sleep cycle, a 24-hour cycle that maintains the balance between feeling sleepy and alert throughout the day.
“For people that have grave difficulties dealing with their shift patterns, even wearing sunglasses on the way home to try and allow the melatonin levels to come up as much as possible,” the neurologist added.
Mr Leschziner, who was speaking at an event at the Cheltenham Science Festival, said genetics played an important role in how shift work and sleep affected people.
“If your sleep is of really good quality and you sit there watching Netflix until 11pm at night, close the computer and drift off to sleep and have a great night’s sleep, then you don’t need to worry about it,” he said.
“There will be some individuals who are exposed to blue light in the evening and have relatively few consequences on the circadian rhythm and melatonin.
“But in other individuals it has massive consequences. Everybody is different and these hard and fast rules are not applicable to everyone in the population.
“It is only an issue if it disrupts your sleep.”
Mr Leschziner said that daytime naps had recently been shown to improve blood pressure but could also risk disrupt night-time sleeping.
“What we know, as you get older there is a view you need less sleep, but this is not borne out by the evidence,” he said.
“It seems older people need the same as when they are middle-aged, it just that the brain is less good at consolidating sleep and remaining in deep sleep.
“Sleeping becomes more fragmented and the drive to remain asleep is a little bit weaker. The quality of sleep may deteriorate in some individuals.
“I think whether you need a nap is related to how much sleep you are getting at night and whether a daytime nap gets in the way of anything else you want to do.”
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