Photo of illuminated neon 24 hours sign by Sam2172,

It’s no secret that Americans are working harder than ever. But newly updated research by Daniel Hamermesh of the Royal Holloway, University of London (and a professor emeritus at the University of Texas at Austin) and Elena Stancanelli of the Paris School of Economics examines another aspect of our work-devoted culture: the tendency to work what the authors call “strange hours,” or nights and weekends.

The authors compare work hours between the United States and four other European countries—the United Kingdom, France, Germany, and the Netherlands. Unsurprisingly, American workers win the prize for the longest average workweek among these countries, clocking an average of 41 hours a week from 2003-2011 (a number that is much higher for a increasing portion of workers in the United States). And the disparity is even wider when looking at average annual hours. The typical American employee now puts in 1,800 hours a year, more than any other wealthy country—including Japan, a country whose killer work ethic even has its own term: Karoshi, or “death by overwork.”

In most other countries, work hours have declined since 1979. But for most Americans, this is not the case. Stagnant wages propelled many of us to work even harder to stay afloat. Combined with the United States’ lack of paid vacation or holiday time requirements (unlike other developed countries), the typical work-life balance began to skew more and more toward work.

To make matters worse, Hamermesh and Stancanelli find that one in three Americans spend time on paid work during the weekend. And more than a quarter of U.S. workers work during night-time hours, which the authors define as between 10 PM and 6 AM. The fraction for both weekend and night hours is much lower in France, Germany, Spain, and the Netherlands. Even in the United Kingdom, which is catching up to the United States in terms of overall hours worked, only 19 percent of workers are burning the midnight oil.

It seems that these two phenomena would be connected—doing at least some work during nights or weekends seems inevitable for those employees with extreme work hours. But while Americans’ long work hours do play a role in the incidence of strange hours, the connection is not as strong as common sense would have us believe. Hamermesh and Stancanelli found that even if all Americans working more than 45 hours per week were to cut back their hours, U.S. workers would still be logging strange hours at a higher rate than the other countries. Rather, the way that work is structured seems to be the major factor driving differences between the United States and the other four countries’ strange-hours incidence.

While most European countries regulate working time (including provisions that limit the total number of work hours and laws pertaining to when people work), the United States’ policy is limited to paying certain workers overtime if they work more than 40 hours per week. The relatively lax regulations may be one reason why it is much more common to find 24-hour restaurants, gyms, or stores, in the United States than it is in other rich economies. But our convenience comes at a cost.

In the United States, those working strange hours are more likely to be low-skilled and minority workers, and sometimes turn to these jobs because of a lack of other options, or because of higher wages. But even if workers receive higher pay to work at these times (which most do not), they still face consequences for their individual and familial health and well-being.

Parents working strange hours have to figure out child care when most centers are closed, and commute when public transportation is not readily available. The stress and sleep deprivation associated with these strange hours put workers’ health at risk. And the time away from home during these periods have been shown to put a major strain on relationships and marriages. What’s more, children of those working these schedules are more prone to behavioral problems and perform lower on cognitive skills tests compared to the kids of those who work more traditional schedules.

Hamermesh and Stancanelli conclude that more research is needed to better investigate the rising incidence of night and weekend work in the United States. But what is clear is that, despite the increasing prevalence of strange work hours, our society continues to revolve around the traditional 9-to-5 work schedule. Considering policy reforms such as paid leave, increased access to child care at odd hours, and a wage premium for night and weekend hours could help these disproportionately low-income workers more successfully balance their work and family responsibilities.