Exposing people to short flashes of light while they’re sleeping could provide a fast and efficient method of preventing jet lag, according to a study by researchers at the Stanford University School of Medicine. 
 
 “This could be a new way of adjusting much more quickly to time changes than other methods in use today,” said Jamie Zeitzer, PhD, assistant professor of psychiatry and behavioral sciences. 
 
 Zeitzer is senior author of the study, which was published online Feb. 8 in the Journal of Clinical Investigation. The lead author is Raymond Najjar, PhD, a former postdoctoral scholar at Stanford now at the Singapore Eye Research Institute. 
 
 Researchers led by Zeitzer have been working on developing an optimal technique for using light exposure to help people adjust more quickly to changes in their sleep cycles. Current light-therapy treatments for sleep disturbances include sitting in front of bright lights for hours at a time during the day, which allows you to transition your body clock to a new time zone in small steps prior to taking a trip. 
 
 Night light 
 
 In an earlier study, Zeitzer and his colleagues found that light therapy works best at night because the body’s circadian rhythms, which control sleep cycles, are more sensitive to light at night, even through closed eyelids. 
 
 In the latest study, Zeitzer and Najjar found that short flashes of light at night are more effective than continuous light exposure and could further speed up the process of adjusting to a different time zone before a trip. 
 
 The transfer of light through the eyes to the brain does more than provide sight; it also changes the biological clock. A person’s brain can be tricked into adjusting more quickly to disturbances in sleep cycles by increasing how long he or she is exposed to light prior to traveling to a new time zone. 
 
 After arriving in a new time zone, the body will eventually adjust on its own, but at a slow pace of about one hour a day. Meanwhile, jet lag, which occurs because your body’s clock is still synced to your original time zone, can cause fatigue, lack of alertness, a general feeling of malaise and sometimes gastrointestinal problems. 
 
 Biological ‘hacking’ 
 
 Light therapy is designed to speed up the brain’s adjustment to time changes. By conducting light therapy at night, the brain’s biological clock gets tricked into adjusting to an awake cycle even when asleep. It’s a kind of “biological hacking” that fools the brain into thinking the day is longer while you get to sleep, Zeitzer said. ||||| New research is exploring whether targeted light flashes can help reset circadian rhythms offset by traveling to new time zones. WSJ's Sumathi Reddy discusses with Tanya Rivero. Photo: iStock 
 
 Exposure to brief flashes of light during the night before a trip could help people avoid jet lag, according to a new study by Stanford University researchers. 
 
 The study, published online Monday in the Journal of Clinical Investigation, might have implications for more than just travelers. It also could point to help for people on sleep/wake schedules that don’t align with their circadian rhythms and people who suffer from seasonal affective disorder, a type of depression. The researchers also are investigating whether... ||||| Image copyright University of Colorado Boulder Image caption The researchers dragged volunteers on to a camping trip in the midst of a Colorado winter 
 
 Spending a weekend out camping resets the clock inside our bodies that influences sleeping habits, scientists at a US university have discovered. 
 
 The team argue that time in the great outdoors could help those struggling to get up in the morning and boost health. 
 
 The researchers said swapping bricks and mortar for canvas was not a long-term solution. 
 
 But exposing ourselves to more bright light in the day (and less at night) could help. 
 
 Our body has a daily "circadian" rhythm that anticipates day and night to co-ordinate how our body works. 
 
 It alters alertness, mood, physical strength, when we need to sleep and even the risk of a heart attack as part of a 24-hour cycle. 
 
 Body Clock: What is happening in your body right now? 
 
 'Arrogance' of ignoring need for sleep 
 
 Light helps the clock keep time, but modern life with artificial light, alarm clocks and smartphones has altered our sleeping habits. 
 
 The report is published in Current Biology and Dr Kenneth Wright, from the University of Colorado Boulder, told the BBC: "We're waking up at a time when our circadian clock says we should still be asleep." 
 
 He says this is damaging to health with studies suggesting links with mood disorders, type 2 diabetes and obesity. 
 
 And it also simply makes us really groggy and sleepy when we try to get up in the morning. 
 
 Reset button 
 
 So Dr Wright organised a series of camping expeditions for a small group of volunteers. 
 
 They had to wear special watches that recorded light levels and had blood tests to analyse the sleep hormone melatonin. 
 
 And the only artificial light they were allowed was the glow of a campfire, even a torch was banned. 
 
 Image copyright University of Colorado Boulder 
 
 The first thing they learned on a week-long camping trip in winter was people were exposed to 13 times more light than at home, even though it was the darkest part of the year. 
 
 Their melatonin levels also started to rise two-and-a-half hours earlier than before the expedition and they went to bed earlier too. 
 
 The campers were now sleeping and waking in tune with their body clocks. 
 
 Another camping trip showed most of that benefit could be gained by just going away for a weekend. 
 
 Dr Wright said: "We're not saying camping is the answer here, but we can introduce more natural light to modern life. 
 
 "It is something we as a society can regulate without people having to change behaviours." 
 
 He thinks homes, offices and schools could be designed to allow in more natural light. 
 
 And the new generation of "tuneable" light bulbs - that can be made far brighter in the day and dimmer at night - could also be used. 
 
 However, at the moment, people's body clocks would start to shift back to their old rhythm once the tent was packed up. 
 
 In order to continue to benefit from the camping reset, people would need to get a large hit of light in the day - for example by going out for a walk before work - and cut down in the evening by using less artificial light. 
 
 And if you want to watch your favourite TV show "record it", says Dr Wright. 
 
 Winter differences 
 
 The researchers also picked up clues that our body clocks alter during the year and that may affect how our body functions. 
 
 In a week of summer camping, melatonin production was altered by two hours, in winter it was altered by 2.6 hours. 
 
 It is a suggestion there is something different about the way our bodies react to the longer or shorter day. 
 
 And we already know that some people suffer from low mood with seasonal affective disorders. 
 
 Dr Wright added: "We have a hint there's something there and maybe at one point it time it was critical and now, in a modern environment, maybe we don't need to worry about putting on more weight in winter, but the impacts may still be hardwired in our physiology." 
 
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– Researchers at Stanford University have discovered what a press release calls a "fast and efficient" way to stop jet lag before it starts: repeatedly flashing light into your eyes while you sleep. "If you are flying to New York tomorrow, tonight you use the light therapy," Dr. Jamie Zeitzer says. "If you normally wake up at 8am, you set the flashing light to go off at 5am. When you get to New York, your biological system is already in the process of shifting to East Coast time." A flash every 10 seconds for one hour, used toward the end of the night, will push the body's circadian rhythm forward by about two hours, the Wall Street Journal explains. Using the flashes of light at the beginning of the night, on the other hand, will delay the circadian clock and could be helpful when the aforementioned traveler heads back to the West Coast. Current in-advance methods for dealing with jet lag and sleep-cycle issues involve continuous light administered while awake. Not only did the study find flashing lights to be more effective—they change the body's circadian rhythm up to three times faster than a steady light—they don't interrupt a person's life. "Most people can sleep through the flashing light just fine," Zeitzer says in the press release. Researchers are hoping to have a light-flashing sleep mask available for consumers later this year. This same method could be used to help people who work the night shift or have seasonal affective disorder. And researchers are currently testing it on a group of teens to improve school performance. "We’re basically looking to intentionally jet lag teens so that they can go to bed at a reasonable time," Zeitzer tells the Journal. (This family of five gave itself perpetual jet lag by switching to Martian time.)