Like hypnosis subjects in a campy old movie, Americans are getting sleepy - very, very sleepy. Meanwhile, they blithely work and drive as if they were well refreshed. The consequences are predictable.

So says the National Sleep Foundation, which has released a study revealing that 64 percent of people in the U.S. sleep less than the recommended eight hours a night, while 32 percent log fewer than six hours of shuteye.And how do they feel when awake? Tired, according to the report.

More than a third said they were drowsy during the day. Nearly that many said it interfered with their on-the-job performance.

Of special concern, said experts at the foundation in Washington, D.C., is that people drive when deprived of sleep. Some 100,000 crashes, involving 1,500 deaths and 71,000 injuries, are caused by drivers who drift into the Land of Nod, according to an estimate by the National Transportation Safety Board.

This is not news to the pros who pilot big rigs on U.S. highways, said Deborah Whistler, editor of Heavy Duty Trucking Magazine, published in Irvine, Calif.

"(Sleep deprivation) is a huge issue in the trucking industry," said Whistler. Drivers are particularly prone to "microsleep, where they just kind of go in and out of sleep (while driving)."

She said one transportation company is experimenting with a computerized gadget that alerts drivers - as well as their home office - whenever they start to sleep at the wheel.

Lack of sleep also can cause less obvious health hazards, said Clete Kushida, director of the Stanford University Center for Human Sleep Re-search.

"There's evidence that if there's sleep deprivation and a person has a sleep-related breathing disorder, it can make the breathing disorder worse," said Kushida.

He said the breathing disorder, known as sleep apnea, afflicts 24 percent of men and 9 percent of women between ages 30 and 60.

Professional competence is also a victim of short sleep hours, Kushida added. "Your work performance deteriorates significantly," he said. "You become irritable. You have short-term memory problems and concentration difficulties."

Getting enough sleep is not a status symbol in competitive society, said foundation researchers.

The sleepiest Americans are in their late teens and 20s, according to Thomas Roth, head of sleep research at Henry Ford Hospital in Detroit. He notes that 18- to 25-year-olds "think they can get by with four to five hours of sleep because Margaret Thatcher can and they are twice the man she is."

Another problem is snoring. Snoring can disrupt sleep even without waking the snorer and can be a sign of sleep apnea.

Nor is snoring beneficial for anyone trying to sleep next to the snorer.

How can we tell when we've have had enough sleep? That's easy, said Kushida. You've had enough sleep when you're no longer sleepy.

The survey was done to launch National Sleep Awareness Week, March 30-April 5, which includes National Sleep Day on April 2.