NIGHT SHIFT

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By Newsweek Editors

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The machines at Volkswagen's sprawling Wolfsburg factory are relentless. Lined up in the cavernous building, row upon row of tall, skinny robots dip and clamp car parts in place, cutting sheets of steel and screwing in dashboards with precision timing. They labor all through the night without tiring, slowing down or nodding off. Every 24 hours they churn out 800 automobiles, more than any other car factory in the world, and they do so five days a week. The machines would work on days six and seven as well, if their human helpers were willing to forgo their weekend respite.

The workers, however, need the rest. The robots set an exhausting pace for the company's 19,000 coverall-suited employees, who perform vital checks, tests and corrections according to printed plans stuck on the inside of each car's hood. Stephan Beitz, 25, who puts together car engines, says the morning shift is fine--"It's light, I'm more awake"--but finds night work grueling. The vast majority of industrial mishaps take place in the early hours when night-shift workers are prone to doze: the nuclear accident at Three Mile Island started at 4 a.m., Chernobyl at 1:23 a.m. Unfortunately, as the global economy demands more productivity, workers in increasing numbers are being called upon to keep factories--and also airplanes, hospitals and call centers--going through the night. "We are asking 20 percent of our work force, including pilots and surgeons, to operate when they're massively impaired," says Russell Foster, a molecular neuroscientist at London's Imperial College.

The round-the-clock society may not be everybody's ideal way to live, but for scientists it's a chance to challenge a natural limitation: what biologists call the circadian rhythm, a biological clock that locks every creature on the planet into a rhythm set by the rising and setting of the sun. Researchers have made great strides in figuring out how this rhythm works in the brain, opening the possibility of intervening in these natural rhythms and manipulating them. The research is just starting to yield tangible products and treatment strategies. Scientists are working out ways to cheat the body's natural need for sleep by developing drugs that could keep workers as alert at 3 a.m. as they are during the day. David Neubaur, author of "Understanding Sleeplessness: Perspectives on Insomnia," says: "In the future, [new drugs] will be beneficial for people who need to make changes in their circadian system, whether because of workplace demands or because they have an underlying circadian-rhythm problem."

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What makes the human body dance to nature's tune is a tiny clump of 20,000 or so brain cells called the suprachiasmatic nucleus, the body's master clock. The decoding of the human genome a few years ago gave sleep scientists a way to pinpoint the genes within this nucleus that regulate body rhythms (the fruit fly has only one, humans have at least five). These genes manufacture proteins that work in a kind of 24-hour negative-feedback loop--as the level of proteins builds up, they act to reverse the process, choking off the supply. This genetic cycle, in turn, regulates the synthesis and release of hormones that induce sleepiness or wakefulness. Now that scientists know this mechanism in detail, they're able to work on drugs that can intervene and manipulate it with precision. Whereas melatonin pills flood the bloodstream with melatonin, a sleep-inducing hormone, U.S. pharmaceutical firm Taneka is testing a drug that targets the brain's melatonin receptors, ensuring the desired effect. The drug may enable workers like Beitz to defy the natural need for sleep.

Many experts caution, though, that drugs may not be the best idea for the workplace. Potential side effects like headaches, fatigue and depression may make them an unsafe option for people operating heavy machinery, driving trucks or wielding a surgeon's knife. And last year Foster made a major discovery that could lead to a way of keeping workers awake without them. He found cells in the human eye that do nothing but detect bright sunlight and tell the brain to reset the sleep cycle accordingly. Foster's research revealed that these cells--separate from vision--are stimulated only by daylight--conventional artificial light won't do. Even on a cloudy afternoon it's 500 to 1,000 times brighter outside than under the lights typically used in factories and offices. "You need light of a long duration and high brightness to shift the [biological] clock," he says. This explains why business travelers crossing time zones eventually adapt, but night-shift workers never do. They get a dose of natural light on their way to and from work, too strong for a factory's dim lamps to counter.

Armed with Foster's discovery, scientists now hope they can mimic the effect of the sun at work to make it a safer place. Researchers from Ludwig Maximilians University in Munich are turning Volkswagen's Wolfsburg factory into a testing ground for circadian manipulation. Unit 13, where the cars' engines are assembled, is known as the "coal mine" it has no natural light and low ceilings. At one assembly line, fluorescent bars barely penetrate the gloom. Another line nearby is a glowing oasis of warm, calming light, produced by lamps that deliver four times the brightness of factory bulbs. Their shades are upturned to emulate the way the sun casts its beams, reflecting light and spreading it over a wider area. Re-creating sunlight indoors was complex, says Volkswagen's in-house medic Dr. Angelika Guth. "You don't want to have a bright, blinding light, and you can't put [the level of natural sunlight] inside, so you have to find technical modifications to make it seem brighter."

Though the study isn't yet complete, initial results are promising. Researchers compared the performance and levels of fatigue experienced by workers under the regular lamps and in the more intense light. They found enough improvement under the new lamps to suggest it's possible to to trick employees' internal clocks. The photoreceptors Foster identified are activated by the new lights and begin suppressing production of melatonin. Beitz says the new lights kept him "more awake and more focused" and able to work to the end of a shift without feeling tired. The VW experiment suggests the possibility of a worker revolution of sorts. "We have no hope of eliminating shift work in the future," says Volkswagen's Guth. "So we're constantly trying to find ways to make it healthier."

Scientists are cautious about messing with something so fundamental as the daily rhythm. Night-shift workers may be more alert, but what happens when they then try to sleep during the day? They might not sleep at all, and sleeplessness has its perils. Studies show that one night's loss of sleep results in a 30 percent drop in cognitive performance, rising to 60 percent after two nights. To what degree drugs or environment can compensate for this deficit, and for how long, remains to be seen. "We are treating sleep as an illness--something to be cured," says Foster. Better to go slow, scientists argue, and learn how sleep works before trying to get rid of it.

What's more, the VW research has shown that there's a wide variation in how people respond to the manipulation of their circadian rhythms. Scientists have long divided people into two genetically determined chronotypes: "larks" (early risers) and "owls" (who do better at night). Ludwig Maximilians professor Till Roenneberg, who's running the VW study, found in a survey of 20,000 people that the majority fall somewhere between these two extremes. Roenneberg developed a detailed questionnaire for factory workers to document their sleep patterns. Comparing these results with a time-stamped test of the workers' accuracy and concentration throughout the night shift, Roenneberg found bright lights greatly improved the ability of this in-between group to cope with shift work. They were least effective for extreme larks.

The work suggests that some workers are better suited genetically to working the graveyard shift than others. Researchers at the University of Utah studied a family of extreme larks--a daughter, her mother and grandmother who all naturally fell asleep at 9 p.m., waking around 4 in the morning--and found that they shared a single genetic mutation. Tests like Roenneberg's that sort the larks from the owls could become standard practice in some workplaces.

Consulting firm Circadian Technologies has created a survey for this purpose. It takes into account the social and biological factors that affect how workers adapt. Women tend to adapt less well to shift work than men, for instance, mainly because they tend to care for kids and parents and shoulder the housework. They also get less exercise and have more musculoskeletal disorders than men. Circadian plans to use the data to create programs tailored to a company's employees to help reduce the ill effects of shift work, cut absenteeism and accidents, and increase productivity. Excercise programs would be key for a company with a largely female work force; for men, the priorities would be antismoking programs and nutritional training.

Where will the new sleep science lead? The worst outcome might be a world in which extreme "owl" chronotypes live and work in an underground night world, like the Morlocks in H. G. Wells's "Time Machine." On the other hand, perhaps this is one way humans will adapt to new worlds, earthly or not. Last month NASA awarded Foster a contract to figure out how astronauts could survive the six-month voyage to Mars and sleep and work in the planet's dim light, without the Earth's rhythms of day and night. Both futures are unsettling. Argentine poet Jorge Luis Borges wrote: "Time is the substance from which I am made." Not, perhaps, for much longer.

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