Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: THURSDAY, May 3, 1990 TAG: 9005030011
SECTION: NATIONAL/INTERNATIONAL PAGE: A10 EDITION: STATE
SOURCE: Associated Press
DATELINE: BOSTON LENGTH: Medium
The approach appears to be the first quick, practical cure for the night-shift blues, the on-the-job sleepiness and daytime insomnia that plague many of the nation's 7 million night workers.
The principal developer, Dr. Charles A. Czeisler of Boston's Brigham and Women's Hospital, said his team is still simplifying the technique so it can be easily moved from lab to work place. But if it matches its early promise, it should readjust people's biological rhythms in just two nights so they stay awake when their bodies ordinarily want to sleep.
"It's a tremendous leap forward," commented Dr. Thomas Roth, a sleep researcher at Henry Ford Hospital in Detroit.
The technique works this way:
People moving to the night shift reported to work - in this case, a hospital lab - at midnight and spent the next eight hours sitting at a desk. While they worked, a bank of lights 4 feet away shined with 16 cool-white 40-watt bulbs.
Then they drove home, pulled down blackout shades in their bedrooms and stayed in total darkness from 9 a.m. to 5 p.m.
After just two days, the time on their internal clocks shifted almost 10 hours. So instead of hitting the low point in their daily cycle about 5 a.m., this happened around 3 p.m. when they were still asleep.
"They certainly have made a breakthrough in understanding the effect of light in humans," said Dr. Mary Carskadon of Brown University. "Their evidence is very powerful. There needs to be more trials in the field to determine the efficacy in a broader sense, but I think that what they've done really gives us a guidepost to pursuing this research."
Czeisler described the results of his group's experimental use of the approach in eight young men in a report in today's New England Journal of Medicine.
If the technique can be successfully adapted to the job, it could be important for an estimated 7 million Americans who work nights. Even after years on these schedules, some people complain they never completely adjust.
"It's very important in critical jobs to make sure that people are alert on the night shift," said Czeisler. "We collected data on 4,000 shift workers and found that 56 percent reported nodding off at least once a week. These include people driving front-end loaders, running nuclear power plants, policemen and chemical workers."
Because people don't have clock hands on their tummies, scientists read the time on their internal clocks by checking their temperatures. Ordinarily, people's temperatures hit their lowest ebb in the wee hours, and this is when they are least alert if they happen to be awake.
During the studies, a comparison group worked at night under regular lights and slept with ordinary window shades pulled. After a week, their temperatures continued to reach their low point during the early morning.
In contrast, those who got the light-dark treatment noticed an immediate improvement in their alertness and performance.
by CNB