What is jet lag?
Jet lag refers to the group of physical and physiological symptoms associated
with rapid crossing of multiple time zones (meridians). These symptoms
are due mainly to the disturbance of the body' s natural rhythm and sleep-wake
cycle. The time for re-establishment of body' s natural rhythm equilibrium
is generally greater with eastward than westward flights.
How do you recognize jet lag?
Symptoms of jet lag include difficulty in sleeping, tiredness, mood
disturbance, tummy upset (e.g. loss of appetite). Jet lag can adversely
affect performance, such as manual and cognitive skills.
Prevention of jet lag
- Travellers should rest fully and not be sleep-deprived at the start
of a trans-meridian journey.
- If the trip lasts less than 3 days, attempt to keep to the Hong Kong
time schedule of sleep and activity instead of that of the destination.
- If the trip lasts more than 3 days, one should immediately adopt the
sleep/meal times of the destination and synchronise with destination's
time as quickly as possible. If necessary, take a short nap during the
day for the first few days to help your adaptation.
- Outdoor light exposure at destination can reduce symptoms of jet lag.
- Avoid too much alcohol and coffee during flight.
- Take plenty of fluid. Limited alcohol intake can also help.
- Refrain from taking sleeping pills unless necessary. Discuss the use
with your doctor.
- Melatonin is a hormone that has been widely publicized to alleviate
jet lag. However, there are uncertainties about its safety, and inappropriate
timing of dosages may worsen jet lag. You should consult your doctor
for further information.
- Avoid making important decisions or driving immediately on arrival
after crossing many time zones.