Flashing lights at night may help lessen jet lag
Nighttime flashes change the timing of body's clock
In experiments, the technique — which is based on the way non-visual parts of the brain respond to light — was much more effective than sustained bright light similar to that from devices sometimes used to combat sleep disorders or seasonal depression.
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Zeitzer was on the committee that removed jet lag as a "disease" from the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), the guide that psychiatrists use to diagnose mental illnesses.
The study included 39 people, 31 of whom were exposed to a series of two-millisecond light flashes with changing intervals while sleeping, and eight of whom were exposed to 60 minutes of continuous bright light.
"In essence, using the night before you traveled from California to N.Y. would move your circadian system two-thirds of the way there before you even left," Zeitzer said.
"The circadian clock is the central conductor of the many clocks that are found in nearly all tissues of your body," Zeitzer said. "This clock remains synchronized with the external day through regular exposure to light."
"For moving your system to a later time, such as would be necessary when traveling East-to-West, light during the first few hours of the night is ideal," he said. "For moving your system to an earlier time, such as would be necessary when travelling West-to-East, light during the last few hours of the night is ideal."
In a previous study, the short flashes of light at night did not interrupt sleep or reduce its quality, he added.
Mistiming light therapy can make jet lag worse, cautioned Anna Wirz-Justice, professor emeritus at the Center for Chronobiology at the University of Basel in Switzerland, who was not part of the new study.