This relationship between nominal and actual working hours also applies to overtime when employees are asked to work beyond the normal workday for a markedly higher rate of pay. Much of the extra time is unproductive, because people tend to adjust to the longer workday by per forming at a slower pace. If productivity drops when the number of required working hours is increased, will productivity rise if the workday is shortened? Some research indicates that it other studies show that a decrease in no working hours has no effect on actual work in hours. In a case of historical interest, during the Great Depression of the 1930s a U.S. manufacturing plant reduced nominal working hours by more than 9 hours a week, yet actual working hours fell only 5 hours a week. Another plant reduced the workweek by 10 1/2 hours, and hourly production rose 21%.
In research conducted in Sweden with white- collar workers, investigators found that overtime resulted in fewer hours of sleep for these employees and greater self-reported feelings of exhaustion (Dahlgren, Kecklund, & Akerstedt, 2006)