Flashing lights at night may help lessen jet lag

Exposing sleeping people to a series of short flashing lights at night might help them adjust more quickly to time zone changes, according to a small U.S. study.

Nighttime flashes change the timing of body's clock

Thomson Reuters Posted: Feb 09, 2016 11:01 AM EST | Last Updated: February 9, 2016

The light therapy tool isn't ready for frequent flyers to try. (CBC)

Exposing sleeping people to a series ofshort flashing lights at night might help them adjust morequickly to time zone changes, according to a smallU.S. study.

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.

"Jet lag itself is really a nuisance syndrome as it isself-resolving," said senior author Jamie Zeitzer, assistantprofessor of psychiatry and behavioral sciences at the StanfordUniversity School of Medicine in California.

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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.

"However, the treatments that are developed for jet lag canbe used for less prevalent, though far more significant societalproblems including delayed sleep in teens [in whom we have anongoing clinical trial using the flash technique]and shiftworkers who try to flip between a night time schedule for workand a day time schedule for leisure," he told Reuters Health byemail.

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.

A series of flashes similar to a camera flash deliveredevery 10 seconds over a 60-minute period delayed sleepiness bytwo hours, compared to a 36-minute delay for those exposed tocontinuous light for an hour, according to the results publishedin the Journal of Clinical Investigation.

"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.

Arriving in New York, you would be synced to the local timeafter one day, he 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."

Nighttime flashes change the timing of the circadian clock,he said.

"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."

The night flashes require special technology and equipment,beyond just a smartphone, which are still in development,

Zeitzer said.

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

"This is one of the real advantages of this system you canchange circadian timing while you sleep, without interferingwith sleep," he said.

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.

As for frequent flyers trying this themselves, it is "fartoo early neither the methodology is available outside

research, nor any guidance about safety, nor tests of simulatedjet lag in an appropriate 'realistic' protocol," Wirz-Justicetold Reuters Health by email.

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Flashing lights at night may help lessen jet lag

Nighttime flashes change the timing of body's clock

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