The jet - lag (the equivalent in Castilian is called "a syndrome of the time zones" and has less success) is an imbalance produced between the internal clock of a person (the one that marks the periods of sleep and wakefulness) and the new schedule that is established on having traveled in plane long distances to the east (it is one more hour for every meridian or time zone that crosses) or on the west (one hour less for every meridian that crosses). The internal clock of the person tends to prevail, therefore, in the first case, it will not feel sleepy when the night has come and, in case of trips to the west, it will feel sleepy in broad daylight.

The treatment, in the trips to the east, can need the use of hypnotic of short action (there is no habituation danger for the sporadic of his capture) as lormetacepam (Loramet) or zolpidem (Stilnox); any of them needs medical recipe for his dispensation. In case of trip to the west it is necessary to try not to sleep (to remain in illuminated places and physics and mentally occupied) until the night comes; if the sleep is invincible a short siesta can shed grain and resort in the night to a hypnotic one of rapid action. The jet - lag can get ready largely taking to the evening melatonina (in USA it is of free dispensation) the days previous and later to the trip.