Dr. Jamie Zeitzer, setting up a flashing light in his lab, said the flashing light did not interrupt sleep while altering its rhythm. Photo by Norbert von der Groeben/Stanford University
STANFORD, Calif., Feb. 9 (UPI) -- Flashing light therapy, delivered while a person is sleeping, can prevent jet lag by helping people adjust to changes in their sleep cycle, researchers in California found in a recent study.
Stanford University researchers found that exposing people to short bursts of light while they sleep tricks the brain's biological clock into shifting its awake cycle based on how long the bursts continue.
In previous studies, the Stanford researchers found light therapy to change circadian rhythms worked best at night when people are more sensitive to light, and found in the new study that short bursts of light work better than continuous exposure to light.
"This could be a new way of adjusting much more quickly to time changes than other methods in use today," said Dr. Jamie Zeitzer, an assistant professor of psychiatry at Stanford University, in a press release.
For the study, published in the Journal of Clinical Investigation, the researchers recruited 39 participants between the ages of 19 and 36. All of the participants were asked to maintain a routine a sleep-wake cycle at the same times for two weeks before sleeping in the lab.
Eight of the participants were exposed to continuous light for 60 minutes while sleeping. The other 31 were exposed to varying sequences of 2-millisecond light flashes separated by 2.5- 240-second intervals.
Flashing lights were found to be more effective than continuous light, with 10-second intervals between flashes as being the most efficient and fastest method of changing sleep rhythms.
The method, Zeitzer said, could be used to change sleep patterns of anybody from doctors with constantly changing schedules to night-shift workers changing how they sleep for the weekend.
Most importantly, he said, "We have found that most people can sleep through the flashing light just fine."