Following World War II, shift work became commonplace in America. Increasing competition and rising costs made it difficult for many industries to justify operating factories for only forty hours a week.
Some people work only at night, and others rotate between day, evening, and night shifts.
Our natural sleep-wake cycle, regulated by light and darkness, is disrupted by night or rotating shifts and irregular work schedules. Shift workers are 40 times more likely than day workers to be involved in accidents- at work, on the highway and at home. Shift workers report problems in fulfilling their sexual roles with their spouses, often leading to marital trouble. Shift workers must leave evening social events in order to get to work on time. Even with as much as 40 percent more pay than their daytime counterparts, shift workers consistently report their job satisfaction lower then do day workers and they keep looking into getting a day job.