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 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.
“Jet lag itself is really a nuisance syndrome as it is
self-resolving,” said senior author Jamie Zeitzer, assistant
professor of psychiatry and behavioral sciences at the Stanford
University School of Medicine in California.
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.
“However, the treatments that are developed for jet lag can be used
for less prevalent, though far more significant societal problems
including delayed sleep in teens (in whom we have an ongoing
clinical trial using the flash technique) and shift workers who try
to flip between a night time schedule for work and a day time
schedule for leisure,” he told Reuters Health by email.
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.
A series of flashes similar to a camera flash delivered every 10
seconds over a 60-minute period delayed sleepiness by two hours,
compared to a 36-minute delay for those exposed to continuous light
for an hour, according to the results published in the Journal of
Clinical Investigation.
“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.
Arriving in New York, you would be synced to the local time after
one day, he 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.”
Nighttime flashes change the timing of the circadian clock, he said.
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“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 traveling West-to-East, light
during the last few hours of the night 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 did not
interrupt sleep or reduce its quality, he added.
“This is one of the real advantages of this system - you can change
circadian timing while you sleep, without interfering with sleep,”
he said.
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.
As for frequent flyers trying this themselves, it is “far too early
– neither the methodology is available outside research, nor any
guidance about safety, nor tests of simulated jet lag in an
appropriate ‘realistic’ protocol,” Wirz-Justice told Reuters Health
by email.
SOURCE: http://bit.ly/1nYsDhD Journal of Clinical Investigation,
online February 8, 2016.
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