Excessive hours of work impair the health, safety and well-being of the worker, act as an obstacle to improvements in productivity and hinder rather than promote the achievement of full employment.
It is estimated that in Europe in the Middle Ages that an average of about 54 hours a week was worked; a total of nearly 2,900 hours a year. However, during the industrialization of Europe the yearly hours rose by about 700 to 3,600. Modern annual normal hours worked are mainly well under 2,500 in Europe, and in the USA under 2,000.
For all non-agricultural sectors, the weekly working hours in the 13 developing countries for which data are available remained practically unchanged at an average of about 47 hours over the 1970s. For manufacturing industries, data are available for 21 developing countries. Again the average of the country figures remained virtually unchanged at around 46 hours. Looking at the extremes of the data by individual countries, the latest figures show Burma and Israel with the lowest average hours of work in manufacturing, both with less than 40 hours a week. At the other end, Brunei, Ecuador, Egypt and the Republic of Korea report a more than 50-hour work week in their manufacturing industries. In the developed market economies, data covering all non-agricultural sectors are available for 17 countries, while there is information on manufacturing industries for 23 countries. For both of these categories the average working period declined over the decade, finally reaching the goal of a 40-hour work week by 1979. Looking at individual countries, by the end of the period Australia, Belgium, Italy, New Zealand, Portugal, Sweden, UK and USA reported an average work week in all non-agricultural sectors of fewer than 40 hours (the lowest figure: 35.6 hours in the USA); for manufacturing industries alone, additional data for Austria, Canada, Denmark and Norway place these countries in the under 40 hours-a-week group as well. For both categories of workers, the top spots in terms of the longest working week were taken by the Federal Republic of Germany, Spain and Switzerland; Ireland and Greece also ranked high for workers in manufacturing. Japanese workers average 42 hours per week.
People who work long hours are too tired to do anything but sleep once they get to bed. A survey carried out by the UK Institute of Personnel and Development found almost a third of people working more than 48 hours a week said that exhaustion was affecting their sex lives. The and their partners also complained that long hours led to arguments and tension at home.
Dangerous or very heavy work, or work exposed to the elements, or work requiring fine detail or complex intellectual operations may not be sustainable on the level of national averages. In many lines of work, hours are excessive with regard to the demands made.