"Jet lag is nobody's idea of fun. A bunch of mathematicians say they can make the adjustment less painful with a smartphone app that calculates the swiftest way to adjust."

"Users plug in the time zone they're traveling to, and the app will do the calculations before spitting out a schedule specifying when the user should stay in bright light, low light or be in the dark, says Olivia Walch, a graduate student at the University of Michigan who designed the app."

"'The conventional wisdom is for every hour you're shifting, it's about a day of adjustment,' Walch says. So Washington, D.C., travelers going to Hong Kong — a 12-hour time difference — could take up to 12 days to adjust. The app can reduce that time to roughly four or five days, the inventors say."