Traveling to faraway places is so much fun in theory, but that pesky jet lag can sometimes get in the way.

Jet Lag 101

Jet lag is a result of the fact that your body has to adjust when you travel to a new time zone. The body’s internal clock, which is more formally called its circadian rhythm, is thrown off when the external cues of the world don’t make sense with what it is used to.

Our circadian rhythm comes from cells in the brain called the oscillatory pacemaker cells. They are located in the hypothalamus. Science can explain jet lag, and it has a lot to do with these cells.

Don’t Blame The Airplane, Blame The Cells

The oscillatory pacemaker cells keep the body on a 24-hour sleep cycle, or very close to it. They not only use information inside the body to keep you on a schedule, but they also use the outside world as well, cues like sunlight, darkness, and alarms. Traveling to a new time zone means that the external and internal signals no longer match up.

You just had breakfast and now it’s bedtime, and your body does can not make sense of it. This is where jet lag officially enters. Your cells are trying to sync up with the new outside world.

Not All Jet Lag Is Created Equal

It gets worse where jet lag and cells are concerned. Not all cells are set to exactly a 24-hour sleep schedule. Some have slightly longer cycles, others slightly shorter cycles. Actually, the average sleep cycle for these cells is about 24 and a half hours. For this reason, traveling east can cause noticeably worse jet lag than traveling west.
Going west, your day is extended. The further west you go, the more daylight you’re getting, for the most part, especially because of how fast airplanes go. However, going east means you lose daylight, and bedtime arrives before your body thinks it should. The thing is, the body’s oscillatory pacemaker cells are already accustomed to a 24.5-hour sleep cycle, so adjusting to the longer day ends up being much easier than adjusting to the shorter day. That’s why traveling east makes jet lag that much worse.
Perhaps you will take that into consideration the next time you’re choosing your travel destination?