Jet lag, also called jet lag disorder, is a temporary sleep disorder that can affect anyone who quickly travels across multiple time zones. Jet lag is caused when your body's internal clock or circadian rhythms, which tell your body when to stay awake and when to sleep in the old time zone, are out of sync with cues from the new time zone, such as light exposure and dining times. The more time zones crossed, the more likely you are to experience jet lag.
Jet lag can cause daytime fatigue, an unwell feeling, difficulty staying alert and gastrointestinal problems. Jet lag is temporary, but it can significantly reduce your vacation or business travel comfort. Fortunately, there are steps you can take to help prevent or minimize jet lag.