Flashing lights at night may help lessen jet lag

In experiments, the technique which is based on the waynon-visual parts of the brain respond to light was much moreeffective than sustained bright light similar to that fromdevices sometimes used to combat sleep disorders or seasonaldepression.

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Zeitzer was on the committee that removed jet lag as a"disease" from the Diagnostic and Statistical Manual of MentalDisorders, Fifth Edition (DSM-5), the guide that psychiatristsuse to diagnose mental illnesses.

The study included 39 people, 31 of whom were exposed to aseries of two-millisecond light flashes with changing intervalswhile sleeping, and eight of whom were exposed to 60 minutes ofcontinuous bright light.

"In essence, using the night before you traveled fromCalifornia to N.Y. would move your circadian system two-thirdsof the way there before you even left," Zeitzer said.

"The circadian clock is the central conductor of the manyclocks that are found in nearly all tissues of your body,"Zeitzer said. "This clock remains synchronized with the externalday through regular exposure to light."

"For moving your system to a later time, such as would benecessary when traveling East-to-West, light during the firstfew hours of the night is ideal," he said. "For moving yoursystem to an earlier time, such as would be necessary whentravelling West-to-East, light during the last few hours of thenight is ideal."

In a previous study, the short flashes of light at night didnot interrupt sleep or reduce its quality, he added.

Mistiming light therapy can make jet lag worse, cautionedAnna Wirz-Justice, professor emeritus at the Center forChronobiology at the University of Basel in Switzerland, who wasnot part of the new study.