Jet-lag
| Jet lag | |
|---|---|
| Classification and external resources | |
| Specialty | Psychiatry |
| ICD-9-CM | 307.45, 780.50 327.35 |
| DiseasesDB | 7045 |
| MeSH | D021081 |
Jet lag, medically referred to as desynchronosis and rarely as circadian dysrhythmia, 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. 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 is a suggested guideline. 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.
The symptoms of jet lag can be quite varied, depending on the amount of time zone alteration, time of day, and individual differences. Sleep disturbance occurs, with poor sleep upon arrival and/or sleep disruptions such as trouble falling asleep (when flying east), early awakening (when flying west), and trouble remaining asleep. Cognitive effects include poorer performance on mental tasks and concentration; increased fatigue, headaches, and irritability; and problems with digestion, including indigestion, changes in the frequency of defecation and consistency of faeces, and reduced interest in and enjoyment of food. The symptoms are caused by a circadian rhythm that is out of sync with the day-night cycle of the destination, as well as the possibility of internal desynchronisation. Jet lag has been measured with simple analogue scales, but a study has shown that these are relatively blunt for assessing all the problems associated with jet lag. The Liverpool Jet Lag Questionnaire was developed to measure all the symptoms of jet lag at several times of day, and this dedicated measurement tool has been used to assess jet lag in athletes.
...
Wikipedia