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What causes jet lag?

Here's what’s behind jet lag: When we ask our bodies to adapt to a different time schedule, we disrupt our circadian rhythm, our body’s powerful internal regulator, which governs our sleep-wake cycle, our ability to fall asleep and to wake feeling rested and ready to get out of bed. Our circadian clocks have a powerful effect on our mood and energy levels and even our immune systems. This internal regulatory mechanism is finely tuned -- even very slight disruptions can have an effect on how we feel and our ability to sleep. Moving across time zones, with changes of an hour or more to the “normal” schedule, can have a significant effect.

Scientifically, it's known as circadian dischronism, but most of us call it jet lag. Our bodies have an internal clock that determines when we are hungry, when we are sleepy and when we are wide awake in a 24-hour period. It is the disruption of that internal clock that causes jet lag. Flying east or west for a few hours will put your body in a new time zone, but it can take a while for the body's internal clock to adjust. This time of adjustment for your internal clock is what is known as jet lag. Some people adjust quickly to the change, and others take more time.

On average, it takes one day for every time zone crossed to get your internal clock to synchronize with the new time zone.

Flying north or south, which doesn't involve changing time zones, is a bit easier on the body. However, the dry atmosphere, stale air, cramped posture and lack of exercise while flying may add to the sense of being out of sync when you arrive at your destination. Generally, drinking some water, getting some fresh air and exercising will take care of the problem.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.