Jet lag

Jet lag (or "jet-lag") is a physical condition caused by crossing multiple time zones during flight. The condition is generally believed to be the result of disruption to the circadian rhythms (ie. the "light/dark" cycle) of the body. It can also be exacerbated by experiencing sudden changes in climate or seasonal conditions, as well as the low humidity commonly experienced in the cabin of an aircraft.

Characteristic symptoms of jet lag include:

Fatigue
Disorientation and/or grogginess
Nausea and/or upset stomach
Headaches and/or sinus irritation
Insomnia and/or highly irregular sleeping patterns
Dehydration and loss of appetite
Irritability
Irrationality

The condition is not linked to the length of flight, but to the east-west distance travelled. Hence a ten hour flight between Oslo and Johannesburg will probably be less inducive of jet lag than a four hour flight between New York and Los Angeles. There is no firm agreement as to which direction of travel is worse. Some believe that travelling east is worse as it "accelerates" the passage through various time zones (a night might only last 3 hours when flying east). Others counter that the impact is worse when one travels away from one's "habitual" time zone, and is minimised when returning to it.

Prevention and recovery

Recent research shows that a pineal hormone, melatonin, is potentially effective in prevention and treatment of jet-lag. It appears to be safe in short term use [1] A lot of remedies of various nature are marketed but rarely effective. Their safety has not been scientifically established.

The condition of jet lag generally lasts a few days or more, and medical experts have deemed that a recovery rate of "one day per time zone" is a fair guideline. Sleep, relaxation, moderate exercise and sensible diet seem to be the simplest recovery agents.

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contact your doctor for health-related decisions.