From ABC News in Science, 11 April 2014:
Countless theories on how to beat jet lag abound, but now two mathematicians have crunched the numbers to come up with what they believe is the quickest, most fool-proof method.
They have developed a free mobile app based on their calculations and are hoping to use it to test their method in the real world, according to a paper published today in PLOS Computational Biology.
Researcher Dr Daniel Forger, a professor of mathematics at the University of Michigan, says it’s the first time mathematics has been applied to the problem of ‘entrainment’ — the term for synchronising the body’s internal clock with the outside hour — which he says is inherently a mathematical problem.
“Every time I take a flight I sit next to someone who tells me they do this or do that,” says Forger. “What we wanted to do was somehow test these things rigorously; we wanted to use mathematical models to compare schedules.”
Refining the models
Using existing mathematical models for the effect of light on the human circadian system, Forger and colleague Kirill Serkh calculate the optimal times for exposure to light and dark for more than one thousand possible trips through different time zones.
“In your eyes are special cells that sense light and send that information to the clock that’s ticking in the brain. That’s how your body adjusts to new time zones or senses the external time of day,” he says.
“The question is: when can you get these cells to get light such that they’ll send the best signals to your clock to adjust it the quickest way to the new time zone?”
The researchers initially expected the schedule of exposure to light and dark would be complex, but the models revealed that in fact the answer was very simple.
“All you have to worry about is essentially dawn and dusk — when you first start getting light and when you stop getting it,” says Forger.
“You could take your day and divide it into two sections: the day section, where you should try and get as much light as possible, and a night section where you should get as little light as possible.”
According to the researchers, this involves a single block of time each day when users should try to get the brightest light possible, and another block when they should seek the lowest light levels possible, even if they’re not actually asleep. Read more.