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] (http://www.ncbi.nlm.nih.gov:80
/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_
uids=12076414&dopt=Abstract) 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.