Jet lag is caused by a difference between the circadian system -- the body's internal clock -- and the surrounding environment. Previous research has shown that in fact there are multiple internal clocks, and they are present in almost every cell and tissue in the body. Each clock relies on its own set of cues to calibrate. For example, the brain's clock depends on sunlight, while the peripheral organs calibrate at mealtime.

"Conflicting signals, such as warm weather during a short photoperiod or nighttime eating -- eating when your brain is about to rest -- can confuse internal clocks and cause desynchrony," said coauthor Yitong Huang of Northwestern University.

The authors developed a theoretical model to study the interactions among the multiple internal clocks under the effects of aging and disruptions like jet lag.  They found that common symptoms of aging, such as weaker signals between circadian clocks and a lower sensitivity to light, result in a system that is more vulnerable to disruptions and slower to recover.

They also discovered a new method to speed up recovery from jet lag and similar disruptions. According to their results, the way to better sleep is through the stomach.

"Having a larger meal in the early morning of the new time zone can help overcome jet lag," says Huang. "Constantly shifting meal schedules or having a meal at night is discouraged, as it can lead to misalignment between the internal clocks."

The authors plan to investigate the other side of the equation and identify the factors that result in more resilient internal clocks. Such discoveries could lead to recommendations to prevent jet lag in the first place, or to keep the circadian system healthy into old age.

To read the article, published in the journal Chaos, click here