A new survey by the National Sleep Foundation, a Washington-based organization that studies sleep and sleep disorders, reveals that Americans are not getting enough sleep due to increased workload. According to the organization, adults should get seven to nine hours of sleep per night.

Nearly three in ten workers have become very sleepy, or even fallen asleep, at work in the past month, according to data coming from a first-ever study on sleep and the workplace. The findings are based on analyzing a random sample of 1,000 workers in 2007.

“It's a very expensive issue for employers, and it can be fatal, too. The 24/7 global economy means work is now around the clock,” says Nilesh Dave, medical director of the Sleep and Breathing Disorders Center at the University of Texas Southwestern Medical Center in Dallas, the USA Today reports.

About 36 percent of the respondents say they have nodded off or fallen asleep while driving, including 26 percent who say they drive drowsy during the workday.

The study also found that 43 percent of the respondents only slept enough a few nights every month, with 25 percent of workers pulling over 10 hours a day at their job. This was the case of employers with more than one job. Moreover, 12 percent of the respondents have arrived late at work in the past month because sleepiness.

More than half of the respondents - 63 percent - say they just shrug off their sleepiness and keep going, while 32 percent say they chug down caffeinated beverages like coffee or soda to help give them a boost.

“You really do have to push yourself to stay alert. I used to sometimes pull over and take a 20-minute nap,” Donald Anerella, 49, who manages a Brooklyn bakery, told The Star-Ledger.

About half of the surveyed people said they were somewhat likely to use weekends to catch up on sleep, which experts do not encourage as the negative effect of sleep deprivation accumulate over time.

“People tend to believe that they can get by on five hours of sleep, but in most cases it’s going to catch up with you. It takes more than one night of good sleep to make up for that impact,” said Christopher Drake, a clinical psychologist at the Henry Ford Hospital Sleep Disorders Center in Detroit.

The lack of sleep was a result of workers putting in longer hours, in part due to increased pressure from employers to ramp up productivity. What is surprising is that lack of sleep leads to the opposite effect: no productivity, impatience with others, and difficulty concentrating on job tasks.

The study also blamed technology for people’s lack of sleep, as things such as cell phones and e-mail keep employees constantly connected to their job.

An estimated 50 to 70 million people suffer from constant sleep loss or sleep disorders, according to the Centers of Disease Control and prevention. Besides having trouble at work, health experts warn that chronic sleep loss is often associated with obesity, diabetes, high blood pressure, stroke, cardiovascular disease, depression, cigarette smoking, and excessive drinking.