Nearly a third of workers in the U.S. aren't getting enough sleep, according to a new government report.

Overall, 30 percent of employed U.S. adults reported getting less than six hours of sleep a night, the Centers for Disease Control and Prevention said in its report. The National Sleep Foundation recommends that healthy adults get seven to nine hours of sleep.

People who usually work the night shift — especially those in transportation, warehousing, health care and social assistance industries — were more likely than day-shift workers to report not getting enough sleep. Forty-four percent of the night shift workers participating in the survey said they got less than six hours of sleep, compared with 29 percent of workers with day shifts.

"Insufficient sleep can have serious and sometimes fatal consequences for fatigued workers and others around them," the CDC wrote. An estimated 20 percent of vehicle crashes are linked to drowsy driving.

Besides poor job performance, too little sleep has been linked with obesity and cardiovascular disease, the report noted.

Those with night jobs face a particular challenge in getting enough sleep. "Attempts to sleep during daylight hours, when melatonin levels decline and body temperature rises, usually result in shorter sleep episodes and more wakefulness," the report said.

Companies should implement ways to improve workers' chances for enough sleep, the report said. For example, training programs on sleep and working hours can be tailored for managers and employees, and work shifts can be designed in ways to improve sleep opportunities.

The reports of sleep-deprived workers varied by industry, with manufacturing faring among the worst. The CDC said 34.1 percent of manufacturing workers reported not getting enough sleep.

When the results were broken down by age group, the findings showed people in the middle of their working years were most likely to report less than six hours of sleep a night: about 32 percent of people between the ages of 30 and 64, compared with 26.5 percent of those ages 18-29, and 21.7 percent of those 65 and older.

There were also differences among races. Black workers (38.9 percent), and Asian workers (33.2 percent) were significantly more likely to report short sleeps than white workers (28.6 percent) or Hispanic workers (28.8 percent), the report said.

People who were widowed, divorced, or separated were significantly more likely to report sleeping than six hours (36.4 percent) than with workers who were married (29.4 percent) or had never been married (28.2 percent).

The results are based on the data gathered during 2009 and 2010 in the National Health Interview Survey, for which a nationally representative sample of more than 15,000 adults were interviewed in their homes. The report was limited in that the data relied on people's own reports of how much sleep they get.

• 7 Tips to Sleep Soundly Tonight
• Top 10 Spooky Sleep Disorders
• The Best Apps for Your Health, Part 2: Sleep Trackers