Jet Lag

This post is provided courtesy of K. T. Weber, Drexel University College of Medicine Class of 2013:

Most travelers are familiar with jet lag. Daytime sleepiness, difficulty focusing, uncoordination, digestive issues and immune system malfunctioning can all plague those who have ventured far from home. Nearly every travel website promises advice for curing jet lag – get outside in the sunshine, try to keep yourself awake, exercise in the evening and so on. But does any of the advice work? … and why?

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Jet lag (“desynchronosis” or “circadian dysrhythmia”) is the result of moving rapidly through multiple time zones. It is caused by disruption of the body’s natural circadian rhythm, specifically the release of melatonin by the pineal gland in response to light and dark patterns. Traveling through more than five time zones shifts a person far enough off his or her normal activity cycle that waking and sleeping are affected. When sleep gets affected, concentration and cognitive performance quickly decline. Traveling west tends to have less jet lag, because it stretches the cycle out rather than shoving the circadian rhythm ahead in the light/dark pattern as traveling east does.

 

Melatonin is the link between the external environment and internal clock. It is released by the pineal gland, and light inhibits the release. Therefore it makes sense that melatonin, associated with dark, acts in favor of decreased activity and promoting sleep. Melatonin supplements (exogenous melatonin) is available from health food stores and a variety of non-prescription sources, and preliminary data suggests it decreases jet lag when taken shortly before bedtime. However, there is relatively little data to support the efficacy of taking melatonin supplements for sleep in other settings, partly because the source and dose of melatonin in supplements are not standardized or regulated. Ramelteon, a prescription melatonin agonist, is used for treating insomnia and may offer some benefit in the transient circadian rhythm disruption of jet lag.

Normal Sleep Regulation

Normal Sleep Regulation

 

Popular remedies for jet lag include:

Drinking coffee to stay awakeCaffeine has been shown to help reduce the effects of sleepiness associated with jet lag. However, it does not improve sleep, and in a slow-release formula, caffeine can actual generate less restful sleep. So a cup of coffee won’t cure jet lag, but it might help provide some alertness to counteract it. Similarly to caffeine, alcohol disrupts the sleep cycle by disrupting sleep architecture. Alcohol often makes people feel sleepy, but it impairs their rest. So both caffeine and alcohol can further upset the sleep schedule!

Getting plenty of sunshineLight exposure is the main connection humans have to the 24 hour day, so it makes sense that getting light (especially at the right time of day) would help resynchronize the biological clock. This clock can be moved about one hour closer to normal each day using light cues. For those who traveled east, and cannot fall asleep until much later in the night, it is important to get exposure to bright light in the morning. For those who traveled west and are sleepy too early in the evening, it is important to get bright light in the late afternoon, and dim light in the mornings.

and finally, refusing to change your schedule. For individuals traveling more than 5 time zones for a 2 day stay, studies have found that those who maintain their “home” sleep schedule and do not try to adjust fare better than those who try to adapt to local time! Of course, one of these studies also found that people prefer trying to adapt, for social and convenience reasons.

Whatever inspires you to next get jet-lagged, keeping in mind the physiologic basis will give you the best tools for recovering. Happy travels!

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