A new jet-lag mobile app called Entrain released by University of Michigan mathematicians reveals previously unknown shortcuts that can help travelers entrain (synchronize) their circadian rhythms to new time zones as efficiently as possible.
Entrain is built around the premise that light, particularly from the sun and in wavelengths that appear to our eyes as the color blue, is the strongest signal to regulate circadian rhythms. These fluctuations in behaviors and bodily functions, tied to the planet’s 24-hour day, do more than guide us to eat and sleep. They govern processes in each one of our cells.
The study, published April 10, 2014, in Public Library of Science Computational Biology (open access journal), relies on two leading mathematical models that have been shown to accurately describe human circadian rhythms. The researchers used these equations and a technique called optimal control theory to calculate ideal adjustment schedules for more than 1,000 possible trips.
The app gives users access to these schedules. Start by entering your typical hours of light and darkness in your current time zone, then choose the time zone you’re traveling to and when, as well as the brightest light you expect to spend the most time in during your trip (indoor or outdoor.) The app offers a specialized plan and predicts how long it will you take to adjust.
The shortcuts the app offers are custom schedules of light and darkness depending on the itinerary. The schedules boil down to one block of time each day when you should seek the brightest light possible and another when you should put yourself in the dark, or at least in dim light. You don’t even have to be asleep.
If you must go outside, you can wear pink-tinted glasses to block blue wavelength light, the researchers say. And if the app prescribes “bright outdoor light” in the middle of the night, a therapeutic lightbox can do the job — yes, its shortcuts sometimes require odd hours.
The Entrain app is available now as a free app in the Apple store.