St. Louis ? Experts recognize sleep deprivation as the most ubiquitous malady in America – 70 million Americans live with some form or degree of sleep problems.

In this mix, one malady has become quite common: shift-work sleep disorder.

Shift work – a term for night work involving any shift between 7 p.m. and 7 a.m. – isn’t your grandpa’s domain any more.

Once dominated by people who did traditional night work – manufacturing workers, shipping workers, truck drivers, late-night custodial service workers, nurses, emergency room doctors, all-night grocers – the computer age has taken the white-collar job into the darkness.

Up to 25 percent of workers in America work night shifts, and more work rotating shifts, say government reports. Nowadays, workers indentured to the graveyard shift could just as well be bankers or computer engineers as they could be postal workers, police officers, people who make sure overnight packages are delivered on time and more.

And regardless of their jobs, experts estimate up to half aren’t getting enough sleep. That shows up in lost productivity, emotional and social problems and, worst of all, life-threatening danger.

Experts attribute much of this to the computer age, where people have or want access to anything 24 hours every day. Their sleep patterns have been damaged because of it, says a recent observational study by Art Rathbun, a counselor and biofeedback specialist at Kansas State University.

300 dpi 4 col x 10.75 in / 196x273 mm / 667x929 pixels Keita Sullivan color illustration of a pajama-clad sleeper curled up in a briefcase. The Sun News 2002

KEYWORDS: work sleep dream overtired overwork job tired sleepy asleep deprivation nap briefcase illustration trabajo exesivo dormir durmiente adormecido sonoliento sueno sonador cartera ilustracion grabado contributed mb sullivan 2002

“There’s the expectation that people will do more,” he says. “We haven’t dropped activities, just added more. We’ve created a culture in which it is easy to become sleep-deprived.”

“Shift-work sleep disorder is when people who work night shifts or rotating shifts have problems with being tired and sleepy during their night shift and/or problems sleeping during the day,” said Dr. Jonathan Schwartz, a researcher at the University of Oklahoma. “This affects their productivity; it affects their quality of life.”

And the problem is more than being overly fatigued.

“Shift workers have more psychiatric problems like depression, ulcers, cardiovascular disease, and if they’re working at night and trying to sleep during the day, they miss time with their families.”

The worst issue, though, is that it’s dangerous. While some shift workers operate heavy equipment that can kill, statistics show the most dangerous time for a sleepy shift worker is driving to and from work. The National Highway Traffic Safety Administration calls it “driving while drowsy.” It’s next to impossible to measure after an accident, but experts know that the rate of accidents increases during the hours of late-night shift changes.

The safety administration estimates that 100,000 to 150,000 vehicle crashes each year and 4 percent of all fatal crashes are caused by drowsy driving.

“People who work nights (upset) that circadian rhythm (the 24-hour body clock),” said Geralyn Frandsen, associate professor of nursing at Maryville University. “You suffer from depression because you don’t see the sun … you have personal conflicts within your family; it can cause loneliness, depression, substance abuse when people use (chemicals such as medication or alcohol) to get to bed …”

Dr. Joseph Espiritu, a pulmonologist who’s helping to put together a sleep disorder clinic for St. Louis University, said, “Studies have shown that shift work is associated with impaired sugar tolerance, increased risk of hypertension, increased triglyceride levels (and) an increased risk of heart disease.”

Federal and private safety agencies also report that hundreds of thousands of accidents, deaths and even major catastrophes can be attributed at least in part to drowsy workers.

The brightest scientific minds still don’t know how sleep works. They do know what happens when people and even animals don’t sleep. They become psychotic.

Sleep tends to operate in a process called circadian rhythm. It’s governed by a mechanism in the brain and responds mainly to the arrival and departure of the sun during a day.

When it’s light, the brain triggers the release of hormones needed for daytime functioning. When it gets dark, the brain starts to release night hormones, including the likes of melatonin, which tells the body to sleep.

“People have evolved to sleep at night and be awake during the day,” Espiritu said. Upsetting that balance throws off the body’s internal clock, and that sparks the problems.

Shift work throws that process into chaos if the worker fails to take steps.

But another problem is that there are so many people suffering from sleep disorders that the medical community can’t handle them all. As a result, health care workers primarily concentrate on the physiological disorders that can be life-threatening.

One agency estimates that if all of the people with sleep disorders descended on the medical community, it would take eight years to begin to treat all of them.