Just one day of work per week is the most “effective dose” to give the mental health benefits of paid employment, research suggests.

A study indicated that the risk of mental health problems reduces by 30% when people move from unemployment or stay-at-home parenting into paid work of eight hours or less per week.

But researchers at the Universities of Cambridge and Salford found no evidence that working any more than eight hours provided further boosts to well-being.

Sociologists had set out to define a recommended “dosage” of work for optimal well-being and their findings are published in the journal Social Science And Medicine.

They did this in the context of a rise in automation which may require shorter hours for all and a redistribution of work.

The researchers used data from a panel survey to examine how changes in working hours were linked to mental health and life satisfaction in more than 70,000 UK residents between 2009 and 2018.

They controlled for characteristics including age, children, longstanding illness and household income.

The study suggests that to get the mental well-being benefits of paid work, the most “effective dose” is only around one day a week – as anything more makes little difference.

“We have effective dosage guides for everything from Vitamin C to hours of sleep in order to help us feel better, but this is the first time the question has been asked of paid work,” said study co-author Dr Brendan Burchell, a sociologist from Cambridge University who leads the Employment Dosage research project.

“We know unemployment is often detrimental to people’s well-being, negatively affecting identity, status, time use, and sense of collective purpose.

“We now have some idea of just how much paid work is needed to get the psychosocial benefits of employment – and it’s not that much at all.”

Supporting the unemployed in a future with limited work is the subject of much policy discussion, such as universal basic income.

However, researchers argue that employment should be retained across adult populations, but working weeks dramatically reduced for work to be redistributed.

“In the next few decades we could see artificial intelligence, big data and robotics replace much of the paid work currently done by humans,” said Dr Daiga Kamerade, study first author from Salford University.

“If there is not enough for everybody who wants to work full-time, we will have to rethink current norms.

“This should include the redistribution of working hours, so everyone can get the mental health benefits of a job, even if that means we all work much shorter weeks.

“Our findings are an important step in thinking what the minimum amount of paid work people might need in a future with little work to go round.”

Researchers suggested creative policy options for moving into a future with limited work, including “five-day weekends”, working just two hours a day, or increasing annual holiday from weeks to months – even having two months off for every month at work.

Dr Burchell added: “If the UK were to plough annual productivity gains into reduced working hours rather than pay rises, the normal working week could be four days within a decade.”

Dr Jed Boardman, lead for social inclusion at the Royal College of Psychiatrists, said: “We know that unemployment is bad for mental health and well-being, and that being in work can be good for you.

“But being in jobs with low levels of control, high demands and complexity, job insecurity, and unfair pay can be as bad for a person’s mental health as unemployment.

“This high-quality study reinforces what we already know, but suggests that reduction of working hours can have benefits for people’s mental health and well-being.

“If this is to be adopted in policy then some caution is required to ensure that any reduction in hours is adopted equally across the workforce and that the psychosocial quality of the working environment is maintained.”