Jet lags lead to head spinning, insomnia and fatigue and these further affect a person's performance. The free smartphone app -Entrain - helps in manipulating the exposure to light so that body clock or circadian clock is not altered much and it's easy to settle down in new time zones.
Light affects the circadian clock which guides people's bodily functions such as sleep, said Olivia Walch, a doctoral student at the University of Michigan who built the app.
"Light has different effects on your circadian clock at different times of the day. Just a little bit of light can shift your clock," Walch said.
The app plans the lighting sessions for its users on the basis of the itinerary. For it the basic rule is to expose to the brightest light possible at one point during the day and to darkness at another point.
"Overcoming jet lag is fundamentally a math problem, and we've calculated the optimal way of doing it," said study author Danny Forger, a professor at the University of Michigan.
First the app asks for the times you usually get up in the morning and go to sleep at night. Then it asks to select your typical light exposure from the four options: low indoor (200 lux), bright indoor (500 lux), low outdoor (1,000 lux) and bright outdoor (10,000) light. Based on the time and light-exposure criteria, the app plans the circadian clock.