Four day weeks are healthier
Employees in the US work on average 10 hour days. The pressure of pace has led to a lot of health related issues such as obesity, reduced sleep and a weaker immune system. Studies suggest that people are happier and healthier when they have more leisure time. Longer working hours are associated with cardiovascular health issues, diabetes, and insomnia. There are also psychological side effects such as depression. A four day working week counters this. Companies who have adopted these measures have found employees to be more refreshed and productive, with a sense of balance. European countries on average have shorter working hours. In Scandanavia there is an emphasis on shorter working weeks, job shares and paid time off. They are ranked amongst the happiest in the world.  A number of health issues also arise from pollution. Studies suggest that longer working hours contribute to higher pollution levels. Americans work the longest hours. Studies have suggested that if Americans worked the same amount of hours as the Europeans, the energy consumption would be reduced by 20%. Another study suggested that a four day work week would also heavily reduce the carbon footprint. 
A four day work week is not beneficial to health. When work is allocated, it needs to be completed, whether you have five days or four to complete it in. A four day week introduces the possibility of four consecutive ten hour shifts, as opposed to five eight hour shifts. A longer than normal working day, therefore has health implications which can accumulate over a period of time. Studies have suggested that longer working hours correlate with chronic diseases later in life. These were particularly substantial for women. Women working on average 12 hours a day were more likely to get heart disease, cancer, diabetes, and lung disease than their counterparts. A four day week may therefore push workers who already have a tendency to overwork, to crunch their work into a four day week. In addition to the physiological impact, there is also a psychological impact on wellbeing, and the ability to function productively is compromised. Four day weeks may be counterproductive to the aims of providing more flexibility/leisure time. If a worker is to complete their tasks within four days, adding two additional hours to the working day will mean less time in the evening, for example, to relax or spend time with loved ones, especially young kids with bedtime schedules.
Rejecting the premises