Jet lag occurs commonly and results if we travel across multiple time zones over a short period of time. It is classified as one of the circadian rhythm disorders. It relates to our body’s innate sleep-wake cycle being misaligned with the local timing of day and night. We may suffer from symptoms of insomnia, excessive daytime sleepiness, headache, difficulty thinking, mood changes, a sense of malaise, and even stomach upset. This is often a temporary condition that resolves with the passage of roughly one day’s time for each time zone crossed, but other treatment is available.
Example: Sam is a 45-year-old businessman who often travels internationally for his work. When he arrives after a prolonged flight, he feels miserable and has a terrible time sleeping at the proper time for several days. If he stays in the area long enough, however, he is able to sleep at the appropriate times and his other symptoms resolve.
Learn more about circadian rhythm disorders.
American Academy of Sleep Medicine. "International classification of sleep disorders: Diagnostic and coding manual." 2nd ed. 2005.