Sleep Education

American Academy of Sleep Medicine 

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Jet Lag - Overview


Jet lag is a temporary condition. It may begin after you travel across at least two time zones. The severity of the jet lag depends on how many time zones you crossed and which direction you traveled. Flying east is usually more difficult of an adjustment than westward travel. It is estimated that it takes one day per time zone for your body clock to fully adjust to local time.

You may have a difficult time functioning when you are jet lagged. You may not feel awake and alert when you need to do your job, socialize or sightsee. Anyone of any age can have jet lag, although older adults are likely to have more severe jet lag, and may need a much longer time to recover. Some people are able to adjust more quickly than others to rapid shifts in time zones. Pilots, flight attendants and business travelers are most likely to have jet lag due to their lifestyle.

Jet lag can be worsened by:

  • Sleep loss due to travel
  • Stress
  • Caffeine and alcohol use
  • Air pressure or poor air quality

Jet lag is a circadian rhythm sleep disorder. Your circadian rhythms are your body’s internal clock that signals when you are supposed to feel sleepy or alert. Your circadian rhythms operate on a roughly 24-hour schedule. Your body uses sunlight to determine how much of the sleep-promoting hormone melatonin it produces. Melatonin production is high during the evening and very low during the day. As a result, you are alert during the daytime and sleepy at night. Traveling across multiple time zones can disrupt your circadian rhythms.

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