US scientists find cause of stronger jet lag moving east

By Barry Eitel

SAN FRANCISCO (AA) – A mathematical model is being used to provide a scientific explanation as to why travelers often complain of recovering much more slowly from jet lag after a flight eastward, researchers said Tuesday.

Scientists found that eastward flights affect certain types of brain cells in a different way than westward flights. The cells located within the hypothalamus area of the brain, are connected to desynchronosis, a condition commonly known as “jet lag” -- a sleeping disorder usually effecting travelers who moved rapidly across several time zones.

Travelers often note that recovering from jet lag is much more difficult after a flight going east compared to a flight moving west. While skeptics claimed the difference was purely imaginary, the latest neurological research showcased evidence to the contrary.

The hypothalamus is responsible for the body’s circadian rhythms, the daily activity cycles that govern, essentially, when a person is sleepy or awake.

Using a computer simulation of the hypothalamus, researchers discovered that travel across multiple time zones disrupts these rhythms and jet lag is often the result.

The influence of natural light is a huge factor, the scientists believe, and the circadian rhythms are usually bound to sunrises and sunsets.

When the controlling factor is deceived as one travels across multiple time zones, brain cells follow a rhythm that isn’t linked to a 24-hour cycle.

"In the absence of a controlling influence, say 'a man with a yellow flag,' the clump of cells completes the circuit within a period of time that may not correspond exactly to one day," lead author Michelle Girvan said in a statement.

Essentially, when a person travels eastward, his or her brain is confused by a much shortened day. When flying west, the extra hours are much less detrimental.

Researchers hope the new information can help pinpoint treatments aimed to alleviate sleep disruptions caused by jet lag, varying work shifts and blindness.

The research was published in the journal Chaos by researchers at the University of Maryland.