A ‘Body Hack’ App That Claims to Fix Jet Lag

For as long as speedy travel across time zones has been technologically possible, humans have suffered the unpleasant—if not quite debilitating—effects of jet lag, the physiological condition that’s caused by disruptions in the body’s circadian rhythms.

Declaring jet lag “fundamentally a math problem,” researchers at the University of Michigan say they have devised a mobile app to overcome it.

Using mathematical models that are explored in a study published today in Public Library of Science Computational Biology, professor of mathematics Danny Forger and then-undergraduate Kirill Serkh built their own methodology for finding “mathematically optimal schedules of light exposure and avoidance.”

“By calculating thousands of schedules, we show how the human circadian pacemaker is predicted to be capable of shifting much more rapidly than previously thought, simply by adjusting the timing of the beginning and end of each day,” the researchers write in their study.

The resulting iPhone app is called Entrain—named after the scientific word for recovery from jet lag—and operates on the premise that natural light is the body’s strongest signal controlling circadian rhythms.

The “body hack” app provides users with schedules of light and darkness, including a block of time to be spent in the brightest possible light and another to be spent in the dark. It makes use of “optimal control theory,” a technique that calculates the best such schedules to help users adjust their bodily schedules for more than a thousand possible trips.

The app is said to be the first to use a numbers-based approach to the process of adjusting to new time zones.

“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,” says Forger in a press release.

Jet lag symptoms vary widely, but they tend to involve sleep disturbance, fatigue, headaches and lack of concentration. While its symptoms are relatively minor, scientists say that those who regularly suffer jet lag are at a higher risk for cancer, depression and diabetes, among other disorders.