Workers in Wales are at risk of accidents as they work longer hours and suffer sleep deprivation, a sleep expert has warned.
Experts have warned that more people are sleep deprived
Gwent Sleep Centre lead consultant, Melissa Hack, said lack of sleep was an increasing feature of life for workers.
Ms Hack said one third of accidents in several industries had sleep deprivation as an underlying cause.
The impact of longer working hours is explored in Wales@work, broadcast on BBC Radio Wales on Tuesday.
Ms Hack, who is also an honorary senior lecturer in sleep medicine for the University of Wales, said shift workers are often most at risk from accidents as their regular sleeping rhythms are disrupted.
She added: "Today's 24-hour economy is pushing people to work longer hours and without proper information on the effects of sleep deprivation, workers are at risk of accidents, injury and depression.
"One third of accidents in trucking industry, rail industry, marine industry and air industry have sleep deprivation as an underlying problem.
Farmer Michael George has less than five hours' sleep a night
"Lack of sleep was one of the factors that caused Chernobyl, the Exxon Valdez disaster and the Challenger space shuttle explosion.
"There's a danger that managers don't realise when there's a problem because workers are too scared to say."
Ms Hack said that workers function better if they have regular breaks, healthy food and drinks, and bright lights in the workplace.
She added she had studied nurses who did a full night shift, but then did not sleep during the day.
Pressures of work
She said their performance on a driving simulator was characteristic of someone who had drunk several glasses of wine.
But when tested again after a normal night's sleep, their performance was improved.
The Wales@work programme finds that self-employed people often work longer hours due to the pressures they may put on themselves.
Pembrokeshire farmer Michael George, who runs two large dairy herds near Wolfscastle in Pembrokeshire, told the programme he never has more than five hours' sleep a night and sometimes has as little as two or three hours.
He added: "Farming is one job where you can't count your hours.
"I wouldn't have the business I have today if I'd slept more.
"When you're milking cows you're never off duty - being short of sleep is part of my job".
Wales@work is broadcast on BBC Radio Wales at 1800 BST on Tuesday and repeated on 26 June at 0705.