Allowing workers to choose the slot of hours they want to work in is good for their well-being, says a study from Loughborough University, England.
The study found that people who become overworked are less satisfied with their lives and experience lower levels of psychological well-being.
The key factor to happiness, according to the study, was whether the hours people work reflect the hours they want to work.
The study, published in the journal Human Relations, examined the working time patterns and well-being levels of 20,000 individuals over an 18-year period.
The researchers found that more than 55 percent of workers who regularly work 50 or more hours a week would like to work less, as would around 40 percent of workers who work between 40 and 49 hours a week.
"When workers are overworked -- working more hours a week than they would like -- life satisfaction and psychological well-being deteriorate," said lead researcher professor Andy Charlwood.
"Thankfully, most workers who experience overwork are able to rearrange their lives so that the hours they work and the hours they want to work come back into balance."
But around one in eight workers who become overworked are in the same situation two years later, and this appears to be a significant source of worry and unhappiness.
"To help protect our well-being levels, government and employer policies need to give workers greater flexibility to choose the hours that they work," Charlwood explained.