Light is shed on how to help night workers stay alert

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People who work night shifts in the future may be able to take "light breaks" to help them stay alert during work hours and sleep during the day.

Night-shift workers frequently have trouble staying awake and perform poorly because they are out of sync with the natural rhythms that govern when we should be active and when we should rest.

But scientists now believe that fitting canteens with strong lights could overcome problems caused by shift work interfering with the body clock.

Bright lights could also counteract the "post-lunch dip" when people working normal hours often feel sleepy. Both syndromes are governed by the same circadian rhythms. Research into sleep patterns has already established that our biological clock, a pinhead size cluster of cells, was designed for a bygone era when life was simple and humans worked by day and slept by night.

But the technological advancements of the 20th century have meant that many businesses operate on a 24-hour basis and airline pilots, surgeons and lorry drivers who work against the clock are the most likely to cause accidents.

Dr Martin Moore-Ede, a graduate of Guy's Hospital medical school in London, recently conducted extensive research into sleep patterns and discovered that even if night-shift workers slept all day and felt refreshed at night, the body's instinct when faced with hours of darkness is to shut down for a "micronap".

Now scientists at the University of Leeds have found that light has a direct effect on the brain mechanism involved, stimulating wakefulness.

They are now about to test whether light can be used in a practical way in the workplace to help night shifters.

Dr Lawrence Smith, from the department of psychology, said: "We know that bright light can nudge performance and alertness up to its optimal level during night-time hours. We are going to look at this with a group of about 30 control room operators, to see how they respond to exposure to bright light during rest breaks."

Most work places are illuminated by about 200 to 1,000 lux of light - lux being a measurement of brightness. This compares with 10,000 to 12,000 lux produced naturally by a dull summer's day. The researchers intend to expose their subjects to between 2,000 and 2,500 lux.

Speaking at the British Association festival of science at Leeds University, Dr Smith said: "I can envisage shift workers taking light breaks as well as coffee or meal breaks.

"Rest areas could be fitted so that people can go there and bathe in bright light. The light there would be brighter than in their working area.

"It may be very beneficial because it's been found that social activity during the night also helps alertness and performance."