Studies show that working more hours increases productivity up a point; after that, the law of diminishing returns sets in. That point is around 49 hours per week.

Research shows overworked employees have an increased risk of fatigue, general poor health, and cardiovascular disease. Another study showed that managers couldn't tell which employees worked 80 hours per week and who just pretended to.

Working shorter hours, such as the 4-day work week or the 6-hour workday, is not always the solution, since it could only work for certain industries.

A six-hour workday would be effective for industries such as hospitals but less effective where the borders between work and private life are blurred.

Instead of asking how many hours to work, smart businesses consider what the best hours are for their team to be working. Flexibility in working hours allows employees to choose working hours that suit their mental peaks and their lifestyle.

According to research, most people are only productive for 4-5 hours a day. With flexibility, you can create daily schedules that work for you. Research shows that employees working flexible hours show greater job satisfaction and commitment to their companies.