Users select the timezone they're flying into, and the iOS program, which is called Entrain, illustrates in a flow graphic when to stay in bright or low light and when to be in dark light throughout their trip, based on the kinds of mathematical equations that NASA and the military use to anticipate how light affects the human circadian clock. For example, people who fly from New York to Tokyo could feel jet-lagged for as many as 12 days, and this app hopes to radically reduce recovery time to 3-5 days altogether, Quartz reports.
To create the app, NPR explains that the developers, a University of Michigan graduate student Olivia Walch and professor of mathematics and computational medicine Danny Forger,
simulated the optimal schedules for more than 1,000 possible trips. They then applied two basic principles. One is to be exposed to one big block of light and one big block of dark in your day, Walch says. Another is to be exposed to the brightest possible light.
The app has not been flight-tested yet, but Forger and his colleagues published a study in PLOS Computational Biology Thursday with research that is supposed to back up Entrain's methodology.