Jet Lag During Eastward Travel Much Worse Than Westward

Recent Scientific Research Data is breaking down why we recover from jet lag differently, based on the number of timezones we travel and based on the direction we go in. The study is showing why flying East is much tougher on the brain than flying west.

The study is based on a mathematical model, with contributions from several physicists. The model was published Tuesday, July 12, and documents the response of the human brain when crossing time zones.

The neuronal oscillator cells in the brain regulate our circadian rhythms. The cells create the synchronicity between our bodies and the external cues of light and darkness around us. Chronobiology documents all the finer aspects of circadian rhythms but in short, they are important in letting the brain know how much rest we can get when we sleep.

The science is showing that a circadian rhythm for most humans is a bit longer than an actual day, reaching 24.5 hours. The extra half an hour doesn’t really affect humanity as the difference is small enough to not have huge repercussions in our daily lives.

The Science of Jet Lag

However, the longer than a day circadian rhythm does affect jet lag in different ways when flying west rather than east.

The study documents that our circadian rhythms have an easier time adjusting to the new condition when flying west rather than when flying east. However, the number of timezones we travel through also affects our degree of adapting as much as the direction we fly through.

A person needs on average four days to adapt to jet lag if they fly three time zones westward. They need six days on average for six timezone. For nine time zones westward, the study shows a person would on average need a bit less than eight days. Circadian rhythms are slow, but this is our brain adapting to a whole new “unnatural” day-night cycle.

When flying eastward, the study demonstrated the numbers are much greater. The effects of jet lag for three time zones eastward flight need on average more than four days to recover. More than eight days of recovery are needed for flying six time zones eastward. Finally, the average human brain needs more than 12 days to fully recover from jet lag if flying nine time zones eastward.

The large differences in jet lag recovery times, the study says, are due to the fact that the brain perceives the day-night cycle is drastically shortening by traveling eastward, while it perceives it as broadening while traveling westward.

Photograph Courtesy of Flickr.