A new mobile app just released by developers at the University of Michigan promises to ease the effects of jet-lag significantly.

Called Entrain, the new iPhone app is believed to be the first to take a numbers-based approach to "entrainment," the scientific term for synchronizing circadian rhythms -- biological functions largely determined by the 24-hour clock, with emphasis on the shift between day and night.

The new and improved remedy for jet-lag is based on new findings by Danny Forger, a professor of mathematics at the U-M College of Literature, Science, and the Arts, and Kirill Serkh, a doctoral student at Yale University who worked on the project while an undergraduate at U-M.

Entrain is based on the premise that light, particularly that from the sun and in wavelengths that appear as the color blue to human eyes, is the strongest signal to regulate circadian rhythms.

Furthermore, the fluctuations in behaviors and bodily functions tied to the planet's 24-hour day not only guide people to eat and sleep but govern processes on the level of individual cells.

Short disruptions in the overall rhythm between day and night, such as jet lag and its symptoms of fatigue and insomnia, can affect an individual's overall mood and performance -- which scientists have linked to much more serious disorders like depression, certain cancers, heart disease and diabetes.

Airline pilots, flight attendants and shift workers, which comprise more than 10 percent of the American workforce, are particularly susceptible to the harmful effects of disrupted physical rhythms.

The new app, however, suggests a specific, managed exposure to light and darkness, depending on one's travel itinerary.

Essentially, the app generates personalized schedules that equate to one block of time every day when a person should seek the brightest light possible and another they should seek the dark, or at least the dimmest light, possible. And, the way the system works, sleep is an option, not a necessity, for the successful and quicker adjustment of one's internal body clock.

"Overcoming jet lag is fundamentally a math problem and we've calculated the optimal way of doing it," said Forger. "We're certainly not the first people to offer advice about this, but our predictions show the best and quickest ways to adjust across time zones."

The research, recently published in the journal Public Library of Science Computational Biology, relies on two main sets of mathematical equations proven to accurately represent describe human circadian rhythms. The researchers used these equations and a technique called optimal control theory to calculate ideal adjustment schedules for light and dark exposure for more than 1,000 possible trips.