Nearly a third of American workers get less sleep than the recommended seven to nine hours of sleep a day, according to federal health officials on Thursday.

The U.S. Centers for Disease Control and Prevention reported that 30 percent, or 40.6 million, of American adults are sleeping six or fewer hours a day, and night shift workers, particularly those in transportation, warehouse and health care industries are at the most risk of not getting enough sleep. 

According to the CDC report, 44 percent who night shift workers got less than six hours of sleep compared to those 28.8 percent of those who work during the day. About 69.7 percent of warehouse and transportation workers and 52.3 percent of health-care and social assistance workers don’t get enough sleep.

Americans who work more than 40 hours a week are also less likely to get enough sleep per night, compared to those who work 40 or fewer hours. 

The report also indicates that people between the ages of 30 to 44 were most likely to be sleep deprived compared to other age groups. 

Other U.S. adults who aren’t getting enough sleep are people who work more than one job, widows, divorcees and recently separated partners, according study in the April 27 issue of the CDC's Morbidity and Mortality Weekly Report.

Sleep deprivation is dangerous and workers who don’t get enough sleep are at an increased risk of injuries that could affect them or others around them, for example the CDC estimates that 20 percent of all car crashes are caused by drowsy driving. 

Previous studies have linked insufficient sleep to depression, a weaker immune system and memory issues, according to WebMD. Harvard medical researchers have also linked sleep deprivation with obesity, high blood pressure and daytime fatigue, which could head to safety problems when working.