University of Michigan researchers analyzed two nationally representative surveys of approximately 2,300 U.S. adults that monitored the same workers for up to a decade. Over the study period, roughly half the respondents said they had trouble sleeping.

Respondents who felt upset or bothered at work on a frequent basis, or had ongoing personal conflicts with bosses or co-workers, were about 1.7 times more likely than others to develop sleep problems, the study said.

"Massive changes over the past half-century have reshaped the workplace, with major implications for sleep," sociologist Sarah Burgard said in a statement. "For many workers, psychological stress has replaced physical hazards."

Physical strain at work tends to create physical fatigue and leads to restorative sleep, but psychological strain has the opposite effect, making it more difficult for people to sleep, Burgard said.

Research has shown that lack of sleep increases the risk of traffic accidents, chronic disease and mortality.

The findings were presented at the annual meeting of the Population Association of America in New Orleans.