by Liza Cameron Wasser

Created on: March 04, 2009

Jet lag, or circadian rhythm desynchronosis, is a temporary problem in the body's ability to adjust to new daylight rhythms. Jet lag is caused by traveling across several time zones within a short period of time. In general, only air travel causes jet lag, but some very sensitive people have been known to show symptoms with automobile or train travel and after the time change associated with daylight savings time.

Your hypothalamus, a small section of the brain, directly above the brain stem, is to blame when you suffer from jet lag. Think of your hypothalamus as a fussy old aunt who becomes flustered and dithery when you show up for a surprise visit on bingo night. At first she cannot imagine how she is going to accommodate you, but she recovers quickly.

The hypothalamus is responsible for controlling various metabolic processes in your body. These include hunger, thirst, fatigue, anger and your circadian cycles. The hypothalamus maintains a balance of glucose and hormones to regulate your body temperature and your blood pressure.

Working with your eyes, which perceive the amounts of light and darkness during a 24-hour period, your hypothalamus releases or withholds melatonin, which is a hormone that helps bring on sleep. When you travel across many time zones, your eyes send new signals of light and darkness that are out of synch with what your hypothalamus is expecting.

The hypothalamus can adjust to these new rhythms, it just takes time. In the meantime, many of the bodily functions that it is responsible for may become temporarily disturbed. You may suffer from constipation or diarrhea. You may be fatigued or have insomnia. Headaches, dehydration or nausea may cause you problems. You may be irritable or have memory problems or an inability to concentrate.

Jet lag only occurs when you travel across time zones, most often three or more time zones. You can fly for eight hours from New York to Lima, Peru and experience no jet lag at all because you are within the same time zone.

Jet lag is more pronounced when flying east than when you fly west. Westward flyers have to stay up a few hours later than their bodies want to, whereas eastbound travelers are facing an earlier bedtime. It is harder to force yourself to fall asleep earlier than your body wants to. However, it is especially difficult for travelers who have been on an overnight flight traveling east and experiencing a 6-hour or more time change to face an entire day after having "lost" the hours that they would have normally been sleeping.

The best way to recover from jet lag is to not give in to the symptoms. Try to adjust to the new time zone as quickly as possible by eating at the new mealtimes and sleeping at appropriate times. Your jet lag will soon be gone.

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