For all kinds of food and even sleep time, the guidelines recommend the most appropriate or healthiest 'amount', but no one puts forward the most healthy working time.
Recently, researchers at the University of Cambridge found that working eight hours a week can significantly promote mental health and life satisfaction.
However, working more, such as five days (40 hours) a week, has no further benefits for mental health.
Researchers believe that moderate work is very important for adults. In addition to making money, work has other benefits, often spiritual, such as enhancing self-esteem and social integration.
The study shows that working about eight hours a week is the most beneficial working time to maintain mental health.
It is worth noting that the researchers believe that the quality of work is also key to maintaining mental health. Work that is not respected or has an unreliable contract does not provide the same mental health benefits as other work.
After following up more than 70000 British adults for nine years, the researchers found that after a person changed from being unemployed or having a baby at home to working up to eight hours a week, the risk of mental health problems decreased by an average of 30%.
However, working more than 8 hours does not further promote mental health.
The study also showed that men's life satisfaction increased by about 30% after switching from never working to working up to 8 hours a week. But to reach this level of life satisfaction, women have to work 20 hours a week.
Researchers said that with the rapid development of machine automation and artificial intelligence technology, many human jobs will be replaced by robots, artificial intelligence and big data, and human job opportunities and time will be significantly shortened.
Therefore, in the future, we need to redistribute working hours so that everyone can ensure mental health.
In addition, the "five-day weekend" working system can be implemented, with only a few hours per working day, or the annual leave can be extended to weeks or months, or even two months per working month.
Researchers believe that shortening working hours and job redistribution can help balance work and life, promote fertility and reduce carbon dioxide emissions from commuting.
For Britons, it is more appropriate to work four days a week in the next decade.