April 11, 2014

Researchers Introduce Smart App To Help Your Body Get Over Jet Lag

Brett Smith for - Your Universe Online

Whether it’s during a hum-drum work trip or the vacation of a lifetime, jet lag can disrupt daytime activities and make sleeping at night extremely difficult.

A new app based on previous research and mathematical modeling claims to cure or prevent jet lag in three days by guiding a traveler’s exposure to light.

Described by a paper in the journal PLOS Computational Biology, the new program applies the concept of ‘entrainment’ or the synchronization of the body’s circadian rhythm with the surrounding time of day.

"Overcoming jetlag is fundamentally a math problem and we've calculated the optimal way of doing it," said study author Danny Forger, a professor of mathematics at the University of Michigan. "We're certainly not the first people to offer advice about this, but our predictions show the mathematically best and quickest ways to adjust across time zones."

The app, called Entrain, was developed on the idea that light, particularly from the sun and in wavelengths that seem blue to our eyes, is the most powerful signal to control circadian rhythms, the variations in habits and bodily functions that regulate operations in every cell of the body. Disruptions in these rhythms can affect mood and performance. Frequent travelers, including pilots and flight attendants, are especially susceptible to the breakdown of the body’s internal clock.

The new study describes the two mathematical models shown to accurately depict human circadian rhythms. The study team used these models and a method known as optimal control theory to determine the ideal adjustment schedules for more than 1,000 potential trips across time zones.

The Entrain app provides a user with the schedule appropriate to their trip. For example, a traveler from New York City to London has to contend with a 5-hour time difference during most days of the year. In this example, the app lays out a schedule of light exposure over three days that begins on the first day with waking and getting light from 7:40 a.m. until around 9 p.m. On the following day, the user would be instructed to rise at 6:20 a.m. and on the third day at around 5 a.m. By the fourth day, the user’s internal clock should be synchronized to local London time, the study team said.

The researchers said if a traveler has a schedule that conflicts with the Entrain schedule or if local levels of daylight do not correspond with the schedule – pink-tinted sunglasses can limit sunlight exposure and a therapeutic lightbox can be used as an adequate substitute for sunlight.

In describing how their approach is novel, the researchers said circadian rhythms are essentially a clock with a point during the day when body temperature is lowest, usually occurs about two hours before waking up. If the low point is typically 5 a.m., it could swing over to 3 p.m. in a different time zone.

"The way other approaches get these points to line up again is by inching along on the outside of the circle, sometimes pushing you towards and sometimes pulling you away from the target. But our schedules can just cut through the middle," said Olivia Walch, a mathematics doctoral student who developed the Entrain app. "This is almost like a body hack to get yourself entrained faster."