Other Names: Desynchronosis, Circadian dysrhythmia,
Jet lag is a physiological condition which results from alterations to the body's circadian rhythms resulting from rapid long-distance trans-meridian (east–west or west–east) travel on high-speed aircraft. For example, someone travelling from New York to London feels as if the time were five hours earlier than local time. Jet lag was previously classified as one of the circadian rhythm sleep disorders.
The condition of jet lag may last several days before the traveller is fully adjusted to the new time zone; a recovery period of one day per time zone crossed. Jet lag is especially an issue for airline pilots, crew, and frequent travellers. Airlines have regulations aimed at combating pilot fatigue caused by jet lag.
The term "jet lag" is used because before the arrival of passenger jet aircraft, it was uncommon to travel far and fast enough to cause desynchronosis. Travel by propeller-driven aircraft, by ship or by train was slower and of more limited distance than jet flights, and thus did not contribute widely to the problem.