Do your take days to get over your jet lag? Well, a newly released app is offering the best and the quickest way that can help you overcome fatigue and insomnia by snapping your internal clock to new time zones.
Danny Forger, a professor of mathematics at the University of Michigan, said that overcoming jet lag is fundamentally a math problem and his team has calculated the optimal way of doing it.
The new iPhone app, called Entrain, is believed to be the first to take a numbers-based approach to "entrainment," the scientific term for synchronizing circadian rhythms with the outside hour.
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.
Short disruptions such as jet lag and its symptoms can affect mood and performance.
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 said. And if the app prescribes "bright outdoor light" in the middle of the night, a therapeutic lightbox can do the job.
The study relies on two leading mathematical models, or sets of equations, 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.
Say you're traveling from Detroit to London, five hours ahead. Your flight leaves at 10 p.m. Eastern Time and arrives at 11:05 a.m. London time the next day. It's a work trip and you'll have to spend most of your time in indoor lighting. Under those circumstances, the app says it can adjust you in about three days. That's less than the rule-of-thumb one day per hour outside the starting time zone.
The entrainment clock for any trip starts at the beginning of the first light cycle in the new time zone. So for the London trip, on the day after your arrival, you'd want to get light from 7:40 a.m. until around 9 p.m., and not after. Rise earlier on the second day, at 6:20 a.m. Lights out at 7:40 p.m. You may feel like going for an evening walk, but being in the light at a time when the app prescribes darkness would lengthen the adjustment period, the researchers say.
On the third day, get up before sunrise, around 5 a.m. Stay in light until 7:20 p.m. Your body will be synched the following morning. If you veer from the schedule, you can tell the app and it will recalculate going forward.
To show how this new method is different, the researchers illustrate circadian rhythms as a clock with a point at the hour when your body temperature is lowest.
This usually occurs about two hours before you wake up. If the point is usually at 5 a.m. and you travel overseas, it could abruptly swing over to, say, 3 p.m. in your destination.
You're likely to experience jet lag until your system adjusts and your body is once again at its lowest temperature just a few hours before your alarm goes off.
The study is published in Public Library of Science Computational Biology.
