What is jet lag syndrome?
Jet lag syndrome is characterized by a temporary mismatch between the timing of the sleep–wake cycle generated by the endogenous circadian rhythm and that of the sleep–wake pattern required by a change in time zone.
Individuals typically report associated daytime impairment, general malaise, or somatic symptoms (gastrointestinal symptoms) within 1 or 2 days after travel.
The severity and duration of symptoms are dependent on the number of time zones traveled, the ability to sleep while traveling, exposure to appropriate circadian time cues in the new location, and direction of the travel.
Eastward travel (requiring advancing circadian rhythm and sleep–wake hours) is usually more difficult to adjust to than westward travel.
